Welcome to the science section
of the Wikipedia reference desk.

Select a section:

WP:RD/S

Want a faster answer?

Main page: Help searching Wikipedia

How can I get my question answered?

Select the section of the desk that best fits the general topic of your question (see the navigation column to the right).
Post your question to only one section, providing a short header that gives the topic of your question.
Type '~~~~' (that is, four tilde characters) at the end – this signs and dates your contribution so we know who wrote what and when.
Don't post personal contact information – it will be removed. Any answers will be provided here.
Please be as specific as possible, and include all relevant context – the usefulness of answers may depend on the context.
Note:
- We don't answer (and may remove) questions that require medical diagnosis or legal advice.
- We don't answer requests for opinions, predictions or debate.
- We don't do your homework for you, though we'll help you past the stuck point.
- We don't conduct original research or provide a free source of ideas, but we'll help you find information you need.

Ready? Ask a new question!

How do I answer a question?

Main page: Wikipedia:Reference desk/Guidelines

The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.

August 21

Noah's Ark

Now, before I start, I'll just state now that I don't really want to start a debate here about whether Noah's Ark was actually real, or whether the Flood happened or not. What I'm actually curious about is this - supposing that one wanted to construct a great ship, capable of housing two members of every extant species of land animal (we can include species that were present in Biblical times but not now, if you wish) for a year or so, with enough space to store the food and fresh water required to keep them alive throughout... then how big would the ship actually have to be? I seem to remember that someone actually tried to work this out once and came out with a rough estimate that (assuming no physics-bending divine intervention) would put the Ark at several times larger than the largest supertankers and aircraft carriers ever constructed - and the amount of raw materials and time required for construction would be utterly staggering. Does this sound familiar to anyone? --Kurt Shaped Box (talk) 00:13, 21 August 2010 (UTC)[reply]

Yes, but can't remember who did the math, either. I think the conclusion was that he stored the genetic material and not the actual animals :) . Besides, most extant species (that is, invertebrates) have a natural life span comparable with the duration of the Flood, if not smaller -- not to mention predation and such -- so they wouldn't have made it alive anyway. Another problem is the narrowing of the gene pool: if a species is down to just one breeding pair, its chances of survival are not too good; inbreeding is a Bad Thing. --Dr Dima (talk) 00:44, 21 August 2010 (UTC)[reply]

Are you including insects and other invertebrates? I'm assuming you want birds. And do you want to limit yourself to animals from a given area, or do you really want it for all species in the entire world? And are you thinking of this article? 86.161.255.213 (talk) 00:45, 21 August 2010 (UTC)[reply]

That wasn't the specific article I read (I think I read mine in a newspaper) but that is a really good read. It covered a few things that I'd never considered. Nice find. I suppose that an argument could be made for limiting the number of species (including birds and invertebrates, as I think that is specifically stated in the Bible) to those present in the *known world* at the time of Genesis, to tie in with the 'it wasn't a global Flood - but a large Flood in the Near/Middle East' theory that some expound... --Kurt Shaped Box (talk) 01:51, 21 August 2010 (UTC)[reply]

I don't think predation would be a problem, since anyone with some common sense would take aboard young animals (taking up much less space). As for smaller animals, such as mice, you would need very little space (or just let them run around free). They were only to take animals "that lived on dry land and breathed through their nostrils", so you would not need to take fish, invertebrates, amphibians, etc. And since the Bible says "every species after its kind", not "every animal after its taxonomically separate species", I think they would have considered elephants, for example, to be just one kind (meaning you don't have to take aboard all three species that existed at the time, just one). And to KSB's earlier comment, the source says it took 120 to build! For a 450 foot long boat, I think it would be quite possible. --The High Fin Sperm Whale 04:00, 21 August 2010 (UTC)[reply]

That is a challenging idea from the High Fin Sperm Whale. If it wasn't necessary for the Ark to carry a pair of each of the two or three separate species of elephant that existed at the time, only one pair, that begs the question how is it that we now see at least two separate species of elephant - African and Indian? How did two separate species spring from just one breeding pair of elephants on the Ark? Could they have evolved from that one breeding pair? Unlikely, since evolution and the story of the Ark are incompatible. Could the two or more separate species have sprung from the one breeding pair by a miracle of God? If God was into performing miracles as a means of populating the world from the animals in the Ark why did there need to be a breeding pair - God could have used miracles to populate the world starting with just one animal. That would have required an Ark only half the size. And pursuing that line of thought a little further, why bother with the Ark at all - just use miracles to populate the world with animals, starting with just fish or microbes. If God could manufacture Eve starting with nothing more than one of Adam's ribs He would have no problem creating a breeding pair of elephants starting with nothing more than a couple of tuna or trout or perhaps a pair of Elephant seals, and they would all have survived the flood without any trouble.

Another possibility is that the whole flood story is just a story that grew with the telling, passed on from one generation to the next until it was eventually committed to writing in what we now know as the Old Testament. This is the Science Reference Desk where people confine their ideas to things that can be supported by information gathered by observation, and without recourse to intuition. Outside the Bible there is no evidence to support the story of the Ark and the flood. Many people have attempted to shoe-horn various observations into the Biblical story but those attempts have never won support outside the group of like-minded people. Consequently the Ark and the flood have no place in science, unless and until someone finds evidence that will objectively support the Biblical account. Science must examine the facts and draw the most consistent conclusion, not search for facts that will support a preferred or pre-determined conclusion.

Answers to questions about the Ark and the flood don't belong on the Science Reference Desk. Dolphin (t) 04:36, 21 August 2010 (UTC)[reply]

Why not? The question encompasses both history and science. --The High Fin Sperm Whale 05:55, 21 August 2010 (UTC)[reply]

I agree that KSB's question encompasses science and a little recent history (someone actually tried to work this out once), but I think your first reply strayed from the scientific a little. My comment about answers to questions on the Ark and the flood was intended to be a general comment and not one directed solely at this thread. Dolphin (t) 07:41, 21 August 2010 (UTC)[reply]

(after edit conflict) ... and the story has been investigated by both scientists and historians. I don't think they have come up with a definitive conclusion yet, but the best explanation I've read that explains both the biblical story and the similar account in the Epic of Gilgamesh is that of the catastrophic flooding of the land around the Black Sea around 5600 BC as a result of the sudden breaching of the Bosphorus. Scientific evidence for this is set out in Ian Wilson's book Before the Flood (ISBN0752846353). Dbfirs 07:48, 21 August 2010 (UTC)[reply]

Unfortunately I haven't read Wilson's book. I doubt an account based on the sudden breaching of the Bosphorus could be found compatible with the Biblical version, because the Biblical version speaks only of continuous rain for 40 days and 40 nights. I have seen a documentary about ancient flood and Ark stories abounding in the vicinity of the Euphrates River. Dolphin (t) 07:56, 21 August 2010 (UTC)[reply]

There are many flood stories from around that time because of the climate change and the scientifically documented rise in sea levels. The continuous rain would only add to the sudden rise of the water in the lake that subsequently became the Black Sea. Wilson presents a convincing explanation, but does not try to justify the "Noah's Ark" story word-for-word. A suspiciously similar story is that of Atra-Hasis Dbfirs 11:37, 21 August 2010 (UTC)[reply]

You should bear in mind that there weren't just two of each kind. According to Genesis chapter 7, There were seven of each bird, and of each "clean" animal (presumably as defined by Jewish dietary law), and two of each of the "unclean" animals. Rojomoke (talk) 10:04, 21 August 2010 (UTC)[reply]

Was there one extra male and two of the males had to fight for the females or was there an extra female and one of the males got two females? Or some other combination like 1 male, 6 females? If it were either of the later two options, what happened to those animals (a number of birds for example) that practice pair bonding? Incidentally, wasn't it lucky Noah was so good at sexing so many different kinds of animals. Nil Einne (talk) 11:07, 21 August 2010 (UTC)[reply]

I have heard that Noah took only the kinds. So he wouldn't take 2 of each species of dog, but just the one original dog. Then the original dog "evolved" to the many species of dogs. But this evolution does not go out of its kind naturally. --Chemicalinterest (talk) 11:33, 21 August 2010 (UTC)[reply]

I've heard such claims before, but all they do is reveal how little people who make them know about evolution or even basic taxonomy. The idea we could get the level of diversity of life we see nowadays from this supposed 'restricted' evolution in a few thousands years, but it's impossible humans evolved from a common ancestor with chimpanzees in several million years is clear cut nonsense. (I wonder is the general idea only one kind of Simiiformes was chosen, excluding humans, which then underwent this limited evolution into Catarrhini and Platyrrhini or did these different 'kinds' already exist?) Being able to compare the increasing number of whole genome sequences is further proving the point. And we're not even getting into the other things people have discussed like the absence of any evidence of a genetic bottleneck for most species Nil Einne (talk) 12:50, 21 August 2010 (UTC)[reply]

Well, we could certainly take a shot at this.

Using numbers from too many articles to list: There are 10,000 species of bird, 5,400 mammals, 5,600 frogs, 7,900 snakes & lizards - and much smaller numbers of other kinds of larger animal...but to be honest (in terms of species count), that's all largely irrelevant compared to the between 5 and 10 million species of arthropod (most of which are insects). A good fraction of those would be marine arthropods - which one assumes wouldn't need a ride on the ark - but if we make a guess at 2 million land arthropod species - then even if each pair needed a 10cm x 10cm x 10cm cage (pretty spacious for, say, an ant!), you're only up to 2,000 cubic meters of space. You could keep a pair of birds in maybe 30x30x30cm (on average - ostriches take more, but love-birds less) - so we're looking at another 1000 cubic meters of birds. Some mammals are much bigger - but 1,100 of those species are bats (100 cubic meters), 2,200 are rodents (maybe 200 cubic meters). Even if the rest are things like dogs and cats and cows and such, there are lots of voles and other tiny mammals to counteract the elephants and giraffes. Let's guess at an average of 1 cubic meter per non-rodent/bat mammal species, so we need maybe 4,000 cubic meters for the mammals. Frogs snakes and lizards would probably consume another 10x10x10 cm cage per species - so we'll need a mere 8 cubic meters for them.

I'd say that for a VERY rough estimate, the living space alone would consume something like 8,000 cubic meters. Let's quadruple that to allow space for food and water, add another 8,000 meters for corridors, access, exercise areas, etc. So perhaps we need 50,000 cubic meters for the entire ship.

The Seawise Giant (the largest cargo ship ever built) is 458m long, 68m wide with a draft of 24m - so a volume of 750,000 cubic meters is easily attainable in a modern vessel. A more typical large cargo ship would be more like 150,000 cubic meters - so we can get away with a relatively small ship. Could this be a wooden ship? You'd be looking at something about five times the size of HMS Victory (10,000 cubic meters). Is that possible? Well, yes! The Greeks built the Tessarakonteres in about the 3rd century BC - it was (very, very roughly) 200m x 30m x 30m - 180,000 cubic meters. Plenty enough to hold one pair of every land animal!

The bible says that the ark was 300x50x30 cubits...there are many definitions of a cubit - but they mostly come out at around a half meter - which makes the ark about half the size of the Tessarakonteres. So the ark (as described) was evidently well within the technology of the 3rd or 4th century BC. The ark could hold 56,000 cubic meters...plenty big enough for 8,000 cubic meters of animals, food and water.

Of course we can be very sure (from fossil evidence, DNA analysis, etc) that Noah's ark is a myth. Doing this is so far beyond the capabilities of the people of the time that it's completely laughable - there are a crazily large number of reasons why this is obviously bullshit.

I don't think the size of the vessel is (in principle) an obstacle...I'm very surprised about that...someone had better check my math!

SteveBaker (talk) 19:32, 21 August 2010 (UTC)[reply]

The article I linked suggests a lot of the animals will die if you try to keep them in those conditions for weeks on end. 86.161.255.213 (talk) 19:51, 21 August 2010 (UTC)[reply]

I've always thought that the story works much better from God's point of view if you assume that the flood was local, but God told us it was global. After-all, human civilization lived almost entirely in river valleys at the time, no need to flood all the way up to the mountain tops.

Anyway, with the ark story as written you'd need some good climate control systems too. Polar bears and Komodo Dragons are not going to do well in the same climate. I wonder which would be easier with the technology of the time : Sailing the ship in arctic waters and using some sort of solar heating rig to keep the tropical animals happy, or sailing in a warmer climate and rigging up some sort of evaporative cooling system. APL (talk) 01:03, 22 August 2010 (UTC)[reply]

There was probably a canopy of water vapor or something that produces the greenhouse effect, making the heating almost equal. --Chemicalinterest (talk) 11:17, 22 August 2010 (UTC)[reply]

That makes it worse not better. If, as you say, the air was saturated with water vapor and the world was globally warm, then Noah would have had a tremendous difficulty with keeping cold-weather animals cool. The cooling technology they would have had back then would have been very primitive evaporative coolers, not only would those not have been powerful enough to reach anywhere near arctic temperatures, those only work properly in very dry weather. A globally warm humid climate would have killed off many species that have clearly survived to this day. Polar bears.

The only way he's going to keep arctic animals happy is if he goes some place really cold, then warms the rest of the boat with solar power and fires. (Fuel for the fires adds to the boat's cargo requirements.) APL (talk) 21:01, 22 August 2010 (UTC)[reply]

Regarding the flooding of the Black Sea, see Black Sea deluge theory. ~A H 1^(TCU) 01:08, 22 August 2010 (UTC)[reply]

Steve Baker has done an excellent job of estimating the order of magnitude of the size of the ark. Well done Steve! I think the next step to challenge our minds is the human resource necessary to feed all these creatures. It might go something like this. One trip by one person to carry enough food for 20 species of bird. That is 500 trips to feed all 10,000 species of bird. Distance from feed store to aviary - 200 metres; with a round trip taking 5 minutes. One minute to feed one species so each trip involves 20 minutes actually dispensing the feed. That is 208 hours to feed all the birds once. Let's assume Noah's family members worked 20 hours a day, so if all the birds were fed once every 2 days it would require 5 people working full time just to feed the birds on the ark, without considering any cleaning of the aviaries or carrying away the droppings.

Now let's consider the mammals. No! I'm exhausted. Dolphin (t) 02:11, 22 August 2010 (UTC)[reply]

Your estimate for birds is very low. You should be able to carry enough for more than 1000 birds in one load (a budgie eats 2 teaspoons a day, which is about 10cc, and weights maybe 12g or so). BTW the Talmud discusses this topic, and concludes that the whole thing is impossible for a person to do (for pretty much the same reasons as listed above), and that the story is a miracle. Ariel. (talk) 02:30, 22 August 2010 (UTC)[reply]

Natural science relates a point in the present to a point in the past by natural laws, which are assumed to be constant. Any variation of the rules of nature by a divine entity invalidates the predictions of natural science. More generally, it is possible that a number of parallel universes exist, each related within itself by natural science, but relatable to one another throughout their extent by a different set of rules. Thus I think it could be meaningful to speak of multiple dimensions of time, each representing a different ruleset - however, scientists can only study the one that affects laboratory experiments as they perceive them.

The story of the Ark is utterly absurd in our universe as we understand it. Yet we should be sensitive to the consideration that there could be some other universe (perhaps one with fewer species...and fewer barriers to inbreeding) where the events make some sense. We cannot rule out that such a universe might have been created "before" our own, whether according to the biography of an Author of universes, or by the operation of a physics ruleset that we have not ourselves observed. In this way, we should recognize that our science cannot disprove the actions of a creator capable of creating and changing physical laws. Wnt (talk) 12:56, 22 August 2010 (UTC)[reply]

The whole thing is obviously ludicrous to the modern mind. Consider the plight of the Granulated Tasmanian snail which lives only in Australia. That means it would have had to travel about 10,000km to get to the location of the Ark - at a peak speed of 1mm per second - taking about 7 years to do so (if it could do it in a straight line overland without coming across any insurmountable obstacles - which for a Granulated Tasmanian snail doesn't take much!). However, how could it cross the ocean? Clearly a lot more than one pair of snails would have to set out in order to be sure that they'd arrive without being eaten by a bird along the way. Worse, those snails don't live for 7 years - they'd have to treat this as a multigenerational trip. Worse still, we'd have to consider animals that live in cold climates that would have been unable to survive in the middle east...animals like the Giant Panda that can only eat bamboo - which didn't grow in that part of the world. What about those hundreds of species of cave-dwellers who are completely blind - how do they find their way there? Species of animal like the Ichneumon wasp that doesn't live long enough to survive the 10 month trip without reproducing - and which requires a living host for its pupea to develop within. I could keep on coming up with problems like this for as long as anyone would be prepared to listen. There are a simply insane number of little problems that would have to be overcome at every step of the way:

How could these animals all be assembled at the right time?
How could predation and sort life-spans ensure they'd all survive?
How could their wildly varied diets have been handled? Even modern zoo-keepers with the benefit of years of study find some species to be impossible to keep in captivity. (How did the Noah crew find bamboo for the Pandas?)
Why is there no evidence of a lack of genetic diversity such as would be expected if just one breeding pair of each species survived the mass-extinction event claimed here?
There is no actual solid definition of a "species" - how exactly did all of the subtle variations between two species that blur together come to be represented in the Ark?
Where did all the water come from to flood the earth to that depth? Where did it all go to afterwards? How did it disappear so insanely quickly?
How come there is no geological evidence for all of this? We ought to at least find a thin layer of salty alluvium at the same geological age over the entire planet.
How did plants survive the inundation? 10 months underwater would have eradicated every terrestrial plant species and likely made the soil so salty that nothing would grow in it afterwards.
What did the animals eat when they were released from the ark?
Were there two of every kind of bacterium present on the ark? If not - then how did the ones that require animal or plant hosts survive?
What about communal species like ants and bees - one male and one 'queen' isn't enough to raise the first generation of pupea after the flood. Even if they could recover, how would the newly regrowing plants get pollinated in the meantime.
...etc, etc, for another few hundred obvious questions...

Clearly this was a story written for a local audience. People who had never gone beyond the next village in their entire lives - who perhaps only knew of a few hundred animal species. For someone like that, this would be a rather believable story. But in the light of modern knowledge, it's just plain silly.

What is sad is that when people like our very own resident fundamentalist have to resort to patently ridiculous "explanations" for a story that should never be taken literally. In response to the tricky issue of how the ark would have provided ranges of temperatures suited to everything from the polar bear to the desert tortoise we are told: "There was probably a canopy of water vapor or something that produces the greenhouse effect, making the heating almost equal."...um...words fail me! Noah's ark is a cutesy story for little children - there is no conceivable way it could be real.

The only answer that can possibly work here is "It's magic...God waved his magic wand and it all came out like the big book says...then (for some unaccountable reason) he did this amazing cover-up job to make all of the evidence point to it never having happened."...and if that's the answer, then it has no place here on the science desk.

SteveBaker (talk) 19:17, 22 August 2010 (UTC)[reply]

It probably doesn't belong at the science desk, but we're misapplying science if we use it to rule out the miraculous. You don't have to be a fundamentalist to appreciate that our world may indeed be a re-creation, or a simulation, or a fictional landscape, whether dreamed up by a Star Trek Holodeck, Demiurge, a solipsist or an Almighty God. Religion seeks to explore the landscape beyond the confines of our observable Universe. Is it possible that the archetypes of living species were drawn up in some small walled garden, like a group of video game programmers might do it? Why not? Is it possible that some were discarded, others saved? Why not? We can't distinguish what God would do and what God wouldn't do, until we at least try to understand such matters on their own terms. Wnt (talk) 04:24, 23 August 2010 (UTC)[reply]

Wnt is right. It doesn't belong at the Science Reference Desk. Science doesn't rule out the miraculous - for example science accepts the existence and performance of polio vaccines, and they are miraculous in many peoples' eyes. Science says don't bother telling us about things you think are miracles, but come back and tell us when you have some objective evidence of these phenomena. Dolphin (t) 04:38, 23 August 2010 (UTC)[reply]

I did a ballpark estimate once and estimated that it would take 15 aircraft carriers just to hold the animals (no food, etc). Bubba73 ^{(You talkin' to me?)}, 04:44, 23 August 2010 (UTC)[reply]

How come your estimate is so violently different from mine (above)? Could you share your reasoning - or at least point out the hole in mine? My conclusion is that the volume required is actually entirely compatible with the dimensions given for the Ark in the bible. SteveBaker (talk) 22:42, 23 August 2010 (UTC)[reply]

I don't remember the details - I did it over 30 years ago. Bubba73 ^{(You talkin' to me?)}, 23:17, 23 August 2010 (UTC)[reply]

Oh well - there were a LOT more species back then. :-(

SteveBaker (talk) 02:18, 24 August 2010 (UTC)[reply]

Space related

Sir, I am just an ordinary person. I am not a scientist. Stephen Hawking in his book namely " A BRIEF HISTORY OF TIME" published during 1988 has narated in his conclusion topic that ' we shall all. philosphers,scientists,and just ordinary people, be able to take part in the discussion of the question of why it is that we and the universe exist. Hence, being an just ordinary person, i would like to express my views to my indian scholars. —Preceding unsigned comment added by Kannappanvelu (talk • contribs) 07:26, 21 August 2010 (UTC)[reply]

I'm not sure I understand your question. If you are asking for an analysis of Hawking's statement, he's commenting on the difference between the nature of science (which is about describing what the Universe does), and other analysis of the Universe, such as its purpose and reason for being. He is stating that all people, not just physicists as himself, have a role in defining for themselves why the universe exists, that is assigning a purpose or meaning to its existance. It is a similar sentiment, from the opposite direction, that Cardinal Cesare Baronio expressed when he stated "The Bible teaches us how to go to heaven, not how the heavens go". In other words, there are seperate domains for Science and for Religion/Philosophy to occupy in the human existance. Hawking is merely reminding us that, while his (Hawkings) domain is the description of "how the universe goes", he isn't going to tell you "why" or "for what purpose" the universe goes. Ordinary people can do that for themselves. --Jayron32 07:40, 21 August 2010 (UTC)[reply]

Hawking expresses that Freedom of speech about existential subjects shall not be limited to those with particular qualifications, such as scientists or philosophers. Viewpoints on these subjects often constitute a Belief system. The rules stated at the top of this page do not allow starting a debate here about such questions. Cuddlyable3 (talk) 14:50, 21 August 2010 (UTC)[reply]

Free speech is not a surrogate to "qualification" - it's a totally independent matter. I think India is a pretty progressive place; so if the OP wants to express his/her views to scholars, he/she can probably write a book, a letter to a major newspaper, or even visit a university and try to meet with a scholar. If I understand correctly, no government regulators will try stop you. But if you voice your opinion, it might not be taken seriously unless you have established credibility - in many cases, this means "an advanced degree in the subject you're interested in." It really depends on the community that you want to participate in - if you have opinions about physics, most physicists will expect you to have a well-rounded background in the "core subjects" of modern physics. If you only want to express philosophical ideas, most philosophers will equally-well expect a solid training (informal or otherwise) in the basic philosophical arguments that have historically been laid out before - so that you don't waste time their repeating other ideas that have been elucidated previously, and instead build new ideas. These are sort of "pre-requisites" for serious discussion in certain communities - it proves that you have invested the time, and been vetted for basic competency by a trustable institution. Nimur (talk) 15:46, 21 August 2010 (UTC)[reply]

Hawking mentions all people, not just those meeting pre-requisites. The OP spoke about "my indian scholars" (from Latin schola school) which may mean the OP is a teacher. Cuddlyable3 (talk) 21:20, 21 August 2010 (UTC)[reply]

That's a completely silly conclusion to reach, and a nonsensical way of reaching it. --Mr.98 (talk) 00:34, 22 August 2010 (UTC)[reply]

Please explain clearer if there is a problem with my post. Cuddlyable3 (talk) 11:37, 22 August 2010 (UTC)[reply]

IMHO, the most logical reading of the OP's post which I think 98 is getting at, is that the OP is an ordinary person who's job is indeterminate and largely irrelevant, who wants to communicate with scholars (meaning learned people or researchers, most likely scientists given the specific question) in India (where they likely live) about their views of why the universe exists apparently because they believed Hawking was encouraging it and/or suggesting they would be interested Nil Einne (talk) 13:56, 22 August 2010 (UTC)[reply]

"My Indian scholars" does not imply, in any way, that the OP is a teacher. Falling back on the Latin roots of "scholar" is a ridiculous way to interpret the word in context. --Mr.98 (talk) 14:30, 22 August 2010 (UTC)[reply]

[1]scholar n.

1.A student; one who studies at school or college.

2.A specialist in a particular branch of knowledge.

3.A learned person.

4.One who educates themself for their whole life.

I make no assumption about which meaning the OP may intend. With respect, neither should you. Cuddlyable3 (talk) 19:20, 22 August 2010 (UTC)[reply]

You seem to miss the point. The key question is not what the word "scholar" means, which is pretty clear without needing either the Latin or dictionary definitions. The key question is whether one should interpret "my Indian scholars" as meaning that the OP is a teacher. There is nothing that warrants that. One could more readily interpret them as being an administrator of an educational system (they are their scholars, after all), but that is clearly ridiculous in the context of the overall question as well. If it was "my fellow Indian scholars," then it would imply that the OP is a scholar, but it doesn't say that. It seems more likely to interpret it as "the Indian scholars in my country". Anyway, all of this shouldn't need elaboration, if not for your pedantry. --Mr.98 (talk) 16:58, 23 August 2010 (UTC)[reply]

"There is a fundamental difference between religion, which is based on authority, [and] science, which is based on observation and reason. Science will win because it works." - Stephen Hawking[2] 67.243.7.245 (talk) 18:20, 23 August 2010 (UTC)[reply]

Hawking is not suggesting that scholars want to listen to you or care about what you say. What he is saying is that the overall question of the origins and purpose of the universe should not be limited to astrophysicists, that it is a broader question, that some of it is deep philosophy. He's trying to encourage you not to defer to scholars just because they are scholars. --Mr.98 (talk) 00:36, 22 August 2010 (UTC)[reply]

In the extract given, Hawking does not say the question is deep anything. One may deduce that he encourages ordinary people to take part in discussing the question, though his actual statement is worded as a prediction ("we shall..."). Cuddlyable3 (talk) 11:37, 22 August 2010 (UTC)[reply]

I'm pretty sure the OP wants to communicate with scholars from the country of India regarding the nature of the universe and share his ideas. He seems to have taken Professor Hawking's ending sentiments quite literally rather than distant future figuritively. 24.177.120.57 (talk) 14:11, 22 August 2010 (UTC)[reply]

Fishbone getting stuck in throat

A fishbone is getting stuck in my throat, and if I leave it there without doing anything for I have been told that fisbone is calcium which can automatically be decayed (though it is quite bothersome), will this be dangerous?

203.131.212.36 (talk) 12:21, 21 August 2010 (UTC)[reply]

We are not allowed to give out medical advice. See WP:MEDICAL.

SteveBaker (talk) 17:12, 21 August 2010 (UTC)[reply]

I don't think deleting my comment was called for. It's not like I told the poster what to do. Wnt (talk) 23:18, 21 August 2010 (UTC)[reply]

Adjusting the cost of energy for using carbon

█ Conventional oil	█ Unconventional oil	█ Biofuels	█ Coal	█ Nuclear	█ Wind
Colored vertical lines indicate various historical oil prices. From left to right:
— 1990s average	— January 2009	— 1979 peak	— 2008 peak

Price of oil per barrel (bbl) at which energy sources are competitive.

Right end of bar is viability without subsidy.
Left end of bar requires regulation or government subsidies.
Wider bars indicate uncertainty.

How would you adjust Template:Cost of energy sources for the external, weather-related cost of using fossil fuel?

Carbon pricing is not much help. Here is a diminishing-returns chart; does that help?

What do we need to learn to answer this question? Why Other (talk) 17:53, 21 August 2010 (UTC)[reply]

A major part of the problem here is that we don't know the full cost of global climate change. We know it's happening - and we know that it's largely caused by fossil fuels and things like the large scale farming of herbivores (specifically "Cow farts"). However, even if we did know that, it's not a flat-rate kind of a thing. Think of it this way...X amount of CO2 in the atmosphere might have almost no effect because it might not cause the polar icecaps to melt - but twice X might be enough to melt the icecaps, create dark water where there was bright ice and therefore much more solar absorption. Twice X worth of CO2 could easily cause ten X worth of warming. So there is no price we can put on X amount of CO2 in the air.

That means that the price that's put on this is a matter of deterrence, politics, economics - not science. SteveBaker (talk) 18:21, 21 August 2010 (UTC)[reply]

Good point, we need cost information per emitted carbon, with which this source-sink flowchart might help, in addition to the source information from livestock. Why Other (talk) 18:30, 21 August 2010 (UTC)[reply]

Cow farts aren't a major contributor to climate change. Cow burps may be. Note that contributions from livestock also come from things like land cleared (a one time thing usually) both for the cows and for the feed due to increasing production are also usually considered a factor. Nil Einne (talk) 19:10, 21 August 2010 (UTC)[reply]

I asked about that on Talk:Climate change mitigation#Low carbon diet. Why Other (talk) 19:20, 21 August 2010 (UTC)[reply]

I just found Economics of climate change mitigation and I am having trouble understanding some of it.

Can we just move all the fossil fuel subsidies to wind and water power subsidies? That's $500 billion a year. How could we determine whether it would be too much or not enough? Why Other (talk) 18:48, 21 August 2010 (UTC)[reply]

Why only wind and water? What about solar? Nuclear? Biofuels? (Incidentally does water include geothermal? Wave?) Nil Einne (talk) 19:09, 21 August 2010 (UTC)[reply]

Solar is good, but does it play much of a role? Nuclear looks expensive to begin with, and I'm not sure it can be built out fast. Some of the storage and transmission energy developments look much more important than geothermal generation. 71.198.176.22 (talk) 19:16, 21 August 2010 (UTC)[reply]

Depends where you're referring to surely. Iceland already gets about 24% of their power from geothermal. Also how/why have you determined solar doesn't play much of a role if you're trying to expand usage by subsidies anyway? Nil Einne (talk) 19:20, 21 August 2010 (UTC)[reply]

Agreed; something like File:Extreme-weather-cost.gif is necessary to approximate the financial value of reducing atmospheric carbon. 71.198.176.22 (talk) 19:32, 21 August 2010 (UTC)[reply]

Wind, water, and solar are certainly all good, but definitely in that order long term. Water includes both hydroelectric and tidal, and geothermal is certainly more important than tidal (which is only used in 2010 to recharge the batteries a few electric yachts with on-board regeneration at anchor.[3]) Why Other (talk) 19:29, 21 August 2010 (UTC)[reply]

Again, how have you made that decision on what's important and what order? Particularly since you talking about using subsidies and considering in many countries the level of usage of all (except nuclear and to a lesser extent hydroelectic) are rather small. Are you sure your suggestions apply everwhere? What about say in the Middle East or tropical countries? Nil Einne (talk) 19:33, 21 August 2010 (UTC)[reply]

That is the order they appear by magnitude in Jacobson, M.Z. and Delucchi, M.A. (November 2009) "A Plan to Power 100 Percent of the Planet with Renewables" (originally published as "A Path to Sustainable Energy by 2030") Scientific American 301(5):58-65 and so that is the order I put them in energy development. Why Other (talk) 19:42, 21 August 2010 (UTC)[reply]

That appears to be one group?'s ideas and while it may be legitimate to present such ideas in the article (something which is not up for discussion here, if you want to discuss what goes in an article that should stay in an article talk page), this doesn't mean that their ideas are the only valid ones as you seem to imply here. In fact, the fact it's presented in a popular science journal somewhat suggests is justs a simplified public proposal rather then a robust peer reviewed scientific analysis. BTW I forgot to mention this earlier. I'm not that familiar with nuclear power developmental time frames but if your suggestions are hinged on some significant developments in energy storage systems then it's not clear to me if you can reasonably dismiss nuclear as taking too long. P.S. From a quick read of the article you mention, it doesn't even seem to agree with your suggestions. In fact their proposal seems to be 51% wind and 40% solar, so I don't see how you can dismiss solar as not playing a role as you did early on. And in fact in their proposal solar appears to play a far bigger part then water. Wind may be more important then solar in their proposal but only by about 20% and it's difficult to imagine that they are really claiming their proposal is so robust that a change from their proposal to say 46% solar and 45% wind is impossible. Nil Einne (talk) 03:06, 22 August 2010 (UTC)[reply]

Is everyone looking at the graph on p. 64 of the November 2009 Scientific American (a NPG publication) entitled "Cost to generate and transmit power in 2020 (cents per kwh in 2007 dollars)" which lists wind at less than 4, wave and hydroelectric at 4, geothermal at 4-7, and solar, fossil, and nuclear at 8? Scientific American is peer reviewed, and the article is based on the costs of raw materials plus labor. Why Other (talk) 01:56, 23 August 2010 (UTC)[reply]

If $500 billion/year currently used to subsidize fossil fuel were moved to wind power, how close would that bring today's prices to Scientific American's projection for 2020? Why Other (talk) 07:01, 23 August 2010 (UTC)[reply]

As I've already said Scientific American is a popular science magazine not a peer reviewed journal. See [4] with a comment from the President of SA himself confirming this fact.

Also, any source which gives only one possible figure, without even an error estimation, for a cost in 2020 is clearly not intending it to be some sort of super reliable, end all estimate as you seem to be treating it.

BTW the cost to generate is only likely to be one factor in considering power sources most suited for future use, hence why the people who wrote the article you are referring to still think solar would represent 40% in their proposal, despite having the differing cost estimations.

Note that I am not suggesting any of the info you have is wrong, rather if you really want to consider it in depth/properly, you need to look at a lot more sources, preferably looking at the actual research or literature reviews rather then coming to a conclusion from one source who's authors I suspect would largely agree with me that their proposal is not intended to be the end all right answer. As with most aspects of science involving predictions of future developments, this is an incredibly complicated area and when you're talking about $500 billion a year people won't think much of an overly simplistic analysis. (For a starters, I suggest you take a look at the sources the SA authors used.)

Nil Einne (talk) 13:14, 23 August 2010 (UTC)[reply]

I'm sorry I was mistaken about Scientific American's peer reviewed status. Where are you seeing the 40% figure and the other percentages you mentioned earlier? Why Other (talk) 15:46, 23 August 2010 (UTC)[reply]

I see, you mean the charts on pages 60 and 61. I had misread the first on the upper left. How much water power do we already have built out? Figure 55 of page 73 of http://www.eia.doe.gov/oiaf/ieo/pdf/electricity.pdf seems to suggest less than a terawatt, and at least it shows more wind growth than other EIA sources. Why Other (talk) 20:45, 23 August 2010 (UTC)[reply]

~~The chart on page 61 of the November 2009 Scientific American doesn't add up. It says "Solar 4.6 TW (40% of supply)" but it only has 0.6 TW shown.~~ (Note, it shows 0.6 GW, because the smaller figures are "per each") Nil, thank you for your good advice to find the cited review: Jacobson, M.Z. (2009) "Review of solutions to global warming, air pollution, and energy security" Energy and Environmental Science 2:148-73 doi 10.1039/b809990c (review.)

http://aiche.confex.com/aiche/2009/webprogram/Paper159471.html is also very interesting. Why Other (talk) 21:40, 23 August 2010 (UTC)[reply]

Identify this animal

Hello Science Desk! I just saw a creature, about the size of a small woodlouse and similar in shape, but light blue in color and with an outer body that looked hard and spiny. What might it have been? 82.44.54.4 (talk) 18:18, 21 August 2010 (UTC)[reply]

We can answer these questions much more easily if you could tell us roughly where you live. Which country, which state? (I also gave your question a more useful title "Question" doesn't really help much!) SteveBaker (talk) 18:23, 21 August 2010 (UTC)[reply]

If the IP address is any help, the questioner is located in the UK. Woodlice normally aren't spiny, though they can appear to be blue. Could it have been a short blue spiny caterpillar or other larva? (Sometimes, the caterpillar's appearance is even described as "woodlouse-form". --Sluzzelin talk 18:42, 21 August 2010 (UTC)[reply]

Sorry, I missed the "hard" part in your question, which make caterpillars and other larvae seem unlikely. For woodlice, we have a list of woodlice of the British Isles. "Blue" isn't mentioned, but Philoscia muscorum looks blue on that picture, though its color is described as "mottled and greyish-brown". I was perhaps a bit quick claiming that woodlice normally aren't spiny. Stenophiloscia glarearum is described to have "a distinctly spiny dorsal surface", but it is also long and white, not short and blue. Another one from that list, Styloniscus spinosus, has a name suggesting spininess, but the entry lacks any description whatsoever. I wasn't able to find photographs of either of the potentially spiny species. ---Sluzzelin talk 14:50, 22 August 2010 (UTC)[reply]

Not a woodlouse, but a silverfish might be what you're referring to from the description. Mikenorton (talk) 15:39, 22 August 2010 (UTC)[reply]

Callus

When you develop a callus, is it there for good (permanent) ... or is there a way to make it go away (i.e., reverse the process of the skin hardening)? I am referring to a small callus on the palm of the hand, as the result of constant (daily) use of a gym treadmill. Once I noticed the callus, I started wearing weight-lifting gloves. But will these small calluses (calli?) eventually go away and disappear on their own? Or can I do something that will make them go away? Or am I stuck with them permanently now that they have arrived? Thanks! (64.252.34.115 (talk) 19:10, 21 August 2010 (UTC))[reply]

Pretty sure a doctor (presumably a dermatologist?) could answer these questions. Medical advice it outside the remit of the Ref Desks, but our article callus has a few ideas - it seems calluses are removed, rather than reversed. 90.195.179.233 (talk) 19:30, 21 August 2010 (UTC)[reply]

Anecdote from personal experience: fifteen years ago, I used to carry a heavy case into work every day. A long and tough callus built up across my palm from the handle. Today, I can still feel where it was, but it's only a soft bump, difficult even to notice. I assume that it vanishes as the skin is constantly renewing itself. Oh, and the Latinate plural is indeed calli, though I think as it's a common English word you'd be fine saying "calluses". Marnanel (talk) 20:13, 21 August 2010 (UTC)[reply]

See Callus#Treatment. They may go away on their own, they may not. You can use pumice to grind it off if you wanted to, if you are not diabetic. There are also chemicals you can use to dissolve them. They sell things like this in the "foot care" section of your local pharmacy. You might talk to a pharmacist about this, if not a doctor. --Mr.98 (talk) 00:28, 22 August 2010 (UTC)~[reply]

Callous care advice and warnings. (video) Cuddlyable3 (talk) 11:25, 22 August 2010 (UTC)[reply]

Not sure how much advice I'd take when the authors can't even spell it right. --Trovatore (talk) 17:57, 22 August 2010 (UTC)[reply]

The Brain

What part of the brain is imagination synthesized, specifically art, music, literature, ect. Maybe someone can satisfy my insatiable desire for knowledge by adding some interesting facts? Like maybe how does someone come to "enjoy" certain representation of art yet not others as much or not at all (e.g. music like deathcore compared to RnB?). 99.114.94.169 (talk) 22:03, 21 August 2010 (UTC)[reply]

There is no definitive understanding of exactly how one derives pleasure. Have a look at Pleasure#Neurobiology, Pleasure center, Emotion#Neurobiological_theories, and Perspective (cognitive).Smallman12q (talk) 22:54, 21 August 2010 (UTC)[reply]

Is that the best of Wikipedia can give me? I was hoping for some discussion on theory? Are there any theory on why people njoy certain types of music/art/literature, while other may prefer something completely different? 99.114.94.169 (talk) 23:52, 21 August 2010 (UTC)[reply]

You usually have to wait more than 2 hours on a weekend. People have lives, you know, and we're just volunteers. But I do suspect that Smallman12q's answer is probably about as good as it gets. You seem to be assuming there are distinct, known, physiological structures responsible for different types of cultural appreciation. I'm not sure there's any evidence of that, at least with out current understanding of the brain. The neurological domain may be a bit too fine-grained for the level of analysis you are talking about. --Mr.98 (talk) 00:30, 22 August 2010 (UTC)[reply]

Harsh? Well, by the tone I was assuming that was the best answer I was going to get, but I was hoping otherwise. Well maybe if I tried something different... What part of the brain processes music, would it be the same part that processes other auditory stimuli, and art likewise? Then what of literature? Or maybe does it starts there and then what part of the brain says its "enjoyable." The I guess i can do some reading on the associated article. 99.114.94.169 (talk) 00:53, 22 August 2010 (UTC)[reply]

Take a look at music-related memory, artistic inspiration, creativity, sleep and creativity, lateralization of brain function, reading comprehension, and imagination. ~A H 1^(TCU) 01:02, 22 August 2010 (UTC)[reply]

There is still a lot of argument about how imagination works, but one popular view, backed especially by Stephen Kosslyn, is that the sensory parts of the brain play a major role in imagining things in a given sensory modality, especially the higher-level sensory areas. So when you imagine music, your auditory cortex is active; when you imagine a painting, your visual cortex is active; and so on. Other areas are active too, though, including parts of the frontal lobes. Looie496 (talk) 01:07, 22 August 2010 (UTC)[reply]

Thank you, I did some looking around and found some more interesting reads. Such as Cognitive Neuroscience of Music, Music and the brain, and Amusia, a disease affecting perception of music. So it is commonly believed that each individual sensory area specializes and forms its own cognitive imagination? Or would it be more likely they all go to a certain part of the brain? And what part of the brain is the picture seen at the top of Amusia? 99.114.94.169 (talk) 01:16, 22 August 2010 (UTC)[reply]

The section highlighted in that image is a portion of the temporal cortex. You could also do a search on google for "audio perception theories", or if you're more determined/interested, go through "theories+of+audio+perception" relevant books. The process of Perception#Theories_of_visual_perception is not yet well understood...though you might like to read Philosophy of perception. Sensory neuroscience is a fairly modern field and currently does not currently offer an in-depth explanation for how senses are perceived. That aside, you are welcome to debate the theories behind perception and pleasure, (as well as Nature vs nurture and stereotypes). Just a friendly FYI, you'll probably get more responses during the week so stick around. Hope I've at least somewhat satiated your otherwise noble unquenchable thirst for knowledge. Cheers!Smallman12q (talk) 02:07, 22 August 2010 (UTC)[reply]

Here is a recent paper entitled "Towards a neural basis of music-evoked emotions", which may be of interest. --Mark PEA (talk) 10:22, 22 August 2010 (UTC)[reply]

August 22

Strange shadow

To the left - what normaly happens when shadows overlap. To the right - what happens here ~~**Xil** (talk) 18:21, 22 August 2010 (UTC)[reply]

I observed few years ago that when one shadow nears another they start to merge, but before they do they appear to ”reflect” each other. I figured description wouln't make much sense, so I took a picture of shadows casted by my fist and pipe - observe how an extra fist appears to be coming out from the pipe (the shadow also shows a welding on the pipe which was behind my hand). I noticed this ilusion again tonight and since I didn't find any explenation the first time around, I decided to ask here - what exactly causes this ? ~~Xil (talk) 01:14, 22 August 2010 (UTC)[reply]

I think this would be an example of an Umbra. 99.114.94.169 (talk) 01:39, 22 August 2010 (UTC)[reply]

I don't think so - as far as I understand umbra is the darker part of shadow, which you can see, but it is not what I want. In case it is hard to see shadows in first pic (I chose it because you can see what is going on with the objects in case placement is important), here is another one which might ilustrate the ilusion itself better ~~Xil (talk) 02:03, 22 August 2010 (UTC)[reply]

What you have photographed is an elementary diffraction pattern. Diffraction accounts for many visual anomalies that exist in our daily lives but that we mostly take for granted. Dolphin (t) 02:19, 22 August 2010 (UTC)[reply]

I don't think you understand what I am asking. Lightwaves bending around small objects still appears to be related to color of the shadow not the shape and as for ”our daily lives” - I have never noticed this happening anywhere else, I assume it needs certain conditions to happen. If not, please, elaborate how difraction causes this mirrored shadow to appear. In any case I want to know how to replicate this somewhere else ~~Xil (talk) 10:23, 22 August 2010 (UTC)[reply]

The region of interest is the overlap of the penumbra or soft gradients at the edges of the shadows. An object produces a penumbra when the light source is larger than a point. The two penumbra of the fist and pipe are due to obscurations of different parts of the distributed light source, which may be uneven. This explains why the umbra grow unevenly as the penumbra merge. I don't expect any diffraction effects where the light is not correlated and the dimensions are many orders of magnitude larger than the light wavelength. Cuddlyable3 (talk) 11:08, 22 August 2010 (UTC)[reply]

I notice that happening too. When I put my hand in the sunlight coming through a window, the shadow "stretches" when it nears another shadow. --Chemicalinterest (talk) 11:14, 22 August 2010 (UTC)[reply]

Cuddlyable is correct. The poster who led you to umbra was also on the right track - you're seeing the conversion of penumbra to umbra based on a narrowing of the light source as indicated in the figure. Wnt (talk) 12:23, 22 August 2010 (UTC)[reply]

I still can't replicate it. I tried nearing my hands to each other under a lamp - the penumbras overlap normaly, no mirroring ~~Xil (talk) 13:13, 22 August 2010 (UTC)[reply]

Put one hand closer than the other. You should try (I think) to reach the apex of the lower triangle among the four made between the Sun and the Earth on the umbra diagram. You can't do that if your hands are at the same distance from the light source. Also note a broader source like a window will yield more visible results. Wnt (talk) 15:38, 22 August 2010 (UTC)[reply]

Black drop effect. ~A H 1^(TCU) 17:46, 22 August 2010 (UTC)[reply]

My hands don't have atmosphere :) besides that appears to be diffrent kind of streaching. I'm not sure it is clearly visible in pictures I took so I'made another ilustration to avoid confusion ~~Xil (talk) 18:21, 22 August 2010 (UTC)[reply]

I don't see an obvious relation to the black drop effect, though Venus' atmosphere may offer a refraction effect that somehow can be compared. For a demonstration, see the crude figure I've added - I've taken the liberty of pushing the others up. (In reference to another thread, a child artist could surely do better...) Wnt (talk) 00:36, 23 August 2010 (UTC)[reply]

You're right that your fist doesn't have an atmosphere, which means there's no refraction involved, but diffraction can play a similar role here. Some light passing close by the pipe bends in around it slightly because of diffraction, just as light refracted by Venus' atmosphere is bent toward it. When your fist obscures that light that would pass by the edge of the pipe, it may darken a region of the wall farther in than you would normally expect, making the shadow stretch as it approaches the shadow of the pipe. But I'm not sure if that effect would actually be large enough to be noticeable. You can see it for instance by looking at your computer screen with one eye and moving you finger in front of your eye. The text will be distorted near the edge of your finger. Rckrone (talk) 03:20, 23 August 2010 (UTC)[reply]

I'm very, very skeptical about the diffraction. Usually diffraction concerns things with a size on the order of a light wave... not on the order of an elbow. I'm not saying you can't observe diffraction - obviously you always can - it's just not a major effect in this situation. Wnt (talk) 03:55, 23 August 2010 (UTC)[reply]

The bottom picture shows the explanation, but it doesn't have anything to do with antiumbras. Note that from the purple area, there is no view of any part of the light source. That would remain true even if you change the light source so that the purple area is in the umbra of both objects rather than the antiumbra of one. Basically what is happening is that the light in the overlap area is what remains after subtracting the light blocked by each of the objects. When the objects are close to each other, it's possible for each to subtract more than half of the incoming light. Because of the nonlinear sensitivity of the eye to light, the brightness of the shadow doesn't give us a good estimate of the amount of light that is being blocked. Looie496 (talk) 03:48, 23 August 2010 (UTC)[reply]

It's true that the umbra/antumbra position is irrelevant (though the two objects can't be at the same distance from the light). I just painted two dots fairly arbitrarily and that's how the figure came out. Sorry if that confused you.

It's also true that the nonlinear sensitivity has something to do with it (though I think the camera has flattened the curve more than your eye alone). But the effect would be visible with nearly any curve for brightness, I think. Wnt (talk) 03:55, 23 August 2010 (UTC)[reply]

Guys, I still feel that you are explaining how two shadows overlaping cause there being another dark shadow, not why it is the other way around than the object, because Wnt your diagram shows how shadows overlap causing streching and darkening and Rckrone your picture seems to show shadows streching and forming penumbra between them. BTW the lightsource is fluorescent lamp (sort of like second from above), I think it gives even spread of light, it is positioned above and to side from the object in the scene though ~~Xil (talk) 12:00, 23 August 2010 (UTC)[reply]

I'm not sure whether this means my explanation was satisfactory or not. If not, I should repeat: my figure shows the umbra (full shadow) of the top object expanding as the other object approaches. Note that the region between them receives more light than either shadow, because it is at an angle where it can see more of the light source between the two objects, whereas below, the lower object is completely in front of the light source and blocks quite a bit of the light, and above the two objects overlap and block out all the light. Wnt (talk) 17:47, 24 August 2010 (UTC)[reply]

Water

Why is water a pre-requisite for life for every known thing in the world. What's in it that makes it invigorate crops and fuel our body's and how does it work after all its only 2 parts hydrogen and one part oxygen, what so special about that? --Thanks, Hadseys 02:10, 22 August 2010 (UTC)[reply]

See water, there is an effects on life section. There are many different reasons why water is important, it is considered a universal solvent, meaning many materials easily dissolve in it and allows compounds to react in ways that are required in metabolism such as anabolism and catabolism. Also, it doesn't fuel our bodies, autotrophic organisms require CO2 and water plus an energy source (usually light in the form of photosyntesis) to produce glucose which is then used for energy and leaves the byproducts water and CO2. Water also has a neutral pH. These are just some of the roles it plays, as to why it has the properties it does is because the arangement of the valance electrons in the atoms that water is composed of and the way those elements bond to one another.--74.67.89.61 (talk) 02:35, 22 August 2010 (UTC)[reply]

Water is special because life originated in water, evolved there, and to this day most living things are made up largely of water. It is a matter only of speculation whether extraterrestrial life might have originated in other solvents - while some speak of the advantages of water for life, it is difficult to say how advantageous it really is by the standards of some other life we've never seen. Wnt (talk) 12:30, 22 August 2010 (UTC)[reply]

Actually no, water really is special. All the hypothetical types of biochemistry have severe problems that probably make them impossible. Ariel. (talk) 17:16, 22 August 2010 (UTC)[reply]

That article is interesting, but it is hardly complete. For example, sulfuric acid was the first solvent that came to my mind just now, which is present in abundance on Venus, and there is indeed a reference proposing it [5] but it is not listed there. If there's one thing that mankind's little tour of the solar system has proved, it's that you can find a remarkable variety of chemistry by looking at just a few planets formed from the same primordial disk of matter. Wnt (talk) 05:47, 24 August 2010 (UTC)[reply]

Spider

Can anyone help identify a spider without a picture? It's body is about the size of the index finder distal phalanx. It's body and legs are hairy. It has about 3 black bands on each leg. It seems to be a reddish/brownish color. The back end of the spider has a black circular spot with 2 yellow dots in it. It is not hiding his fangs as they are massive. It seems to be extremely aggressive. The web is massive. It is spinning it starting from the outside then going inside. I currently reside near Pittsburgh next to a wooded area. I'm mostly concerned if it is poisonous but I'm not going to mess with it either way. I'll have someone else take care of it. :) 74.109.217.103 (talk) 02:36, 22 August 2010 (UTC)[reply]

After taking a quick look it seems to be a typical Orb-weaver spider. 74.109.217.103 (talk) 02:57, 22 August 2010 (UTC)[reply]

Could be a European garden spider? 99.114.94.169 (talk) 03:37, 22 August 2010 (UTC)[reply]

You might like to try this site Spiderzrule. Incidentally, I would suggest your little spider friend is being more defensive than aggressive - unless it came out of the woods chasing you to start with! Richard Avery (talk) 07:21, 22 August 2010 (UTC)[reply]

According to our article on spider bite, virtually all spiders are venomous (venom is an injected toxin; poison refers to other delivery methods, so spiders are venomous, not poisonous), with only three genera not being able to inject venom. That being said, most spiders are not venomous enough to do you serious damage and would much rather not have any dealing at all with monsters thousands of times their size (i.e. you). Matt Deres (talk) 13:37, 22 August 2010 (UTC)[reply]

Dissolved oxygen

Why warm water has less dissolved oxygen?117.193.106.26 (talk) 06:00, 22 August 2010 (UTC)[reply]

Basically this is Le Chatelier's principle and results from the fact that dissolving oxygen in water is exothermic. This website has a good and fairly non-technical explanation: [6]. I actually had to look up the answer to this question, which is scary considering that I studied a chemistry module at university only 2 years ago... time to dig out my old textbooks for a refresher! Equisetum (talk | email | contributions) 09:16, 22 August 2010 (UTC)[reply]

Warm water (or soda) contains less carbon dioxide too. You can see when you pop a can of warm soda, it fizzes much more. --Chemicalinterest (talk) 11:11, 22 August 2010 (UTC)[reply]

The dissolution of gas into fluid tends to be an unstable mixture. Gas particles tend to be light and subject to large changes in energy with typical collisions. Warm water contains more high energy liquid particles which are better capable of bumping gas particles out of the liquid and back into the air. 24.177.120.57 (talk) 14:05, 22 August 2010 (UTC)[reply]

Hydroxyl interaction between air and water may be affected by temperature. ~A H 1^(TCU) 17:43, 22 August 2010 (UTC)[reply]

Titan's atmosphere

Titan has a pretty dense nitrogenous atmosphere (http://en.wikipedia.org/wiki/Titan_(moon)#Atmosphere). How has it been able to have such a gravitational field, being not heavy or large?Zachilles (talk) 08:01, 22 August 2010 (UTC)[reply]

Titan has a much weaker gravitational pull than Earth, indeed. However, it is also much further away from the Sun, so it is much colder. If you take a look at the Barometric formula (Equation 2 to be exact), the height at which the density (and pressure) of the atmosphere drops by a given factor -- say, by a factor of 1/2 -- is proportional to the ratio of gravitational pull to atmospheric temperature. This is one of the factors contributing to the atmosphere of Titan being so dense. There are probably others: maybe magnetic field of Saturn offers some protection from the Solar wind, maybe Solar wind is just too weak at those distances, and so on. Besides, Earth's atmosphere could have been much denser if it wasn't lost once already to the impact that split off the Moon, if you believe that hypothesis. --Dr Dima (talk) 09:26, 22 August 2010 (UTC)[reply]

How directly is the object's mass and distance from the sun related to its atmosphere? Venus has 85% of the volume of the Earth, 81% of the mass and 90% of the surface gravity, and is 70% of Earth's distance from the Sun. Yet the surface is twice Earth's absolute temperature, and the atmospheric pressure is 93 times Earth's. (Yes, I know Venus's atmosphere is mainly CO₂, which accounts for the temperature). CS Miller (talk) 19:09, 22 August 2010 (UTC)[reply]

Computer science

1. how computer works? how hardware, software, firmware, driver software, cmos bios setup, operating system, inter chip level program etc... are inter linked and works? explain with clear text, flow chart, diagram, animation, example and video-audio?

2. i want to make some own embedded system project. How can i integrate (hardware, software, firmware, driver software, cmos bios setup, operating system, inter chip level program etc...) these things?

3.How software controls and operates hardware with examples? —Preceding unsigned comment added by Pachaimalai (talk • contribs) 11:24, 22 August 2010

Please do your own homework.

Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. 90.193.232.65 (talk) 12:44, 22 August 2010 (UTC)[reply]

You have to be more specific...which type of computer...which hardware...which embedded system.Smallman12q (talk) 13:14, 22 August 2010 (UTC)[reply]

Well, the question is so broad, I'm not even sure it's homework. But in any case, the best place to start is in the articles: computer; hardware, software, and so on. We have articles on all of these topic with clear explanations, charts, diagrams, and so on. After you read the articles, come back with any questions you have, or if anything is still unclear. Nimur (talk) 16:17, 22 August 2010 (UTC)[reply]

Also take a look at computer engineering, integrated circuit and CMOS. ~A H 1^(TCU) 17:39, 22 August 2010 (UTC)[reply]

To try to answer one part at a time:

how computer works? how hardware, software, firmware, driver software, cmos bios setup, operating system, inter chip level program etc... are inter linked and works? -- This is a vast subject, the things you've listed might take a full degree program in Computer Science to adequately explain. The starting point is our computer article. Start reading there, then follow the links as necessary to broaden the topic from there.
i want to make some own embedded system project. -- OK - but if you truly don't have the basics (which seems apparent from Question (1) then you're a long way from being able to do this. If you actually know more than your question (1) implies, then I would recommend you get an Arduino embedded computer and start to learn to program it and build hardware for it. You can pick up an Arduino computer for around $26 and there are VAST amounts of internet resources you can find to help you with hardware and software that you might wish to create to work with it.
How software controls and operates hardware with examples? -- Generally, there are 'special' memory locations inside the computer hardware which are either connected to drive external hardware - or to monitor it. On something like an Arduino computer, you can (for example) flash the LED on the board by writing either a '1' or a '0' to a particular location that the LED circuitry connects to. Similarly, if you were to connect a switch to one of the specialised pins of the Arduino circuit board, you'd be able to have your software read from some other special memory location and the value that you'd get back might be a '1' if the switch is closed and a '0' if it is not. On a more complex computer such as the one you'd find in a laptop or a cellphone, the mechanism is basically the same, but the "operating system" software (like "Windows Vista" or "Android") will take care of the details of how that works and allow the application software to talk in higher level terms such as files on disk rather than individual commands to the disk drive motors, etc.

SteveBaker (talk) 18:21, 22 August 2010 (UTC)[reply]

For 1. There are a number of universities that offer joint computer programming and electronic engineering courses. I'd highly recommend them if you are interested in designing your own computer from the CPU (or even logic gates) upwards. CS Miller (talk) 19:19, 22 August 2010 (UTC)[reply]

For the details of 3. see memory-mapped I/O, direct memory access and interrupt for some specifics. CS Miller (talk) 19:12, 22 August 2010 (UTC)[reply]

Instructions for Filtering Water in Urdu Language?

Can the above be found anywhere? Preferably with drawings or photos? It's for PK flood relief workers to pass out to IDPs. Am reading Twit posts about babies being given dirty water to drink. The disease risk is obvious, and basic instructions will help prevent the more serious maladies. Any and all help is appreciated. —Preceding unsigned comment added by Juju31 (talk • contribs) 11:29, 22 August 2010 (UTC)[reply]

I wonder whether WP:RD/L might be a better place for this Nil Einne (talk) 12:14, 22 August 2010 (UTC)[reply]

We can file a translation request for water filtration. As you can see from پانی, even the basic articles have poor coverage in Urdu; by comparison to other languages, we don't have many Urdu-speaking Wikipedians. I wonder if the World Health Organization might be a better resource in this case - they have a lot of information in many different languages. Here's their Pakistan Office website and their Basic Development Needs program (which includes water quality and sanitation). You might telephone their office to see if they already have a water-quality brochure that you can help distribute. Nimur (talk) 16:29, 22 August 2010 (UTC)[reply]

Indeed one advantage there is it would hopefully be better adapted for the local situation. For example, in Bangladesh a common recommendation is cloth filter of an old sari. This probably isn't such good advice in Pakistan as they aren't so common there (Sari#In Pakistan). Nil Einne (talk) 16:57, 22 August 2010 (UTC)[reply]

Juju31 here. Thank you for this. I'm emailing WHO PK office to ask what they have. If I get the info, I will repost it here so you can add it. —Preceding unsigned comment added by Juju31 (talk • contribs) 03:01, 23 August 2010 (UTC)[reply]

Responding to the above need, Hesperian Foundation has kindly allowed one of their publications as a free download relating to basic care for use by disaster relief workers in Urdi, Sindhi and English languages. Here is the link: http://www.hesperian.org/pakistan.php

Wasn't sure where to post it but wanted to pass this on to you so that the initial question wasn't left hanging. Thanks so very much for all your efforts. Juju31 —Preceding unsigned comment added by Juju31 (talk • contribs) 01:48, 20 September 2010 (UTC)[reply]

For Every Human

1. WHAT IS THE OBJECTIVE OF OUR LIFE( FOR HUMANS AS WELL AS A LIVING BEING)? 2. WHAT ARE THE PRINCIPLES OF LIFE? 3. HOW TO LIVE IN LIFE? —Preceding unsigned comment added by Pachaimalai (talk • contribs) 11:33, 22 August 2010 (UTC)[reply]

See meaning of life. I don't think anyone here (or anywhere) can answer your question. 90.193.232.65 (talk) 12:41, 22 August 2010 (UTC)[reply]

This is a matter of perspective. For analyzing life, see Life course theory. As for objective...Nihilism#Existential_nihilism argues that life is without objective meaning, purpose, or intrinsic value.Smallman12q (talk) 13:12, 22 August 2010 (UTC)[reply]

Put another way, probably everyone on here has a different opinion on this, but there is no way at all to distinguish with any reliability a good opinion from a bad one. Certainly no way to scientifically do it. It isn't a science desk question. --Mr.98 (talk) 14:23, 22 August 2010 (UTC)[reply]

If there was an ideal objective of life for every human, that would be both idealism and a specific ideology. It could just as well be different for everyone. The biological purpose is reproduction, the philosophical approach may be to seek purpose, and the humanistic ideal is humanism and so on. ~A H 1^(TCU) 17:37, 22 August 2010 (UTC)[reply]

From a scientific perspective - we (and all other living things) have evolved to pass on our genes to the next generation. Humans (and many other species) also take care of and guide their offspring until they too can pass their genes on. We do this because evolution favors lifeforms that can do that and rapidly eliminates those who cannot or do not pass on their genes. SteveBaker (talk) 18:06, 22 August 2010 (UTC)[reply]

However, human population growth has gotten so out of control that people in poorer countries who once had many children are now having few children. Can purpose evolve? ~A H 1^(TCU) 18:18, 22 August 2010 (UTC)[reply]

Passing genes does not mean "reproduce indiscriminately." It means, "make sure your genes survive into the next generation," which might be more ideally done if, say, you only have one child that you invest a lot of resources in, or, say, if you kill off all of your competitors. Evolution is rather "blind" about the means. This is one of the reasons it is not seen as particularly useful in looking for a meaningful sense of "purpose". It just makes clockwork machines of us all. It is not a very satisfying sense of "purpose". --Mr.98 (talk) 22:24, 22 August 2010 (UTC)[reply]

That's debatable. For those who have a religious "obligation" to fulfill. Genesis 1:28 states to "God blessed them. God said to them, 'Be fertile and become many. Fill the land and conquer it. Dominate the fish of the sea, the birds of the sky, and every beast that walks the land." (or a similar translation). For those whose purpose is to worship god...the act of procreation fulfills that purpose.Smallman12q (talk) 01:49, 23 August 2010 (UTC)[reply]

Procreation is good but when debating about marriage (Mat. 19:12) Jesus opined that making oneself a eunuch would be preferable for one who can manage it. People should not try this at home - oops oops!.Cuddlyable3 (talk) 14:45, 23 August 2010 (UTC)[reply]

Laser Cutting of Metal Sheets

Sometimes after Laser cutting of M.S. Plates, they show the tendency of lifting up by almsot 50 mm - 300 mm. What will be the reason behind this behaviour of M.S. Plates? Which of any mechanical or chemical parameter playing the major role in this performence of Plates? —Preceding unsigned comment added by 220.225.75.226 (talk) 12:05, 22 August 2010 (UTC)[reply]

Are you sure you don't mean 300 micrometers? Lifting a steel plate by 300 millimeters is a heck of a lot. I suspect the cause is thermal expansion from the cutting laser. Nimur (talk) 16:39, 22 August 2010 (UTC)[reply]

Yes, but there were no substantial faults in the textbooks WE used!

Textbooks in scientific subjects allways have been, and presumably forever will have to be, rewritten time and time again (because the scientific knowledge and understanding grows as time goes by).

Still, a surprising lot of people, more or less consciously, seems to cling to a strange belief, which one occasionally may hear expressed by the claim: Yes, but there were no substantial faults in the textbooks WE used!
What I am refering to is the situation where the person seems to fully understand that science has progressed over the years, but seem to think that the textbook that himself or herself used is the full, complete and final truth about the subject, and that IT will stand unchanged forever.

I need some approved (published) research reports, proving that this kind of false belief really do exist.
Do you know of any? If so: Could you please help me with some references to it?

P.S.
I am familiar with the concept of the Bias blind spot, so that is not what I am looking for here.
--Seren-dipper (talk) 17:01, 22 August 2010 (UTC)[reply]

Not sure about research reports, but many textbooks in the United States promote Intelligent design, or label evolution or global warming as a "controversial" theory. ~A H 1^(TCU) 17:33, 22 August 2010 (UTC)[reply]

That is surely interesting but not quite what I am after.
Moved clarification up into my original question
--Seren-dipper (talk) 18:12, 22 August 2010 (UTC)[reply]
--Seren-dipper (talk) 17:53, 22 August 2010 (UTC)[reply]

That seems like a strange position to take. Most people I've met have the opposite experience of discovering that the stuff they were taught from textbooks was wrong. SteveBaker (talk) 18:00, 22 August 2010 (UTC)[reply]

I fully agree that it is strange! But still I have met quite a few people who seem to think this way :-)
--Seren-dipper (talk) 18:12, 22 August 2010 (UTC)[reply]

Also take a look at lie-to-children. ~A H 1^(TCU) 18:04, 22 August 2010 (UTC)[reply]

Also have a look at ignorance, confirmation bias, and the scientific method which describes how theories are corrected/changed as new evidence/interpretations are made.Smallman12q (talk) 20:01, 22 August 2010 (UTC)[reply]

People often cling to the high value of things that existed when they were young. See nostalgia. I haven't seen that apply to textbooks very much, personally. --Mr.98 (talk) 20:06, 22 August 2010 (UTC)[reply]

I'm with the others. I know lots of adults who cling to "what they were taught in school" about certain things, but that's in the face of any and every type of evidence (more recent advances in the field, corrected/amended editions of textbooks, more nuanced/specific/mature analysis, etc.). Is it even possible to distinguish textbook "mistake" from "newer knowlege" and "more advanced textbook"? DMacks (talk) 20:38, 22 August 2010 (UTC)[reply]

This may be off the topic, but I think there are certain systematic biases in science from generation to generation. For example, the capabilities of ancestral organisms and cultures are always underrated. This is due to a certain religious fanaticism about Occam's Razor. In the rush to avoid speculation, people will come up with explanations for how, for example, humans came to Australia without building ships, how a dozen phyla came up with eyes from a blind ancestor, how ancient pharmacopoeias included known effective treatments without any conception of a scientific method, and so on. Wnt (talk) 04:09, 23 August 2010 (UTC)[reply]

Oops - I said "overrated" above, meant underrated. Sorry for confusion. Wnt (talk) 17:53, 23 August 2010 (UTC)[reply]

Yes I thought that. Your comment didn't seem to make much sense otherwise Nil Einne (talk) 00:57, 24 August 2010 (UTC)[reply]

To give the next great example: mushroom bodies and the cerebral cortex are both derived from a common ancestral structure.[7] People were too timid to propose that this structure could have existed 600 million years ago, but there it is. Note that it took only two weeks for such a good example to come out. Wnt (talk) 03:53, 7 September 2010 (UTC)[reply]

Well, one cannot really tell what is "bias" and what is "brilliant" until one has gotten a little bit more distance. But on the general point that certain types of scientific explanations are appreciated by different generations — something which is a bit different than saying "science improves" — this has been well-studied by historians of science, and bears out to a large degree. It's especially obvious in anything to do with human beings, because we tend to superimpose our unexamined and often unconscious cultural values onto descriptions of human origins and practices. So it's not terribly coincidental, for example, that people looking at human evolution in the 1950s often saw 1950s values being repeated (male hunter, female cooker), or that in the 1960s and 1970s focus on hominid evolution began to look at bonobos and other "non-violent" alternatives, and so on. (These are very broad examples and most are of course a bit more subtle.) I certainly think that the anxiety about Creationism in the United States has led evolutionary biologists to be constantly on the offensive — every new odd species gets to be a "missing link" and so on quite immediately. (This is not to say I endorse Creationism at all, just that the anxiety is rather obvious and culturally and temporally specific.) --Mr.98 (talk) 13:56, 23 August 2010 (UTC)[reply]

I don't think the 'missing link' thing is simply to do with creationism but also to do with the self-promotion and publicity whether for the researcher or more common the institution they work with that's often common/necessary? in the modern scientific world. 'We found some ancesteral (proto-)lemur' is must less existing then 'WE FOUND THE MISSING LINK!'. It's notable claims are sometimes made by PR departments that the researcher themselves don't really agree with. And you see this in most other areas of science. Journalists of course are all to happy to help. Nil Einne (talk) 14:13, 23 August 2010 (UTC)[reply]

Thank you, all, for your replies! (Even though I did not get exactly what I had hoped for, they were still useful to me :-)
--Seren-dipper (talk) 00:42, 28 August 2010 (UTC)[reply]

Interspecies crying

Hi. It is known that animals of one species, other than humans, often befriend a member of another species (do we have an article on that?). Often, a predatory animal befriends its prey, either domesticated or wild. There have also been reports of domestic animals crying. This often occurs as the animal realises it's about to be killed. My question is, and I thought of this one this morning, are there any documented cases of an animal (other than humans) crying over a member of another species? Thanks. ~A H 1^(TCU) 17:23, 22 August 2010 (UTC)[reply]

Emotion in animals has some interesting links...but I think that some of the things you are stating as truth here are far from solidly known facts. Anyway - Koko the gorilla is known to have expressed sadness when her pet cat died - I'm not sure whether she actually shed tears though. Our article on the cat (All Ball) says that Koko made a sound akin to human crying - but there is no mention of actual tears. SteveBaker (talk) 17:57, 22 August 2010 (UTC)[reply]

Have a look at crying and this ask yahoo link, this link on crocodile tears. Are you asking if animals shed tears at the loss of another animal, or simply the display sadness/other emotions at the loss/separation.Smallman12q (talk) 20:06, 22 August 2010 (UTC)[reply]

Mostly the first one, I'm asking whether any animals shed tears during a display of sadness at the loss of another animal of a different species. ~A H 1^(TCU) 20:37, 22 August 2010 (UTC)[reply]

This little piece seems to rule out other primates. Sean.hoyland - talk 13:56, 23 August 2010 (UTC)[reply]

I was listening to a PBS story about emotional expression on the radio this morning -- the reporter said that humans are the only animal that sheds tears. Looie496 (talk) 15:48, 23 August 2010 (UTC)[reply]

...for emotional reasons, yes. But tears lubricate the eye and eyelids - and they can form for other reasons (allergies, for example). So I'm sure there are a wide range of animals that "shed tears" - but I could well believe that only humans do it for emotional reasons. The example of Koko the gorilla (see above) shows that one of the closest animals to humans doesn't produce tears even when they are expressing the precise emotion and vocalization that humans produce. Unless chimps are known to cry - that's a pretty sure reason to believe that other animals don't do that. SteveBaker (talk) 22:33, 23 August 2010 (UTC)[reply]

Contact lenses

How can I tell if someone is wearing contact lenses, preferably without staring them in the eye for extended periods. Asking them in this context would be too personal and impolite, but I'm curious. 76.228.196.92 (talk) 20:10, 22 August 2010 (UTC)[reply]

You probably cannot. Contact lenses are pretty discreet and unnoticeable, even if you were to stare the person straight in the eyes for extended periods. Why not just ask them? It's not a particularly impolite question. And, with this individual, you must at least have a suspicion that they wear contacts. (64.252.34.115 (talk) 22:46, 22 August 2010 (UTC))[reply]

If you are ever sitting beside the person, this would be the best angle to try see from ihmo. I've spotted people with contacts more then a few times from this angle, in particular if you sit next to someone on a train or bus and they are looking forward. Usually the contact lens isn't perfectly fitted to the cornea and you can see the edge of the contact lens on the surface of the eye. Vespine (talk) 03:54, 23 August 2010 (UTC)[reply]

Thistle varieties that spread by root

What varieties of thistle (particularly those known in the Pacific Northwest) are spread by rhizomes or root pieces? I know that Canada Thistle is but that fortunately does not appear to be the more prevalent of the multiple thistle types we are now seeing in our pastures and fields. I simply don't have the time to go down the whole list of thistle varieties and check through multiple references for each to see. Help would be much appreciated. —Preceding unsigned comment added by Crwind (talk • contribs) 20:59, 22 August 2010 (UTC)[reply]

This says "Extensive rhizomes of Canada thistle make it unique among the thistles." - are you certain that they aren't Cirsium arvense? If you could take a photo and upload it here or elsewhere then someone will probably be able to help. Smartse (talk) 11:45, 23 August 2010(UTC)

Carduus nutans and C. acanthoides are invasive species that can easily overtake pastures. They do not spread by rhizome as far as I know.

what kind of spiders?

What kind of spiders are these? They seem to be known here as banana spiders, but they don't seem to match. Bubba73 ^{(You talkin' to me?)}, 21:05, 22 August 2010 (UTC)[reply]

~~: The images are not showing up for me. Click on the box and then Full Resolution. Bubba73 ^{(You talkin' to me?)}, 21:12, 22 August 2010 (UTC)~~[reply]

The first one appears to be a female Argiope aurantia. Deor (talk) 21:44, 22 August 2010 (UTC)[reply]

And although one can't really see the markings on the second one very well, the distinctive zigzag stabilimentum in the web suggests that the second photo is of a female Argiope aurantia as well. Deor (talk) 03:10, 23 August 2010 (UTC)[reply]

Yes, they were 15-20 feet from each other, so they were probably the same species (and the leg markings look the same). Bubba73 ^{(You talkin' to me?)}, 03:13, 23 August 2010 (UTC)[reply]

Where are they located? What country or region of a country? Googlemeister (talk) 12:59, 23 August 2010 (UTC)[reply]

Bubba's user page says that he lives in Georgia (U.S.A.), so I assumed that the spiders also lived there. Deor (talk) 13:17, 23 August 2010 (UTC)[reply]

Yes, they were making their webs on the outside of a house in coastal Georgia (U.S. state). Bubba73 ^{(You talkin' to me?)}, 14:19, 23 August 2010 (UTC)[reply]

What's in between the dunes?

So, looking at the featured image of the day for August 22, between the sand dunes there's a large quantity of flat-looking gray/white/blue stuff. It looks to me like the surface of a frozen-over lake, or possibly a sky reflection. I don't think either of those makes sense, so what is it? Are there a lot of salt flats in that area, maybe? The NASA page the image came from doesn't give an explanation. --Anonymous, 21:52 UTC, August 22, 2010.

best guess is that this is a mirage - a reflection of the sky in trace amounts of water vapor boiling out of the sands and gathering in the troughs between dunes. notice how the effect gradually gets stronger towards the lower right (pretty much what you'd expect to see in a reflection with changing angles of incidences of sunlight). --Ludwigs2 22:07, 22 August 2010 (UTC)[reply]

The second picture in the Rub' al Khali article appears to show the same feature and is referred to as a "pale gravel plain", which would be a deflation surface covered with rock clasts too big to transport by wind, see Aeolian processes. Mikenorton (talk) 22:10, 22 August 2010 (UTC)[reply]

According to the description on Wikipedia: "The image, acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard NASA's Terra satellite, shows dunes as brown with gray regions being the underlying gravel plains." ~A H 1^(TCU) 22:38, 22 August 2010 (UTC)[reply]

Here's a close-up of those "gravel plains" from another angle -- I wonder if a better description might not really be "salt flats" though -- anyway, not a mirage. Wikiscient (talk) 03:08, 23 August 2010 (UTC)[reply]

Not a salt flat, unlikely these areas get wet at all, they really will be flat areas covered in gravel. Mikenorton (talk) 07:09, 23 August 2010 (UTC)[reply]

<- It's a bit hard to tell because it's unclear what we're looking at in terms of ASTER bands in the satellite image. For example, apparently clay and silt rich areas have high reflectance in band 1 (0.520–0.600 µm wavelengths = visible green/yellow) and look blueish. Sean.hoyland - talk 07:33, 23 August 2010 (UTC)[reply]

Originally the Rub' al Khali area was covered in coarse alluvial deposits. When the climate turned arid, aeolian processes took over, reworking all of the finer sediment from the alluvial deposits (mainly sand) into dunes, leaving behind only that which the wind cannot move, gravel and coarser material. However, some ephemeral lake deposits are described in interdune areas, with white calcite-rich layers and some finely stratified silts and clays (but no salt)[8]. Mikenorton (talk) 16:35, 23 August 2010 (UTC)[reply]

Thanks. --Anon, 19:15 UTC, August 23, 2010.

Desert pavement?- Jarry1250 ^{[Humorous? Discuss.]} 21:19, 23 August 2010 (UTC)[reply]

Yes that's the term that I'd forgotten, and I've added a picture from the Rub' al Khali of just that. Mikenorton (talk) 11:29, 24 August 2010 (UTC)[reply]

What's the scale of that NASA image? Would one be able to make out an individual camel for instance? SpinningSpark 15:59, 20 September 2010 (UTC)[reply]

Unknown special character

Saw this double-arrow, inequality-like character here (p. 69 and forth), but can't figure out how to render in wiki (digged through Wikipedia:Math#Arrows, Wikipedia:Math#Logic and Template:Unicode chart Arrows, but found nothing like that). Copying from pdf doesn't help either. Twilightchill t 22:33, 22 August 2010 (UTC)[reply]

It's in Table 96 of this list of characters and is a form of 'very much greater than', I think. Mikenorton (talk) 22:49, 22 August 2010 (UTC)[reply]

A single arrow means greater than. (When turned 180 degrees it means less than.) The double arrow means much greater than. (When turned 180 degrees it means much less than.) Dolphin (t) 01:01, 23 August 2010 (UTC)[reply]

Copy it from here: Unicode mathematical operators and symbols. Ariel. (talk) 01:48, 23 August 2010 (UTC)[reply]

August 23

Wipe chimenea with "oily rag"

The instructions that came with my cast iron chimenea and advice found on the Internet suggests wiping the chimenea with an oily rag to prevent surface rust. These sources neglect to mention what type(s) of oil is acceptable. What type(s) of oil is acceptable? ----Seans Potato Business 01:23, 23 August 2010 (UTC)[reply]

Any oil will stop the rust, but I would use Mineral Oil, also called Baby Oil. Organic oils will decompose or oxidize, especially with heat. You can also use tool oil, basically any oil from the hardware store. Fresh (new) motor oil is also good since it's specially made to resist heat. Ariel. (talk) 01:51, 23 August 2010 (UTC)[reply]

Best wavelengths for interstellar communication

Which electromagnetic radiation frequency band that can be focused directionally has the lowest combination of background power and opacity in interstellar and interplanetary space? 208.54.5.76 (talk) 08:09, 23 August 2010 (UTC)[reply]

From 1420 to 1666MHz. See Waterhole (radio) - that's where SETI are putting most of their efforts. SteveBaker (talk) 22:27, 23 August 2010 (UTC)[reply]

Study of anti-HIV drugs, where there was little evidence of effect as the drugs became widely used by everyone before the trial finished

Hi, I'm looking for a study I read once before that looked at a drug to treat HIV, but before the trial could be completed the drugs became widely used by everyone (being purchased off the internet I think?) and so in the analysis there was little evidence of their effect as they were being compared to controls who also had access to the drug. Can anyone help me find it again please? Thank you. Last Polar Bear (talk) 10:20, 23 August 2010 (UTC)[reply]

I asked a relative of mine who is a pharmacokineticist and the only drug that comes to mind is AZT (zidovudine). He says it was on Glaxo's shelves for quite some time since it was being used to treat other ailments. That was back in the late '80s. Hope this helps... Dismas|^(talk) 23:40, 23 August 2010 (UTC)[reply]

Redox confusion

This paper discussing the enzymes of Phanerochaete chrysosporium has a sentence which states "Cellobiose is oxidised by two electrons for the reduction of a wide range of electron acceptors". How can something be oxidised by electrons, when oxidation is the loss of electrons?! Thanks in advance. Smartse (talk) 11:31, 23 August 2010 (UTC)[reply]

They don't specify that those electrons are gained. Maybe they mean that it is oxidized by the loss of those two electrons. —Preceding unsigned comment added by 96.227.210.71 (talk) 11:35, 23 August 2010 (UTC)[reply]

It's a common "shorthand" way of saying things: in redox reactions, electrons are the "currency", so "oxidized by two electrons" doesn't mean the electrons were the oxidizing agent, it means that the molecule lost two electrons (and not one or three). Physchim62 (talk) 23:47, 23 August 2010 (UTC)[reply]

Species

When a new species is discovered, do they still give them a latin name? Why, hasn't latin be depreciated? 82.44.54.25 (talk) 13:05, 23 August 2010 (UTC)[reply]

Yes, a new species will be given a two-part Latinized name - this is called binomial nomenclature. This is a convention that is practical, useful and well understood by biologists and other scientists. Many fields of study and human interest have created their own terminology - biology happens to have developed a richer and more structured nomenclature than, say, wine-tasting or baseball, possibly because it has more things to name. Why do you think this system should be "depreciated" (or perhaps you mean "deprecated") ? What would you replace it with ? Gandalf61 (talk) 13:18, 23 August 2010 (UTC)[reply]

The OP thought that Latin wasn't used anymore and wonders why it is still used in binomial nonclemature. --Chemicalinterest (talk) 13:26, 23 August 2010 (UTC)[reply]

Occasionally it's not Latin e.g. Proceratium google. Sean.hoyland - talk 13:31, 23 August 2010 (UTC)[reply]

Apparently it is permissible to call an insect "Google" but not "eBay"[9]. Alansplodge (talk) 16:13, 23 August 2010 (UTC)[reply]

It's of note that the entire point of using Latin was always that Latin was not much of a "living language" — because it didn't change regularly, it could be relied upon by people who spokes lots of different languages to be a "universal language". Of course, in practice anything that gets used probably "lives" a bit. But the point is still a nice one: use nobody's language when you mean something to be equally understandable in everybody's language. --Mr.98 (talk) 13:50, 23 August 2010 (UTC)[reply]

For the same reason, Switzerland uses the Latin form of its name on its stamps (see picture); it's far easier to use just "Helvetia" than inscribing the stamp "Suisse Schweiz Svizzera Svizra". They've issued a few stamps in modern times with significant amounts of text, but (if I remember rightly) in such cases they'll generally issue several different stamps with no differences except the language of the inscription. Nyttend (talk) 12:11, 24 August 2010 (UTC)[reply]

Key gets tight in lock

I have a lock that worked well. After I transferred it to another door, the key suddenly became very tight in the lock. It is very hard to push the key in. What could be causing this? --Chemicalinterest (talk) 14:10, 23 August 2010 (UTC)[reply]

When the key is hard to push into a lock, this can usually be solved simply by lubrication. Perhaps the process of transferring the lock from one door to another caused a slight change in alignment of the internal parts, leading to a higher-friction arrangement. A little graphite should fix the problem. Dry hem (talk) 14:25, 23 August 2010 (UTC)[reply]

Maybe you overtightened it? Or maybe the lock is slightly miss-aligned in the new lock, perhaps the hole for it is not as large or in the right place? Ariel. (talk) 18:38, 23 August 2010 (UTC)[reply]

I did some analysis on the lock (it is a keyed entry) and one of the pins inside seem to be bent. I just threw away the lock because I do not think that the pin can be adequately unbent. Thanks for the hints though. --Chemicalinterest (talk) 20:17, 23 August 2010 (UTC)[reply]

Sunny side condensation

I park my car every night outdoors in my driveway. On days that are dewy in the morning, there is often condensation on my car's windows, but rarely on all of them. In fact, the condensation is usually only on the windows that face the morning sun. Although the sun is not warm and bright in the morning hours, shouldn't those windows be the warmest ones, and therefore the ones with least amount of condensation? Dry hem (talk) 14:25, 23 August 2010 (UTC)[reply]

My guess is that the sun evaporates more dew from surrounding objects than the shade does, creating a sort of supersaturated atmosphere which readily condenses on the car windows. Where the sun doesn't shine the water doesn't evaporate so there is not as much condensation. Only a guess though. --Chemicalinterest (talk) 16:03, 23 August 2010 (UTC)[reply]

Is the condensation on the outside or the inside of the windows? 87.81.230.195 (talk) 16:37, 23 August 2010 (UTC)[reply]

The condensation is on the outside. Dry hem (talk) 15:35, 24 August 2010 (UTC)[reply]

Water condenses on cold surfaces - it seems more likely to me that the water is condensing onto the windows the previous night - so the side of the car that the sun set on (the West) stayed warmer for longer and the water therefore condensed on the Eastern side of the car where the window got coldest, soonest. Since the sun rises in the East - you'd see the condensation on the side of the car nearest the sunrise the following morning. SteveBaker (talk) 22:22, 23 August 2010 (UTC)[reply]

The car is generally in the shade late in the day, so the two sides of the car should start the night at about the same temperature. Dry hem (talk) 15:35, 24 August 2010 (UTC)[reply]

The sun could be a red herring. It could have to do with air-flow. If you park your car somewhere where a fog regularly rolls in from the east, you'd expect to see that pattern. Happened all the time in the house where I grew up, surfaces that faced the marsh would be covered in dew, but surfaces that faced away wouldn't be. APL (talk) 02:27, 24 August 2010 (UTC)[reply]

I'm not sure exactly which way the wind tends to come from, but this answer is (at the very least) consistent with my observations. Dry hem (talk) 15:35, 24 August 2010 (UTC)[reply]

Abiogenesis and RNA

So I understand that RNA could possibly form on its own due to crystalization of salt water bringing nucleic acid bases together, and these polymerize into RNA. But how did the nucleic acid bases like Uracil, Guamine, etc form in the first place? I know how Amino Acids, and peptides can form naturally. Are they related? 148.168.127.10 (talk) 14:23, 23 August 2010 (UTC)[reply]

The abiogenesis article talks about the possible origins of nucleotides (search for "uracil" and others in that article). The RNA world hypothesis, the specific type of abiogenesis you mention, has more details about the issue and difficulties in original-sourcing. One recurring comment I see is that "the nucleic acid bases like Uracil, Guamine, etc" are just the components of RNA as we know them today, but the same ideas could be applied to alternative bases. To answer your final comment: no, nucleotides and amino acids are not structurally related. They chemically interact and one can encode another in certain situations, but the compounds themselves are drastically different from each other. DMacks (talk) 15:50, 23 August 2010 (UTC)[reply]

Yeah, I checked those articles before, but I couldn't find anything. The RNA article does state, "Since there were no known chemical pathways for the abiogenic synthesis of nucleotides from pyrimidine nucleobases cytosine and uracil under prebiotic conditions, it is thought by some that nucleic acids did not contain these nucleobases seen in life's nucleic acids." So is the formation of nucleic acids bases currently unknown?

No, I didn't mean if they were structurally related, I was wondering if amino acids could have led to the formation of nucleic acids or if they are unrelated. I don't know if I'm phrasing this correctly... I know that amino acids can lead to the formation of peptides, and eventually protiens. I want to know if they can also lead to the formation of nucleic acid bases found in RNA. 148.168.127.10 (talk) 17:15, 23 August 2010 (UTC)[reply]

None of the "origin of life" experiments actually develops working enzymes - if they ever do, you'll hear researchers trumpeting to the heavens that they've evolved "life" in a test tube. Without catalysis, an amino acid is one compound and a nucleic acid is another, and they're not the same. They are all similar - carbon, nitrogen, oxygen, hydrogen, with a dash of sulfur or phosphorus for specific compounds.

Purely as a matter of speculation, I once devised a rather elaborate scheme by which I hypothesized that RNA chains might once have been converted directly into proteins by a splicing-like process. This was based on the modern (and universal) pathway of biosynthesis of histidine and tryptophan from PRPP. But it's far too elaborate to go into here. Wnt (talk) 18:12, 23 August 2010 (UTC)[reply]

Human feeding

How rarely can a human be fed and still remain alive? Let's use a healthy young adult with no health issues, who's not overweight or underweight, is not pregnant, etc. If this human is given one hour every week to eat as much food as she wants, can she stay alive? How about one hour every two weeks? What are the health issues associated with such intermittent feeding?

This question stems from a story I read where a girl was held captive and fed only once every week, and managed to live quite a while. I was skeptical as to whether this was possible. --121.29.125.172 (talk) 14:40, 23 August 2010 (UTC)[reply]

Assuming you need 1,000 food calories a day to survive, then you would need to eat 7,000 food calories in one meal to maintain the minimal standard. Very, very few humans would be able to consume that amount of food (equal to 13 Big Mac hamburgers). One could I suppose try to eat 2 pounds of butter to meet pure calorie needs, but then they would not get any of their other nutrients. You also need to consider that some nutrients can not be stored in the body, like vitamin C. So knowing this, I would say that it is not possible to survive long term on this feeding schedule. It will make a person utterly miserable, and while it might make them starve to death slower, it would still not be sustainable. Googlemeister (talk) 16:16, 23 August 2010 (UTC)[reply]

If you made a vitamin fortified brownie and could eat 2kg of them in an hour according to this you'd get 8,000 calories, you'd probably be sick though! It's important to bear in mind that the stomach shrinks when you don't eat, so if you went a week without eating, you'd be able to eat less than if you only went a day. Smartse (talk) 16:30, 23 August 2010 (UTC)[reply]

Big bag of chips, large can of cashews, container of string cheese... I don't think it's hard for some people to reach 7000 calories. But I think most extraordinary claims involving food come down to semantics. You typically end up finding out that "a little juice" or some stale bread or something was left out of the original count. Wnt (talk) 17:22, 23 August 2010 (UTC)[reply]

You don't necessarily need 1000 calories per day to stay alive for months or years of slow starvation. Elizabeth Hughes (edited to direct to the name used in the Wikipedia article) was diagnosed with Type 1 diabetes before the invention of insulin, and was put on a slow starvation diet which kept her from dieing of diabetic ketoacidosis or other organ damage from high blood sugar. Per "The fight to survive, (Cox, 2009)" she started at 14 years of age and 75 pounds in the fall of 1918, and slowly dropped to 45 pounds and the brink of death by the summer of 1922 when insulin became available. She was fed an average of 400 calories a day for very extended periods. The body digests fat and then muscle. Victims of Nazi slave labor camps, prisoners of war held by the Japanese in WW2, and prisoners in Soviet gulags were worked to death similarly and made to use up their bodies' stores. Old-time diabetics, COPD or cancer patients similarly wasted away on deficient calories. Accounts of persons rescued from vile captivity show concern by doctors not to suddenly feed them big meals, although Miss Hughes was immediately given 1100 to 1200 for ten days, then quickly advanced to 2500 calories per day, and more than doubled her weight in a few months. A starved animal, suddenly given unlimited food, often gulps down a lot and throws up. In the hypothetical story, reduced stomach volume might be a problem, If the person could fill the stomach with water on starvation days, I wonder if that would allow him to fill it with food on binge day? Edison (talk) 19:09, 23 August 2010 (UTC)[reply]

Her article is at Elizabeth Hughes Gossett, it has little details though. Ariel. (talk) 20:02, 23 August 2010 (UTC)[reply]

It is great to note that she had a long and presumable happy and fulfilling life after insulin became available and she could actually eat food. Edison (talk) 02:30, 24 August 2010 (UTC)[reply]

It's not so much the underfeeding as the intermittent feeding that you're wondering about, right? There's an article on "refeeding syndrome" which says: "significant risks arising from refeeding syndrome include confusion, coma, convulsions, and death." So it doesn't sound like being able to eat only one hour every week would be very healthy. I don't know if the exact limits of that sort of thing have ever been experimentally determined, but something like it seems to have been done in the Minnesota Starvation Experiment. Wikiscient (talk) 17:54, 23 August 2010 (UTC)[reply]

Re-feeding only happens if someone was starved previously. I think the 1000 calorie minimum food number is incorrect though. If someone is very passive and moves little, I think the minimum number is much lower than this. This talks about 800 a day - including exercise! I could not find a direct ref, but based on the holocaust I think the minimum is closer to 300, (500 including activity). So if your prisoner got 2100 calories in this weekly meal they could live for a very long time, assuming they rested almost constantly. Ariel. (talk) 18:54, 23 August 2010 (UTC)[reply]

A 470 g pizza might have 1200 calories, and two cans of Coca Cola would be 310. Add a banana split at DQ with 510 calories, and you have 2020 calories in one meal of a size that many gourmands have eaten and lived. One such treat per week would average 289 calories per day, still less than Miss Hughes (cited above) got over a period of 4 years or so of the old diabetes starvation diet. I can't picture eating a bigger meal than that if I had gone all week with an empty stomach. Even if one started as a 75 pound girl, and even if one could keep down all the food and digest it efficiently, it would be less calories than the slow starvation diabetic diet provided to Miss Hughes in 1919-1922. If an antinausea drug prevented regurgitation, and a feeding tube were stuck down the throat into the stomach, maybe a high calories food could be used to quickly fill the stomach. The max volume and the max nutrient content would be helpful information. Edison (talk) 19:26, 23 August 2010 (UTC)[reply]

But the OP wanted to know about the case where "this human is given one hour every week to eat as much food as she wants". The problem here is going to be refeeding syndrome as I posted above. So it's not about the average caloric intake over the course of that week, and it's not about stomach shrinkage either so much as about suddenly shifting out of the "starvation mode" of metabolism as described in refeeding syndrome#syndrome. The caloric content of that one meal a week might be enough to keep her alive for a week, but its ingestion will lead to serious physiological complications every week, too. That can't be healthy, but it's probably not known exactly how much of a process like that would kill a subject. Wikiscient (talk) 20:11, 23 August 2010 (UTC)[reply]

You would have more trouble without water than without food. Human body stores fat to use as energy source to survive with no food, and I believe that when the fat is gone other tissue also can be used. Some people acctualy don't eat for extended periods of time on purpose, you may want to research them - I once read one such persons claim that her record of not eating was 29 days in a row. Eating once a week sounds pretty realistic to me, especialy if one gets to eat as much as they want, I don't think one week is enough to cause so severe malnorishment that it would cause refeeding syndrome. Also on avarage recomended diet is 2000 calories a day (varies depending on gender, lifestyle and if you are overwight or not). However there may be a diffrence between how long one can willingly survive without food and not being fed in captivity as a prisoner will also have to cope with stress and possible abuse ~~Xil (talk) 22:02, 23 August 2010 (UTC)[reply]

Well, the Starvation mode article does say: "People who practice fasting on a regular basis [...] can prime their bodies to abstain from food without burning lean tissue." So, I guess something like that would probably happen in this case, too, and so there probably would not be a refeeding syndrome issue as I figured above there would be. :S Wikiscient (talk) 22:27, 23 August 2010 (UTC)[reply]

Nobody has mentioned the issue I was thinking of: can the digestive system absorb an arbitrary amount of nutrients in the time that a meal takes to pass through it? If somebody eats a huge meal with 2200 calories' worth of food, how much of it would be absorbed compared with, say, if the 2200 calories were spread out over 7 days?

An additional question: would this intermittent feeding achieve its goal of making the prisoner perpetually suffer hunger cramps, or at least severe discomfort? In the story, the point is to make the prisoner suffer, not to run a medical experiment. --121.29.115.22 (talk) 17:37, 24 August 2010 (UTC)[reply]

Can planets form and orbit around a white dwarf or neutron star?

Topic says it all. 148.168.127.10 (talk) 14:45, 23 August 2010 (UTC)[reply]

A white dwarf is the final remnant of a low-to-medium mass star that has exhausted its nuclear fuel supply, so it is as likely to have planets as any main sequence star, although any inner planets may not have survived if it passed through a red giant phase. A neutron star is the remains of a supernova event, so you would think it was unlikely to have any remaining planets; but, surprisingly, some neutron stars do have planets - see pulsar planet. Gandalf61 (talk) 14:58, 23 August 2010 (UTC)[reply]

I should have clarified this a bit better. Accretion disks form around white dwarfs and neutron stars (although I don't know if this is always the case). Now in our system, the planets were formed by the accretion disk surrounding the proto-star that later became our sun. Can the same thing happen in accretion disks surrounding white dwarfs/neutron stars or is that matter doomed to fall into the star? 148.168.127.10 (talk) 15:05, 23 August 2010 (UTC)[reply]

An isolated stellar remnant (e.g. white dwarf / neutron star) is unlikely to have an accretion disk as there is no new material to accrete, and all the original material was eliminated during the main sequence life of the star. In general, when we talk about an accretion disk for these objects it is usually because they exist in a binary system and are stealing material from a companion star. That kind of accretion disk would be dominated by hydrogen and helium, and be unlikely to contain enough heavy elements to form planets. Dragons flight (talk) 19:11, 23 August 2010 (UTC)[reply]

So we don't know of any white dwarf/neutron stars that have accretion disks without a larger companion star near by? 148.168.127.10 (talk) 20:12, 23 August 2010 (UTC)[reply]

I suspect that one could find some exceptional cases (e.g. neutron star fed by flying through a giant molecular cloud, or some such), but accretion from the interstellar medium is usually too inefficient to be appreciable. So, in general, you are only likely to have an observable accretion disk for a stellar remnant when it is being fed by a nearby companion. Dragons flight (talk) 23:54, 23 August 2010 (UTC)[reply]

tomatos

YEARS ago someone told me or maybe I saw a tv program that said that sewers have LOADS of tomato plants growing there, because of all the tomatos people eat the seeds end up at the sewers. Is this true? —Preceding unsigned comment added by Prize Winning Tomato (talk • contribs) 15:40, 23 August 2010 (UTC)[reply]

Very little light in sewers, therefore photosynthesis can't occur. Do trolls eat tomatoes? --Mark PEA (talk) 15:50, 23 August 2010 (UTC)[reply]

Go ahead, throw the food on the ground; the troll isn't there.--Chemicalinterest (talk) 16:01, 23 August 2010 (UTC)[reply]

What about open sewers? Also, I don't mean the pipes as such, I mean more wherever it all ends at like a treatment plant or whatever, where they clean the water. —Preceding unsigned comment added by Prize Winning Tomato (talk • contribs) 15:57, 23 August 2010 (UTC)[reply]

(edit conflict)According to this you are correct, but it doesn't make it clear where they are growing in the sewers. _{A lack of light didn't stop this pea growing.}Smartse (talk) 15:59, 23 August 2010 (UTC)[reply]

It says they aren't growing in the sewers, but at the treatment plant, where the sewage dries and is presumably exposed to the light. --Mr.98 (talk) 16:48, 23 August 2010 (UTC)[reply]

They do grow where the solids are exposed to the air and left static, but it would be unwise to eat any as sewage contains a lot of heavy metals. On the other hand it is sometimes used for agricultural fertilizer. I wonder how the solids are otherwise disposed of. 92.28.246.109 (talk) 21:51, 23 August 2010 (UTC)[reply]

More confirmation, again from Northern Ireland. --Tagishsimon (talk) 22:23, 23 August 2010 (UTC)[reply]

And a more scientific (and less recent) confirmation. This research found that using sewage sludge as fertiliser for tomato plants doesn't lead to higher levels of heavy metals. Smartse (talk) 23:57, 23 August 2010 (UTC)[reply]

Honey

Is it true honey doesn't go off? —Preceding unsigned comment added by Prize Winning Tomato (talk • contribs) 15:41, 23 August 2010 (UTC)[reply]

Bacteria won't grow in it. It can get moldy, though. Looie496 (talk) 15:53, 23 August 2010 (UTC)[reply]

Yes: Honey#Preservation. Moulds can only grow on top of it. Smartse (talk) 15:54, 23 August 2010 (UTC)[reply]

what's the (then) oldest honey anyone's eaten? 92.224.207.105 (talk) 18:05, 23 August 2010 (UTC)[reply]

Very old. Some honey was found in an Egyptian tomb, and the explorer tasted it. (Most of the refs are from hone-health sites, I didn't find any original sources of this.) Ariel. (talk) 18:59, 23 August 2010 (UTC)[reply]

This newspaper claims that honey from 1400 B.C. is kept in the Agricultural Museum in Cairo, but it is doubtful anyone has recently eaten from it! Nimur (talk) 20:44, 23 August 2010 (UTC)[reply]

A couple questions for a sci-fi world

I'm starting up a campaign for an rpg, so I'm only really looking for approximate answers. The first question being-If a colony ship landed on a planet and it was of a homogeneous group (IE all white/black/asian) and they spread out over a planet similar to earth, how long would it take before they broke up into different races? Are we talking 100s of years, 1000s or 10s of thousands? The second question, is I'm wondering what sort of effect having year long days would have on plant life. The planet I'm thinking of making would have very little spin, so it would be the travelling around its sun that made the day change into a very long, cold night, making most of the population migrate with the dawn/dusk to avoid the really harsh climates. Would plants (as we know them at least) respond well to the year of light, or would it be too brutal for them to grow? I'm also thinking of having eclipses of the sun with the moons bringing storms and such. Realistic?

Thanks for any help 68.149.151.242 (talk) 16:43, 23 August 2010 (UTC)[reply]

Answering each separately:

Racialisation: The degree to which different populations diverge is a function of how richly they interact with one another. If your colonists quickly spread across the new world and then (perhaps due to some catastrophe) lose the capacity to travel long distances, you're back to the the condition of pre-historic humans. Mitochondrial Eve lived as recently as 45,000 years ago, so you get at least as much diversity as humans now exhibit from separation of that time (if your fantastic planet is more restrictive of motion, probably you'd get a bit more diversity sooner). If, on the other hand, the colonists retain the technological civilisation they arrived with, and can travel with aircraft etc. then it's quite credible that there would be much less diversity (more of a kind of spread of a single continuous population). If you want to justify diversity, you'd want a) major barriers to intermixing, like oceans, mountains, deserts and b) environmental diversity (really cold places, really hot places, etc.) - modern humans are (rather badly) adapted to the different climates to which they're indigenous. If you want much more diversity (aqua-men, flying-women, volcano-livers, desert burrowers) then you'll need a radically more varied landscape (super-tall mountains, super-deep dry valleys, giant forests, voids under glaciers full of life) and 10 to 1000 times as long. But it's SF, so you can fudge evolution away altogether - they racialised, or even speciated, deliberately, using genetic technology (perhaps now lost). See pantropy for this. Frankly if I was playing an SF game and the only differences between the tribes of people was trivia like skin colour and eye shape, I'd be pretty disappointed. Mer-men fighting the arborial sloth women - now that's fiction.
Plants: the situation to describe is very similar to what plants in the high arctic have to endure right now (maybe 3 months of constant sunlight, six months of twilight, and three months of near total darkness). Brian Aldiss' Heliconia novels describe a planet which has hugely long (millenia) seasons, so that might interest you.
Eclipses: eclipses on Earth are rare and mostly inconsequential because Earth has one moon, which is small enough and far enough away to barely cover the Sun (and Earth's moon is really very big compared with those of other planets), and because it rotates around the earth on a plane that isn't the ecliptic. If you want eclipses to be more than an occasional novelty, you need one or several moons on the ecliptic and ideally subtending a much bigger angle in the sky than the sun does. That means they're either much closer or much bigger than Luna; I suspect you'd get more fun out of the wacky tides this would cause than the storms. Some (very unrealistic) science fiction puts small moons in the atmosphere (the moons of Mongo in Flash Gordon) which means they can (with difficulty) be travelled to. In reality this would have devastating environmental effects, but you can always say "it's that way because some ancient technology (tractor beams, whatever) makes it so".

But frankly planets are for squares. If you want real diversity, and a milieu that's not just "20th Century California in Space", get yourself a Dyson swarm and the worlds are your oyster. -- Finlay McWalter ☻ Talk 17:22, 23 August 2010 (UTC)[reply]

For the first, I'd guess more than tens of thousands of years, and even more if it's a modern (mobile and intermixing) society.

For the plants, the year of dark might be a bigger problem, depending on what you're doing with temperature. Sci-fi or fantasy, though, this is an area where you can do some handwaving and move on. Plants are very hardy, or hibernate well, or they're giant colonial organisms and survive by covering both dayside and nightside, or whatever. On the surface, however, this sort of Mercury scenario rules out recognizable megaflora.

For eclipses, not realistic at all. Eclipses have no effect on Earth's weather, and the rigors of orbital mechanics mean that Earth eclipses are a very good projection for eclipses generally. However, you might pull off something like Io and its interactions with Jupiter's magnetosphere. — Lomn 17:26, 23 August 2010 (UTC)[reply]

Races are social constructs, and can arise (and be persecuted) very quickly. See Burakumin. Or consider American myths/prejudices about blondes, brunettes, and redheads. There is no predetermined amount of difference that makes a geographic or caste variant of humans distinguishable by cultural prejudices.

If you want a physically distinct race, then consider that the differences between current races represent roughly 10,000-100,000 years of largely random change, though certain features such as skin pigmentation and stature were also clearly influenced by sun and cold exposure. This rate doubtless can be sped up drastically if the environmental circumstances are severe and differ between your regions to force rapid selection. Note that natural selection doesn't actually have to mean death, if people can freely migrate between regions and choose the one best suited to them; the traits simply have to be removed from local populations by some means. Likewise a racist regime would have a major impact, if they send brunettes to the Camps and blondes to the Breeding Pits (or vice versa, depending on the Führer's tastes). Wnt (talk) 17:38, 23 August 2010 (UTC)[reply]

Regarding races, note that the colonization of the Americas is thought to have occurred on the order of 15,000 years ago, pretty much everywhere at once, and there has been pretty minimal racial divergence since then. So I would say tens of thousands of years. Looie496 (talk) 01:04, 24 August 2010 (UTC)[reply]

Ah, that brings up another point: genetic diversity. Native Americans have been said to have originated from a very small number of Asian founders (though I doubt that all of the peoples of the Americas have been properly studied...) The lack of initial genetic diversity makes it harder to create new racial characteristics by genetic drift or selection from a pool of ancestral traits. Note however that race is cultural: as noted in Human genetic variation, sub-Saharan Africa, where humanity began, has the greatest phenotypic variation; and Africa as a whole is the one continent with all three of the main genetic subdivisions of humanity - yet in many societies there is very little sense of distinction made between any of these people. I would even go so far (too far, expert opinion would say) as to speculate that the next human species may already have evolved there, like so many before it, and awaits only the opportunity to escape from persecution to the shaping rigors of interstellar travel... Wnt (talk) 05:30, 24 August 2010 (UTC)[reply]

Libellula

Are these two dragonflies Libellula pulchella or Libellula forensis (or perhaps some other Libellula species)? Thanks, --The High Fin Sperm Whale 16:49, 23 August 2010 (UTC)[reply]

Looks like male L. forensis to me. Almost certainly not L. pulchella or Plathemis lydia. --Dr Dima (talk) 17:21, 23 August 2010 (UTC)[reply]

Galilean moons

Are all the Galilean moons tidally locked with Jupiter? Are there any of the large moons (say 1,500km diameter or larger) not tidally locked with their planet? Googlemeister (talk) 18:50, 23 August 2010 (UTC)[reply]

1. Yes, 2. No. There is a detailed list and discussion in Tidal locking. --Dr Dima (talk) 19:36, 23 August 2010 (UTC)[reply]

What bug is it?

File:Critter 09.JPG

The critter from Hawaii

Could anyone tell me the name of the critter I saw in the picture? It was very peculiar looking.Smallman12q (talk) 22:25, 23 August 2010 (UTC)[reply]

Looks like an Earwig. -- Finlay McWalter ☻ Talk 22:29, 23 August 2010 (UTC)[reply]

Ye that looks right...thanks!Smallman12q (talk) 22:43, 23 August 2010 (UTC)[reply]

Which of the 1,800 species though? Smartse (talk) 23:44, 23 August 2010 (UTC)[reply]

Try posting it on What's That Bug?. Richard Avery (talk) 07:12, 24 August 2010 (UTC)[reply]

Maybe no need for that, "hawaii earwig" in google brings up this page about the imaginatively named black earwig (Chelisoches morio) which looks very similar. Smartse (talk) 12:56, 24 August 2010 (UTC)[reply]

August 24

What kind of lizard is this?

I found this little guy last Friday while looking at ghost towns in Juab County, Utah. Its environment is desert, if that helps any. I saw the same species of lizard on Antelope Island last May. The Raptor ^{You rang?}/_{My mistakes; I mean, er, contributions} 00:14, 24 August 2010 (UTC)[reply]

My guess is the Lesser Earless Lizard (Holbrookia maculata) who lost part of its tail. ---Sluzzelin talk 00:19, 24 August 2010 (UTC)[reply]

Completing my physics education

I'm enrolled in a physics undergrad program program in a Quebec university, which means that my program is three years instead of four years. The reason is that we have a CEGEP-system; that is, high school ends a year earlier and university starts a year later, with a two-year CEGEP thing in the middle. Now, normally this wouldn't be a problem, except that I took a total of three physics courses during my stint at CEGEP. And they were baby courses to begin with (classical mechanics without calculus, waves without the wave equation, etc.) I'm a little worried about the quality of my education, and that I will be behind those students who've had a four year education, so I've decided that I'll do some self-study to fill in the gaps. Here's my program schedule:

U1 Required Courses

(27 credits)

MATH 247 (3) Honours Applied Linear Algebra

MATH 248 (3) Honours Advanced Calculus

MATH 249 (3) Honours Complex Variables

MATH 325 (3) Honours Ordinary Differential Equations

PHYS 241 (3) Signal Processing

PHYS 251 (3) Honours Classical Mechanics 1

PHYS 257 (3) Experimental Methods 1

PHYS 258 (3) Experimental Methods 2

PHYS 260 (3) Modern Physics and Relativity

U2 Required Courses

(24 credits)

MATH 375 (3) Honours Partial Differential Equations

PHYS 253 (3) Thermal Physics

PHYS 350 (3) Honours Electricity and Magnetism

PHYS 357 (3) Honours Quantum Physics 1

PHYS 359 (3) Honours Laboratory in Modern Physics 1

PHYS 362 (3) Statistical Mechanics

PHYS 451 (3) Honours Classical Mechanics 2

PHYS 457 (3) Honours Quantum Physics 2

U3 Required Courses

(6 credits)

PHYS 551 (3) Quantum Theory

PHYS 352 (3) Honours Electromagnetic Waves

U3 Complementary Courses

(21 credits)

6 credits selected from:

PHYS 459D1 (3) Honours Research Thesis

and PHYS 459D2 (3) Honours Research Thesis

PHYS 469 (3) Honours Laboratory in Modern Physics 2

PHYS 479 (3) Honours Research Project

15 credits selected from:

PHYS 332 (3) Physics of Fluids

PHYS 434 (3) Optics

PHYS 479 (3) Honours Research Project

PHYS 514 (3) General Relativity

PHYS 521 (3) Astrophysics

PHYS 557 (3) Nuclear Physics

PHYS 558 (3) Solid State Physics

PHYS 559 (3) Advanced Statistical Mechanics

PHYS 562 (3) Electromagnetic Theory

PHYS 567 (3) Particle Physics

PHYS 580 (3) Introduction to String Theory

What texts would you recommend I look into? Thanks. (And if you're really generous, what complementary courses should I take in the third year?)76.68.247.183 (talk) 00:25, 24 August 2010 (UTC)[reply]

I'm somewhat unclear on what the question is. Are you currently starting the programs of courses outlined above and looking for advice on how to further supplement that on your own? Dragons flight (talk) 00:37, 24 August 2010 (UTC)[reply]

Yes exactly, sorry for being unclear. 76.68.247.183 (talk) 01:05, 24 August 2010 (UTC)[reply]

I would definitely call up the university and see if they can put you in touch with one of their advisors. What you are asking is very detailed and depends on a detailed knowledge of the unusual course you've done and the precise syllabus are pre-reqs of one you are going into - and the odds are slim that we'll be able to get you an answer that's any better than guessing. SteveBaker (talk) 00:43, 24 August 2010 (UTC)[reply]

That's too bad, but thanks anyhow. 76.68.247.183 (talk) 01:05, 24 August 2010 (UTC)[reply]

My advice, if you have time to spare for something like this, is to contact a lab that does something you are interested in and see if you can volunteer, or even get hired, as an undergraduate assistant. Practical research experience is worth ten times as much as studying. Looie496 (talk) 00:54, 24 August 2010 (UTC)[reply]

Thanks for the suggestion, I'll look into it. 76.68.247.183 (talk) 01:05, 24 August 2010 (UTC)[reply]

In reply to Dragons field, I parse the situation to be that the OP is about to start this year's Honours Physics program at McGill. I think in the OP's position, I'd be concentrating all of my efforts on getting through the first year, about half of which is mathematics. Lack of prior physics tuition looks only to be a problem from year 2 onwards. Only the OP will know his or her areas of mathematical weakness, but for instance, right now, a decent book on calculus might be indicated. --Tagishsimon (talk) 00:56, 24 August 2010 (UTC)[reply]

I think my math is fine (Cals 1 through 3, linear algebra, and even an intro to differential equations). My general misgiving not that I am improperly prepared, but rather that I'll miss out on some of the physics that, although interesting, isn't absolutely necessary for, say, grad school (which is what this program is preparing for). 76.68.247.183 (talk) 01:13, 24 August 2010 (UTC)[reply]

(ec) That's not really the way it works. In a three year course in any of the sciences, the first two years try to cover the material which ever practitioner in that science (here, every physicist) should know: in the final year, you get to drop some of the bits you don't like and specialize a little bit (but nowhere near as much as you specialize in grad school). By the time you get to the third year, there will be some of those optional courses that you just don't want to take because the subject matter doesn't interest you – it's pointless asking yourself which ones at the moment, because you haven't yet been exposed to the physics at university level so you don't really know what's going to interest you in two year's time or not.

In my own case (I'm a chemist, but the principles are similar), I was certain (and my grades backed me up) that I didn't want to be an organic chemist, so I specialised in my final year in inorganic and theoretical chemistry, not in organic or physical chemistry: I then did my PhD in inorganic chemistry. That doesn't stop me editing organic chemistry articles on Wikipedia, because I know the basics, I'm just not a specialist in that field: I have to look things up that a specialist would know almost instinctively, but at least I understand them when I look them up! Physchim62 (talk) 14:59, 24 August 2010 (UTC)[reply]

I don't see anything significant missing from the physics coverage compared to what is typical at other grad school preparatory programs. I will note that Solid State is often a required course, and some grad schools assume you've taken it, so that is probably a good choice under the optional work. I do notice that there doesn't seem to be any requirement for statistics or computer programming, both of which are skills that are very valuable to many practicing physicists. For some specialties (e.g. particle physics, string theory, general relativity) it would also be useful to take additional math courses (e.g. Group Theory, Differential Geometry, etc.). If you goal is to learn practical everyday physics, then I would suggest that Fluids is quite valuable (as well as being useful for some experimentalists). However, people focusing on nuclear and particle physics do often skip Fluids with no real detriment. Personally, I like Astrophysics for its breadth and ability to consider a wide variety of unusual problems. On the other hand, I've seen people who consider Particle Physics to be a critical bit that every physicist should know even though most will never use it for anything. Ultimately, I'd suggest you base those U3 choices on what interests you at the time. This is especially true if you are thinking about grad school at that point and want to try out a topic area you are thinking of specializing in.

I would also like to second the comment by Looie. If you think you might want to go to grad school some day, then getting involved with research (even as only a part-time volunteer) is probably the best thing you can do for yourself. Physics is a rich discipline, and undergrad programs often tend to try to cover all of physics, but in doing so it is easy to miss skills that are important in the day to day life of many researchers. For example, computer programming, statistics, electrical / circuit engineering, etc. Working in a lab can help you learn the mindset of a scientist and pick up some of those skills that may not be part of the curriculum. If you are interested in grad school, then getting involved in research as an undergrad is probably the single best thing you could do improve your chances with top schools. Of course, some areas of research will only be accessible to advanced students (string theory, particle physics, etc.), but many of the experimental projects have work that even early undergrads can be trained to do. Depending on your preferences (and other workload) it may make sense to wait till U2 before looking for a place to volunteer, so that you'll have a better foundation in physics, but I would encourage you to get involved in research no later than that if you do want go to a top school afterward. It is also not uncommon to see undergrads who volunteer a little bit during the school year but also work full-time (for pay) in a lab during the summers, so that is something to consider. A lot of potential opportunities aren't advertised, so it makes sense to learn the research interests of the various faculty and reach out to them directly. Dragons flight (talk) 14:48, 24 August 2010 (UTC)[reply]

You want http://www.oercommons.org/courses/collection/light-and-matter-physics-and-astronomy-resources -- start with the "Simple Nature" title to get an overview. For your third year, go with Fluids, Nuclear, Solid State, Advanced Statistical Mechanics, and Electromagnetic Theory to avoid the unapplied fluff. Ginger Conspiracy (talk) 22:56, 24 August 2010 (UTC)[reply]

Coral identification (from the Great Barrier Reef)

I'd appreciate any help you can give in the identification of these two corals. I've tried a fair bit myself, but didn't come up with much. Thanks. 99of9 (talk) 01:11, 24 August 2010 (UTC)[reply]

The spherical one is probably a porites, no idea which variety. Mikenorton (talk) 11:56, 24 August 2010 (UTC)[reply]

I'm not even convinced by that, it doesn't have "finger like" structure... --99of9 (talk) 21:42, 24 August 2010 (UTC)[reply]

There are many different types of Porites, not all of which have finger-like structure, see here for example, - that's particularly a reference to Porites porites I think. Mikenorton (talk) 22:05, 24 August 2010 (UTC)[reply]

How would those dents in the top originate — damage, or does it naturally grow that way? Nyttend (talk) 11:59, 24 August 2010 (UTC)[reply]

They're certainly not recent damage, but perhaps some early damage has been grown over and left the dimples in the surface. --99of9 (talk) 21:42, 24 August 2010 (UTC)[reply]

What is Galactic Alignment?

Kindly enlighten me with a word i have come across Galactic Alignment.What would be its effect on earth. —Preceding unsigned comment added by 59.182.236.67 (talk) 07:25, 24 August 2010 (UTC)[reply]

Often, this sort of term ("galactic alignment", "celestial alignment", and so on), is used in a pseudoscientific way. In actual fact, astronomical alignments can and do occur, but they have little or no effect on Earth or any events here. A lot of mysticism and mythology has been concocted to conjure up "important effects", but in reality, any such alignment passes without really affecting anything. It's "neat" for people who like observing planets and stars. "Galactic" alignment is a pretty loose term - what, exactly, in the galaxy is aligning? Galaxies move very slowly; any "aligning" that they do with respect to anything else, especially as viewed from Earth, would occur over the course of millions of years. Nimur (talk) 07:53, 24 August 2010 (UTC)[reply]

The article covers this topic rather well. Bear in mind:

the zodiac is a circle around the Earth, and the Milky Way is (in appearance) a circle around the Earth, so the two have to intersect, in fact twice. (Though since the center of the Galaxy is in Sagittarius, it is arguably the better of two choices)
the Earth intersects as a function of precession, but when it intersects depends on what time of the year you look, since the Sun goes all the way around the Zodiac every year. So the choice of "winter solstice" for the alignment is one of four options for traditional solstices and equinoxes. (Even so, that's once every 26,000/4 = 8500 years
the exact timing of the intersection depends on the exact middle plane of the Galaxy meeting the exact center of the Sun. But there's a huge amount of wiggle room there for the idea to be pounded around to meet the facts, because the Galaxy is a fuzzy object. I can't say exactly how much this blurs the time frame

In conclusion, it is not entirely a bogus concept - it does have a certain logic as a way to derive an astronomical Year Zero - but the 2012 thing is not an astronomical coincidence, so to speak. Wnt (talk) 15:01, 24 August 2010 (UTC)[reply]

Histrionic Personality Disorder

Do people who have histrionic personality disorder cheat more often than other people? Have there been any studies done on this? I couldn't find any —Preceding unsigned comment added by 76.169.33.234 (talk) 07:59, 24 August 2010 (UTC)[reply]

Body Fat Level

Why is it that two people that are equally active and eat the same number of calories can weight different amounts? I know that their thyroid hormone levels can be different, but I can't see this making that much of a difference. Shouldn't they be both burning the same amount of calories? Can your genes make so much of a difference that one person will be overweight and the other very skinny? —Preceding unsigned comment added by 76.169.33.234 (talk) 08:02, 24 August 2010 (UTC)[reply]

See our article on Basal metabolic rate, which might vary widely between the two and is "usually by far the largest component of total caloric expenditure." Gabbe (talk) 11:23, 24 August 2010 (UTC)[reply]

Unfortunately, this article is not very complete - it gives simple formulae for BMR which do not admit easy change, and thus are not very satisfying for our purposes. See [10] for a study in which BMR (also caloric intake) was rapidly altered in experimental subjects. Wnt (talk) 14:45, 24 August 2010 (UTC)[reply]

According to a study for the BBC's Horizon, Jan 2009, there seems to be pre-set fatness level for everyone, presumably genetically predetermined. They took otherwise healthy volunteers and fed them twice their normal calorie intake, whilst reducing the amount of exercise they took. The volunteers' weights did rise, but some of them only slightly. The BBC article is a bit light on the details, and doesn't have a decent cite, but it might be a useful area to start websearching from. CS Miller (talk) 15:08, 24 August 2010 (UTC)[reply]

This question gets asked at least 1000 times a day in doctors offices around the world. Yes, it is quite obvious that two persons of similar size may have dramatically different calorie needs and that one may lose and the other gain on the same calorie intake. This inherent rate of calorie expenditure for basically staying alive is referred to as the basal metabolic rate. There are genetic components, with genome wide array studies discovering increasing numbers of genes associate with differences; these are unchangeable. There are probably early life programming factors that are not easily changed at an older age. There are likely ongoing factors that can gradually change the BMR of adults, such as activity level, diet composition or pattern, stress, illness, etc. The BMR is at least partly controlled by a hypothalamic mechanism that functions as a "set point thermostat", shifting energy expenditure mechanisms when weight exceeds or falls below the set point. It is a safe bet that a hundred pharmaceutical companies have lab scientists hard at work at finding ways to safely manipulate your BMR and when someone has an effective, safe product, it will be marketed to you every 15 minutes on every website, spam email, or television channel and will be more famous than Viagra. I long ago lost count of the number of times I have answered this question for overweight people or their relatives. Pass it around. 159.14.241.253 (talk) 16:39, 24 August 2010 (UTC)[reply]

That argument applies only to products that are patented and sold under monopoly - there is no special funding for other aspects of diet and lifestyle that might affect weight, including herbal supplements such as guggul (as well as related Commiphora described by Dioscorides). Once a weight loss product is developed and marketed, as a rule, it causes sudden death in large numbers, e.g. 2,4-dinitrophenol, amphetamines, fen-phen, and ECA stack supplements. This is one issue on which people definitely need to do their own research, and not rely on the regulatory system to support or protect them. Wnt (talk) 17:34, 24 August 2010 (UTC)[reply]

Need help understanding some poorly written chemistry info...

From the writings of a colleague: In high temperature, sodalite would transform to cancrinite of which twelve-ring channels cage prefer bigger cation. So when Ca2+ exists in solution, it prefer occupying the cage to instead of two Na+s, forming Na6[Al6Si6O24]•2CaCO3•nH2O.

My attempt at rephrasing: Sodalite transforms into cancrinite when exposed to high temperature. Cancrinite's twelve-ring channel cage prefers larger cations and thus preferentially selects Ca2+ over two Na+s when the former is present in solution. The final product in this case is Na6[Al6Si6O24]•2CaCO3•nH2O.

Does that make sense?

First, my chemistry knowledge is next to nothing - for example, I have no idea what a twelve-ring channel cage is. Second, while this is a language question, I figure the technical ability on the Science RD would be more valuable than the language parsing ability on the LRD. Third, thank you for any writing assistance you can provide! 61.189.63.185 (talk) 12:30, 24 August 2010 (UTC)[reply]

I would say "the pseudo-twelve-coordinate site in cancrinite". Cancrinite certainly has a pseudo-12C site (see here, and click on "Large pop-up" to see it more clearly), and Ca²⁺ would be a better fit than Na⁺. Physchim62 (talk) 16:06, 24 August 2010 (UTC)[reply]

Drunk

Can you get drunk from alcohol on tongue? Like if you just dipped your tongue into a cup of vodka but didn't drink. Would it diffuse into you? —Preceding unsigned comment added by Prize Winning Tomato (talk • contribs) 15:52, 24 August 2010 (UTC)[reply]

It would certainly diffuse into you. Whether it would do so faster than your body can process it (thus eventually rendering you drunk), I'm not sure. — Lomn 16:03, 24 August 2010 (UTC)[reply]

Maybe. This might be a fun experiment: hold a mouthful of ethanol-based (20 proof? 40 proof?) mouthwash in your mouth for a minute, rinse thoroughly, and then measure your blood alcohol content with those test strips or a breathalyser if you have access to one. I wonder if the uptake rate would vary much between individuals. Ginger Conspiracy (talk) 23:55, 24 August 2010 (UTC)[reply]

Light

Is light from a light bulb the same as natural sunlight? Or are there different types of light? Because well watered plants indoors with no sunlight tend to die —Preceding unsigned comment added by Prize Winning Tomato (talk • contribs) 15:54, 24 August 2010 (UTC)[reply]

Light is made up of a spectrum of colours. Light from the sun will tend to have a different spectrum (that is, a different mix) of colours, than light from a bulb. Reading Grow light might be helpful - these are bulbs designed to produce a spectrum which is suited to nurturing plants. --Tagishsimon (talk) 16:01, 24 August 2010 (UTC)[reply]

No, yes. See colour temperature. 92.15.15.228 (talk) 18:04, 24 August 2010 (UTC)[reply]

Even if the spectrum (color temperature) of light is the same, the intensity is vastly different. Direct sunlight is about 100,000 lux, and a sunny day in the shade is over 10,000 lux. Even an overcast day is around 1,000 lux. In contrast, a typical living room is only 50 lux. That's over 1000 times dimmer than direct sunlight. We tend not to realize this because our eyes are so efficient at adapting to a wide range of light intensities. -- 140.142.20.229 (talk) 19:19, 24 August 2010 (UTC)[reply]

The comment above is correct, but as additional info, the light from an incandescent bulb is quite a bit redder than natural sunlight. However chlorophyll absorbs best in the red-yellow part of the spectrum, so the spectral difference wouldn't be harmful. It's the intensity that makes the difference. Looie496 (talk) 03:09, 25 August 2010 (UTC)[reply]

Milky Way Galaxy

What is the Milky Way galaxy made of?165.212.189.187 (talk) 15:58, 24 August 2010 (UTC)[reply]

Galaxies are made of stars and stellar byproducts, dust, and (probably) dark matter. Dark energy, as I understand it, is generally pervasive rather than clumped in galaxies. — Lomn 16:02, 24 August 2010 (UTC)[reply]

There is a lot of speculation about dark matter these days; but it may turn out to be "uninteresting" cold hydrogen gas that just isn't warm enough to be incandescent. It may also turn out to be some form of exotic matter. Unfortunately (because it is dark and far away) we have few tools to study it directly. Nimur (talk) 19:56, 24 August 2010 (UTC)[reply]

Galaxies are made of "everything". A few hundred billion stars, a honking great black hole in the middle - and the dust, gas, moons, planets, asteroids and comets - but also people, trees, fish, elephants... When you come right down to it - it's hard to think of anything that a galaxy ISN'T made of! SteveBaker (talk) 23:37, 24 August 2010 (UTC)[reply]

Why did some prick throw a brick into this washing machine?

What did he hope to accomplish? To solve? Why did this prick want to commit harm to it when he could've done good (or at least harm to something else) instead?

(And why was the washing machine smoking in the first place?)

http://www.youtube.com/watch?v=364dzVsBs2o

--70.179.165.170 (talk) 15:31, 24 August 2010 (UTC)[reply]

Are you seeking to accomplish or establish something by the repeated use of the idiom "prick"? To be honest, it merely rebounds onto you, leaving us to think that you may in fact be one. Why, for instance, could you not have "done good" and avoided the aggresive and unhelpful language. --Tagishsimon (talk) 16:22, 24 August 2010 (UTC)[reply]

A trip to your local dump / civic-amenity / recycling centre will reveal a horrid truth about modern society : we throw away a huge collection of manufactured goods that are defective but repairable, but that are nevertheless beyond economic repair. It's likely that this machine had such a defect - a bad controller card, a bad pump assembly, an agonisingly worn main bearing. If a new machine would be cheaper than the repair (which is very often the case) or the parts just aren't made (which seems to be very common indeed for machines older than a decade) then you end up having to chuck out something that otherwise still works. I'm guessing that's the case here (and may well explain the smoking). -- Finlay McWalter ☻ Talk 16:24, 24 August 2010 (UTC)[reply]

Concur. I was unable to get an old but high quality TV repaired simply because parts were no longer available. I was forced to take it to the local recycling centre. Exxolon (talk) 16:47, 24 August 2010 (UTC)[reply]

A friend at work had his 2 year old flat-screen TV start acting up. When he took it to get it repaired, the cost estimate was 70% of the original cost of the TV, and because flat screen TV's have gotten cheaper since then, that was about the same as the cost of a replacement (which had more features - better quality, etc). In light of that, it's not surprising that he was going to chuck it out. However, by searching for the model number and the fault condition online, I discovered that the problem was 90% certain to be one of the capacitors in the power supply. Within 10 minutes with nothing more than a torx-wrench and a soldering iron (and a bunch of generic capacitors that I had in my junk bin, probably recycled from something else that I'd pulled apart), I had the TV working again and saved the guy several hundred bucks - cost $0. Sadly, there doesn't seem to be a way out of this noose for the majority of the population. Even if you know it's a 10 cent part - very few people know how to use a soldering iron - and for some reason they don't realize that there a bajillion websites that explain how to use one. Whatever happened to "You aren't a 'real man' unless you have a garage full of tools and know how to use them"? SteveBaker (talk) 23:27, 24 August 2010 (UTC)[reply]

To see what happens. Vimescarrot (talk) 16:29, 24 August 2010 (UTC)[reply]

Perhaps for entertainment. Lot's of people have spent a good deal more than the price of a used washing machine to make an entertaining youtube video.

There is no law that says that a person must devote every penny's worth of property they own to the betterment of mankind.

Craigslist tells me that the price of a damaged (notice that it's smoking) washing machine is about $100. Are you really berating this person for wasting the equivalent of two video game's worth of stuff? You've never spent $100 or more on entertainment?

(P.S. My favorite video of this kind is this one. Mostly because I wish I owned a hat like that.) APL (talk) 18:47, 24 August 2010 (UTC)[reply]

I agree: entertainment, curiosity, and the lurking lust for destruction. This is a good way of living it out. Not prickishness. There are also people who satisfy these needs by experimenting with or destroying what belongs to others (not just primitive vandalism of private or public property, also reckless experiments on college campus, for example). I agree with APL (though I admit I have my own personal limits of sensitivity toward destroying inanimate objects for show when it comes to food or musical instruments). In any event, it is likely that the smoking washing machine wasn't in mint condition, and even if it wasn't beyond repair, at least this was a creative and entertaining form of wastefulness. Didn't Letterman drop things from buildings for a while? ---Sluzzelin talk 19:00, 24 August 2010 (UTC)[reply]

7 degrees of separation

Most people know the old adage, "You're only 7 people away from knowing everyone in the world?" What is the etiology of this? Have there ever been any well-controlled studies about it? Are the scholars (philosophers, sociologists etc.) who've focused a great deal of time looking into it's supposed validity? Are there any good books about it? Buddpaul (talk) 17:48, 24 August 2010 (UTC)[reply]

Six degrees of separation has a lot of information. -- Finlay McWalter ☻ Talk 17:54, 24 August 2010 (UTC)[reply]

It's certainly not a cast iron RULE. There are undoubtedly people who can't be reached in so few steps. But it is an exceedingly solid average. There was a rather good Discovery channel documentary on this - which they tested by picking a bunch of people around the world and asked them to get a message to a specific US researcher by passing it on to someone they knew - amazingly, they all managed to get the message to it's destination - and in each case, within the six degrees. There is a significant body of mathematics that show why this is true - and it has applicability to all sorts of systems. For example, you can almost always get from your computer to any other on the Internet by routing the message through about six other computers.

The game "Six degrees of Kevin Bacon" requires you to find a chain of actors, producers or directors who are linked to Kevin Bacon by participating in movies that link them along the way. (eg Elvis Presley was in Change of Habit (1969) with Edward Asner who was in JFK (1991) with Kevin Bacon) - someone who studied the Internet Movie Database (IMDB) discovered that of the 1.6 million people listed there, only 150 of them could not be connected to Kevin Bacon in 6 steps or less. However, we're restricting them to being connected only by movies they've participated in - if we were allowed to connect them by friends, aquaintances, neighbors, co-workers, etc - I'm sure the paths would be much shorter.

An experiment on Facebook connects friends of friends of friends...it finds that the average number of friend links to get from anyone to anyone else is 5.7...again, less than 6 degrees. There have even been experiments right here in Wikipedia to see what the fewest number of links you have to click on to get from any article to any other...and again, the answer is less than 6.

The result is so ubiquitous across so many fields that it starts to seem like a rather fundamental result.

SteveBaker (talk) 22:43, 24 August 2010 (UTC)[reply]

Common Descent

What are the odds that we are actually descended from the particular, specific fossils we've found in Africa like Lucy? What if she had no children herself? Is there any way to prove we're directly descended from a fossil and not one of their siblings? TheFutureAwaits (talk) 19:00, 24 August 2010 (UTC)[reply]

The only way to do that would be by means of archaeogenetics. The "Ancient DNA" article only mentions this technique having been applied as far back as eg. "Ötzi the Iceman" and the Ancient Egyptian mummies -- ie., maybe five or six thousand years, nowhere near the 3 or so million years ago for the "Lucy" remains!

So much for "proof." As to odds, those will depend on things like the population size and distribution, etc., of contemporary Australopithecus afarensis and I will leave it for others to try to estimate those if they can... Wikiscient (talk) 19:19, 24 August 2010 (UTC)[reply]

You might also want to consider the information in the Mitochondrial Eve article, though I'm not sure this is going to address the specific question you seem to be asking. Wikiscient (talk) 19:23, 24 August 2010 (UTC)[reply]

If you are asking about the probability of a specific early fossil being an ancestor of you, personally - then the odds are surprisingly high. Someone who lived just 30 generations ago (600 years - in about the 1400's) would by now have over a billion descendants. Several estimates say that someone who lived in the 6th century BC could easily be the ancestor of everyone alive today - other estimates put it MUCH more recently than that (unless you happen to be a native of the Amazon basin or something equally out of the way). The most recent ancestor of all people of European descent probably lived less than 1000 years ago.

Our Most recent common ancestor article is worth reading.

The most likely chance for a fossil (rather than just a rather old skeleton) would be a fossil from about 70,000 years ago when human population crashed (according to the Toba catastrophe theory) to less than 10,000 individuals - perhaps only 1,000 breeding pairs. The La Ferrassie 1 fossil is about that old - and is highly likely to be your ancestor.

Back at 1.2 million years ago, there were around 26,000 people in the world - and that number is probably fairly constant all the way back to the time of Lucy (3.2 million years ago).

The difficulty is that beyond a few thousand years ago, the issue isn't so much whether you, personally, are descended from a particular individual - the question is whether ANY of that person's offspring survived. If they had a blood line continuing for more than a handful of generations, then the odds are extremely high that you are a descendent - but obviously if that person had no children, or those children all died before child-bearing age - then the odds are zero.

That means that the odds are all about the number of surviving children from each generation that made it through to child-bearing age back at the time of the fossil you're thinking about. I don't think we have a clue about how many children a Lucy-era Australopithecus would have had - let alone how many would have survived - so it's tough to know whether we are all likely to be ancestors of Lucy or not...maybe she died childless...maybe she bore a dozen healthy kids who all gave her a bunch of grandchildren - if that's what happened, then she is an ancestor of all of us.

SteveBaker (talk) 22:18, 24 August 2010 (UTC)[reply]

There is only one way, in principle, to prove descent from a specific individual from long ago -- that's if the individual had a novel genetic mutation that was not present in either parent, and is present in you. The odds of ever being able to prove that for an ancient individual are extremely slim, with emphasis on extremely. Looie496 (talk) 03:03, 25 August 2010 (UTC)[reply]

Searching for fossils by radar

How come this hasn't taken off? It sure seems easier than digging blind! http://www.americanscientist.org/issues/pub/2001/1/fossil-hunting-by-radar TheFutureAwaits (talk) 19:05, 24 August 2010 (UTC)[reply]

Radar has limited penetration through rock or soil except where conductivity is low - dry sand is ideal, anywhere that is wet (particularly if at all saline) or consists of mainly clay for instance would yield far less useful data. I don't suppose that this sort of thing comes cheap either, any group would need to be well-funded. I see that the article linked to is nine years old, maybe they couldn't either raise the funding or the results of the pilot project were not that good. Mikenorton (talk) 19:24, 24 August 2010 (UTC)[reply]

Geophysical survey (archaeology) has some nice links and photos. For archaeology, the advantage is that human artifacts tend to be near the surface (not very deep) and are often metal or highly contrasting material to the surrounding overburden. With more ancient fossils (like dinosaur bones, for example), RADAR penetration and reflectivity contrast is not very good. Nimur (talk) 20:10, 24 August 2010 (UTC)[reply]

I would expect the main problem is false positives. You're going to get hugely noisy signals. Looking at something comparable, take a look at the kinds of things you get from side scan sonar. For every photo like this, where you can tell pretty well what it is, you get millions like this, or this, or this, or this. (And THOSE are probably chosen as the most illustrative of their own surveys!) Now imagine that instead of just going sideways in the ocean looking for solid structures on the surface, you are actually looking down into the rock and so on of the last few thousand (if not millions) years of history. You get images like this. What is that? It turns out it is a cemetery. (Using Ground-penetrating radar.) Is getting a survey like that likely to be useful, or is it going to send you off on a thousand false positives, thinking you've found a cemetery (or dinosaur, or whatever), and instead finding a bunch of buried parts from an industrial factory, or some odd shaped rocks, or whatever else is underground? This is just my hunch but I'd think that such a thing would be a pretty difficult endeavor. --Mr.98 (talk) 00:37, 25 August 2010 (UTC)[reply]

motors

Are electric motors and dynamos the same thing? So for example I could take the motor from a fan and put it on my bicycle and it'd power the light? Or are they different —Preceding unsigned comment added by Prize Winning Tomato (talk • contribs) 20:04, 24 August 2010 (UTC)[reply]

DC motors containing a permanent magnet can generate electricity when rotated, just like a dynamo. Electric motors not containing a permanent magnet need a more complicated mechanism to produce electricity. Dynamos are specialized for their use though, so they probably generate a higher voltage than electric motors would. --Chemicalinterest (talk) 20:24, 24 August 2010 (UTC)[reply]

Talking of motors, I too raise my hand. I have a DC motor with permanent magnet. It works well on 3 volts, but does not work on 9 volts DC or more. why ? Jon Ascton (talk) 01:10, 25 August 2010 (UTC)[reply]

Human IQ

a) How long ago was it when the IQ of human ancestors was equal to the IQ of contemporary chimps? b) Why do humans have so much surplus IQ? Surely evolutionary speaking we just need enough IQ to feed and reproduce, but not to deduce that E=mc^2? How or why did this surplus IQ evolve? c) If in a population the less intelligent parents have more children that average, could this reduce the average IQ of the population? How many generations would it take? Is there any indication that this may be happening currently? Thanks 92.15.3.135 (talk) 20:10, 24 August 2010 (UTC)[reply]

I really don't know how applicable IQ tests are to animals. There is a fair amount of bias in IQ tests between human cultures, let alone non-humans. Googlemeister (talk) 20:18, 24 August 2010 (UTC)[reply]

(ec) There is not an easy answer to any of these questions. You can start by reading Evolution of human intelligence and theories of human intelligence. It is not even clear how to measure and compare "average" intelligence between different people in the same era, let alone through multiple decades, centuries, or so distant into the past that evolutionary biology becomes the dominant factor. It will be hard to give an exact historic timeframe for when we became "smarter" than chimpanzee, but human evolution discusses this well. Sapiens, or "wise human", is the name commonly given to those first fossil hominids that we identify as "modern" and "intelligent" - and they appeared around a half-million years ago - but understand that this transition toward "intelligence" occurred over a wide swath of the timeline and our best fossil evidence is "size of skull" as an indicator of intellect. Other evidence, such as behavior, lifestyle, toolmaking, and so on (things we would consider the hallmarks of "intelligence") are largely inferred from indirect evidence as we go deep into prehistory hundreds of thousands of years back - so exact dates are impossible to proscribe. Regarding the evolution of additional intelligence, beyond the basic need for survival - I would call this a sort of "evolutionary inertia." We may have evolved "merely to survive," but as a side effect, we proliferated and thrived - because conditions were good enough, and we became the apex predator. Intelligence has helped humans to maintain their position as apex predator, and the rise of civilization throws much complexity into the simplistic view of straightforward natural selection. The definition of "fit enough to survive and reproduce" significantly changed as humans began to make easy work out of "basic survival." In light of this, even your last question is not easy to answer; you might also want to consider the nature versus nurture debate. Modern intelligence is a plethora of different skills - innate and learned - so it is not even safe to say with certainty that "dim" parents will produce "dim" progeny. Nimur (talk) 20:26, 24 August 2010 (UTC)[reply]

a) I think you mean "intelligence" here much more informally than its rigorous definition according to "IQ". You can't give an IQ test to a chimp. So the answer is that humans started developing "human intelligence" as soon as human ancestors and chimp ancestors parted ways evolutionarily (which was as long ago as maybe 15 million years depending on how you look at it).

b) Again I think you are wondering about surplus "intelligence" and not "IQ" per se. One thing to consider is that this intelligence, informally speaking, is in large part due to cultural development. Einstein could derive "E=mc²" only because he lived at a time when the math and physics he used to do so had been sufficiently developed. As the theory goes, he could have been born a million years earlier and still have been as "capable" of developing his theories as he was a hundred years ago -- had he simply had the same cultural tools available to him a million years ago. (For more on how this could be, see eg. "exaptation" (= "using a trait for some purpose other than that for which it evolved") and "positive feedback loops" and etc.)

c) According to the Fertility and intelligence article, there are indeed indications that "this" may be happening currently in some ways. But I expect it would take much, much longer than that trend is likely to last (even if that turns out to be hundreds or even thousands of years) for Homo sapiens to evolve a "genetically" "lower IQ."

Wikiscient (talk) 21:10, 24 August 2010 (UTC)[reply]

You may enjoy the novel Galapagos, by Kurt Vonnegut, which is told from a viewpoint a million years in the future, and which postulates that the big brains of today's humans has been one big evolutionary mistake; humans end up evolving into creatures with much smaller brains, able to swim in the water and catch fish as seals do, but without the predilection or even the capacity to create nations or war or mass environmental destruction. Comet Tuttle (talk) 21:31, 24 August 2010 (UTC)[reply]

I don't think that the assumption that "we have IQ to spare" makes a lot of sense. We (more or less) agree that IQ isn't about memory capacity - in computer terms, it's more like "CPU speed" than "RAM size". That being the case, you don't "run out of IQ" like you might run out of memory. You might need a certain amount of brain power to conceive of the shape of a stone arrowhead and to figure out how to knap that from a large flint rock - or to figure out how deer behave when you encircle them in a particular way at a particular time of day when they are not near a water supply and have calves with them at the time. That's probably not much different from the amount of "CPU power" it takes to figure out E=mc². When people are thinking hard about problems like that, they tend to need quiet, no distractions, not to be doing anything else at the time - which suggests that we're using close to the full amount of CPU power that we have available.

There just isn't any evidence that we're smarter than our homo-sapiens ancestors. Einstein didn't come up with E=mc² just from nothing - he needed the results of experiments - the benefits of prior thinking from the likes of Newton. He needed writing and printing and mass-production and the ability to have a job that allowed him to spend long periods without distraction without having to (say) search for drinking water or make a fire or...whatever. We can do what we do because our brains aren't being used for a whole bunch of other things that we'd be using it for if we didn't have all of the benefits of modern civilisation...not because we're smarter than the cavemen. Obviously, there was a time when we weren't this smart - and looking back at fossil hominid skulls would probably allow us to guess when our brain size started to get bigger than that of modern chimpanzees. So we have obviously been getting smarter - but never smarter than was necessary in order to thrive in the environment of the time.

SteveBaker (talk) 21:36, 24 August 2010 (UTC)[reply]

Re. your first paragraph: this is basically what I'm saying about "exaptation" above.

For example: consider alexia, the neurological condition of having very specifically lost the ability to read only (ie., no other visual impairment, etc) due to damage to specific parts of the occipitoparietal region of the brain. So reading (an aspect of "intelligence" as the term is being used informally here) is a specialized, hard-wired, phenotypical trait of the human brain.

Reading has been around for a few thousand years. Have our brains evolved such a complex ability that quickly? No. Then why have we been carrying around a "reading gene" without using it for a million years or so?

As Oliver Sacks wrote a couple of months ago:

"Writing, a cultural tool, has evolved to make use of the inferotemporal neurons’ preference for certain shapes. The origin of writing and reading cannot be understood as a direct evolutionary adaptation. It is dependent on the plasticity of the brain, and on the fact that experience is as powerful an agent of change as natural selection. We are literate not by virtue of a divine intervention but through a cultural invention and a cultural selection that make a creative new use of a preëxisting neural proclivity."

"Intelliegence" is all like that! :) Wikiscient (talk) 22:25, 24 August 2010 (UTC)[reply]

Nobody knows what IQ even measures.--92.251.132.249 (talk) 22:30, 24 August 2010 (UTC)[reply]

Well, that's not really very true. There are entire disciplines of psychology dedicated to the study of intelligence quotient and standardized testing - the people who design and analyze these tests are very sure they know what they are measuring. And though individual performance may vary due to statistical outliers, there is absolutely no doubt at all that when measured across large populations, IQ strongly correlates to things like salary, mortality-rate, performance on Army rifle-range scores, dental hygiene, and so on - the number of things that IQ positively correlates to is actually quite striking. Correlation does not imply causation. But standardized tests definitely measure things like the ability to focus; the ability to think clearly; and the ability to reason through difficult problems. Modern tests also go to great lengths to eliminate cultural, language, and educational background biases. So, while it may be fair to claim that "many people do not know how to properly interpret the meaning of an IQ or other standardized intelligence metric," it is completely incorrect to say that "nobody knows what IQ measures." Nimur (talk) 23:37, 24 August 2010 (UTC)[reply]

Getting off-topic, but see also: What is Intelligence? Wikiscient (talk) 00:20, 25 August 2010 (UTC)[reply]

You're making a number of presumptuous assumptions. First off, you would have to define exactly what it is your measuring in your IQ test. The you would have to balance the test, which across species would lead to an inherent bias due to a lack of understanding/misinterpretation. See Stanford-Binet Intelligence Scales.Smallman12q (talk) 01:40, 25 August 2010 (UTC)[reply]

Floating Metal Ships

Ships made of metal with a density greater than that of water float because they are not entirely made of that metal and much of the volume will be taken up by air, whose density is clearly less than that of water. I think this principle has a specific name but can't for the life of me remember. Anyone have any ideas? Thanks asyndeton talk 21:23, 24 August 2010 (UTC)[reply]

Are you just looking for the term "Buoyancy"? Wikiscient (talk) 21:27, 24 August 2010 (UTC)[reply]

Archimedes principle. Mikenorton (talk) 21:42, 24 August 2010 (UTC)[reply]

Have you thought about an airtight vessel made of metal with a density greater than that of water, but not full of air, infact it is full of nothingness, but still it will float ! What do you say to that ? Jon Ascton (talk) 00:31, 25 August 2010 (UTC)[reply]

\rho _{metal+nothing}={\frac {m_{metal}+0}{V}}\ \approx \rho _{metal+air}

Wikiscient (talk) 00:52, 25 August 2010 (UTC)[reply]

Medical doctor specialties

Medical doctors often specialize ... for example, a cardiologist is a heart doctor and an oncologist is a cancer doctor (etc.). What type of doctor would I see if I were interested in weight loss? I don't mean as a morbidly obese person ... but just as a regular person trying to lose 10 or 20 pounds. Is there a medical specialty for weight loss? I'd rather not see a general practitioner, as they probably know no more than I do about weight loss ... or they can only tell me in general terms what I could probably find for myself in a book or on the internet. Thanks. (64.252.34.115 (talk) 21:34, 24 August 2010 (UTC))[reply]

Dietician? Clarityfiend (talk) 22:26, 24 August 2010 (UTC)[reply]

A nutritionist or a dietitian is a specialist, but not a doctor. Check carefully - these terms have significantly different meanings in different regions; in some places, there are no requirements, training, or licensing of any kind to be called a "nutritionist"; while in other regions, these terms are regulated and can only be used by trained professionals. It is rare to find a person of either specialty who is also a medical doctor, though. Nimur (talk) 22:28, 24 August 2010 (UTC)[reply]

Thanks. Then what type of medical doctor handles obesity? Thanks. (64.252.34.115 (talk) 03:34, 25 August 2010 (UTC))[reply]

Unidentified moving blob in a sewer

http://www.youtube.com/watch?v=ELoqZiamr4E

what is that? Is it some kind of bacterial colony? Perhaps some kind of colony like a portugese man-o-war? Something fake?--92.251.132.249 (talk) 22:29, 24 August 2010 (UTC)[reply]

According to Dr. Timothy Wood, "They are clumps of annelid worms, almost certainly tubificids (Naididae, probably genus Tubifex). Normally these occur in soil and sediment, especially at the bottom and edges of polluted streams. In the photo they have apparently entered a pipeline somehow, and in the absence of soil they are coiling around each other. The contractions you see are the result of a single worm contracting and then stimulating all the others to do the same almost simultaneously, so it looks like a single big muscle contracting." This information is according to this article. — GorillaWarfare ^talk 22:42, 24 August 2010 (UTC)[reply]

See Tubifex tubifex. Ghmyrtle (talk) 22:46, 24 August 2010 (UTC)[reply]

Top soil and a layer of clay

I've been turning over the soil in the back yard a couple of days ago -- a fairly heavy clay-rich soil -- and the following has occurred to me. I always turn the soil about one spade deep; say, 10-15 inches. What then prevents the smallest mineral particles in the soil from being washed down and forming a watertight layer of clay at the depth of about 15 inches? Or does this really happen? I guess the earthworms can burrow deeper than that, so it's not completely watertight, but still, does this really happen? And is there something I'm supposed to do for this not to happen? --Dr Dima (talk) 22:30, 24 August 2010 (UTC)[reply]

Yes, if you get a hardpan clay subsoil layer that won't drain, you have a few options. You can plow it or otherwise mechanically mix in the soil or you can plant something with really aggressive roots at the layer involved (alfalfa?) or ideally both.

These kinds of agriculture questions depend heavily on your locale, geology, and climate. When I was a kid, whenever such questions would come on the USDA-run write-in radio program for farmers (why the heck was I listening to that? I must have been a really weird kid) the announcer would always say something like "consult your local university, college, or community college agriculture outreach program" which is probably pretty good advice for any gardeners who are facing those kind of problems. There might be some obscure plant that loves the kind of clay you get so much that just a little bit with a lot of water will tear it all up with roots and turn it into draining, fertile soil for tubers or whatever you want. Ginger Conspiracy (talk) 23:29, 24 August 2010 (UTC)[reply]

The problem certainly occurs at an agricultural scale, which is why clay rich soils need artificial drainage – in Holland, they even used windmills to pump the water out of the drainage ditches. At the back yard scale, there's little you can do in practice except to keep the top layer healthy, unless you have somewhere convenient to dump any excess water. Large plants with deep roots around the edge of the yard will help, but a lot depends on the size of the yard as well. Physchim62 (talk) 23:43, 24 August 2010 (UTC)[reply]

August 25

Growing Tree

A tree is growing. I am 3 feet tall. I stand near the tree and just at near where my head-top corresponds to the tree, i.e. at 3 feet from the ground level, I make a mark of adequate depth that (let's suppose ) will last forever. The tree will grow. What will happen to the mark ? Will it's distance from the ground increase as it will grow Jon Ascton (talk) 01:02, 25 August 2010 (UTC)[reply]

No. Trees (and almost all plants) grow from the top. Grass grows from the bottom though. Ariel. (talk) 02:13, 25 August 2010 (UTC)[reply]

Getting an old scientific article - how?

Hi, I would like to read the article "Thinking about the brain" from Francis Crick, which was published in 1979 in the Scientific American of September (241 (3), p.181-188). Is it possible to get that article easy and for free? The licence of my library seems only to reach back till 1984. -- 89.196.35.247 (talk) 02:38, 25 August 2010 (UTC)[reply]

Usually Google Scholar is the best bet for things like this, but it shows no online versions, not even non-free. Have you tried looking for hard copies of Scientific American from that era in your library? Looie496 (talk) 02:59, 25 August 2010 (UTC)[reply]

Copies from 1979 should be readily available. I suggest you go to your library and ask about inter-library loans. Most libraries are happy to arrange inter-library loans. It is part of their function. Dolphin (t) 03:01, 25 August 2010 (UTC)[reply]