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.

June 25

What is the most laminar liquid?

Question is in topic. Malamockq (talk) 18:24, 25 June 2015 (UTC)[reply]

Pitch Count Iblis (talk) 18:31, 25 June 2015 (UTC)[reply]

Laminar as in flow regime like Reynolds number, or laminar as in some sort of microstructure? shoy (reactions) 18:38, 25 June 2015 (UTC)[reply]

Laminar as in a laminar flow, smooth. Malamockq (talk) 23:45, 25 June 2015 (UTC)[reply]

Fluids are not laminar: flows are laminar. Review the definition of laminar flow (and laminar, in general). Also see intrinsic and extrinsic properties (not to be confused with intensive and extensive properties!). We don't use "laminar" as an intrinsic property of a fluid; it is extrinsic, in the same way that pressure or temperature are extrinsic properties. When you ask "which liquid is most laminar?" ... the question is malformed. It is similar to asking "which liquid is the hottest?" There is no correct answer. These properties depend on the circumstances, both qualitatively and quantitatively. Nimur (talk) 00:38, 26 June 2015 (UTC)[reply]

Agreed, though one would struggle to produce non-laminar flow in anything more viscous than treacle or syrup (at room temperature). Count Iblis and I assumed that Malamockq intended to refer to the intrinsic property of viscosity. Dbfirs 07:40, 26 June 2015 (UTC)[reply]

Ok but some liquids are easier to make a laminar flow from than others correct? Would running a current through a ferrofluid make its flow laminar? Malamockq (talk) 12:41, 26 June 2015 (UTC)[reply]

Stars

Moved to 'Cronology of the universe' 'talk' page

When was the population III stars were created? In the ‘recombination epoch’ or in the ‘reionization epoch’? - Article's point to start from
What about population II and I stars? any specific dates?

Space Ghost (talk) 18:28, 25 June 2015 (UTC)[reply]

Population III stars appeared during the ionization epoch. Population II stars followed shortly after them (by a few hundred million years). Population I stars started to appear after Population II stars and continue to form now. Ruslik_Zero 20:55, 25 June 2015 (UTC)[reply]

I can't find any 'ionized epoch' article. I pressed CTRL+F and searched for the 'ionized' word. This two diagram illustrates during/after the reionization epoch ^[1] ^[2] also the article I stated. This article states what you stated ^[3].

Assuming that the population III stars were created after the 'Dark ages' and that it started reionizing, the article I stated, in the 'recombination epoch' 'plasma' was already there, why its is saying that from the 'reionization epoch' 'the universe is composed of plasma'?. Which plasma is it talking about?

If the first stars and quasars were created 400 million years after the Big Bang, then its not stated in the article I stated in the beginning. Can someone fix it after rechecking if I'm correct please? - I believe it should be entered in the 'Structure formation'^[4] point. Also 'Star formation'^[5] should go up, before 'reionization'^[6].

Space Ghost (talk) 09:13, 26 June 2015 (UTC)[reply]

literacy in animals

Can non‐human animals be taught how to read? Are there chimpanzees that can read? --Romanophile (talk) 18:36, 25 June 2015 (UTC)[reply]

Well you can teach a dog how to read. I know that apes can sign language. But in regards to literacy that is "moderate" (to the extent a non-human animal could read a children's book say) I think you are out of luck. Perhaps one of the smart people on WP/reference desk have further information. Agent of the nine (talk) 18:50, 25 June 2015 (UTC)[reply]

Sort of, yes. See Great_ape_language#Plastic_tokens. Kanzi_(chimpanzee) seems to be the best, though Sarah_(chimpanzee) was the first. This book also looks pretty good, but I can only see a few of the relevant pages about Sarah [1]. Essentially, as I understand it, Kanzi can read and write various things using magnetic symbols. This is not reading and writing English, but it is reading and writing some language in the core sense of those words. David_Premack was one of the key researchers to first seriously look at non-human-ape language acquisition. (It would be really interesting to learn how Kanzi would respond to simple short stories written by humans, something on the level of Goodnight Moon or Dick and Jane. I suspect they've tried something of the sort, but I can't look into it at the moment).

For dolphins, see the work of Denise Herzing (TED talk here [2]). She has a symbol board she uses to create a "shared language" with dolphins, it's not clear to me if any of them do anything like writing though. SemanticMantis (talk) 19:17, 25 June 2015 (UTC)[reply]

Resveratrol content in cranberries

Hi. Could someone improve the Resveratrol content table? I was specifically looking for the amount in cranberries. A decreasing table by highest content would be great. Thank you. — Preceding unsigned comment added by 2602:306:CF86:1660:A80A:109C:37C6:1033 (talk) 19:44, 25 June 2015 (UTC)[reply]

The article is at Reservatrol. You can make the tables sortable by looking at how it'd done in other places, e.g. List_of_countries_by_firearm-related_death_rate. This paper [3] says "The concentrations of resveratrol were silmilar in cranberry and grape juice at 1.07 and 1.56 nmol/g, respectively." You can use that ref to add that info to the table too. SemanticMantis (talk) 19:55, 25 June 2015 (UTC)[reply]

I could be wrong, but I think the OP is asking for the average resveratol content in raw cranberries rather than in juice. Nil Einne (talk) 00:58, 26 June 2015 (UTC)[reply]

Oops, yeah, probably. This paper [4] says cranberries have 900 ng/g by dry weight. Perhaps of note, regular Grapes have 6471 ng/g dry. For the heck of it (and since it is paywalled), I'll also post all the the other values from tables 1 and 2.

Unformatted data from Rimando et al (2004), table 2

scientific name (common name) cultivar source resveratrol a (ng/g dry sample) n b V. angustifolium Ait. (lowbush blueberry) not known c Nova Scotia 863 2 V. ashei Reade (rabbiteye blueberry) Tifblue United States 1691 3 V. corymbosum L. (highbush blueberry) not known c Southern United States 1074 3 V. macrocarpon Ait. (cranberry) not known c Nova Scotia 900 2 V. myrtillus L. (bilberry) not known c Nova Scotia 768 2 V. vitis-idaea var. vitis-idaea (lingonberry) not known c Nova Scotia 5884 2 V. vitis-ideae var. minor (partridgeberry) not known c Nova Scotia 924 2 V. vinifera L. (grapes) Table grapes Nova Scotia 6471

Table 1, even messier, slightly better readability in editor view

scientific name (common name) resveratrol a (ng/g dry sample) n b V. arboreum Marshall (sparkleberry) not known Lucedale, MS 125 V. ashei Reade (rabbiteye blueberry) Tifblue Poplarville, MS Stone Co., MS Climax Lamar Co., MS Poplarville, MS Stone Co., MS 583 Premier Lamar Co., MS c 4 Poplarville, MS c 4 Stone Co., MS c 3 V. corymbosum L. (highbush blueberry) Bluecrop d 2 853 e 2 V. elliotti Chapman (Elliot’s blueberry) not known Monticello, MS 453 V. stamineum L. (deerberry) not known B-59 Jackson Springs, NC B-76 Jackson Springs, NC Batesburg White Jackson Springs, NC NC 78-8-1 Jackson Springs, NC NC 78-8-21 Jackson Springs, NC SHF3A-7:13 Jackson Springs, NC SHF3A-2:14 Jackson Springs, NC SHF3A-2 − 108 Jackson Springs, NC V. vinifera L. (grapes) Pinot Noir Corvallis, OR Merlot Corvallis, OR cultivar source Leakesville, MS 519 2 1 Lamar Co., MS 106 4 154 3 61 3 390 4 77 4 4 7 16 10 Corvallis, OR 327 Poplarville, MS 406 1 1 Leakesville, MS 204 2 331 2 503 2 47 2 322 1 104 2 291 2 242 2 115 2 Cabernet Corvallis, OR 2475 2 5746 2 6356

It's unformatted but fairly human readable, the value for each Vaccinium spp. comes after the place name (Nova Scotia or United States in table 2). Hopefully someone can add some of the values to the article. SemanticMantis (talk) 16:19, 26 June 2015 (UTC)[reply]

Do it! Be Bold. Here's a link on making Sortable Tables. (I would suggest making an account first, but you don't have to.) Ariel. (talk) 20:17, 25 June 2015 (UTC)[reply]

June 26

What happened to the INSC?

Please answer me at Wikipedia_talk:WikiProject_United_States_Government#INSC. --Ysangkok (talk) 12:28, 26 June 2015 (UTC)[reply]

I am not convinced that the International Nuclear Safety Center ever existed. The history pages at the USDOE (here), which go into considerable detail about its activities ("November 25, 2002. The Department's Los Alamos National Laboratory fires two security guards and places three employees accused of theft on paid administrative leave."), make no mention at all of this organization. Tevildo (talk) 23:21, 26 June 2015 (UTC)[reply]

Some more detailed searching has revealed the existence ([5]) of an "International Nuclear Safety Center Database", hosted at the Argonne National Laboratory in the mid-90's. Tevildo (talk) 23:40, 26 June 2015 (UTC)[reply]

Determining gender of parrot from behaviour

Is a male parrot likely to be more sociable towards human females, and a female parrot more sociable towards human males? Enough so for it to be a reliable indicator of the parrot's gender? People keep saying this, but I'm not sure if it's true. Something to do with pheromones? But I'm not sure if those even work cross-species. Thanks. --87.112.205.195 (talk) 14:57, 26 June 2015 (UTC)[reply]

What kind of parrot? Some types of parrots have sexual dimorphism, but many don't. For monomorphic species, there may be some behavioral tendencies that can provide evidence that would support one sex or the other, but it is never fully reliable and accurate. Even for species that are normally considered monomorphic, there are often subtle differences. See here [6] for a guide on sexing African Grey Parrots (Determining the sex of an animal is called "sexing", and you can find guides more easily by google searching /sexing [species]/). But even those are not 100% reliable, just good enough for a casual interest. Nobody would set up parrots for breeding based only on visual or behavioral cues, but it's good enough to confirm that your lovely pet Sally is at least most likely a female.

The only reliable ways to sex birds with no obvious sex-distinguishing characteristics is to have a surgical exam done by a vet, or do DNA testing. These days if people want to know for sure, they usually just send off a small blood (sometimes feather) sample to a lab for DNA sex testing, as it is less risky for the bird than anesthesia and surgery, and roughly equivalent in price. There are many such services, this is one I just found via google [7]. I can try to find more info on behavioral evidence if you'd like, but I can't do that without knowing what kind of parrot you're interested in sexing. SemanticMantis (talk) 19:38, 26 June 2015 (UTC)[reply]

It was more of a general question. The 'male parrots like women, female parrots like men' is a factoid that I see parrot owners on the internet repeating sometimes - hell, there are still people who use *dowsing* to determine their parrot's gender! It's seems to be quite common for people to own parrots without actually knowing what gender, or even what *species* their bird is. --87.112.205.195 (talk) 17:45, 28 June 2015 (UTC)[reply]

on waking

I ask this out of curiosity only. I take a low dose (10 mg) of of Doxepin as a sleep aid. This drug is especially helpful with the later hours of sleep. The curious thing is that sometimes I wake up with a wonderful sense of peace and relaxation. I'm in no hurry to get up, I feel very positive about the day. However, most of the time this is not the case at all. The contrast is very pronounced. I wonder why? --173.17.244.250 (talk) 15:00, 26 June 2015 (UTC)[reply]

Talk to the doctor who prescribed your medication and/or consult the fact sheet that came with it, to read about possible side effects. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:10, 26 June 2015 (UTC)[reply]

It's an Anticholinergic, and has many mental effects. It's not surprising it could do that. Is your question why it does it sometimes, and sometimes not? I don't know the answer to that. Ariel. (talk) 23:05, 26 June 2015 (UTC)[reply]

Sorry, I didn't realize I wasn't logged in on my original post. Yes, that's my question. Thanks for the information. I wonder if the pleasant effect might be due to oxytocin? --Halcatalyst (talk) 18:31, 27 June 2015 (UTC)[reply]

Metrophobia

Question moved to "Metrophobia" on the Language desk. -- Ariel. (talk) 23:08, 26 June 2015 (UTC) [reply]

Where in the body the water we drink is absorbed?

Where in the body the water we drink is absorbed? Is the water even manage to get on their way to the small intestine? What place in the digestive system is 'terminus' to absorb water?5.28.181.99 (talk) 23:19, 26 June 2015 (UTC)[reply]

Water is absorbed in several places along the digestive tract; because water acts as a "universal solvent", anywhere other nutrients are absorbed, water takes the trip too; so as the bulk of nutrients are absorbed in the small intestine, lots of water gets absorbed there; though some water gets to the blood stream at every stop along the starting in the stomach. See here (page down to absorption) or here, which notes that 80% of water which will be absorbed has done so before reaching the large intestine. --Jayron 32 00:04, 27 June 2015 (UTC)[reply]

Yet one of the major functions of the large intestine is to reabsorb the water from the bolus before it is excreted, else one suffers diarrhea. μηδείς (talk) 02:28, 27 June 2015 (UTC)[reply]

True, but that doesn't mean that, proportionally, most of the water hasn't already been absorbed. --Jayron 32 14:15, 27 June 2015 (UTC)[reply]

Thank you. But maybe you know where is the last place of the absorption of the water in the GI? 5.28.181.99 (talk) 22:29, 27 June 2015 (UTC)[reply]

The Large Intestine. After that, it isn't in the GI tract at all. It's in your toilet. --Jayron 32 02:41, 28 June 2015 (UTC)[reply]

To clarify, water is still being absorbed in the rectum (see this paper), but not in the anal canal itself. The actual terminal point is the pectinate line. Tevildo (talk) 09:13, 28 June 2015 (UTC)[reply]

Is there a medical term that describes the non knowledge of the mechanism of disease?

The term "idiopathic" is given when the cause is not known but I'm taking about condition that the cause is known and just the mechanism of this cause is not known. Is there? 5.28.181.99 (talk) 23:52, 26 June 2015 (UTC)[reply]

I assume you mean "The term "idiopathic" is given when the cause is not known" because that's what idiopathic means. There is a two-word phrase, "unknown mechanism", which could meet the requirements you seek. This seems to indicate it is widespread, and I can't find any other single word. --Jayron 32 00:10, 27 June 2015 (UTC)[reply]

Thank you, I edited it. 5.28.181.99 (talk) 01:03, 27 June 2015 (UTC)[reply]

"Idiopathic"" literally means having to do with a self-caused illness, so that is a way of using Greek so as not to say unknown cause. (It doesn't really cause itself. It is just that the physician doesn't know what causes it, and does know a Greek term.) Robert McClenon (talk) 21:57, 27 June 2015 (UTC)[reply]

It would be helpful to describe a specific situation where the cause of a disease is known but the mechanism is not known. A purely hypothetical situation would be okay; I'm just trying to figure out exactly what you mean by this. Looie496 (talk) 11:36, 28 June 2015 (UTC)[reply]

June 27

Possible to stop eyes from watering?

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis, prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page.

Tevildo (talk) 23:12, 28 June 2015 (UTC)[reply]

Capillary refill in newborns

In the article capillary refill is written that "The upper normal limit for capillary refill in newborns is 2 seconds." But who look at the source of this sentence (source No. 3) will find that the upper normal limit is 3 seconds rather than 2 sec. 5.28.181.99 (talk) 11:37, 27 June 2015 (UTC)[reply]

Fixed. (You could have done that yourself.) --70.49.171.136 (talk) 22:04, 27 June 2015 (UTC)[reply]

Chimpanzee#Anatomy_and_physiology

I don’t know how to put this politely. As I view films of chimpanzees, I notice that their rears look very unusual. One particular documentary that I saw on YouTube (I can link to it if necessary) included a chimpanzee with a disturbing growth on its bottom. At first, I assumed that it was a sign of poor health, but the narrator said that it’s attractive to male chimpanzees. The article above doesn’t mention anything about their arses. So, may I please know what this weird thing is? --Romanophile (talk) 14:29, 27 June 2015 (UTC)[reply]

Maybe you could do the research and edit the article. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:08, 27 June 2015 (UTC)[reply]

Uhh… doesn’t asking here constitute research? I’m confused. But perhaps I was foolish to ask this awkward question here. --Romanophile (talk) 17:01, 27 June 2015 (UTC)[reply]

If the article doesn't have the info, then someone needs to research it. There's no reason you couldn't do that work, unless someone turns out to be willing to do it for you. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:14, 27 June 2015 (UTC)[reply]

E.C. Hey Romanophile. Welcome to Wikipedia and thank you for asking such an interesting question; I look forward to reading the answers. I don't believe that BB intended his remark to sound quite as harsh as it does, and I assume that he is simply saying that if you don't get an answer here, but do eventually find out elsewhere, then please either be bold and add that referenced material to our article, or if you are concerned that the material may not belong, then add it to that article's discussion page at Talk:Chimpanzee where other editors can help decide where it belongs. Also, we appreciate follow up posts here on the reference desks providing answers to previously unanswered questions. We have several well informed biologists who frequent this desk, so I suspect that you will soon receive both an answer and, most likely, a link to a relevant Wikipedia article. Thank you for looking for the answer in our articles first and for pointing out that you didn't find it where you expected to. Such information helps us improve our encyclopedia. -- ToE 21:34, 27 June 2015 (UTC)[reply]

This document[docx] from the Maryland Zoo states that the swelling is associated with estrus, and that "Females have an estrus cycle which lasts approximately 36 days. During the course of this cycle, as her hormone levels change, a female experiences changes in the size, shape, and color of her genital skin. As circulating estrogens increase during the follicular phase of the cycle, the size of the swelling increases. When the anogenital skin is fully engorged, it is typically bright pink, and can measure from 938 to 1400 cc. The state of maximal tumescence (swelling) is of variable length in different individuals and at different stages of maturity, but lasts an average of 6.5 days. It is during this time that females are sexually receptive and that the bulk of copulations with mature males occur." It also states that "Every day the chimp keeper is responsible for scoring the females stage of the cycle." and includes the following scoring chart:

Complete Detumescence: Minimum size, extensive wrinkling
Partial Tumescence: Slightly enlarged labia
Labial Occlusion: Medial surfaces of labia pressed tightly together
Significant Tumescence: Slight wrinkling, tissues raised significantly above anus
Maximum Tumescence: All tissues taut and pink, no wrinkling, anus deeply recessed

though there seems to be some confusion in that document whether the scoring range is 0-4 or 1-5. -- ToE 22:20, 27 June 2015 (UTC)[reply]

Aha! I finally found our article, though it is but a stub: Sexual swelling. There is some related material in the lede of our Concealed ovulation article, which starts:

Concealed ovulation or hidden estrus in a species is the lack of any perceptible change in an adult female (for instance, a change in appearance or scent) when she is "in heat" and near ovulation. Some examples of such changes are swelling and redness of the genitalia in baboons and bonobos Pan paniscus, and pheromone release in the feline family. In contrast, the females of humans and a few other species have few external signs of fecundity, making it difficult for a mate to consciously deduce, by means of external signs only, whether or not a female is near ovulation.

The photo you linked is of a bonobo, and our Bonobo#Sexual social behavior does say, "During oestrus, females undergo a swelling of the perineal tissue lasting 10 to 20 days. Most matings occur during the maximum swelling." Bonobos are closely related to common chimpanzees, being the other extant species of the genus Pan; Our article Chimpanzee is for that genus. Our species specific article Common chimpanzee#Mating and parenting says, "Estrous females exhibit sexual swellings." -- ToE 22:46, 27 June 2015 (UTC)[reply]

Life expectancy, what difference requires an explanation?

Given a list of countries ordered by life expectancy like here https://en.wikipedia.org/wiki/List_of_countries_by_life_expectancy, you can see the gap between Japan (84), Canada (82), Denmark (80), and so on, until you reach Sierra Leone (46) at the bottom.

It's clear that a difference like Japan to Sierra Leone would prompt a question and be worth an explanation.

However, how small does a difference in years need to be to NOT require an explanation? — Preceding unsigned comment added by Scicurious (talk • contribs) 15:47, 27 June 2015 (UTC)[reply]

That's actually a statistics question, essentially, given the distributions of life expectancy in each country, what is the minimum difference in means between two countries that is significant, statistically, at your chosen level of significance. Boring eh? Greglocock (talk) 01:53, 28 June 2015 (UTC)[reply]

The article states that the differences are primarily due to the quality of health care, and refers to some other factors, such as HIV rate. As the previous poster said, a detailed answer about a comparison between any two countries is a statistics question, rejection of the null hypothesis that the underlying distribution is the same. Given that the number of people in each mean is large, the null hypothesis can very likely be rejected with high confidence, but statistics sometimes only states that there is causation without saying what causes what. Robert McClenon (talk) 02:12, 28 June 2015 (UTC)[reply]

When you get down to the 40's, that's a sign of some rather basic problems, like a lack of clean drinking water. More subtle differences could be due to differences in diets, genetics, activity level, etc. StuRat (talk) 03:49, 28 June 2015 (UTC)[reply]

The best way to compare countries and where there are differences is in actuarial tables that measure "average remaining years" for each age. Life expectancy from birth sufferes from many anomalies that include the definition of infant mortality as well as chilghood mortality. For example, I believe Japan excludes deaths that occur after birth but in the first X number of days. That makes a huge difference when comparing to the a country like the U.S. where death after live birth is counted. Third world countries also have a mortality in childhood that is much higher than first world countries. The interesting metrics to look at are remaining years at age 40, 50, 60, 70, etc. That comparison takes out a lot of factors unrelated to elderly care/diet/lifestyle/etc. The U.S. publishes these tables and breaks them down by race, gender, etc. Infant mortality is what seperates most demographics. There is very little variance in remaining years past age 60 in the U.S. but infant mortality makes overall variance larger. --DHeyward (talk) 09:48, 28 June 2015 (UTC)[reply]

June 28

Rhizophoraceae, could it be narrowed down taxonomically?

Hi Ref Desk,

I just found some photos I could stitch to a panorama of mangroves I took 5 years ago at Anse du Canal near Petit-Canal on Grande-Terre, Guadeloupe, Lesser Antilles. The family of mangrove plants is the Rhizophoraceae, but I was wondering if the identification could be further narrowed down to the genus level or perhaps even species level based on the photo alone and the location? -- Slaunger (talk) 07:12, 28 June 2015 (UTC)[reply]

Great photo! Using the photo for species level ID would require an expertise I don't think we have here. Fortunately, the specific location will help you rule out several genera. Just a note, Mangrove#Taxonomy_and_evolution lists several other families in addition to Rhizophoraceae that also have species known as mangroves in them, you might want to browse through those also. SemanticMantis (talk) 14:35, 29 June 2015 (UTC)[reply]

How can one induce sleep paralysis?

I read the article on sleep paralysis but it doesn't say how to induce it. I'd really like to experience it for myself. Thanks — Preceding unsigned comment added by 117.169.218.7 (talk) 11:59, 28 June 2015 (UTC)[reply]

You can't induce it, there are just certain things that make it more likely [8]. Mikenorton (talk) 12:22, 28 June 2015 (UTC)[reply]

Have your doctor strap you into your bed. That should do the trick. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:32, 28 June 2015 (UTC)[reply]

Why did birds survive the extinction of other dinosaurs?

It seems to be generally accepted that modern birds are descended from the dinosaurs, I'm left wondering why specifically the birds survived the dinosaur extinction event? It seems very surprising that no other kinds of small dinosaur made it through the mass extinction alongside the birds, reptiles and mammals that seemingly had similar lifestyles, body size and diet to small non-avian dinosaurs.

What feature of birds enabled them to get through the catastrophe?

SteveBaker (talk) 14:50, 28 June 2015 (UTC)[reply]

"My answer to a related question about aquatic dinosaurs may help, I at least point to a Radio Lab episode where they discuss the KT impact with geologists. Basically, anything that was on the surface of the Earth got cooked, but anything under a few inches of soil would be ok. This favored small mammals, birds, and reptiles that nested underground. While modern birds don't typically bury eggs, ancient birds may have, to hide them from predators. – user137 Nov 18 '14 at 20:52" Count Iblis (talk) 15:53, 28 June 2015 (UTC)[reply]

Sure, but surely there were small dinosaurs (comparable in size and lifestyle to mammals and reptiles) that weren't adapted to flight at the time? Seems unlikely that ALL small dinosaurs were birds...and clearly you didn't need any of the special bird adaptations such as flight or egg-laying in order to survive. So if birds could survive - then why no tiny dinosaurs or other kinds? SteveBaker (talk) 17:16, 28 June 2015 (UTC)[reply]

This is probably related to bird's capability of flight. Ruslik_Zero 17:35, 28 June 2015 (UTC)[reply]

But the mammals and reptiles that survived couldn't fly. Why did the dinosaurs need to be able to fly in order to survive? SteveBaker (talk) 19:15, 28 June 2015 (UTC)[reply]

Wasn't it the less the case that birds survived as such, but that birds later evolved from the small number of dinosaur species (or one species even?) that managed to survive the extinction? --87.112.205.195 (talk) 17:38, 28 June 2015 (UTC)[reply]

No, that was my first thought too - but when I was trying to figure this out for myself, I discovered that the evolution of birds happened long before the extinction event. Microraptor was around 120 to 125 million years ago and was capable of powered flight and looked a lot like a modern bird (except for the small matter of having four wings!). But the rest of the dinosaurs didn't go extinct until 66 million years ago - so birds had been evolving for 55 to 60 million years before the rest of the dinosaurs vanished. SteveBaker (talk) 19:14, 28 June 2015 (UTC)[reply]

it might be that a few kinds could fly higher that other dinosaurs so they survived

We don't know. We lack a complete understanding of the events of the impact, or of the ecology that existed before and after the event. We do know that at least some mammals and birds survived, though far from all of either. We also know that non-avian dinosaurs went extinct, but a variety of other reptiles (e.g. alligators, turtles) survived. Some of the differences is undoubtedly due to adaptation, lifestyle, and flexibility, but some of the difference between who died and who survived is also probably down to dumb luck. Imagine killing 99% of all individual animals alive and then seeing which survivors manage to form successful breeding populations, not an easy thing if your species is large and sparsely populated. It also isn't very clear how much differentiation already existed prior to the event. For example, if small burrowing mammals were already more successful than small dinosaurs in occupying the burrowing niches, there may have been few or no dinosaurs designed for hiding underground during the event. Cretaceous–Paleogene extinction event provides some detail on the speculations about the role that traits like small size, burrowing, swimming, ectothermy v. endothermy, etc. may have played in favoring some groups over others. Dragons flight (talk) 22:38, 28 June 2015 (UTC)[reply]

Agreed we don't (and likely can't) know for sure. Paleoecology is hard stuff. It's probably not even deterministic - when you get to low population levels after Disturbance_(ecology) , things like allee effects and founder effects pose a serious challenge to any kind of long-term, deterministic prediction of how competition will sort out the community ecology of a certain clade. It's not so much about who survived the first few years after impact, but also about who was able to have positive growth rates in the new world - it's not just existence, but species coexistence in the community context that matters. There's also the extremely likelihood of multiple basins of attraction in the population processes, known as Alternative stable states in ecology. Even in homogenous worlds, we can see evidence of emergent endogenous heterogeneity and non-deterministic competitive outcomes over time. And of course the real world has lots of heterogeneity that further complicates deterministic prediction.

That being said, there is indeed speculation on why things worked out the way they did, though it doesn't always get published in reputable journals. This [9] is a nice write up of the specifics of kill mechanisms. This [10] is a nice general perspective piece on extinction vulnerability, with some discussion of K/T. This one [11] might be your best bet at getting a view of how morphology is thought to play into the sauropod/avian evolution around the K/T. Incidentally, there is still at least some debate over when the avian radiation occurred, and how many birds or birdlike things survived. These two papers seem to be part of the emerging consensus that avian radiation was well underway before the K/T extinction [12] [13]. If you believe that there were many birds around before the asteroid hit, then they would have already gone through several iterations of Niche_differentiation, and that by itself is enough to suggest that most extinction mechanisms would have a selective effect, even though it doesn't tell us exactly why any one clade was selected. SemanticMantis (talk) 15:04, 29 June 2015 (UTC)[reply]

Some good stuff above; I would only caution/reaffirm that a) it's honestly unknown at this point b) palaeontology is undergoing huge shifts in understanding and has been for the last few decades, and c) the dividing lines between birds and dinos, such as they exist right now, are being routinely re-written. Experienced dino guys, like Robert Bakker, have asked similar questions about other groups of animals: what catastrophe is big enough to kill off all the dinosaurs but too small to kill off the frogs? We know using present day data that frogs and other amphibians are great indicators of the health of an ecosystem - they don't tolerate much change - yet they apparently had no problem with the global catastrophes we associate with the KT extinction. Matt Deres (talk) 19:22, 29 June 2015 (UTC)[reply]

Memory question

During the day when you do something you typically remember doing it. Can you tell me what chemical is released into the brain at night that prevents you from remembering your dreams? Also, how is it so fast acting that one can wake for a few moments in the middle of the night and remember doing so, but not remember the dreams either side of the awakening? — Preceding unsigned comment added by 183.217.239.165 (talk) 17:20, 28 June 2015 (UTC)[reply]

I've read somewhere that this has to do with the way memories are stored in the brain. When you dream, your memory works differently, similar to how it works in animals and small children. At the age of about 5 the memory starts to work differently due to the development of language. When the vocabulary of the child becomes rich enough, memories are filed in the brain using abstract language more instead of the primary experience. It has been found that events in early childhood could be clearly remembered by children until about that age of about 5 and then all of a sudden the child will fail to be able to recollect the event. This is then purely a matter of the brain starting to use a different filing system to store and recollect memories, old memories filed according to the old system then become untraceable.

Now, when we dream, we revert back to using the old system for memory again, because in dreams we typically don't use language a lot. Then, when you wake, your brain will use the usual language based system form memory recollection, and then you'll have difficulties remembering the dream. You can also notice this effect when you remember another dream inside a dream, or memories from early childhood inside a dream. Count Iblis (talk) 17:53, 28 June 2015 (UTC)[reply]

Another point of view (because this is an area of active research), dreams are not transferred from short term to long term memory. Short term memory lasts a few minutes. If you talk about your dream as soon as you awake, you can remember what you said, but you will forget the dream. 75.139.70.50 (talk) 19:34, 28 June 2015 (UTC)[reply]

Who says so? ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:55, 28 June 2015 (UTC)[reply]

First, to summarize... Norepinephrine appears to be required to move memories from short-term to long-term memory. I have not seen any studies that satisfactorily explain the full mechanism. It appears to be more complicated than just triggering the hippocampus to move the memories - though that is certainly used because people with cancer or damage to the hippocampus fail to move memories into long-term memory. It appears, across many VERY easy to find studies in psychiatric journals, that the prefontal cortex is also used to decide which memories the hippocamus should move and norepinephrine is used in the process. While sleeping, levels of norepinephrine drop. Without norepinephrine, memories are not moved from short-term memory to long-term memory. When you wake up, norepinephrine levels rise and your ability start remembering things returns. So, WHO says so: Try Fricke and Mitchison from Berkeley, Crick and Kotch from CalTech, Hartmann from Tufts, and pretty much anything in the Journal of Sleep Research.

As for your comment below that you can "remember" a dream by concentrating on it - that falls into false memories. There are countless experiments that expose how false memories work. I recently saw a television program in which a "crime" took place and witnesses were questioned. They were asked to concentrate and remember the event. They convinced themselves that they were remembering the criminal's jacket, hat, and shoes (he wasn't wearing a hat). They remembered the color of the victim's dress (she had on a shirt and slacks). As I mentioned above, if you think about a dream as soon as you wake, you can remember thinking about the dream and move those thoughts to long-term memory. However, you will forget the actual dream. With false memories, you can fill in all the gaps in your memory and convince yourself that you have remembered your dream, but you are actually just remembering thinking about the dream - not the dream itself. 199.15.144.250 (talk) 11:55, 29 June 2015 (UTC)[reply]

The TV series "Brain Games" often has segments showing how unreliable and incomplete witness memories can be. And I should clarify that I usually don't remember an entire dream, just the parts that made a strong impression; at the same time realizing there was more to it, but it's gone. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:59, 29 June 2015 (UTC)[reply]

Sleep study experts would likely tell you that you are remembering the impression that the dream had on you and not the dream itself. Another way I've seen it described is that you are vividly remembering your reaction to the dream that you had once you woke, but you are not remembering the dream itself. Your reaction likely contains short-term memories of the dream, which then are transferred to long-term memory because they are part of the reaction. In the end, there is a muddy definition of "remembering the dream." Is remembering a memory of the dream the same as remembering the dream? For the scientific studies done at the sleep lab in our hospital, memories of memories don't count as remembering the dream. Side note: study of dream recall is getting more funding now that it is moving into general studies of memory storage and recall. If you are really interested in this area and have a related degree, check with your local sleep lab. There will likely be opportunities for research. 209.149.113.185 (talk) 16:01, 29 June 2015 (UTC) — Preceding unsigned comment added by Baseball Bugs (talk • contribs) [reply]

I'd like to see a citation for the claim that "...you typically remember doing it." Unless you're like Carrie Wells, your routine activities will fade from memory. For example, driving to and from work every day for thousands of work days, you'll remember the route, but you're not likely to remember any particular drive to or from, unless something unusual happened and made an impression. ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:01, 28 June 2015 (UTC)[reply]

I wrote a blog post about this a few months ago, The frustrating puzzle of dream amnesia. The basic message is that we rather surprisingly don't know the answer. Looie496 (talk) 03:00, 29 June 2015 (UTC)[reply]

In contrast to the OP's claim, it is possible to remember dreams, at least in part, by concentrating on them. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:41, 29 June 2015 (UTC)[reply]

Yes, though it's impossible to say how much is legitimately remembered and how much is just false memory (how would you even know?). I've read and can back up based on experience that the ability to recall is severely hampered by movement. Lying perfectly still and concentrating on the dream may give you some impressions, but it's usually a lost cause once you stand up. Matt Deres (talk) 19:36, 29 June 2015 (UTC)[reply]

Asteroids

If some asteroids collided with one of the solar system gas giants like Uranus, would there be an ouflow of matter or would it just be bottled up and increase the pressure? --109.149.199.246 (talk) 18:24, 28 June 2015 (UTC)[reply]

Something similar happened with Comet Shoemaker-Levy 9 and Jupiter. --TammyMoet (talk) 18:56, 28 June 2015 (UTC)[reply]

Actually more than one time: Category:Jupiter_impact_events. Ruslik_Zero 20:01, 28 June 2015 (UTC)[reply]

We know that asteroid impacts with Mars were enough to cause chunks of rock to be thrown all the way to impact on Earth (See: Martian meteorite). The fact that we've found 132 of them so far suggests that this is not an uncommon thing. Less remarkably, we've also seen chunks of moon rock arrive here on earth via the same mechanism. That being the case, it wouldn't surprise me if gasses from Uranus wouldn't also reach the escape velocity of that planet never to return. Uranus' escape velocity is about four times greater than Mars - but that would also result in impacting asteroids being accelerated to higher speeds as they head inwards to the surface.

Uranus has 27 moons and a bunch of rings that might also capture ejected material and prevent it from returning to the planet itself without it having to reach escape velocity.

It doesn't seem likely that the total mass lost in this manner would be likely to exceed the mass of the incoming impactor...but I think that would be hard to prove conclusively. SteveBaker (talk) 21:14, 28 June 2015 (UTC)[reply]

Mars and the Moon are rocky bodies, and rock shatters on impact. Jupiter is a gas giant, and Uranus is an ice giant. If matter were ejected due to impact, it wouldn't be in a form capable of impacting another planet such as Earth. I haven't researched it, but I would think that the gassy or icy nature of a giant planet would minimize the amount of ejected matter as opposed to a collision with a rocky planet. Robert McClenon (talk) 00:52, 29 June 2015 (UTC)[reply]

I wasn't suggesting that the matter from Jupiter or Uranus would be capable of reaching Earth - I was merely pointing out that there is clearly enough energy present in a falling asteroid to propel rocks outwards at speeds beyond escape velocity. Therefore, an impact with a gas giant could easily propel gasses outwards at similar speeds and result in a total loss of that material.

If you need a mental image of this - consider that if you toss a brick into a swimming pool, the splash goes way higher than if you drop it into a sand box from the same height.

Furthermore, you don't need to push the material outwards as fast as escape velocity if it can be pulled towards another body before it falls back...and Uranus has a rich set of moons that could capture sub-escape-velocity material.

There is no doubt that material will be lost in this way...the question is whether the amount of material that's lost exceeds the mass of the asteroid itself...which is a tougher thing to estimate.

SteveBaker (talk) 04:39, 29 June 2015 (UTC)[reply]

Commercial space flight mishaps

Today's launch of a SpaceX Falcon 9 suffered a catastrophic explosion that destroyed the launch vehicle and its payload. This event was originally described as an "anomaly" by NASA. Later, at the first press conference, an FAA spokesperson described the occurrence as a "mishap." This terminology has specific meaning in the context of commercial space flight (it is defined by 14 CFR §437.75).

How were previous SpaceX failures categorized? Do we yet have a Wikipedia article listing anomalies and mishaps during commercial space operations?

Nimur (talk) 20:58, 28 June 2015 (UTC)[reply]

Have you seen this article^[1]? The 'See also' and the 'External links' section; might help you...I haven't checked... -- Space Ghost (talk) 18:55, 29 June 2015 (UTC)[reply]

References

^ https://en.wikipedia.org/wiki/SpaceX_CRS-7

Do these new driverless cars comply with the three laws of robotics?

(see Three Laws of Robotics)

Q as topic. It seems that we're coming to a point where this is becoming an important issue. With something like a Roomba, it doesn't matter so much, but robots/AI/whatever being in charge of road vehicles with the potential to kill humans seems different.--87.112.205.195 (talk) 21:04, 28 June 2015 (UTC)[reply]

No. They almost certainly lack the intelligence to reliably identify human beings, and have no abilities to 'obey orders' beyond their designed purpose - driving on roads, in traffic. They aren't 'robots' in the general sense that Asimov describes, and don't need to be to do the job required of them. AndyTheGrump (talk) 21:11, 28 June 2015 (UTC)[reply]

Asimov's laws are exceedingly subtle in their wording and implications. For example, the first law says that a robot may not allow a human to come to harm because of it's own inaction. Arguably then, it should drive itself off and help the underprivileged rather than drive you to work this morning! On the other hand, because even with perfect software, there is a non-zero chance of you dying in a car wreck when you are driven by it, it might simply refuse to drive anyone anywhere.

The second rule says that says that a robot must obey the orders of any human providing it doesn't result in it infringing the first rule...so a car thief can order it to drive away and be dismantled for parts...maybe...depending on the fuzzy definition of "come to harm". The third rule requires the car to protect itself...but not if that would infringe the first or second rules...so that rule doesn't help here.

But it's very hard to understand these rules - what does "come to harm" mean for a human? Is loss of money "harm"? If not, then the robot will drain your bank balance in order to obey the command of a random vandal who thinks it's fun to tell cars to crash themselves into the nearest brick wall. If loss of money does constitute "harm" then the car might feel that it's better if you take a taxi today in order that it can protect it's own existence by not wearing out it's parts by driving you to work.

So no, for sure not. I don't think any robot of any kind will ever truly be able to follow these rules...and if it could, I think it would be an entirely useless device - so I doubt anyone will even try to implement them.

If you read the Isaac Asimov books that explore the three laws that he proposed, virtually every story is an example of a robot that does something exceedingly bad because it's following the three laws. In some cases, he claims that the robots can balance relative strengths of the three laws - but that seems to imply a complicated equation between "harm" as in loss of money, "harm" as in minor scratches and scrapes or "harm" as in death balanced against verbal orders that rage from outright demands to mere suggestions from humans.

The laws aren't even all that useful. Should a car save your life by driving into a crowd of 100 small children - doing so with enough care to ensure that they all live, despite losing limbs and spending the rest of their days in wheelchairs? That's a difficult ethical decision - and the laws don't help the robot to decide in the slightest.

SteveBaker (talk) 21:38, 28 June 2015 (UTC)[reply]

Isaac Asimov wrote some great stories, but they were science fiction. More specifically, his robot series were very old science fiction. How old? So old that when Asimov conceived of his Three Laws of Robotics, he never considered that robots would have computers in them! Asimov wrote some very excellent stories about robots, and some very excellent stories about computers, but I am not aware of any story where he connected the facts together: his robots are not programmed using computer software! (If anybody can cite any Asimov story which even slightly contradicts this, I will happily rescind my assertion!) Instead, Asimov posited a special machine, a positronic brain, which could not be reprogrammed: rules about decision-making were built into this machine. This is the opposite of how computers work! General purpose computing machines can be reprogrammed to follow any algorithm that we can describe as logical sequences of steps represented in a formal machine language!

If you would like to read a very interesting and much more modern robot science fiction story, The Robot and the Baby by John McCarthy explores software programming rules that govern the ethical behavior between robots and humans. The story was written only a few years ago, and its author was a foundational contributor to the field of artificial intelligence programming. Unlike Asimov's robots, this robot actually must follow a computer program to calculate how it interacts with a human when it is faced with an ethical conundrum. McCarthy's story provides a more accurate representation of the way a computer-software-controlled robot would behave, even down to the fact that every robot who runs the same software is expected to behave identically. Asimov's fictional stories about his U.S. Robots and Mechanical Men robots don't seem to follow this logic! If you want to know how Asimov envisioned robotic cars, and how his Three Laws would apply, we don't have to speculate: we can read Sally (1953)! Those cars are a lot more emotional than modern robotic cars (like Stanley), and their decisions never are described to be the results of calculation.

Nimur (talk) 21:53, 28 June 2015 (UTC)[reply]

I agree that Asimov didn't have software in his robots - but he very much did expect them to behave identically - in Little Lost Robot, Dr Susan Calvin tries to find one robot with a slightly modified design amongst 62 identical robots...and the job is tough because the odd one out has been ordered to "get lost" - which it does by impersonating the others. All 63 robots behave identically in almost every test.

His robots behave very much as if they were running software.

But, "...the fact that every robot who runs the same software is expected to behave identically" - only true in theory. In practice, robots only behave identically in identical circumstances. My robotic vacuum cleaner starts out from it's charging socket every day, and with the precise same software, trundles around vacuuming the house. But it doesn't take the exact same path every day. Microscopic variations in the floor make it diverge a little to the left and right as it drives along, and when it comes to the point where it has to turn left or right in order to avoid the opposite wall, it chooses (I think) based on how much it has to turn in either direction - sometimes the wall is at an angle of 89 degrees, other times it's at 91 degrees - so it's essentially random. Two AI robots will similarly have slightly different sensory inputs, slightly different initial circumstances. It's like identical twin humans. Sure, they start off with identical DNA - but before very long, they are living quite different lives.

The world is chaotic (in the mathematical sense of extreme sensitivity to initial conditions) - and robots are not immune to that.

But it is unfortunate that people who read Asimov's robot stories hold up these fictional rules as being a great starting point for real robots. It's certainly not true - and there is no evidence that Asimov ever believed that.

SteveBaker (talk) 23:52, 28 June 2015 (UTC)[reply]

What would be some good rules for real robots then, do you think? I know that people have suggested that all robots/AIs be taught the Ten Commandments. Which could either go very well, or very, very, very badly indeed. Another one (and probably the most important) should probably be NO SELF-REPLICATING MACHINES UNDER ANY CIRCUMSTANCES. --87.112.205.195 (talk) 00:20, 29 June 2015 (UTC)[reply]

Remember that Asimov started writing his robot stories in 1939 and formalized the Three Laws of Robotics in 1942. Computers in any sense that we know them had not been invented. The closest that there was to what we now call software was the early work of Alan Turing. In the 1950's, when Asimov was still writing robot stories, computers existed, but were so large and energy-intensive that they were not seen as an alternative to the hypothetical positronic brain. Asimov, like other science fiction writers of the Golden Age, was sometimes too optimistic and sometimes not optimistic enough in anticipating technology. Robert McClenon (talk) 00:40, 29 June 2015 (UTC)[reply]

The ten commandments are woefully inadequate - let's have a quick run-through:

You shall have no other gods before Me. -- Hmmm - probably not an issue.
You shall not make idols. -- Shame, with 3D printing, robots are pretty good at that.
You shall not take the name of the LORD your God in vain. -- OK - make a note of that in the vocabulary database.
Remember the Sabbath day, to keep it holy. -- Robots are good at remembering stuff: const char*sabbath="Sunday"; ...but "keeping it holy" evidently pulls in a whole raft of other rules about what exactly that means. I don't know that we want our robots to basically shut down and praise god on one day of the week.
Honor your father and your mother. -- Don't have those, so no problemo.
You shall not murder. -- Aha! A useful law finally! Not quite as good as Asimov's 1st law, but definitely A Good Thing. God evidently doesn't care if you allow someone to die through your inaction, or if you cause them non-fatal injuries during extreme torture sessions.
You shall not commit adultery. -- Um...yeah, that's probably a good one to toss in there, but until robots get considerably more anthropomorphic than they currently are, it's probably not an issue for anything fancier than an artificially intelligent dildo.
You shall not steal. -- Ooooh! Good rule! Asimov's robots are perfectly OK with stealing (depending on how you define "harm to humans").
You shall not bear false witness against your neighbor. -- OK, no problem there.
You shall not covet stuff. -- Not hard for an arguably emotionless device.

So it seems likely that a very few lines of code would take care of most of those things - but in truth the only useful protections these offer is that the robot won't murder or steal. But sadly, there is no prevention for maiming small children or deliberately driving into other cars on the freeway just to see how much damage they'll take. Since the robot doesn't have to follow anyone's instructions, you could get into your car at the end of a long day at work and discover that it just doesn't feel like driving home today.

The ten commandments are totally useless here. Asimov's rules work better - but they're still nowhere near adequate.

We'll need *SO* many rules. First of all, the robot must ingest the entire corpus of the constitution and laws of the places it's going to visit - including case law and 'common law'. It'll have to know that driving at the speed limit on a freeway is going to upset all the humans behind it - and breaking the law by driving 10% faster is considered acceptable. It'll have to follow customary rules of politeness..."Thou shalt not yell 'FUCK YOU' at maximum audio volume and/or raise robotic middle finger at persons who cut you off in traffic - even though your owner does exactly that when in 'MANUAL DRIVE' mode."...for example.

The rules and customs of life are vastly more complex than can possibly be encapsulated in a small, convenient number of rules. Robots will either need hundreds of millions of lines of code to cover all of the eventualities (which, I guarantee will be bug-ridden as all hell) - or they'll have to learn, making many horrible mistakes along the way...just like people.

SteveBaker (talk) 03:10, 29 June 2015 (UTC)[reply]

Industrial robots are "made safe" by prohibiting humans from getting within their reach while they are on. Many guided missiles are designed to self-destruct if they lose target guidance. Of course they are intended to harm humans, of the "other" political persuasion. Roger (Dodger67) (talk) 12:05, 29 June 2015 (UTC)[reply]

Indeed - but that tactic isn't going to work out so well with robotic cars! SteveBaker (talk) 15:08, 29 June 2015 (UTC)[reply]

Although the story of Light Verse (short story) suggests to get the identical behaviour the robots may have required adjustment in some cases. Nil Einne (talk) 13:42, 29 June 2015 (UTC)[reply]

Indeed - and when your computer starts misbehaving, the most common suggestion is to "Reinstall Windows" to return it to normal behavior...but suppose you've tweaked settings and installed a bunch of plugins and applications, and made your own folders and such. Doing a "recalibration" by reinstalling Windows will wipe out a bunch of positive characteristics that your computer has picked up over the years - and you might well be upset if someone did that without asking you first. That pretty much mirrors Asimov's story - so it's as true with simple computers as it is with "positronic brains". SteveBaker (talk) 15:08, 29 June 2015 (UTC)[reply]

I'm amazed that robotic cars were allowed without some type of national debate on whether we want to go in that direction. However, when inevitably a robotic car kills somebody (possible due to a glitch, or perhaps just something unavoidable as happens with human drivers), then I'd expect the debate will take place. Another example of a tombstone mentality. StuRat (talk) 20:07, 29 June 2015 (UTC)[reply]

Big Bang

Are there any tests made for the Big Bang like Abiogenisis? -- Space Ghost (talk) 23:02, 28 June 2015 (UTC)[reply]

Observations are made, see Observational cosmology. Bubba73 ^{You talkin' to me?} 00:27, 29 June 2015 (UTC)[reply]

High energy particle accelerators (such as the Super Proton Synchrotron and the Large Hadron Collider, both at CERN, and the Relativistic Heavy Ion Collider at Brookhaven) create quark–gluon plasmas. These experiments replicate conditions during the quark epoch, when the universe was less than 10 milliseconds old. Detailed analysis of the results from these experiments have (so far) confirmed that the Standard Model of particle physics is correct. And the Standard Model allows cosmologists to make very precise predictions about the subsequent evolution of the universe that very closely match observational data such as the cosmic microwave background radiation and the relative proportions of elements in the universe. Gandalf61 (talk) 10:22, 29 June 2015 (UTC)[reply]

I just hope it doesn't take years to understand what you guys stated... Anyway thank you both

I'll read it soon. -- Space Ghost (talk) 19:02, 29 June 2015 (UTC)[reply]

Life form(s)

Have scientists yet come up with simulations of life forms that may be available at a Goldie lock zone of/in a planet, during a steller evolution? Say for example, a T Tauri Sun’s ray will destroy the Earth in its goldie lock zone. If we move Earth to a distance where it will receive the equivalent temperature of our yellow sun and rotate it like it rotates in this solar system, and so on. If so, what are the results of life forms of steller evolutions? -- Space Ghost (talk) 23:48, 28 June 2015 (UTC)[reply]

Just a minor point but it's spelled "Goldilocks" as in the character from Goldilocks and the Three Bears. Dismas|^(talk) 07:13, 29 June 2015 (UTC)[reply]

Agreed. It's from in the story where she found one bowl of porridge was too hot, another too cold, and one was "just right". StuRat (talk) 18:00, 29 June 2015 (UTC)[reply]

Sorry friends, I didn't know. I heard the word in a science telecast program once. -- Space Ghost (talk) 19:01, 29 June 2015 (UTC)[reply]

Current evidence, gathered by examining star and planet formation, is that the star forms before the planets are formed. Therefore, your question is based on something that is not expected: a planet forming before the star forms. 199.15.144.250 (talk) 11:35, 29 June 2015 (UTC)[reply]

[[File:|25px|link=]] I recalled, then again, computer simulations can do any kind of tricks these days. -- Space Ghost (talk) 19:01, 29 June 2015 (UTC)[reply]

It's not just the star's formation that could wipe out life on a planet. The Sun's expected red giant phase should do so on Earth, not to mention a nova or supernova. StuRat (talk) 17:58, 29 June 2015 (UTC)[reply]

But I thought the hotter the Sun becomes the different molecules it produces, considering a red giant and considering its a population I star, shouldn't it produce molecules which should satisfiy the hypothesis of alien life form(s)? -- Space Ghost (talk) 19:01, 29 June 2015 (UTC)[reply]

Stars don't directly produce molecules at all, as it's too hot for molecules, which are composed of 2 or more atoms joined together, to form. They do produce larger, more complex atoms (see chemical element) the hotter they get (although the heat isn't just the cause, but also the result). Life does require these larger, more complex elements, but they can be leftover from a previous generation of stars. In our case, our Sun mostly just produces helium now, and all of the heavy elements on which life relies come from some supernova long before the solar system was formed. StuRat (talk) 19:47, 29 June 2015 (UTC)[reply]

See Goldilocks zone. StuRat (talk) 17:56, 29 June 2015 (UTC)[reply]

Okay, thanks. -- Space Ghost (talk) 19:01, 29 June 2015 (UTC)[reply]

June 29

Identify a submarine

This photo of a submarine was found among a collection of documents and photos related to a South African warship, HMSAS Transvaal's trip to Australia in 1951. Unfortunately there is no other information about the encounter with the submarine, though we suspect it was probably Australian. Roger (Dodger67) (talk) 06:39, 29 June 2015 (UTC)[reply]

The silhouette is very similar to a British T-class submarine, a number of which operated from Australia during and after the war. WegianWarrior (talk) 07:00, 29 June 2015 (UTC)[reply]

A quick bit of research on Wikipedia suggests the Royal Australian Navy had no submarines in 1951. See Royal Australian Navy Submarine Service#1945 to present. (In fact, the RAN had no submarine from April 1931 when HMAS Otway (1927) and HMAS Oxley (1927) were returned to the RN, until HMAS Oxley (S57) et al were commissioned in the late 1960s.) Dolphin (t) 07:07, 29 June 2015 (UTC)[reply]

Thanks this info narrows down the research task considerably: Which Royal Navy T-class subs were in Australian waters during January 1951. Roger (Dodger67) (talk) 09:28, 29 June 2015 (UTC)[reply]

A March 1951 newspaper report of a Commonwealth naval exercise in Australian waters, in which two unnamed British submarines "acted as hares" for the combined surface fleet; Modern Submarine Main Danger. It might be difficult to pinpoint as the RN maintained a whole submarine flotilla at Singapore during the 1950s and early 1960s. Alansplodge (talk) 10:10, 29 June 2015 (UTC)[reply]

It was called "Operation Convex" according to The West Australian, 12 March 1951: "Big Naval Exercise". Alansplodge (talk) 12:05, 29 June 2015 (UTC)[reply]

Another photo of the sub has turned up, in Sydney Harbour, date not known but definitely early 1951. If anyone is interested, a forum discussion about the HMSAS Transvaal documents and photos is at http://www.saairforce.co.za/forum/viewtopic.php?f=18&t=8225&p=103962#p103962 -- Roger (Dodger67) (talk) 10:45, 29 June 2015 (UTC)[reply]

Just found that the Royal Navy's 4th Submarine Flotilla was based at HMAS Penguin in Sydney, the last British submarine leaving in 1969. According to The Royal Navy 4th Submarine Squadron Based in Sydney, AUSTRALIA, those based there in 1951 were: HMS Telemachus (P321), HMS Thorough (P324) and HMS Taciturn (P314). Alansplodge (talk) 12:25, 29 June 2015 (UTC)[reply]

But we can rule out HMS Taciturn, as she had been modernised in 1948 to look like this. Alansplodge (talk) 18:07, 29 June 2015 (UTC)[reply]

Thanks all I think the three names are as close as we're ever going to get unless another photo showing a hull number or other distinctive marking turns up. Roger (Dodger67) (talk) 18:06, 29 June 2015 (UTC)[reply]

What is relation of the bacterium "Helicobacter pylori" to the pylorus?

I don't find the answer In the article Helicobacter pylori "The bacterium was initially named Campylobacter pyloridis, then renamed C. pylori (pylori being the genitive of pylorus, the circular opening leading from the stomach into the duodenum, from the Ancient Greek word πυλωρός, which means gatekeeper.[110]). When 16S ribosomal RNA gene sequencing and other research showed in 1989 that the bacterium did not belong in the genus Campylobacter, it was placed in its own genus, Helicobacter from the ancient Greek hělix/έλιξ "spiral" or "coil".[110]" 192.117.186.252 (talk) 14:34, 29 June 2015 (UTC)[reply]

Found in the stomach, named for a part of the stomach? DMacks (talk) 17:07, 29 June 2015 (UTC)[reply]

Well, the article states that it is linked to duodenal cancers, leading to me to assume it's found in the duodenum as well as the stomach. It seems entirely reasonable that it was named pyloridis/ pylori simply be because of where it was first found, around the bottom of the stomach, top of the duodenum, in particular the pylorus. But that's just my guess' at present.

Now, for a reference that supports the claim, I got to this article [14] by searching for /pyloridis new/. That led me to the original describing article UNIDENTIFIED CURVED BACILLI IN THE STOMACH OF PATIENTS WITH GASTRITIS AND PEPTIC ULCERATION paywalled here [15] (you might be able to find an accessible copy by searching the title). In it, Marshall says

“

If

it is premature to talk of "Campylobacter pyloridis" perhaps the name "pyloric campylobacter" will do to define the site where these organisms are commonly found and to indicate the similarity to known Campylobacter spp.

”

- emphasis mine. So I'd say that we've now confirmed that it is named after where it is commonly found. If you want to thank me, you could do so by editing the H. pylori article to cite that ref for the claim that Marshall first detected it in the second sentence, and possibly later for a new sentence explaining the name :) SemanticMantis (talk) 17:08, 29 June 2015 (UTC)[reply]

Home-made air conditioner

The air-con projects I have seen so far are build based on ice (from the freezer) in some isolating box and blowing a fan on it.

Is there a home-made air-con project that would not work with the principle above? Something based on evaporating water could also work, couldn't it?--YX-1000A (talk) 17:01, 29 June 2015 (UTC)[reply]

Yes, evaporative cooling is our general article, the devices are commonly called swamp coolers in parts of the USA, though many names are used. These get a lot of use in greenhouses, where you might not mind exchanging some heat for humidity. I just recently saw a decent installation of one in an orchid house near Corpus_Christi,_Texas. Quite cooling indeed, even in a humid environment, despite reports that the maker of said cooler warned that it might not work well at that ambient heat and humidity. Might not be very suitable for in-home use in very humid climates though. Here's a homemade version I found on youtube [16]. SemanticMantis (talk) 17:21, 29 June 2015 (UTC)[reply]

An even simpler method is to drape a damp towel over a box fan (being sure to leave enough air flow to not overload the fan). You will need to rewet the towel often, though. You can toss it in the washing machine periodically with some bleach to avoid mildew. StuRat (talk) 17:51, 29 June 2015 (UTC)[reply]

Another way to make a homemade air conditioner would be to get a long hose (ideally thin-walled), connect to the faucet, loop the hose around the room, have it drain someplace safe, and turn the water on. This relies on underground water pipes supplying cooler water than the air temperature. Advantages are the simplicity and no electricity use. However, it is extremely wasteful of water, so would only make economic sense if you drain the water someplace you can use it anyway, like to irrigate a garden/crops, fill a bathtub (that would only take a few minutes, though), etc.

An alternate version could use a water pump and rain barrels (although the pump could be omitted if the rain barrels are elevated enough above the area you want to cool). Here it would only work early in the day, when the rain barrel water is still cool from night, but that water is free, so you don't have to worry about wasting it (although irrigating a garden or crops with it still makes sense). Both variations would likely only work to cool a small area, unless you are a farmer, and have need for massive amounts of water to irrigate your crops anyway, in which case the first method might cool the entire house (but a farmer is more likely pumping water out of a stream or underground reservoir, so there would be some increased electrical use to pump it through the house, too). StuRat (talk) 17:37, 29 June 2015 (UTC)[reply]

Swamp coolers are not very effective when evaporation is limited due to humidity (it just makes the room feel like a swamp by adding moisture to the air). The hose method is used in places where it is easy to cool water - such as Hawaii. Just run the hose extremely deep into the ocean to cool the water down and then loop it back up to the house. The actual system there is more complicated - but the principle is to send the house's heat into the ocean. Another method, not mentioned, is simply moving the air. If it is hotter at the top of a room than it is outside, automate a system of trapping the hot air at the ceiling and sending in slightly less warm air from outside - a rather poor version of a heat pump. Overall, none of those works as well as running coolant through a radiator and blowing air past it. Doing so also gives you the benefit of dehumidifying the air because condensation will collect on the radiator and drip down. 209.149.113.185 (talk) 17:47, 29 June 2015 (UTC)[reply]

And I suppose I should mention the method I actually use to cool my house. Put box fans (not those silly, tiny, underpowered twin "window fans" shown at the top of that article, but rather the large, single fan, shown below it) in windows, to blow hot air out and cool air in at night. Put all the fans blowing in at the lower floor and out on the upper floor to take advantage of the tendency of hot air to rise (or put fans pointing in on one side of the house and out on the other, for a single story home). Try to seal the area around each fan as well as possible to prevent local recirculation (air going the wrong way around the fan). I've cut a circular "mask" out of plastic sheeting for each fan, custom fit to each window opening, to do this. Don't leave any other windows open without fans. Can cool the house quickly when it is cool and dry at night and hot during the day. However, if it's humid out, say over 60°F dew point, the humidity getting inside makes it not practical. Also, you will have to make the house uncomfortably cold by morning to keep it cool all day, so wear a sweater to bed, and even then it's only good to keep the house maybe 10°F cooler than the outside temp. And if you leave the fans on too long in the morning you are paying to blow warm air into the house. Also, can't use this method when there's a risk of rain or bad fumes (like from cars in the driveway) that may be blown inside, or security issues with open windows. Still, with all these caveats, I can cool my house much faster than with A/C, under ideal conditions. Note that I mean the air is cooled quickly, but to cool the walls, floors, ceiling, furniture, etc., takes hours. If you don't cool those down, then the air temp quickly rebounds as soon as you turn the fans off.

One other caution is to always maintain positive pressure in the house, by having more fans blowing in than out. This means you turn the fans blowing in, on first, and off last. If you don't do this and create a negative pressure, it may suck exhaust (water heater, etc.) down chimneys, and you don't want that. StuRat (talk) 18:13, 29 June 2015 (UTC)[reply]

Number of bones and joints in human body

Ironically, Google search engine shows 360 joints according to non-reliable sources if you just type the following "number of joints in human body". However I'm really surprised why such very old question doesn't get interest of the scientific community to answer. I searched some other sites (like this), found that bones are about 206 in an adult human and about 250-350 joints. I assume that if a joint is linking two (or more bones unless there are two or more consecutive joints) and thus total number of joints should be always less than or equal total number of bones which should limit that of human body to 206 joint. Do you have an explanation?--Almuhammedi (talk) 21:18, 29 June 2015 (UTC)[reply]

[1] ttps://en.wikipedia.org/wiki/Chronology_of_the_universe#/media/File:CMB_Timeline300_no_WMAP.jpg

[2] ttps://en.wikipedia.org/wiki/Reionization#/media/File:Reion_diagram.jpg

[3] ttps://en.wikipedia.org/wiki/Metallicity#Population_III_stars

[4] ttps://en.wikipedia.org/wiki/Chronology_of_the_universe#Structure_formation

[5] ttps://en.wikipedia.org/wiki/Chronology_of_the_universe#Formation_of_stars

[6] ttps://en.wikipedia.org/wiki/Chronology_of_the_universe#Reionization

[7] ttps://en.wikipedia.org/wiki/SpaceX_CRS-7

[1]

[2]

[3]

[4]

[5]

[6]

[1]