Wikipedia:Reference desk/Science

From Wikipedia, the free encyclopedia
Jump to: navigation, search

The Wikipedia Reference Desk covering the topic of science.

Welcome to the science reference desk.
Want a faster answer?

Main page: Help searching Wikipedia

How can I get my question answered?

  • Provide a short header that gives the general topic of the question.
  • Type ~~~~ (four tildes) at the end – this signs and dates your contribution so we know who wrote what and when.
  • Post your question to only one desk.
  • Don't post personal contact information – it will be removed. We'll answer here within a few days.
  • 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.

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.
See also:
Help desk
Village pump
Help manual

April 24[edit]

What came first, the chicks or the chicken?[edit]

What came first, the chicks or the chicken?

Do women lay an evolved egg (which is internal and better protected), or, do chicken lay an evolved ovum (which has its own nutrients, and can be laid anywhere and forgotten about)? What evolved from what? --Llaanngg (talk) 01:38, 24 April 2015 (UTC)

Explained here. Count Iblis (talk) 01:58, 24 April 2015 (UTC)
Mammals (including humans) evolved from egg-laying animals, although not specifically from chickens. StuRat (talk) 04:24, 24 April 2015 (UTC)
Indeed monotremes still lay eggs; only the other mammals evolved vivipary. Note that vivipary has evolved many times in many different groups of organisms, even full-fledged hemotrophic vivipary (i.e. sustenance from the maternal blood supply) in sharks with yolk sac placentas. A cruder example is Limnonectes larvaepartus, a frog that bears tadpoles that apparently eat feces and one another while inside the mother's body. Wnt (talk) 13:06, 24 April 2015 (UTC)
Minor correction: from vivipary - "When considering squamate reptiles in particular, there is a correlation between high altitudes or latitudes, colder climates and the frequency of viviparity. " - Viviparous reptiles are a little different than viviparous mammals in terms of the means and mechanisms of reproduction, but they are still considered viviparous. SemanticMantis (talk) 15:15, 24 April 2015 (UTC)
  • Modern amniotic vertebrate eggs arose with the amniota 330 million years ago, flying dinosaurs have been around since the Jurrasic, and the land and waterfowl (Galloanseres) have been around since before the K/T event. The genus Gallus has been around since the mid-Pleistocene at least. Since we use the term chick nowadays to refer to all baby birds, they have been around since before the dinosaurs went extinct, the modern domesticated chicken only since the end of the last ice-age, and the hard-shelled egg since the late Carboniferous.

What are the signs that there's a sinkhole beneath the ground you're on?[edit]

Are there telltale signs that there's a sinkhole below the ground you're on or the building you're in? -- (talk) 02:48, 24 April 2015 (UTC)

watch here. Count Iblis (talk) 03:05, 24 April 2015 (UTC)
Not until it's rather too late, when the ground starts to sink. Sometimes there's enough warning to evacuate before total collapse, sometimes not. To avoid this risk, you'd want to use ground-penetrating radar (dragging a device that looks like a lawn mower back and forth across the surface in a grid pattern), especially if you are in an area with karst topography. StuRat (talk) 04:21, 24 April 2015 (UTC)
Here's what happens when you don't realize you are walking on a sinkhole. μηδείς (talk) 20:20, 24 April 2015 (UTC)
Have a look at Detection & Warning Signs of Imminent Sinkhole Collapse --Aspro (talk) 21:54, 24 April 2015 (UTC)
We had a sinkhole forming around a manhole above a sewer. The manhole kept getting lower, and there were holes along the sides going all the way down to the sewer. When we first sounded the alarm, they just patched over the holes with asphalt, but I knew that was no good. Soon enough the holes were even larger. Fortunately, they then repaired it correctly. StuRat (talk) 23:37, 24 April 2015 (UTC)

meteorology vs aerology[edit]

What is the difference between meteorology and aerology? --IEditEncyclopedia (talk) 13:13, 24 April 2015 (UTC)

Meteorology is a part of aerology—atmospheric sciences. Ruslik_Zero 13:43, 24 April 2015 (UTC)
"Aerology" is an old term that is rarely used any more. It had two main usages. First, it was the U.S. Navy's term for meteorology in general. (The Navy tends to have their own way of doing things.) Second, it was the study of the free atmosphere, above the boundary layer. In the second sense aerology is part of meteorology, not the other way around. Short Brigade Harvester Boris (talk) 19:49, 25 April 2015 (UTC)

April 25[edit]

Drilling holes and magma[edit]

If you drill into the Earth deep enough, will you eventually hit magma? Will this work anywhere on the planet? Malamockq (talk) 18:43, 25 April 2015 (UTC)

One issue is that if you drill toward very hot material, the drill bit stops working - see Kola Superdeep Borehole. Another issue is that rock in the mantle (geology) is not really liquid but "plastic" in nature, and only becomes magma when it moves up enough for the pressure on it to be relieved. In theory, an open borehole would relieve the pressure, so does that make it magma? But you couldn't make an open borehole because the "plastic" rock would push in on it too much to keep it open, I think. (ought to research that further) But if you use "your mind's eye" to scout for "true liquid" under the ground, then there's nothing guaranteed short of the outer core, which is molten iron and hence not really magma either. Wnt (talk) 18:55, 25 April 2015 (UTC)
If you could drill such a hole, then the magma would cool, thicken, slow, and finally solidify, as it rose through cooler surrounding rock, so I don't think you'd get a volcano, if that's what you meant. A volcano requires a large magma chamber close to the surface, from which it can then erupt. StuRat (talk) 19:07, 25 April 2015 (UTC)
A practical method is described here. Count Iblis (talk) 19:39, 25 April 2015 (UTC)
See previous discussion that discussed the challenges of drilling into shallow magma chambers beneath volcanoes. Mikenorton (talk) 21:39, 25 April 2015 (UTC)

Soooo, the answers to the actual questions are yes and yes, in case that wasn't obvious from the above verbiage. I am assuming what the OP really wants to know is is there molten rock under us no matter where we are on earth. See Magma#Migration (magma comes from the mantle or crust of earth). Richard-of-Earth (talk) 20:22, 26 April 2015 (UTC)

April 26[edit]

Aircraft propeller design[edit]

My traditional idea of a propeller blade is something like this. However, some modern aircraft have propellers that look like this or this, where the angle of the blades looks (to a non-expert) to be hopelessly wrong, more like a paddle-wheel that would drive the aircraft sideways. What is the reason for this change? (talk) 01:52, 26 April 2015 (UTC)

See Propeller (aeronautics)#Feathering. -- ToE 01:57, 26 April 2015 (UTC)
Even the first photo's props could be feathered, notice the cylindrical escutcheon (or casing if you must) around the root of each blade. That houses the feathering mechanism.Greglocock (talk) 02:45, 26 April 2015 (UTC)
Your photos are of a C-130 (or variant thereof); and either a TBM or a Meridian turboprop (I can't tell from this angle). All of these aircraft use a constant-speed propeller: the pitch of the propeller blade varies with power setting in order to keep the rotation speed constant. For more on the theory and practice of these propellers, see the section on transitioning to complex aircraft (Chapter 11) in the Airplane Flying Handbook, or read about constant speed propellers in the Pilot's Handbook of Aeronautical Knowledge. Constant speed, variable pitch propellers exist because they enable the engine to operate at a maximally efficient RPM no matter how much power is needed for any specific flight configuration. Conversely, fixed-pitch props waste power - and therefore, fuel - by running the engine in an inefficient configuration (low RPM) when low power is required. In effect, the airfoils (blades) of a fixed-pitch prop are slipping through the air for almost all operating conditions except at one particular peak-efficiency power setting.
Also note that a variable pitch propeller need not be driven by a turbo engine: for example, the Super Decathalon is a piston-powered Citabria whose powerful engine drives a constant speed propeller; the Cessna 182 is a conventional general aviation aircraft whose piston engine drives a constant speed propeller. Constant speed propeller is one among three required elements of a "complex" aircraft, as defined by the FAA: a single-engine land aircraft must have flaps, retractable gear, and a constant speed propeller to qualify as "complex."
Nimur (talk) 03:13, 26 April 2015 (UTC)
The photograph of your traditional idea of a propeller shows a radial, reciprocating engine. The other two photographs show turbine-propeller engines. The former type of engine tends to be much older than turbine-propeller engines. The design standards for aircraft in that era allowed the pilot to manually feather the propeller of an engine that suffered a complete loss of power, even though it was well-known that a "windmilling" propeller on a failed engine generated a very large amount of drag, especially when the aircraft was flying at high speed. The design standards in that era didn't contain any incentive for prompt, automatic feathering of the propeller following an engine failure. In these engines, there is no need for the pilot to feather the propeller when the engine is being shut down at the end of a flight.
The design standards for modern aircraft, and especially those with modern turbine-propeller engines, contain a significant penalty (in terms of payload) for any multi-engine aircraft that relies on the pilot to recognize an engine failure, identify which engine has failed, and then manually feather the propeller on that engine. There is a strong incentive for designers to equip the engine and its propeller with sensors and pumps to automatically coarsen the pitch or feather the propeller whenever the engine is delivering less power than it should. Pilot action is not required for these propellers to feather at any stage of flight, including the end of a flight when the engine is being shut down. As a consequence, the propellers on these engines feather automatically whenever the engine is shut down. Even when one of these engines is installed on a single-engine aircraft, the automatic pitch-coarsening and feathering functions are retained. The two photographs you have supplied of turbine-propeller aircraft show aircraft that are stationary on the ground with their propeller blades in the position they automatically move to whenever the engines are shut down. Dolphin (t) 06:25, 26 April 2015 (UTC)

Bum hair[edit]


I am curious about why evolution has decided to keep hair on our anal region. I can't imagine it serving any particularly useful service, and it certainly has a detrimental affect in terms of cleanliness.

I've read stuff like The Ancestor's Tale, and have a reasonable lay-person's perspective on evolution.

I know that most seemingly-inexplicable traits (massive antlers, peacock tails, etc) are down to sexual selection, and that it's often best to assume sex-sel plays a role. But I can't see how that affects our bottoms.

I can understand how apes-humans lost their hair, and that keeping hair on our heads and beard makes some sense (heat-loss, usually exposed). I can understand that perhaps hair on genitals might be an indicator of sexual maturity (back to that oh-so-common evolutionary reason, sexual selection).

But I cannot imagine any survival-of-the-fittest logic in our keeping hairy bums.

Any ideas? — Preceding unsigned comment added by Bobbertybob (talkcontribs) 08:41, 26 April 2015 (UTC)

My layman's understanding is that things don't have to be useful to be selected for, they just have to be "not detrimental enough" to be selected against, so maybe it's the case here. And hygienic conditions were bad as they were for 99% of human history (as a species) anyway, so what's a little hair in the bum Asmrulz (talk) 09:38, 26 April 2015 (UTC)
You are assuming that evolution has stopped. Perhaps it has not. In thousands of years, we might have totally bald bottoms, or masses of fibrous keratin threads sprouting from every follicle!DrChrissy (talk) 09:48, 26 April 2015 (UTC)
I'd say it most surely hasn't stopped, but I don't see where in my post I assume that it has Asmrulz (talk) 10:23, 26 April 2015 (UTC)
My post was directed at the original question, not yours.DrChrissy (talk) 10:33, 26 April 2015 (UTC)
Then you indented incorrectly. Matt Deres (talk) 14:19, 26 April 2015 (UTC)
@Matt Deres Perhaps you would care to enlighten me as to the correct way of indenting - rather than just leaving a rather terse, negative, not-very-friendly message.DrChrissy (talk) 16:14, 26 April 2015 (UTC)
You indent one more tab than section you are replying to. So, if you were replying to the original post, which was not indented, you would use a single tab indent. If you don't do this, it gets very confusing, but you can always explicitly list the name of the person you are responding to. StuRat (talk) 16:42, 26 April 2015 (UTC)
There's really very little hair in the area compared to relatively recent ancestors - and remember, for many species like fruit flies that have a vastly shorter generation time and much more change at the genetic level, the actual physical changes over mere millions of years seen amount to much less, maybe a dark spot on the wing. Getting rid of hair near the anus requires an enhancer (genetics) that is exquisitely well-programmed to stop all induction of hairs in that region, while allowing hairs where they are needed. Such things take considerable design, all done in random steps, to make enough sites for transcription factors, etc. to process this logic, which starts off with quantitative differences in level and activity, into something approaching an absolute cutoff.
But also, I am not convinced the hairs there are a net negative, though I can only engage in rampant speculation. Remember for example that hairs are associated with a sebum production and distribution mechanism that might lubricate surfaces that slide against one another. They might disrupt caking of feces, though I doubt human ancestors put up with that anyway; or the sensation of feces twirling around on the hairs might have made the ancestors clean themselves... who knows? We only know evolution didn't find it to be a huge problem, i.e. there was not a very strong selection coefficient favoring changes that reduced the hairiness. Wnt (talk) 12:14, 26 April 2015 (UTC)
It may be that the hair acts as a dry lubricant, easing the friction of running/walking. Matt Deres (talk) 14:19, 26 April 2015 (UTC)
Yes, I suspect it's a pleiotropic effect, it is probably a side effect of the fact that the person has lots of body hair for some reason. That, or it's meant as a place to keep your dingleberries. It's certainly not a universal trait. μηδείς (talk) 18:16, 26 April 2015 (UTC)
(Prior to streaking in front of the police) Hyde: "I'm going to write 'I hate the fuzz ' on my ass !"
Fez: "If you hate the fuzz on your ass, why don't you just shave it off ?" - That '70s show - StuRat (talk) 21:56, 26 April 2015 (UTC)

Dying from eating too many eggs[edit]

I heard of someone that died from eating too many eggs. But the description of how they died sounded odd. They described the person dying suddenly while sitting in a chair without any signs of pain or distress and with their eyes still open at the time of death. If someone died of eating too many eggs wouldn't this have been preceded by a heart attack and the victim clutching their chest? Malamockq (talk) 16:58, 26 April 2015 (UTC)

Maybe he just happened to be eating eggs when he was stricken. I recall when Mama Cass died, it was alleged she had choked on a sandwich, but it turned out she just happened to be eating one at the time she had her fatal heart attack. ←Baseball Bugs What's up, Doc? carrots→ 17:14, 26 April 2015 (UTC)
Do you mean a diet chronically too high in eggs, possibly leading to a cholesterol overdose ? Or do you mean dying from an acute binge of too many eggs at one time ? If so, if they were eaten with salt, then that could cause high blood pressure and a stroke, if they had sodium sensitive hypertension. StuRat (talk) 17:15, 26 April 2015 (UTC)
For what it's worth, there is a memorable scene in the 1967 prison film Cool Hand Luke, where the title character played by the great Paul Newman wins a prison bet by eating 50 hard boiled eggs in an hour. Cullen328 Let's discuss it 17:28, 26 April 2015 (UTC)
Diet chronically too high is what is alleged. He was a father of 3, not some college frat boy eating tons of eggs on a dare. Malamockq (talk) 17:39, 26 April 2015 (UTC)
It still sounds more like a silent stroke (or likely a series, leading to the fatal event) than a heart attack. As you noted, a heart attack can kill quickly, but not instantly. Somebody dying of a heart attack would be expected to show signs of distress (although the symptoms are more vague in women). But a severe stroke or related event could potentially kill instantly. StuRat (talk) 17:58, 26 April 2015 (UTC)
The U.S. government is poised to withdraw longstanding warnings about cholesterol. Alansplodge (talk) 22:30, 26 April 2015 (UTC)
Yes, but what they really should do is come up with separate guidelines for LDL and HDL cholesterol, along with recommendations that foods should be explicitly labeled to show how much of each they contain. StuRat (talk) 17:36, 27 April 2015 (UTC)
Recent studies also show the recommended 1500-2300 mg salt recommendation may do more harm than good.
As for just dropping dead, this happened with my great aunt. She and my aunt were talking in the living room, my aunt went to pour a cup of tea, when she came back 30 seconds later my great aunt looked like she had fallen asleep, but shortly thereafter fell over and was declared dead on the scene. No autopsy was done, given she was in her 90's. μηδείς (talk) 01:15, 27 April 2015 (UTC)
There seem to be genetic differences in those with sodium sensitive hypertension which makes excess sodium more dangerous for them (including me). StuRat (talk) 17:39, 27 April 2015 (UTC)
Yes, I am certainly not advising people to act against medical advice. The various articles I have seen mention people with kidney and specific metabolic problems as exceptions. μηδείς (talk) 22:33, 27 April 2015 (UTC)
Also, people don't necessarily "clutch their chest" during a heart attack. Often, they just collapse. My wife's co-worker died of a heart attack at work. He was walking down the hall passed her, and just fell down in a heap mid-step. He made no obvious signs of distress until he just up and died. That someone was eating eggs, and then just died, does not mean the one caused the other. See Correlation does not imply causation and Post hoc ergo propter hoc for some understanding why people make such errors in understanding. --Jayron32 14:40, 27 April 2015 (UTC)

Does the size of the right ventricle indeed equals to the left ventricle size?[edit]

In our article ventricle is written: "The right ventricle is equal in size to that of the left ventricle, and contains roughly 85 millilitres (3 imp fl oz; 3 US fl oz) in the adult.". While in another wiki (echopedia) if i'm not mistaken it seems that the left ventricle is bigger (look at this: 18:20, 26 April 2015 (UTC) — Preceding unsigned comment added by (talk)

The relative sizes can vary. Also note that the interior and exterior volumes are not always proportional. See left ventricular hypertrophy, for example. Although if both articles purport to list the normal healthy values, this may not apply. StuRat (talk) 18:42, 26 April 2015 (UTC)
But why should not they have the same volume? They have to pump the same volume of blood. Ruslik_Zero 18:43, 26 April 2015 (UTC)
The right part only has to pump the blood through the lungs which happens at low resistance and hence requires low pressure. The left part has to pump the blood to the rest of the body, and unless you live a sedentary lifestyle this requires on average more effort for the heart. So, the left part tends to be larger than the right part, especially in athletes. Count Iblis (talk) 19:29, 26 April 2015 (UTC)
In the link that mention above, we can find apparently that in normal values of heart, the left ventricle is the bigger. So the sentence on our article needs citation q source. (talk) 19:59, 26 April 2015 (UTC)
In the following article is written that "The right and left ventricles differ greatly in their size". So till now, there's a mistake in our article. [1] (talk) 20:05, 26 April 2015 (UTC)
Before getting to the comparison, lets be clear of about the terminology:
  • Firstly, in literature ventricular volumes refers to inner volumes of the chambers, which are useful by themsleves, and required to calculate the diagnostically important parameters of ejection fraction and stroke volumes.
  • Secondly, it doesn't make sense to talk of ventricular volume without indicating whether one is talking about end-diastolic (ED) or end-systolic (ES) volume. So the sentence in the wikipedia article is almost meaningless as currently written (though it perhaps refers to end-systolic volume).
  • Thirdly, the original question and many of the responders are not clear about whether they are referring to the ventricular volume or the ventricular mass. The latter refers to the muscle mass of the two ventricles, and for reasons mentioned above, LV mass is significantly greater than RV mass.
Now coming to the question of volumes: The volumes of the two ventricles are indeed very much comparable, with RV volumes at both ES and ED being slightly larger; see this paper using MRI and and this paper using CT (ignore the abstract of the second paper which has some errors, and see Tables 1 and 2 instead).
Caveats: given the difficulty in measure in vivo volumes; dependence on the exact imaging modality and technique used; and large population variation, take the numbers cited in any of these papers with a pinch of salt; don't treat them as "true" measurement of ventricular volumes; and don't directly compare numbers obtained using different techniques unless you really know what you are doing and the adjustments that need to be made. Abecedare (talk) 21:06, 26 April 2015 (UTC)
Let's make it easier, if you take a heart of dead, which of the ventricles is the bigger? (I mean to the inner space) (talk) 22:50, 26 April 2015 (UTC)
The internal ventricle volumes are roughly the same in a healthy person, having it otherwise would make no sense at all, as they are in the same circulation. What is causing the confusion is that the left ventricle is far larger on the outside, as the muscle layer surrounding is is far thicker. Fgf10 (talk) 07:15, 27 April 2015 (UTC)


I have just finished this book, and in it, the author states that "Gaiduchenko suggested that...the high levels of N15 isotopes in human bone suggested that horses, very low in N15, were not eaten frequently. Foods derived from cattle and sheep, significantly higher in N15 than horses, probably composed most of the diet". My question is, why would the level of N15 be higher in cattle and sheep than in horses? Is it something to do with the fact cattle and sheep are ruminants? My googling didn't really get me anywhere.

As a side question, I found the book rather heavy on archaeology, and just a little light on PIE filling. Is there a decent, comprehensive layman's book on the Proto-Indo-European language? — Preceding unsigned comment added by BbBrock (talkcontribs) 21:44, 26 April 2015 (UTC)

Our article Isotopic signatures states "The ratio of N15/N14 tends to increase with trophic level, such that herbivores have higher nitrogen isotope values than plants, and carnivores have higher nitrogen isotope values than herbivores". This statement is uncited at the moment, but this paper has some experimental results and references to some theoretical bases for it. It would seem that this is an area where research is still ongoing. Tevildo (talk) 22:55, 26 April 2015 (UTC)
I would suspect that the difference lies in the fact that cattle and sheep are ruminants, and digest plant fiber differently compared to horses, while horses are neither ruminants, nor closely related. μηδείς (talk) 01:05, 27 April 2015 (UTC)
  • Mallory's In Search of the Europeans gives a broad overview fit for a layman, although he focuses a lot on where they came from. Indo-European Language and Culture: An Introduction by Benjamin W. Fortson IV is recommended, but I haven't read it. The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World (Oxford Linguistics)Nov 9, 2006 by J. P. Mallory and D. Q. Adams is an encylopedic source, a must have if you really want to study deeply. The American Heritage Dictionary of Indo-European Roots, Third Edition by Calvert Watkins is much more compact, and focuses mainly on PIE vocabulary found natively or by borrowing into english. It starts with a good sketch of the peoples, and weighs 1/8th of Mallory and Adams. There are many other texts. A good beginning work on linguistics in general is Anthony Burgess's A Mouthful of Air. It assumes very little prior knowledge, and maybe some grade-school familiarity with one or two languages besides English. μηδείς (talk) 03:39, 27 April 2015 (UTC)

Many thanks for the responses, and Medeis, thanks too for the suggestions. I will order the Fortson and Burgess books to start with. BbBrock (talk) 11:54, 27 April 2015 (UTC)

Should you be interested, I can give more specific recommendations based on your specific interests, BbBrock, much available online, or which I can email you at some point. Burgess is helpful because he introduces the IPA painlessly, which is the door to the rest of linguistics, once you've got a grasp on it. You should also explore all our articles on PIE, historical linguistics and the related articles that interest you. μηδείς (talk) 22:25, 27 April 2015 (UTC)

surface temperature versus satellite measurements[edit]

Is this true about the big difference in surface temperature measurements and satellite readings? What is the explanation for the difference and what is the consequence? Bubba73 You talkin' to me? 23:28, 26 April 2015 (UTC)

Satellites do not measure temperature. They measure radiances in various wavelength bands, which then must be processed using various assumptions and corrections to make inferences about temperature. Thus it's not surprising that satellite "measurements" of temperature disagree depending on who is doing the processing, and that they also disagree with the surface temperature measurements. Short Brigade Harvester Boris (talk) 23:56, 26 April 2015 (UTC)
Yes, and the radiance depends on the emissivity of the surface. In other words, a barren dry landscape under a clear night sky will cool down far more than an area that has vegetation. During the day one has to take into account reflectance also. During the night, clouds cause some radiance to be reflected back down to the surface again. There are many variables to take into account. So, as knowledge of remote sensing accumulates, adjustments are made to make them more accurate.--Aspro (talk) 00:52, 27 April 2015 (UTC)
Bear in mind we only have satellite data for say 35 years, and is a reasonably good global estimate of whatever it is they measure, although coverage of the poles has more errors than the bulk of it. We have surface temperature measurements going back perhaps 130 years to 160 years with some sort of steadily increasing accuracy, but they are subject to all sorts of sampling error in their own right, and again coverage of the poles and other places is dodgy. As such they are both /estimates/, not measurements, of global surface temperature. I believe that in the small time period where they overlap, the trend is roughly similar, a rise from 1980- 1998, followed by a plateau from 1998 to 2014. There's various bumps and valleys in that trend, but that's the gist of it. For instance here's a comparison between HADCRUT4, a thermometer based global surface temperature estimate, and RSS, a satellite based global surface temperature estimate, both averaged over 4 years.:hadcrut vs rss If we had a longer satellite record we could see whether the difference in trend between the two is just short term effects or actually significant. If it is significant then one or other or both will need to be corrected. I chose 4 years for no reason in particular, play around with it and see what difference it makes. Greglocock (talk) 00:24, 27 April 2015 (UTC)
We have an article on the author of the blog entry, Christopher Booker. I would want to see some scientific reliable sources before placing too much weight on what he says. Also the Global Warming Policy Foundation he refers to is... well, we must be civil here, so I shall hold my tongue. (talk) 00:30, 27 April 2015 (UTC)
Hilarious to see an anonymous ad hominem attack in response to an objective question. Here's a graph that demonstrates that whatever the satellite is estimating and whatever the surface temperature people are estimating, they pretty much agree on 48 month moving average trends over the last 35 years. HADCRUT3 offset against RSS. Greglocock (talk) 00:38, 27 April 2015 (UTC)
Interesting. If replotted using a 12-month moving average RSS tends to have wider swings than HADCRUT3, i.e. here. Also the point made by 88.x is relevant: Booker is not a scientist, and GWPF is not a scientific organization (the "P" in GWPF stands for "policy"). Short Brigade Harvester Boris (talk) 01:20, 27 April 2015 (UTC)
Not many journalists are scientists, Booker's job is to write stuff in newspapers. The people leading and conducting the investigation need to be scientists and statisticians, not journalists, the people who write about it in newspapers can be journalists. Greglocock (talk) 02:26, 27 April 2015 (UTC)
I do not consider it inappropriate to point out that there are people and organizations with long established biases and agendas. Or expect them to provide evidence in support of their claims that contradict the overwhelming body of scientific evidence. There are professional conspiracy theorists out there; read the articles linked above and decide for yourself if describing these people as such is an "attack". The history of how these people have been conducting their business is a perfectly valid data point on their credibility.
For myself, I find it hilarious that you take a potshot at me on the basis of my anonymity while accusing me of an ad hominem attack. Pot/kettle, &cetera. (talk) 01:14, 27 April 2015 (UTC)
I'll spell it slowly for you, pointing out that someone is making an ad hom comment, by making an ad hom comment, is an example of irony. Perhaps I should have added a smiley emoticon to make it even more obvious. Greglocock (talk) 06:38, 27 April 2015 (UTC)
Anyway to get back to the main point of this investigation, it isn't satellite vs surface thermometers, the main investigation is into the on-going adjustments to the historical and present day surface temperature record. Greglocock (talk) 02:26, 27 April 2015 (UTC)
The OP asked specifically about "the big difference in surface temperature measurements and satellite readings." Short Brigade Harvester Boris (talk) 02:40, 27 April 2015 (UTC)
As to that I think I've demonstrated the differences are essentially tiny in a time frame of 4 years or longer, for the mere 35 years for which comparisons are available. But the referenced article is to do with corrections to the long term surface record, not satellite vs surface.Greglocock (talk) 04:02, 27 April 2015 (UTC)
The OPs question has clearly been shown to be invalid, and is based on a politically motivated falsehood. Just move on. Fgf10 (talk) 07:13, 27 April 2015 (UTC)

April 27[edit]

Rollerball & Ballpoint mechanical differences--any?[edit]

From my reading of the articles for rollerball and ballpoint pens, it sounds like as far as the physical parts of the pen are concerned, there isn't a difference, and that the difference is in the quality of the ink, with ballpoint ink being thicker and rollerball ink being more watery. But am I wrong? Ignoring everything about the ink, is there a common constant mechanical/parts difference between ballpoints and rollerballs? (talk) 17:05, 27 April 2015 (UTC)

Rollerball pen and ballpoint pen are the articles in question. It sounds like the oil-based ink in traditional ballpoint pens makes for a better lubricant, allowing a larger ball. The gel used in some rollerball pens seems to be an inadequate lubricant, resulting in skipping even with the smaller ball. StuRat (talk) 17:31, 27 April 2015 (UTC)

April 28[edit]

Parrots and chillies (probably about the 15th question on this topic)...[edit]

So, it's fairly common knowledge that (most?) parrots have a natural tolerance for the capsaicin in chilli peppers - and a parrot can eat something like a habanero, the seeds, placenta and all, without the slightest apparent distress.

What I was curious about this time though - was how high this tolerance actually goes. Would a parrot be able to eat one of the superhot chillies, with a heat in the range of the millions of Scovilles? I've heard it said that parrots are immune to capsaicin, but OTOH, some people have said that it just affects them somewhat less than humans. --Kurt Shaped Box (talk) 00:52, 28 April 2015 (UTC)

The whole question is closely related to the evolution of mutualisms between birds and plants, e.g. frugivory, zoochory, and seed dispersal. It's not just parrots - virtually all birds have virtually no aversion to capsaicin, at least compared to mammals. The idea goes like this, speaking teleologically as not-quite-correct short hand: Plant species usually "want" their seeds to be dispersed, to deal with environmental heterogeneity and uncertain growing conditions, as well as to get a better mix of mates in sexual reproduction. Mammalian digestive tracts tend to be more damaging to seeds than bird digestive tracts. So, some plant species deal with the problem by adaptation to tougher seed coats that can survive passing through a mammal. Others, like piper_(genus), forego the resistant seed, and instead try to make sure only birds eat their seeds, so that they will survive the easier digestive tract. This way, dispersal is more likely than without a mammal deterrent, and it is also farther ranging, giving plenty of selective pressure to plants that can make compounds that mammals avoid and birds don't mind. Of course modern artificial selection and breeding programs have made things like the ghost pepper, which probably wouldn't have evolved so hot on its own. But that's all just context and background.
As to your actual questions - I think capsaicin is mostly invisible to the bird taste receptors. Here's a few scholarly papers that relate to the topic, I might be able to find better references tomorrow [2] [3]. Here's an interesting one that discusses behavioral effects of capsaicin on birds- when injected subcutaneously... [4]. SemanticMantis (talk) 02:28, 28 April 2015 (UTC)