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April 22

What's the brain size requirement for a life form to be intelligent?

I'm curious about how small alien intelligent life could be. Binmos (talk) 02:31, 22 April 2015 (UTC)

Define "intelligent." Short Brigade Harvester Boris (talk) 02:33, 22 April 2015 (UTC)

Like human intelligence. Binmos (talk) 04:53, 22 April 2015 (UTC)

Define human intelligence. Nil Einne (talk) 12:46, 22 April 2015 (UTC)

Amazingly, it seems the brain-to-body size ratio matters far more than the actual brain size. As the intro to our cuttlefish article states: "Recent studies indicate cuttlefish are among the most intelligent invertebrates. Cuttlefish also have one of the largest brain-to-body size ratios of all invertebrates." And whales and elephants are not the supergeniuses one would expect, based on brain size alone. StuRat (talk) 02:45, 22 April 2015 (UTC)

Is it scientifically possible for a brain/animal of that size to have human-level intelligence though? There must be a limit, I imagine ant brains are too small for even the possibility of human-level intelligence, regardless of the brain-body ratio. Binmos (talk) 04:53, 22 April 2015 (UTC)

I've been reading Ant Encounters, written by a preeminent authority on ant intelligence. This is a great book if you'd like a modern approach to the science of collective intelligence. For many decades, scientists have described ant and other colonial insect intelligence as "communal." The actual "intelligence" is not stored in the ganglia of any individual; analogously, your human intelligence is not "stored" in any individual neuron. Dr. Gordon's presentation is a very fun read, and she re-explores many ideas related to localization and physiology of intelligence. Perhaps you will find her review enlightening. In particular, use caution about projecting your interpretation of intelligent behavior onto a different form of life. Gordon writes extensively on the historiography of this problem, referencing scientific and cultural depictions of ant intelligence dating as far back as Proverbs 6:6, then through the Scientific Revolution, up to the present day. Historical descriptions of animal behavior - in particular, ant intelligence behavior - seem to be deeply colored by prevailing popular ideas about philosophy, religion, politics, economics. So, today you might read about animal intelligence defined in terms of microbiology or neurochemistry, but (and this is especially critical if you're interested in the SETI angle!) there's no real reason to assume that this is even the correct framework to formulate the question of intelligence. Nimur (talk) 05:57, 22 April 2015 (UTC)

Note that while individual humans have a fair amount of intelligence, it's still the case that the collective intelligence of all mankind far exceeds that of any individual. So, in that way, we are like the ants. StuRat (talk) 19:00, 22 April 2015 (UTC)

Encephalization quotient has some info along these lines. It's not the ratio of brain size to body size, but rather the ratio between actual brain size, and that predicted by some assumptions of allometry. SemanticMantis (talk) 13:31, 22 April 2015 (UTC)

• Basically the difference between human consciousness and animal consciousness is that we have thousands of concepts for ideas of varying levels of abstraction (e.g., tree, plant, deciduous, dicot, Prunus) which we either express with spoken or gestured words (allowing us to manipulate them perceptually) and recursively through syntax. Some sort of perceptual tag is necessary for manipulating concepts beyond the animal level. (Basically an intelligent animal can do anything you can do without use of words--that is without thinking aloud in your head--they can surf, walk 50 miles to a watering hole they visited 12 years ago, and get food from the fridge, but they can't do long division.)

Those animals that do manipulate a small set of concepts (some monkeys are believed to have dozens of calls and gestures) do so with simple concatenation, and cannot handle deeply embedded and abstract thoughts like "The man I killed two days after my last birthday out of jealousy was actually innocent of cheating with my ex-wife, so I plan on killing her when she gets remarried next Saturday, unless the minister is Lutheran, in which case I will kill both her and the bastard she's about to marry on their honeymoon wherever they take it.)

I would strongly suggest Merlin Donald's two books on the subject, in chronological order: Origins of the Modern Mind and A Mind So Rare which I came across as they are highly recommended by Oliver Sacks.

μηδείς (talk) 20:13, 22 April 2015 (UTC)

Another approach would be to consider that an insect like a bee only has one million neurons while humans have a hundred billion neurons. Now, we're still far of from being able to simulate anything like a human brain using the most powerful computers we have, but a bee's brain is feasible. E.g. recently experiments have been done to control a drone using software modeled on the basis of a bee's brain. While the computer was still not as capable as a bee's brain it was good enough to control the drone. Also the most powerful supercomputer we have would be capable of controlling a machine with the full power a bee's brain. Now, suppose then that somehow a million neurons is good enough to generate human-level intelligence. That would then imply that we could make an artificially intelligent system with human-level intelligence using only the computational resources that are available today. But no expert in the field of AI believes that this is possible. Count Iblis (talk) 20:31, 22 April 2015 (UTC)

@Count Iblis: Got a cite for that simulated bee-brained drone? Sounds interesting. SemanticMantis (talk) 22:19, 22 April 2015 (UTC)

I heard that brain simulation story, but it was with some far simpler organism, with only a hundred or so neurons. StuRat (talk) 22:37, 22 April 2015 (UTC)

see here. Count Iblis (talk) 02:52, 23 April 2015 (UTC)

If you want to read about computer minds (not simulated brains, but actual electronic minds) read Jeff Hawkins' On Intelligence. He works on the same method of increasing abstract levels of thought. What matters is not computational power itself, since GIGO. What matters is how that power is structured.

From the introspective view, one should read Ayn Rand's Introduction to Objectivist Epistemology (the first unexpanded edition is probably even better for the first read). According to my undergraduate advisor (an editor of Daniel Dennett's) it's the best 20th century work on epistemology he's read. Both books work on the same perception>concept>abstraction model. μηδείς (talk) 22:56, 22 April 2015 (UTC)

The really hard part about this is that we don't have a definition for "intelligence" or a way to measure it - certainly not in non-human animals, computers or whatever. Since we can't say whether a cuttlefish or a grey parrot is "intelligent", we can't really say whether something that small is capable of whatever intelligence is. We don't have a strong understanding on what makes the human brain exhibit this trait either. In Alex (parrot) it is claimed that this particular parrot had the intelligence of a 5 year old child - comparable to a dolphin or the great apes. This is a controversial view - but if we take it as a fact, then since we clearly agree that 5yr old humans are "intelligent" - then this research implies that something a couple of centimeters across is sufficient.

But even so, Alex could only learn about 400 words - and was clearly unable to do many things that 5 year-old children can do...learning to read, to make up long, complicated stories, to memorize long passages from favorite books. We now have to carefully segregate learning and memory from intelligence - and now things get complicated.

This question is clearly unanswerable as a definite matter - but it seems reasonable that some kind of glimmerings of intelligence are possible on that kind of scale - but any kind of bright-line definition seems impossible to attain. SteveBaker (talk) 04:43, 23 April 2015 (UTC)

We actually know much more about human intelligence than one person can master, it's not true to say intelligence as such is something mystical or mysterious or undefined. The only problem, if one goes back to the OP's original question, is that he's using the term intelligence in an absolute sense, rather than in the relative sense one uses when one compares a host of organisms on a varying scale. There's no absolute point at which organisms become intelligent any more than there is a specific speed at which they become fast, size at which the become big, or point at which they become "powerful". But we can certainly explain why a monitor lizard is smarter than a nematode, and why an elephant is more intelligent than an earthworm. μηδείς (talk) 18:12, 23 April 2015 (UTC)

Faster than speed of light

If we assume that we have a very long stick, and this stick is so long that it goes through the universe to an other planet. would´t it be possible to send information faster than speed of light just by moving the stick slightly, back and forwards. /Bro(sv) (talk) 13:21, 22 April 2015 (UTC)

Nope, the fastest you can send information down such a stick is actually much slower than the speed of light; mechanically moving a stick of such a size would only be able to transmit information as fast as the speed of sound in that stick. --Jayron32 13:27, 22 April 2015 (UTC)

I think you misunderstood the question, what I meant was that you are moving the entire stick slightly back and forwards and you are communicating with some sort of Morse code/Bro(sv) (talk) 13:31, 22 April 2015 (UTC)

Yes, if I move my end of the stick, the opposite end will only move once my push reaches that end. The fastest any mechanical movement can be propagated through a medium, whether it is a push, a pull, a pulse, a vibration, a waggle, or any other movement, is the speed of sound in that medium. If I push and pull my end of the stick back and forth, it will take some very long time for those movements to reach the other end of the stick. --Jayron32 13:33, 22 April 2015 (UTC)

Like they say in the Matrix, there is no stick. Or at least, there's no such thing as a rigid body. See Born rigidity, which itself leads to the Ehrenfest paradox. This is a very deep rabbit hole and I've gone nowhere near the bottom of it. Wnt (talk) 13:35, 22 April 2015 (UTC)

There is no stick quite true. Most of an atom, and consequently, most of things, is empty space. Peter Michner (talk) 16:22, 23 April 2015 (UTC)

(EC)...And that would generate compression waves in the stick, and the message would get there at the speed of sound. This is actually a very common question/misconception, but that doesn't mean it isn't tricky to understand. See this previous question Wikipedia:Reference desk/Archives/Science/2010 October 24#Light speed and giant sticks, or this one Wikipedia:Reference desk/Archives/Science/2008 January 10#Communicating Faster than Light Using a Rotating Rod, and many other similar can be found by searching the archives using the box at the top of the page. The main thing is that in the real world, there is no such thing as a "perfectly rigid" rod or stick. Even at normal scales, there is some lag between when you push a stick and when the other end moves. It's just too short to notice without very specialized equipment. SemanticMantis (talk) 13:39, 22 April 2015 (UTC)

Thanks for answering I have been wondering about this for 3 years! I have just one small question; If we give the stick a starting velocity that is higher than the speed of sound through the stick, would the transferring speed still be the speed of sound?/Bro(sv) (talk) 17:54, 22 April 2015 (UTC)

You can strike the end of the stick at a speed greater than the stick's speed of sound, but as happens in air, a shock wave would form and the general pulse of vibration would only be transmitted at the speed of sound. There would be some slightly complex behaviour near your end of the stick, but along its general length sqrt(E/rho) rules. Greglocock (talk) 22:14, 22 April 2015 (UTC)

Unlike the speed of light, the speed of sound is relative to the transmitting medium. So yes, with respect to the stick, but no with respect to the unmoving observer. But that can never result in faster-than-light communication, because for the unmoving observer, you must add the speed of the stick and the speed of the signal in the stick using relativistic addition of velocities. --Stephan Schulz (talk) 18:09, 22 April 2015 (UTC)

Doesn't the speed of light also vary depending on what it's traveling through? ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:19, 22 April 2015 (UTC)

Yes, and it also depends on properties of the light - see Speed_of_light#In_a_medium. Often, "speed of light" is shorthand for "speed of light in a vacuum". SemanticMantis (talk) 19:48, 22 April 2015 (UTC)

In particular, the "universal speed limit" is the speed of light in a vacuum, it's possible for particles to travel faster than light within a particular medium (See Cherenkov radiation for a pretty, blue consequence of this) MChesterMC (talk) 07:36, 23 April 2015 (UTC)

It would be impossible, as planets rotate. Sooner or later, the stick would not be pointing in the right direction for the receiver on the other planet. It'd be faster to send an email. KägeTorä - (^影_虎) (もしもし！) 18:25, 22 April 2015 (UTC)

This is a very common question. See e.g. 1, 2, 3, 4, [1], [2], [3], [4], [5], [6], [7], [8], [9], etc. -- BenRG (talk) 19:22, 22 April 2015 (UTC)

I think it's important to point out that the inability to send matter, energy or information faster than the speed of light is a general property of the universe that is completely fundamental. So when you ask yourself any kind of question like this one, it's very safe to assume that the answer will ALWAYS be "No"...I don't even have to read the explanation of your question to know that this is the answer.

The only question of any importance is "Why doesn't it work?" - and that can often be interesting. In this case, the problem is that we're thinking of the stick as being a "solid object" - but we know that it's really just a rather sparse collection of atoms that push and pull each other around with various forces. The right mental model is that it's a bit like they are all connected with springs that keep them more or less the same distance apart all the time. So when you push on one end, the atoms that are repelled by the atoms in your finger go on to repel more atoms further down the rod - and the resulting wave travels down the length of the rod at a rate determined by the springiness of the spring. Hundreds to thousands of miles per hour - but nowhere near as fast as light.

But the take-away message is that no matter what devious trick you come up with - possibly involving million mile long rotating rods with magnets on the ends and electrically charged black holes spaced at intervals along them with supersonic rocket-powered weasels running along it's length signalling to each other in morse-code with flashlights...or who-knows-what other complications...you KNOW that the answer is always going to be "No!"...you don't have to worry about WHY it won't work...it just won't. It's a similar kind of deal to perpetual motion machines - or cars that are claimed to run on water...the answer is "No...it definitely won't work"...and you only need to worry about the details of how it's claimed to work if you care about WHY it won't work.

SteveBaker (talk) 04:09, 23 April 2015 (UTC)

Pronouncing XYZ "is a general property of the universe that is completely fundamental" is likely to be true in most cases but not all, thus to claim infallibility in capital letters and ignore further inquiry you divorce yourself of the scientific method. See Scientific method#Pragmatic model where it says "The scientific method – the method wherein inquiry regards itself as fallible and purposely tests itself and criticizes, corrects, and improves itself." For example, I have framed a toy model that contradicts relativity but works well enough that if I apply Occam's razor it is probably true, and unlike current theory it merits the machine that I'm building, which if it works would be progress. Learning about how the world is and not just what you happen to think it is is very much a creative process. -Modocc (talk) 06:37, 23 April 2015 (UTC)

I don't think anyone is suggesting that we should presume anything is completely infallible and in particular, that there should be no further inquiry. In fact, the nearly opposite. What is being suggested is that we should look at the existing evidence. The existing evidence really strongly suggests "XYZ (the speed of light here) is a general property of the universe that is completely fundamental". Therefore any inquiry should be based on this understanding. This doesn't mean you should completely exclude the possibility that what all the multitudes of evidence is wrong, but rather it should be way, way, way down in your list of possibilities. In this particular case, with due respect to the OP, as BenRG and to some extent SemanticMantis and others have said, this isn't a particularly revolutionary question that few people think of. Instead it's something many people think of and has been asked and answered many times over. Even for a more complicated case, it still makes sense to assume there's probably something you're missing, rather than assume you've come up with some flaw which means something widely regarded to be true as supported by a multitude of evidence is wrong. This is fully supported by the scientific method. Nil Einne (talk) 16:06, 23 April 2015 (UTC)

Assuming the theory of relativity is roughly correct, we have a choice between causality and faster-than-light communication. I like both, but causality is dearer to my heart ;-). --Stephan Schulz (talk)

{EC) Of course when you think you've discovered a flaw in something as fundemental as the second law of thermodynamics and have found free energy, it may make particular sense to investigate whether you're wrong before you spend 3+? years of your life working on something which is probably fundamentally flawed. Besides scientific method and Occam's Razors considerations, it's just common sense, there's surely better hobbies out there. Wasting so much of your time on something which is probably due to confusion or error on your part, is not likely progress. Nil Einne (talk) 16:27, 23 April 2015 (UTC)

Although I could be more diligent and commit more time to my work, I'm not wasting my time which is well spent. There is no need for strongly opinionated "take away messages", against the guidelines, which are chocked full of misplaced pedantic oughts on this science board. Modocc (talk) 17:37, 23 April 2015 (UTC)

I was fairly kind in my response, but if you don't want me to be, so be it. How you waste your time because you're too afraid to actually investigate what your doing wrong or unwilling or unable to understand it or whatever else your'e surely doing wrong, is up to you, you aren't the first person to do so and won't be the last. But as with all such people, the problem becomes when you try and mislead other people with your flawed thinking despite providing no actual evidence for your claims. So yes, what is against the guidelines is sprouting such pseudoscientific nonsense on the science desk, as you have done before and did above. Challenging people on their pseudoscientific nonsense on the science desk is well within the RD guidelines. If you want to continue to sprout pseudoscience, you're welcome to hang out in places where such people hang out (there must be hundreds if not thousands of free energy and similar forums), but not wikipedia or the RD, particularly not the RD/S. Nil Einne (talk) 00:30, 24 April 2015 (UTC)

I gave a simple counterexample that was germane to the issue that Baker raised and I made no unsubstantiated claim in what I wrote and cited our article on science. Popper would be proud. Modocc (talk) 02:03, 24 April 2015 (UTC)

"it should be way, way, way down in your list of possibilities." No, as one may have fallen into a rabbit hole. Teaching why paradigms and current knowledge applies is fine, but regarding incomplete knowledge as unassailable is not scientific. -Modocc (talk) 18:11, 23 April 2015 (UTC)

Still missing the point. I didn't say it's unassailable, and it doesn't look like anyone else did either. What I did say, is that if we have a large amount of evidence which points to one conclusion, and a tiny bit of evidence which may be misunderstood, has never been repeated, etc etc that points to another, we shouldn't throw out all that other evidence straight away. Instead you should investigate, with the recognition that all that evidence pointing in the other direction is probably right. This is fully within the scientific method, seeing paradigm shifts in every tiny bit of evidence which remotely suggests a contradiction(*) or throwing out all the evidence straight away because you don't understand something is not. (*)Particularly when it actually doesn't as multimillions of other people have found out before when they investigated, a tiny percentage of which are recorded on the internet but which still means there are probably many thousand such discussions on the internet. As is the case for the OPs question and therefore ultimately what we're talking about. Nil Einne (talk) 00:27, 24 April 2015 (UTC)

I was referring to Baker's opinionated answer and your multiple replies towards me defending him. Modocc (talk) 02:03, 24 April 2015 (UTC)

To give an example of how confusing this can be, consider if you whack on a "rigid" rod and move it by a meter, and the compression wave moves down the rod at 0.999c. So there might be, say, a 1-mm region where the rod is packed 1000x times more tightly due to the compression, moving at 0.999c, or maybe it's more like a 31.6-mm region that's 31.6 times more tightly packed. But the Lorentz contraction for anything moving at 0.999c is sqrt(1000) = 31.6, so if the second case were true, with the local atoms moving 0.999c relative to your frame, then in their own frame they're still spaced just as far apart as in the rod at rest, which means (?) that it is a rigid rod despite the obvious compression wave (?). I imagine someone must have gone much more deeply into this sort of calculation... Wnt (talk) 20:59, 23 April 2015 (UTC)

I haven't checked your math, but I'm fairly sure its no different for the compression wave which contracts than for a ship that traverses between stars. -Modocc (talk) 21:51, 23 April 2015 (UTC)

No, pressure waves in a medium and inertial motion in a vacuum are different. In the case of a pressure wave there is no physical object traveling at the speed of the wave: the atoms making up the medium travel at a much slower speed while the electromagnetic interaction between them travels (or at least updates) at c. (Compare speed of electricity.) The higher the speed of sound, the less compression you'd expect to exist at any point. You can easily compress a slinky by pushing it, but the (Newtonian) limit of an infinite speed of sound is a perfectly rigid object, which can't be compressed at all. -- BenRG (talk) 18:33, 24 April 2015 (UTC)

Which means the ships (the medium's molecules) contract less. Paradox resolved. Modocc (talk) 19:22, 24 April 2015 (UTC)

April 23

asperger's syndrome and autism: how do they relate to schizoid and schizotypal

Are people on the autism spectrum considered a subset of the people with schizoid personality and/or schizotypal personality? Thanks.144.35.45.65 (talk) 02:57, 23 April 2015 (UTC)

No. (That was an easy question!) SteveBaker (talk) 03:46, 23 April 2015 (UTC)

The articles autism spectrum and schizoid personality disorder may be helpful. As Steve says neither is a subset of the other, though they do have some overlapping characteristics. Dragons flight (talk) 03:56, 23 April 2015 (UTC)

The two are not subsets, but there is some genetic overlap. See [10] for example; there's a lot more on PubMed if you dig. To be sure, the roles of many of these genes are unknown, and I am tempted to speculate that traits like "trust of psychologists" and "failure to lie to make oneself look better" might be numbered among their disorders ... still, it's possible that there really are some underlying factors in common. What they tell us, mostly, is that the clinically recognized entities in psychology don't show up with as distinct of a basis on the genetic level as something like sickle cell anemia. Wnt (talk) 21:05, 23 April 2015 (UTC)

Superathlete

Lets say you constructed a giant centrifuge and had a house attached to it. An athlete would live in the house in twice the normal gravity. After a few months or year, would this person be a super athlete in normal gravity? — Preceding unsigned comment added by 88.115.38.169 (talk) 17:05, 23 April 2015 (UTC)

I think a continuous 2g would kill them. Specifically, the blood would pool in the low spots rather than circulate. But if you drop that down to 1.1 or 1.2g, then yes, they would probably get bigger muscles, but injuries would be more likely and more severe. Also, they might somewhat counter the benefits by becoming more sedentary. StuRat (talk) 17:15, 23 April 2015 (UTC)

, please. SemanticMantis (talk) 18:14, 23 April 2015 (UTC)

Possibly relevant: "Human subjects have been exposed to continuous high-G environment at most for seven days at 1.5 G. Although no immediate ill effects were found, extrapolation of the data to longer periods may be dangerously risky." [11] AndyTheGrump (talk) 18:22, 23 April 2015 (UTC)

Report on a proposed NASA experiment which intended to test subjects at 2 G for 22 hours. [12] I'll have a look later to see if I can find the results. AndyTheGrump (talk) 18:29, 23 April 2015 (UTC)

I've not been able to find any subsequent material on this proposed test, perhaps suggesting that it never went ahead. AndyTheGrump (talk) 21:39, 23 April 2015 (UTC)

A later article on the NASA experiment. [13] Sadly, it doesn't give any real data on the G levels actually tested, and I've not been able to find any reports of the conclusions. AndyTheGrump (talk) 21:55, 23 April 2015 (UTC)

Paper on how "Artificial gravity training improves orthostatic tolerance in ambulatory men and women". [14] 35 minutes per day at +1 to +2.5 G apparently has significant positive cardiovascular effects on "normal, ambulatory men and women" - I've only read the abstract though. One could probably extrapolate this to athletes, though there are simpler methods for exercising the cardiovascular system. AndyTheGrump (talk) 18:50, 23 April 2015 (UTC)

Of interest may be the book Great Mambo Chicken and the Transhuman Condition [stub] which discusses, amongst other things, experiments in which chickens were raised in high artificial gravity. Time magazine's 1960 article Science: High-G Life [paywall] discusses similar experiments on mice and hamsters. -- ToE 19:15, 23 April 2015 (UTC)

An excerpt from Great Mambo Chicken and some references can be found here. -- ToE 01:24, 24 April 2015 (UTC)

Yes, there seems to have been a fair bit of research done on long-term exposure to hypergravity in smaller animals and at the cellular level - see Google scholar: [15]. AndyTheGrump (talk) 21:46, 23 April 2015 (UTC)

Is it even possible to do it without making the subject incredibly dizzy? According to my understanding of centripetal force, $t={\sqrt {4\pi ^{2}s \over g}}$, or $s={{gt^{2}} \over {4pi^{2}}}$, where $g$ is the simulated gravity, $s$ the radius of the centrifuge, and $t$ is the period of revolution. A 1 km radius centrifuge, rotating once every 63 seconds will generate 1g. Then add the enginering effort required to build a centrifuge that can support a modest house. LongHairedFop (talk) 10:43, 24 April 2015 (UTC)

I'm not sure why you've decided to build him a whole spinning city. Cut it to 20 meters and let the floor curve a little. Why should he get dizzy? Do you get dizzy on the Tilt-a-Whirl? I don't. It just feels like being pressed into the structure. --Trovatore (talk) 19:13, 26 April 2015 (UTC)

Many people do get dizzy on the tilt-a-whirl, and the main difference there is that you don't get up and try to walk around while it is moving. That can be very disorienting, as out bodies are set up for a constant G-force, and any up-down movement changes the apparent G-forces you experience. And trying to sleep or eat under such disorienting conditions would be difficult. StuRat (talk) 19:32, 26 April 2015 (UTC)

Since this is of interest even for cases with 1G or less, there's some discussion at Artificial gravity. You also find other discussions e.g. [16] [17] [18] [19]. Of course we are talking about speculations on speculations here since as the above highlights, the long term effects of living at 2G is unclear and so are the long term effects to simulated 1G or less via rotation. So the long term effects of 2G simulated via rotation doubly so. (When it comes to rotation, remember this includes how people adaptacclimatise, which may conversely mean they will have problems when reintroduced in to 1G environment as per the question.) However from my reading, the evidence that does exist suggests for 2G, a 1km radius will probably be close to being as fine as you can be at 2G. Most research is looking at far smaller radii (albeit for 1G or less), primarily because it's what we're likely to be able to achieve in space in the short term. BTW [20] may be useful to check calculations. Nil Einne (talk) 15:18, 24 April 2015 (UTC)

BTW, some athletes train wearing ankle weights, possibly supplemented with wrist or back/front pack weights. This increases the load on their muscles, and promotes their growth. It might be possible to wear them all the time; I don't know how much benefit this would give. LongHairedFop (talk) 11:20, 26 April 2015 (UTC)

April 24

What came first, the chicks or the chicken?

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?

Are there telltale signs that there's a sinkhole below the ground you're on or the building you're in? --108.52.38.146 (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

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

Drilling holes and magma

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

Aircraft propeller design

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? 81.152.230.173 (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

Hi,

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 (talk • contribs) 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)

• Not all traits are adaptive traits. See also Spandrel_(biology). SemanticMantis (talk) 15:03, 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)

Dying from eating too many eggs

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)

Does the size of the right ventricle indeed equals to the left ventricle size?

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: http://www.echopedia.org/wiki/Normal_Values) 18:20, 26 April 2015 (UTC) — Preceding unsigned comment added by 213.57.30.219 (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. 5.28.181.196 (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. [21] 5.28.181.196 (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)

N¹⁵

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?