Wikipedia:Reference desk/Archives/Science/2007 March 27

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March 27

What kind of squirrel is this?

(I asked this a week ago, but didn't get a response, so I'm trying again now.)

I took a picture of this squirrel in New York City (Queens, near the river); it looks like an Eastern Gray Squirrel, but I wanted to confirm before I uploaded it to Commons. Is that what it is? Is this one also an Eastern Gray Squirrel? (The second was taken in eastern Connecticut.) grendel|khan 04:25, 27 March 2007 (UTC)

Yep, they are both Grays (the latin escapes me at this hour of the morn). Grays also come in black morphs and occaisionally partial albino.Rana sylvatica 09:02, 27 March 2007 (UTC)Rana sylvatica

It says Sciurus carolinensis on the Eastern Gray Squirrel page linked to in the question :) HS7 14:38, 27 March 2007 (UTC)

Thanks! Uploaded as Camouflaged squirrel.gk.jpg and Squirrel closeup profile.gk.jpg. grendel|khan 04:52, 28 March 2007 (UTC)

Electrical Resistance Of Rubber

When we use a mains tester to check the mains voltage, it glows even if we are wearing rubber slippers. Maybe rubber would conduct lightning( Very very very high voltage & current), but how does it conduct domestic household (220v RMS)Mains??210.212.194.209

Is it possible that a charge is flowing into your body through your hand, and the charge is accumulating, even though it has no route to flow back out ? If so, I would expect the flow to end quickly. StuRat 04:49, 27 March 2007 (UTC)

Your rubber slippers aren't conducting; your body's self-capacitance is sufficient to enable a tiny amount of current to flow through your body, which is enough to light the tester. MrRedact 04:55, 27 March 2007 (UTC)

Also,if its one of those neon lamp testers, you only need a very small (safe) current of a few hunderd microamperes to light them up —The preceding unsigned comment was added by 88.110.24.123 (talk) 18:29, 29 March 2007 (UTC).

Cost of argon

In Canada and the U.S., what's the average price of a small argon tank, used for welding, that holds approx. 30 cubic feet of argon? --Bowlhover 04:45, 27 March 2007 (UTC)

eBay says $65.00 USD for a 20 CFM tank. this site says a refill will cost you $0.50/CF for a refill. You will need a regulator, also. -Arch dude 13:47, 27 March 2007 (UTC)

piston analysis

i wanted to know about the experimental stress and thermal analysis done on the piston with details on calculation, material propertis and related performance values conducted on two wheelers.

waiting for the answer

likhith shetty

—The preceding unsigned comment was added by 59.92.135.80 (talk) 06:27, 27 March 2007 (UTC).

"The piston"? Which piston? "Calculation"? Which calculation? "Material properties"? Which materials? I don't even have the slightest clue what you're asking for, could you elaborate? -- mattb @ 2007-03-27T19:14Z

Motorcycle engines perhaps? —The preceding unsigned comment was added by 88.110.24.123 (talk) 18:32, 29 March 2007 (UTC).

Rolling bush

Hi! I'd like to know, what is the name of the ball-like, rolling bush wich usually runs in the american desert? (I.e., it's usually shown in comics or tv-shows to represent the effect of a bad Joke...) --IlSoge aka Sogeking 08:27, 27 March 2007 (UTC)

Tumbleweed. Natgoo 09:02, 27 March 2007 (UTC)

Thanks a lot!! I'm going to translate the article on it.wikipedia. Bye!! --IlSoge aka Sogeking 09:23, 27 March 2007 (UTC)

"A rolling stone gathers no moss ... but a stationary Bush gathers all sorts of crap." StuRat 15:23, 27 March 2007 (UTC)

concurrent multiplier in nephron

i understand that the concurrent flow multiplies the gradient of ~200mOsm b/w the ascending loop of Henle and adjacent medullary interstitium, in to a gradient of approximately ~900mOsm b/w the inner meduallary ('elbow' of loop of Henle) and cortex, but what is the purpose of this system? (if anyone could make it my knowledge of the system clearer- how the functional anatomy and physiology are related e.g. what is the purpose of urea cycling?- would be very much appreciated)

atom

Hey I would like to know ALL the energy and particles that are released from the nuclei of an atom. I just want to confirm that I have them all...

I'm not sure I fully understand what you're looking for. Could you list for us what you have so far? TenOfAllTrades(talk) 13:06, 27 March 2007 (UTC)

Yes, that may be best because there are quite a bit and it depends on the application and level for which ones you "want." If it is radioactive decay, in high school, it's normally just alpha particle, beta particle, gamma ray. [Mαc Δαvιs] (How's my driving?) ❖ 15:02, 27 March 2007 (UTC)

Markers

Which biochemical molecule/enzyme/protein can be used as a marker for Pancraetic juice and duodenal juice in regards to calculating the oxidative stress? 218.248.47.12 11:40, 27 March 2007 (UTC)

Common chimp vs. bonobo

I never understood why scientists focus so much on the patriarchal Common Chimpanzee. It's clear that the egalitarian and sex-positive Bonobos are way cooler. Any thoughts on this?--Sonjaaa 13:41, 27 March 2007 (UTC)

Maybe it is because we found the chimps earlier, and most of the original scientists were men :) HS7 14:03, 27 March 2007 (UTC)

Nice question phrasing :). Perhaps we study chimps more because they are more widely available for study? [Mαc Δαvιs] (How's my driving?) ❖ 15:06, 27 March 2007 (UTC)

• Regular Chimpanzees are more convienently located. WilyD 15:09, 27 March 2007 (UTC)

Human society is historically patriarchal. I also think Chimpanzee's are a closer relative genetically. --Tbeatty 15:11, 27 March 2007 (UTC)

True, but who cares? Bonobos are located in the interior of Zaire - not the easiest place to go study them. It's simply an issue of pragmatism. It's the same as why we know more about the Earth than about Neptune - it's just easier to study the earth, because it's easier to get to. The idea what we'd choose which to study based on the outcome of the study is fairly easy to identify as flawed. WilyD 15:24, 27 March 2007 (UTC)

You could study them though. Find out why Bonobo's can't drive cars.  :) --Tbeatty 15:16, 27 March 2007 (UTC)

I'm not sure it matters if men or women found the apes, and not sure if a patriarchy or matriarchy matters to most scientific study either. [Mαc Δαvιs] (How's my driving?) ❖ 15:48, 27 March 2007 (UTC)

Soon, the question may be meaningless as it appears that Bonobos, at least in the wild, are on the verge of going extinct. :-(

Atlant 16:18, 27 March 2007 (UTC)

Crossed covalent bonds

What's the meaning of a "crossed" bond in a molecular diagram like between carbon and nitrogen in sinigrin? 193.171.121.30 13:52, 27 March 2007 (UTC)

I'm gonna go with "mouse slipped while drawing the structure." DMacks 15:42, 27 March 2007 (UTC)

Yes, in this case it is a mistake: there should be a N=C double bond there, like in this image. I'll fix the image. Laïka 19:18, 27 March 2007 (UTC)

Gas Laws

How can the gas laws work for all gases, even though molecules are different sizes in each gas? —The preceding unsigned comment was added by 199.197.123.76 (talk) 15:19, 27 March 2007 (UTC).

That's why they're sometimes called the "Ideal gas laws". You've got some good intuition about how reality is different...see ideal gas for more discussion. DMacks 15:45, 27 March 2007 (UTC)

In particular, look at the assumption about the actual volume occupied by the gas molecules that is built into the ideal gas model. The Van der Waals equation gives a better approximation when the size of the gas molecules cannot be neglected, and, as you would expect, it contains a term that does depend on the molecular size. Gandalf61 16:47, 27 March 2007 (UTC)

Search for life

should we expend considerable energy and resources looking for intelligent or natural life in the universe or is it a waste of those resources? —The preceding unsigned comment was added by 198.190.213.4 (talk)

Personally I think it is rather a waste. The likelihood of finding any intelligent life at this particular moment seems to me to be quite small (I take a pessimistic reading of the Drake equation) and the vast interstellar distances make communication quite difficult and actual travel nigh impossible (unless our understanding of physics is vastly, incredibly wrong). On top of that I have a rather pessimistic view of how contact between intelligent species would occur — humans can't seem to be civil with their own species, lord knows how they would interact with aliens. That being said, the current "search for life" (i.e. SETI, etc.) does not strike me as "considerable enrgy and resources", so I am not necessarily advocating slashing their funding. But I wouldn't try to make an all-out effort, no. But nobody really asked me, did they? ;-) --140.247.249.200 15:55, 27 March 2007 (UTC)

Intelligent life is a separate prospect altogether, but a more feasible target is primitive life forms. If either Darwin or the Terrestrial Planet Finder ever get off the ground, we'll (hopefully) be able to analyse terrestrial exoplanet atmospheres, which could indicate life. (Who knows, they might even turn out to be intelligent!) Note that those missions are primarily designed to look for planets, not life. And in our own solar system, there's the possibility of life on Mars, Enceladus, Europa and Ganymede, in rough order of likelihood. Mars is well covered, and it seems very likely that NASA's next flagship mission will explore one of those last three. So while there's no chance of definitively finding life for a very long time yet (ie without sending something specifically to look for it) we might have a slightly better grasp of the probabilities in the next few decades - all without spending vast sums designed only to look for life. Spiral Wave 16:18, 27 March 2007 (UTC)

What about the ide that, if intelligent life existed and it were more intelligent than us, there would be no need to search, because they would more likely find us. And speking about a less developed alien civilization, we have no tools to detect them. --193.16.218.66 16:59, 27 March 2007 (UTC)

Not really - finding us is very different from contacting us. The first is probably straightforward for anyone within like 30 parsecs, much worse farther out. Contacting us takes the same time back as our signal took to get there. Even though a more advanced civilization would be better equiped to detect us, they'd have a much larger and deeper footprint (radio emission and who knows what else) that they'd be much easier to us to detect than the reverse. So we'd see any older civilization before they'd see us.

That said, if they're very far away (say kiloparsec scales) it'd be almost impossible to do anything about knowing where they were - the position the signal came from wouldn't be enough to let us know where the civilization is now, or where it'd be when we could get a signal to it. WilyD 17:16, 27 March 2007 (UTC)

Or if it even still existed... Hey, I doubt that extraterrestrials are above doing bad things to each other and their planet(s). --Kurt Shaped Box 17:32, 27 March 2007 (UTC)

Agreed, but if they are as self-destructive as humans, you could expect them to self-destruct shortly after getting nuclear weapons, just like we probably will. So, the violent, intelligent species are likely to be rare, as they don't last long. Personally, I think plant eaters would likely evolve into a more gentle intelligent race, given enough time, than predators. Of course, there are some violent herbivores, like hippos, so there's no guarantee. StuRat 17:47, 27 March 2007 (UTC)

I don't agree that any intelligent life could easily find us, as the emissions we've sent out thus far (radio, TV, etc.) are so weak you'd be lucky to pick them up much past the Moon. For someone on another planet to pick the signals up they might need an antenna the size of a planet, and then the signals might still be impossible to distinguish from background noise. I suppose we could send a strong signal, but it would be difficult without a specific target for a narrow beam transmission. A very powerful signal would be needed for a general direction signal to be picked up by even the nearest solar systems (say a series of nuclear bombs detonated at the edge of the solar system in a prime number sequence). But, since we aren't doing anything like this, this leaves us the option of detecting signals sent from other planets. The likelihood of there being other intelligences trying to contact us seems low, I agree, but considering how drastically it would effect humanity (hopefully positively) if contact were made, it seems reasonable to spend some resources on it. StuRat 17:37, 27 March 2007 (UTC)

Lists are frequently made of "best guess" stars that are fairly near and hold reasonable prospects for supporting a civilisation, and - although I can't source this, so I think I might be imagining it - a few years back SETI or some other organisation might have transmitted a narrow-angle radio beam (the Arecibo message, again?) towards half a dozen of them. It'll be a few decades before we get a reply, of course!

Another frequently raised issue is the everyone's listening problem, but there are reasonable arguments against it. Spiral Wave 18:31, 27 March 2007 (UTC)

I think the existence of life seems most interesting from a philosophical point of view. Most scientists seems to agree by sheer numbers its likely something is out there, but what conversation could we have if it takes decades or even longer to send a message. Certainly unlikely to be any face to face contact. At best it'd make religious people think again, and maybe tell us something about abiogenesis. I don't believe we can tell anything at all about the probability of life starting from a sample of one.137.138.46.155 07:18, 28 March 2007 (UTC)

It's hard to say what life elsewhere tells us about the probability of abiogenesis events. If the nature of their biology is broadly similar to life on earth then panspermia would perhaps be a more reasonable hypothesis with abiogenesis remaining a statistically very improbably event. SteveBaker 17:05, 28 March 2007 (UTC)

Pluto, still technically a planet?

(Moved from Village pump (news) )

Well, to start out i do not really know much about this subject. I actually wanted to know if pluto is still a planet and will be that way, or is there still heated discussions about if it is.This topic is so old, but i would like some confirmation on the subject.

keeping its title as planet or not? Inkwhitw 02:43, 26 March 2007 (UTC)

This is the wrong forum. The short answer is "it's a dwarf planet, technically different from a (unqualified) planet". See Pluto and 2006 definition of planet. --Stephan Schulz 02:55, 26 March 2007 (UTC)

As brought up in a previous discussion, there is no such thing as a all-powerful governing body that can demand what is and is not a planet. The same group that decided to call Pluto a planet when it was discovered has now decided that they will no longer refer to it as a planet. They strongly suggest others decide to use their definition. However, it is up to you. If you like, you can call your dog a planet. Nobody will arrest you - though you may risk spending time in a padded room. --Kainaw ^(talk) 17:10, 27 March 2007 (UTC)

And the debate just centers around a classification. There are several kuiper belt objects that are the same size as or larger than Pluto, and there are some fairly large objects in the asteroid belt. Rather than calling all of these planets, they decided to separate the definition into "Planet" and "Dwarf planet". There are probably several possible justifications for doing so, but it's largely just a matter of separating the objects by their "importance". -- Consumed Crustacean (talk) 17:18, 27 March 2007 (UTC)

As a matter of interest, are the "Give us back our 9th planet!" people still campaigning and gathering signatures? --Kurt Shaped Box 17:47, 27 March 2007 (UTC)

I say it's a planette. Clarityfiend 21:56, 27 March 2007 (UTC)

Just be aware that 2006 definition of planet contains at least one error. "Debate within the IAU led Julio Fernández and Gonzalo Tancredi of Uruguay[5] to suggest proposals to redefine the term "planet" so as to ....." The error is the word "redefine". As Definition of planet tells us, there never was a scientific definition of planet until 2006. That may sound surprising, but it's the case. In view of certain developments in astronomy, the IAU decided it was time for a formal definition, and took a stab at it. The definition they came up with excluded Pluto. JackofOz 22:24, 27 March 2007 (UTC)

But it also seems to exclude many other planets too. --Honeymane_{Heghlu meH QaQ jajvam} 04:54, 3 April 2007 (UTC)

Dehydrated fruit

What chemical changes happen when you dehydrate fruit (besides the obvious loss of water) ? The color often changes, like blue grapes changing to brown raisins, or plum plums turning into black prunes. The taste changes as well. These changes are apparently not reversible, as soaking raisins or prunes in water doesn't get you back to grapes and plums. Also, would the dried fruit plus the amount of water removed be nutritionally identical to the original fruit ? StuRat 17:19, 27 March 2007 (UTC)

According to dried fruit, it loses Vitamin C. --Kainaw ^(talk) 17:24, 27 March 2007 (UTC)

I believe browning in food from cooking or drying is due to the Mallard reaction or Maillard reaction - I forget the spelling. This reaction is connected with the production of acrylamide, a possible carcinogen. I've never been able to find any information about the amount of acrylamide in raisins or sultanas, but prune juice and hence presumably also prunes have a very amount of acrylamide in them, as do olives. Perhaps not many people know that olives are processed before we eat them; off the tree they are very bitter I think. 62.253.48.20 21:52, 27 March 2007 (UTC)

Thanks, but a word was missing in your reply. Did you mean "very high" or "very low" ? StuRat 03:20, 28 March 2007 (UTC)

Sorry I meant to type "very high". The article on browning in food says there is also enymic browning, which occurs in black tea they say. 80.1.88.53 08:33, 28 March 2007 (UTC)

An FDA test in March 2004 found no acrylamide (this probably means less than 1 ppb) in raisins (but up to 267 ppb in prune juice). [1] Icek 01:04, 29 March 2007 (UTC)

Saponification

Why is NaOH added slowly during saponification? (This isn't how we did it in the lab, but I have a question which mentions the process used for mass production of soap and it says that the NaOH should be added slowly) —LestatdeLioncourt 17:19, 27 March 2007 (UTC)

Bit of a guess (maybe a soap expert will arrive soon): Saponification is an endothermic reaction. If you add the NaOH all at once, the temperature of the mixture will drop, slowing the reaction. Sorry for lack of definates. Skittle 19:14, 27 March 2007 (UTC)

Burning Question

ok within the past 2 months i saw two shows that contradicted itselves. it was about bullets hitting a car. Mythbusters said that a car cannot protect you if your inside it when its being shot at. that the bullets go straight through killing or damaging what ever is inside. however on a recent show on Discovery (sorry cant remember the name think its new) they said that its not easy for bullets to enter your car that they might go in but they wont be leathal if they do. I want to know which one is telling the truth? am i safe inside my car or would i stand a better chance making a run for it? thanks for your time! Maverick423 17:28, 27 March 2007 (UTC)

There are many kinds of bullets and many different cartridges firing them. The answer won't be as simple as a plain yes or no. I would not depend on a normal car offering much protection- they're not designed for this. However, when a bullet hits something, even it it goes through, it may fragment, get deflected, or slow down. A heavier bullet will usually penetrate more than a lighter one. It's going to depend a lot on what it hits. Simple sheetmetal or glass won't give you much protection, but other parts of the car may stop some bullets effectively. See also terminal ballistics. Friday (talk) 17:39, 27 March 2007 (UTC)

For example, if someone is shooting from far in front of your car, and you duck down behind the dashboard, they would have to shoot through the engine compartment to hit you, and the bullets are likely to be stopped or at least deflected by the engine block and other components. On the other hand, if they fire through a window, there is very little protection for you. StuRat 18:03, 27 March 2007 (UTC)

Sweet thanks much! Maverick423 17:47, 27 March 2007 (UTC)

Mythbusters actually did the experiment - right there - where you could see it. They took a pretty typical car and shot at it with a wide range of guns - and the bullets went right through - and in most cases back out the other side. You could see it happen. You can't deny that evidence. However: Yes the bullet must lose some energy in punching through the car's body - and if much of your body is hidden behind parts of the car it may be a little harder for the shooter to aim at you - so hiding in a car might not be such a terrible idea. The engine block of the car and the heavy suspension parts ought to stop pretty much anything though - hiding on the opposite side of the engine bay to the shooter would be effective. SteveBaker 17:00, 28 March 2007 (UTC)

So, if we were to detect a fleet of alien ships entering orbit above the earth tomorrow...

...and they started honking/grunting/screeching/whatever over the airwaves at us, how on earth would we even begin to try communicating with them? I mean, it's not as if there'd be anything with which to compare their language with and as far as I know, the concept of a 'universal translator' is still in the realms of science fiction. So, what would humanity's collective linguistics boys and girls do? --Kurt Shaped Box 17:45, 27 March 2007 (UTC)

put their heads between their legs and kiss their um. well that does sound intresting however i belive that if a alien race did enter our solar system, they would be able to study our language via radio waves which means they can make a translator for us and stuff =P.Maverick423 17:49, 27 March 2007 (UTC)

If they have been studying us they may have already decoded our languages before they make contact. If not, assuming they have visual sensors of some type, you could show pictures and give a word for each item (you would need to pick one language to teach them, of course). This would work well enough for physical objects. Next, verbs could be conveyed by showing "jumping", etc. We might never get to the point of communicating about intangible concepts like "God", however. StuRat 17:56, 27 March 2007 (UTC)

And if they leave a book behind and you decode the cover to say "To Serve Man", beware ! StuRat 17:58, 27 March 2007 (UTC)

There's a good chance we'd start with something like the Arecibo message or the Pioneer plaque, attempting to establish binary representation of numbers and agreement on basic physical constants. — Lomn 18:41, 27 March 2007 (UTC)

Even if language doesn't follow a universal rule it does, by its very definition, have conventions and ways of establishing meaning. Which is not to say it would be easy, but once you got beyond the question of "how, in a technical sense, do they communicate" (i.e. hearing the right frequencies, looking for the right signs, etc.) I am not sure as a decoding problem it would be at all insurmountable, or much different from how people were able to show up on odd islands half-way around the world and find ways of communicating with natives. --24.147.86.187 18:42, 27 March 2007 (UTC)

Ah, but you're assuming they do hear, or see, or whatever; just maybe at different frequencies than we do. If there's one thing we should learn from nature, it's that it frequently throws up anything we can think of, and several things we can't. In that regard, some of you might be interested in this forum thread where the same subject was discussed; including what any aliens might make of our multitude of languages, assuming they get to decoding first. Spiral Wave 18:56, 27 March 2007 (UTC)

It stands to reason that they would have to have some way to sense the world around them, using the electromagnetic spectrum, sound or vibrations, touch, chemical sensors, etc. I can't imagine aliens who are totally oblivious to their environment ever being able to travel to other plants. StuRat 20:56, 27 March 2007 (UTC)

Of course; but I think the main point, as someone mentioned in that thread, is that unless you know what that sense is, you've no way of knowing where to even start. Spiral Wave 21:26, 27 March 2007 (UTC)

Take a look at the Arecibo message and the Pioneer plaque - don't read the descriptions - just try to figure out what they mean. They are practically useless - you can figure out the numbers OK - but even humans with a knowledge of earthly biochemistry would have no chance at guessing those few pixels in a wiggly line with an ungodly large number next to them represents the spiral structure of DNA along with the number of base-pairs that compose it...that's useless! The standard (and plausible) method used in most sci-fi scenarios such as 'Contact' is to send beeps representing the prime numbers - then send them again with a base-10 representation of the number to establish how we represent numbers - then send stuff like 2 squiggle 2 splotch 4, 6 squiggle 3 splotch 9 ....from which the aliens can deduce the symbols we use for + and = and that we use infix notation for arithmetic...we can build on that to show most of our mathematics. We can use numbers to convey numbers of protons and neutrons in the elements and scale from that to show chemistry. We can send pictures of objects using prime-number-sized raster images and attach names to objects to start to list nouns. We can send videos to show how these things look in life. Once they know the words for apples and elephants we can show an apple above an elephant and use 'apple wibble elephant' and then an elephant above an apple and use 'elephant wibble apple' to show the meaning of the word "above"...with time and some inginuity we can teach them our language. Then we can match sounds to words and teach our audio communication strategy. All the while, we can imagine they'd be trying similar strategies with us - and with luck this will make sense. SteveBaker 03:29, 28 March 2007 (UTC)

Why wouldn't they stealthily acquire access to the World Wide Web and be Wikipedia editors (and likely admins) before they ever uncloaked the ships and hailed our leaders? Edison 05:10, 28 March 2007 (UTC)

I thought we were postulating intelligent aliens! ;-)

Meanwhile, folks might want to consider the question of bandwidth and the fundamental forces. Any communications medium worth its salt would need to have a bandwidth that is proportionate to the rate at which data is processed and it would have to employ one of the fundamental forces. Primarily because the strong and weak nuclear forces are kinda short range, and because gravity is so difficult (for us, at least) to manipulate, we've settled on electromagnetic interactions. (And yes, the pressure waves of sound in air are, at their root, an electromagnetic interaction of molecule acting on molecule.) Within the scope of the electromagnetic force, we've also settled on bandwidth-appropriate communications. Sounds extend from infrasonic to ultrasonic, but are still limited by how well sound waves propagate in physical materials. We've pretty much got the EM band covered as well. And even if the encoding is odd (say they communicate by changing an area of chromatophores on their, umm, err, "bellies"), we'd probably figure it out given enough time. Of course, if the first message is "Surrender or we'll anihilate your planet with antimatter!", we may not have much time to figure it out.

Atlant 11:17, 28 March 2007 (UTC)

Na, that'd be a bluff - they wouldn't destroy the planet. It'd be a complete waste of all that time, effort and energy spent travelling many light years to get here. Sure, if the aliens were hostile, they may want to colonize the earth or strip it of resources and consider humans a pest to be eradicated but I doubt they'd just think 'aw, fuck it!' blow the whole place up, then head for home. --Kurt Shaped Box 15:17, 28 March 2007 (UTC)

Yeah, but wot about ta bypass? Got to have bypasses, y'know! Progress, don'tcha know?

Atlant 16:08, 28 March 2007 (UTC)

What do you mean, WHY does it have to be built? It's a bypass... You've got to build bypasses. -- mattb @ 2007-03-30T23:31Z

(Undent) Aliens might have a much longer term view of the universe than we do. Suppose they've placed their intelligence into computers (a likely advance that we might well make sometime soon) - they could copy their minds from one machine to another and attain immortality of a sort. They might have very long memories - and they might plan over very long timescales because they anticipate living that long. From a perspective of millions or hundreds of millions of years - they might well have found from long and painful experience that new upstart civilisations will eventually compete with them for resources. They may have had long and difficult wars with other advanced civilisations. With that long term view - it would make a lot of sense to wipe out new civilisations long before they become problematic. As discussed below, they could wipe us out with very little effort if they did it right now - if they wait a million years, it could be much more difficult for them. So it's perfectly possible - logical even - for them to seek out civilisations that (whilst not a threat right now) are growing in technology - and to wipe us out with no more qualms than we have in killing off troublesome vermin like rats or whatever. SteveBaker 16:39, 28 March 2007 (UTC)

Or perhaps they could wipe out alien civilizations by seeding them with genes to make them violent enough that they always self-destruct, once their weapons become powerful enough (due to technology) ? This might help them get past any moral objections they have with destroying civilizations which aren't a threat, since, if those civilizations never develop powerful weapons, they never self-destruct. StuRat 17:06, 28 March 2007 (UTC)

We have an entire article on the question, Communication with Extraterrestrial Intelligence, which might benefit from the above answers. -- Beland 21:24, 31 March 2007 (UTC)

silencer

If you shoot a gun directly on a persons chest would the person have acted as a silencer on the air propelled by the explosion? —The preceding unsigned comment was added by Bastard Soap (talk • contribs) 19:40, 27 March 2007 (UTC).

This was proven in a episode on Discovery channel think it was one of those forensic evidence thing and then again i think it was on TLC either way they proved that shoting a bullet into a body at point blank range *meaning acctual contact with the skin* can creat a silencing effect. they tried this out on a dead pig and got the same results. now that i think of it it might of been a mythbusters thing since they like to use pigs alot. anyways i hope it helps. Maverick423 20:25, 27 March 2007 (UTC)

Interesting. I would have expected the pressure to force the gun away from the body, creating an escape route for the sound. StuRat 20:52, 27 March 2007 (UTC)

yea well they said that the pressure goes into the body following the bullet and the hollow hole left behind from the bullet passing through acts as a silencer. Of course as like all silencers it doesnt completely silence the bullet but it muffels it. it sounded like a thud instead of a shot. its really quite intresting =)Maverick423 20:58, 27 March 2007 (UTC)

Do not request gun silencing advice. Ask a professional hit man instead. Edison 05:07, 28 March 2007 (UTC)

It's the sudden release of built-up-pressure as the bullet exits the muzzle that produces the "bang!". Contain (and slowly dissipate) the gases and there's no bang. Powder-actuated tools are a pretty good example of this. Most of the gas expansion goes into doing work on the load (via a piston) and no sharp release of gas occurs. As a result, the tools are surprisingly quiet.

Atlant 11:24, 28 March 2007 (UTC)

In the event of alien spaceships arriving at earth

Does anyone here doubt that at least one country on earth will have already developed some kind of top-secret 'UFO killer' weapon, to prepare for this eventuality (just in case the worst happens and the bugs are not friendly)? --84.68.222.205 22:14, 27 March 2007 (UTC)

The USA, China, and Russia have all developed anti-satellite weapons. Further, for targets in low orbit, intercontinental ballistic missiles can be re-targeted to hit them. --Carnildo 22:40, 27 March 2007 (UTC)

It's hard fighting from the bottom of a gravity well. And anti-satellite weapons are only good against satellites, which aren't noted for dodging very much. Just pray that they don't see us as prey. Clarityfiend 01:32, 28 March 2007 (UTC)

I most definitely doubt we have secret UFO-killing weapons. In fact I very much doubt we'd stand any chance at all against a determined interstellar attacker. As Clarityfiend points out - if they have the capability to travel between stars - they can drop mountain sized rocks on us by nudging them out of the asteroid belt with the right orbital characteristics to hit earth. It might take years for them to hit us - but these hypothetical aliens would have to be a patient species to have undergone decades of travel to get here. There is absolutely nothing we could do about a swarm of incoming asteroids - we'd be unlikely to even detect they were coming until they were just a few weeks away. We have no weapons that could reach as far as the asteroid belt - and we have no way to stop incoming house-sized asteroids. They could probably aim them with enough precision to wipe out entire cities. But if they had the technology to get here in the first place - their technology would more advanced that we could possibly imagine - who knows what they could do to us if they felt like it? The 'asteroid bomb' idea is just one of a bazillion ways they could get us - and we'd probably never see it coming. They wouldn't even need to be that far ahead of us. We won't have interstellar travel for a hundred years - but we'll probably have nanotechnological replicators in 20 years. If the aliens are 100 years ahead of us in interstellar travel - then they could easily be 20 years ahead of us in nanotech. If so, they could seed our atmosphere with self-replicating nanotechnology 'bots - a container the size of a coffee can would probably do the job - and the nanobots could selectively take out higher life forms leaving the majority of our ecosystems intact. We'd die in a few weeks or months without ever knowing the reason why - let alone having a way to unleash our hypothetical secret weapon on them. SteveBaker 02:51, 28 March 2007 (UTC)

I think you made a huge leap there, self replicators in 20years, man how can you produce a nanosynthetic lab which can synthesis other nanolabs and is also a killing machine? I think we will need a lot more than 20 years, if ever.Bastard Soap 09:04, 28 March 2007 (UTC)

(Nanotech robots that can replicate themselves using local resources are not at all infeasible - just look at terrestrial bacteris!) OK - so if you don't believe 20 years - pick 100 years, 200 years. Whatever number you decide. These aliens could quite easily be a BILLION years more advanced than us. What we do know for sure is that we have absolutely no clue as to how to solve all of the problems of interstellar travel - they (by definition) do - so we know for sure that they are a lot more advanced than we are. Let's go with 100 years as an utter minimum - they must be a minimum of 100 years more advanced than us. How much can technology advance in 100 years? Let's not speculate - let's use our own history.... If you look back to humans from 100 years ago - 1907 - seven years before the first world war - and think about how easy it would be for us to take them out (humans from today playing the role of 100 years more advanced aliens). In 1907 we had no radar - we had machine guns and battleships - no submarines - no military aircraft (civilian aircraft had only been around for three or four years) - no tanks - no missiles - defensive technology was all about digging a trench and hiding in it - or having 10" of steel plate wrapped around your ship which has wooden decks - horse-born cavalry with sabres were still considered a pretty nifty weapon. A one hundred year more advanced civilisation could have nuked them into oblivion - or carpet-bombed them from 40,000' - heck just one modern battle tank could take out most of an entire division of the period - they'd have no defense against even our conventional forces. Put yourself in the position of a 1907 military officer - our forces can see in the dark! They can communicate over distances of thousands of miles! They can see where all of your troops are (from orbit!). They have missiles that can chase you as you run away. They can drop soldiers out of the air! Bombs just fall from the sky from craft that are just a tiny dot in the sky! They have one tiny bomb that can annihilate an entire city! Their troop transports are immune to our weapons! Their soldiers are unkillable...I shot a one of them square in the chest at point blank range and he just kept on coming! (Bullet-proof vests were unknown in 1907!) Let's face it - even just 100 years of technological advance is indistinguishable from magic. These hypothetical aliens could be a thousand, a million or a billon years ahead of us. We'd die without even knowing we were under attack - it's ridiculous to think otherwise. SteveBaker 16:06, 28 March 2007 (UTC)

I perfectly agree with you that we would be completely toast, basically just the gravity well could be our demise but self-replicating bots seem an impossibility. You would need countless reagents and machines to make the necessary alloys or polymers or whatever and mould them into shape, not to metion building incerdibly complex electric circuits, maybe they would even need a nuclear reactor to be able to synthesis the necessary elements they would need to build themselves (you know I wouldn't imagine bots could be created from dirt). Biological warefare is an other thing but still for some reason that never really kills off any population it halfs it out doesn't it? But probably they would have come up to some solution to that, maybe a virus that mutates continously releasing new children every day.Bastard Soap 20:09, 28 March 2007 (UTC)

I wonder: how do you develop a defense system without knowing anything about the enemy's weapons? --Bowlhover 04:07, 28 March 2007 (UTC)

I expect it would work as well as Montezuma having prepared a "Spanish galleon killing weapon." Edison 05:05, 28 March 2007 (UTC)

We have nuclear weapons. We can make bigger nuclear weapons. I suppose it would be possible to design a fast, powerful surface-to-orbit missile capable of carrying a huge nuclear payload (if the need arose). We may not know anything about alien weapons and technology but it would be reasonable to assume that most things that exist can be harmed by a large enough thermonuclear explosion (or several in quick succession). --Kurt Shaped Box 15:25, 28 March 2007 (UTC)

Did you read ANYTHING I wrote? If these aliens are sitting out in the asteroid belt pushing big rocks out of orbit to drop onto us - our fastet rocket would still take three months to reach them. They have all that time to move out of the way of it...or shoot it down with a counter-missile a couple of months before it reaches them. But if they hit us with a customised virus or nanobots - we'd die before we ever knew that aliens existed - let alone finding them - let alone taking action against them. SteveBaker 16:06, 28 March 2007 (UTC)

Yes, I wasn't ignoring what you wrote. I was merely hypothesizing on the options that would be open to us in the event of a fleet of ships entering orbit above the earth with hostile intent (supposing that they didn't do any of the nasty things you suggested to us). --Kurt Shaped Box 16:20, 28 March 2007 (UTC)

But why would they get that close? We tend to think in terms of weapons having to be launched from short ranges in order that the victim has no time to dodge or defend themselves - but when the target is a planet and your weapon of choice is a mountain of rock or a teeny-tiny vile of lethal viruses or nanobots or something - there is no need to get close. They'd be several AU's away. Any of our weapons would take months to reach them - so they'd have plenty of time to react and avoid them. Why would they get within range of our weapons? SteveBaker 17:32, 28 March 2007 (UTC)

They may be technologically advanced but it doesn't mean that they are intelligent, they may be intellectual snobs who don't percieve us as able to do them any damage. Comming near us would be a way to show how superior they feel.Bastard Soap 12:33, 29 March 2007 (UTC)

Wouldn't we just send Will Smith and Jeff Goldblum (with his PowerBook)?

Atlant 11:40, 28 March 2007 (UTC)

Or we could use their own Martian heat ray against them. Spiral Wave 18:18, 28 March 2007 (UTC)

I remember hearing that President Raygun said something along the lines of how great it would be if aliens came and threatened earth as it would give the various nations a reason to unite and kill the invaders. At the time I was just dumbfounded that the best scenario he could come up with for us/them contact or a united planet was war. --killing sparrows 04:44, 29 March 2007 (UTC)

Cinema sound v. ordinary sound

When I've been to the cinema (or movie theater as our transatlantic friends would say) I've noticed how the sound has a particular quality to it. I assumed this was due to the acoustics of the cinema.

Yet recently I saw and heard a movie DVD being played in a shop, and it had the same quality of sound.

How does this sound differ from ordinary sound, how is it obtained please? 62.253.48.20 22:18, 27 March 2007 (UTC)

It mostly has to do with the quality of speakers. Put on some headphones that say "Professional" or "Bose" on, and you'll notice that sound is much better. Clean sound, with nice bass and lack of sound coloration are a few things. I'm sure somebody can give you better answer than I can. [Mαc Δαvιs] (How's my driving?) ❖ 22:29, 27 March 2007 (UTC)

Thanks, but I do not mean sound-quality in terms of fidelity, but the characteristic cinema sound, which might be due to - I'm just wildly guessing here - the attenuation or amplification of lower sounds, reverbaration, close miking etc. 62.253.48.20 22:34, 27 March 2007 (UTC)

Cinema sound systems use at least four channels: left, right, center, and surround. This difference might account for the effect you're hearing, and high-quality home theater systems do have these extra channels as well.

It would help to answer the question if you could somehow describe this "characteristic" particular quality you're hearing, if you could. —Steve Summit (talk) 22:57, 27 March 2007 (UTC)

Well, I think it is mostly the fidelity, the loudness, and the channels. Perhaps even an equalizer kind of presetting? On a lot of televisions you can set it to "movie" in the sound options and it will sound more "movie-ish." I've found a lot of high-definition shows sound better, like House and 24. [Mαc Δαvιs] (How's my driving?) ❖ 00:19, 28 March 2007 (UTC)

Were those speakers at the store Bose? Bose is known for their wooden sound chambers where sound travels through before actually exiting, as well as the vibration from the wood itself. Those would create a sound not unlike cinema sound, I think. --Wirbelwindヴィルヴェルヴィント (talk) 04:18, 28 March 2007 (UTC)

The sound I heard in the shop came from an ordinary LCD television with built-in speakers. I do not know how to describe 'cinema' sound. Perhaps the bass is more amplified than normal, or maybe higher pitches are surpressed. Think about the difference in sound between a tv documentary and a high-quality movie in a cinema. 80.1.88.53 08:42, 28 March 2007 (UTC)

I think part of what you're hearing is a lack of compression. That is, the cinema sound occupies a very wide dynamic range whereas television sound is pretty much two volumes: Medium for the shows and LOUD for the commercials.

Atlant 11:45, 28 March 2007 (UTC)

That could be it! Why some songs sound much more... "epic" than other ones. I bet 300 (movie) sounded great at the theater :) [Mαc Δαvιs] (How's my driving?) ❖ 22:42, 28 March 2007 (UTC)

How to increase IQ

Someone recently asked if there was a pill to increase IQ. My prescription for increasing IQ would be to get into the habit of regularly reading any non-fiction books that interest you, and doing puzzles and so on. I would suggest regularly eating small quantities of raw unsalted nuts, since the brain is mostly fat and its now thought that there are many different types of fat, and that these less common fats found in nuts etc are beneficial. Plus, of course, eating oily fish such as sardines, which have the least amount of mercury in them due to being young fish.

But is there any evidence that doing a lot of reading really increases your IQ? 62.253.48.20 22:29, 27 March 2007 (UTC)

The verdict is normally the best way to increase IQ is to practice taking IQ tests. "IQ is just a number and doesn't mean that much." Eating small quantities of raw unsalted nuts, or fish does not make you smarter or increase your IQ. Go with reading books and the Wikipedia and going to a university. I'm sure somebody else can give better replies on this one too. [Mαc Δαvιs] (How's my driving?) ❖ 22:40, 27 March 2007 (UTC)

Mac Davis, you are absolutely incorrect in this statement. A properly calibrated IQ test cannot be studied for. Psychologists debate whether any "properly calibrated" tests do exist, but they work pretty darn hard to make some, and corporations and research institutions exist to constantly evaluate present testing methods. The real question is whether you believe in the idea of general intelligence, which IQ measures. You should read the IQ article to get a better idea of what it means. Nimur 16:34, 29 March 2007 (UTC)

If one is suffering from a particular deficiency or reversible pathological process which limits higher brain functions, then a pill replacing or repairing these things could increase IQ. However, short of that, I don't believe it is possible. IQ theoretically is a measure of reasoning ability (the article adds a few more things, but none contradict the rest of this entry). It does not depend on factual knowledge (thus reading, while possibly serving as practice in decoding reasoning scenarios, will not increase IQ). It does not depend on brain size (as long as the brain has all the right parts, there does not appear to be a correlation between size and intelligence). Also, the neurons of the central nervous system are pretty much in place by adulthood. If the supporting cells (the parts that use fat to insulate long axons, schwann cells and oligodendrocytes) do not have enough fat to make myelin, then one will have worse problems than low IQ. ^tucker/_rekcut 22:47, 27 March 2007 (UTC)

Rebuttal: Although User:tuckerekcut raises noteworthy points, I will assume that it is indeed possible to raise "IQ" just for the sake of argument, and provide unsubstantiated speculation as to how it could be accomplished. In case you didn't get that, this does not reflect serious research, and is merely offered as food for thought. YMMV.

Step by step:

1. To the extent you can, become increasingly aware of the purely symbolic nature of human knowledge representation and understanding
2. To the extent you can, become increasingly aware of your own dominant modalities for processing those symbols, and appropriately adjust your learning strategies to best reflect your personal strengths. Treat this as a form of regular exercise.
3. To the extent you can, practice the previous steps until your chunking capacity for symbolic manipulation increases. This will include your ability to discover novel relationships, the speed and consistency with which you make these discoveries, and your ability to translate that understanding to new categories of knowledge.
4. If and when you have succeeded with the previous steps, you should discover a new set of symbols to work with, repeat the process.

To put in more concrete terms, although you may never become a Chess grandmaster, you can certainly improve your ability by practicing the game on a regular basis, against increasingly skilled players. A beginning player will think in "chunks" of how the individual pieces move on the board. A grandmaster will think in "chunks" that consist of strategies, entire games, entire classes of players and even factors beyond the gameboard itself. dr.ef.tymac 23:18, 27 March 2007 (UTC)

Those are actually some of my favorite replies back ever on the reference desk. Great job guys! :) [Mαc Δαvιs] (How's my driving?) ❖ 00:16, 28 March 2007 (UTC)

As with anything, practice makes you better. So if you want to do better at IQ tests, do more of them. Whether this actually makes you more intelligent is another question.--SlipperyHippo 00:19, 28 March 2007 (UTC)

My personal feeling about the important kind of intelligence, which in my view means being able to make unexpected creative leaps in whatever your field of endeavor might be, is that you need a lot of raw material stuffed in your brain in order to give those leaps some footholds. You could do worse than spending a few hours per day reading Wikipedia. --TotoBaggins 01:46, 28 March 2007 (UTC)

There is strong evidence that some (if not all) IQ tests get easier with practice. However, there are several distinct types of IQ test - if you practice one kind - get a higher score - then re-test with the other kind - your score on the second kind of test isn't any better. That shows that you aren't getting smarter by practicing IQ tests - it just means that IQ testing methodologies need more work. The trouble with intelligence is that there is no solid definition of what it is. Most people distinguish intelligence from knowledge - so reading lots of non-fiction books (which increase your knowledge) probably don't increase the thing we understand to be intelligence. But without a solid definition of what the word means, it's hard to be definite about that. Read widely across all subjects - and read deeply into a few that interest you - that's the best you can do. Make a practice of hitting "Random article" on Wikipedia every night before bedtime - read all of all three articles you get. I've been doing this almost since the start of Wikipedia. You'll be amazed at how fast your general knowledge grows by doing just that. But don't cheat - if you get a random article that doesn't interest you - read it anyway! But you need to read deeply in some widely disparate subjects. For me - I'm currently learning how the 'Unreal game engine' works (because I'm trying to get a job that needs that knowledge) and I'm learning to read Egyptian Hieroglyphics because a beginners book on the subject was reduced to $3 in my local bookstore! SteveBaker 02:33, 28 March 2007 (UTC)

To add to my original question (different address numbers - same person) I would also suggest reading a quality newspaper everyday. This gives you confidence as you know as much as or more about things than other people, and you can understand and assess what people in intellectual tv programs are going on about. Plus of non-fiction books, I'd suggest reading more science and psychology books, less or no literary- or art-criticism, since the former helps you think about the actualities of the real world and do or think constructively.

As someone who has taught many different ability ranges, my impression is that achieving success in life is as least as much related to an individuals conscientiousness and diligence as their IQ. Perhaps we should have CQ tests to focus people on the desirability of being conscientious. Personally I have little faith in IQ tests - I failed the old-fashioned British IQ test eleven year olds called the eleven plus but still went on to obtain post-graduate degrees. I remember the old IQ tests were very culturally-dependant, and I expect they still are. Being unfamiliar with puzzles and maths etc will give you a lower IQ score than you deserve. People can have a high paper-test IQ, but they are held back by so many things such as low self-confidence, timidity, fear of failure, self-image, and many other things that superficially they seem to be someone of lower IQ. 80.1.88.53 09:08, 28 March 2007 (UTC)

That's a bogus answer. What makes you think that the testing that goes on in the process of awarding a post-grad degree is a better test of intelligence than passing an intelligence test?!? That's a ridiculous proposition! Degrees in most (if not all) subjects require vast amounts of rote learning as well as some intelligence. So a good memory (which most people agree does not correlate with whatever it is we think of as "intelligence") might have gotten your through your degrees despite your poor "intelligence-as-measured-by-IQ-test-results". SteveBaker 18:14, 29 March 2007 (UTC)

Getting a post-graduate degree could easily be a better test of intelligence than doing an IQ test. Because the degree measures many things not just the narrow things measured in an IQ test; its a bit much to expect on short IQ test to measure your IQ for all time. On the other hand IQ tests could reveal high intelligence in someone who does not think of themselves as academicly orientated. I failed my eleven-plus, but I got high scores in IQ tests I did years later as part of assessment for promotion, plus I got a high score in the GMAT test. I'd also add to my prescription that you should also buy a good dictionary and look up words you don't know. 62.253.44.173 18:50, 30 March 2007 (UTC)

Yes, there is a pill! (Or rather, to qualify it, there there may soon be). Read this article from Scientific American: The Quest for a Smart Pill --JianLi 04:34, 1 April 2007 (UTC)

Ooops, sorry that link requires a subscription. You can get it free at [2]. --JianLi 04:35, 1 April 2007 (UTC)