Wikipedia:Reference desk/Archives/Science/2007 April 10

= April 10 =

motorola razor v3
hi! how can I download a song to my motorola razor v3 (which is not an mp3 player ) from the internet? and set it as a ringtone? —The preceding unsigned comment was added by 75.69.195.133 (talk) 02:44, 10 April 2007 (UTC).
 * The easiest way is via Bluetooth. Your carrier is also important, if you have Verizon then you need to go through them, for example, while a Cingular customer would be able to bluetooth it to their phone directly without having to do anything wacky like reflashing the firmware. - C HAIRBOY (☎) 02:46, 10 April 2007 (UTC)
 * You can use Motorola Phone Tools for this. As mentioned above, you can do this via Bluetooth, or you can also do this with a USB cable.  I've used this with my cell phone, and now I have a custom ring tone and some pictures that I've transferred from the PC.  I'm not sure if this works for Verizon phones, since they seem to disable some things in their firmware, but I'm a Cingular customer and it works fine for me. --Elkman (Elkspeak) 16:53, 10 April 2007 (UTC)

Control that Oscar Meyer..
Can preventing yourself from masturbation or sex cause you to be more aggressive or energetic? PitchBlack 02:56, 10 April 2007 (UTC)


 * I think quite a few people had theories like this, but I'm not aware of there being any proof. StuRat 04:59, 10 April 2007 (UTC)


 * I remember some mentioning of this in the news coverage of the last soccer world championship. Some coaches required their players to not have sex before an important match, and some players said that they feel especially energetic after good sex. ;-) Simon A. 18:03, 10 April 2007 (UTC)
 * All the more reason to hire the team prostitutes. 22:32, 10 April 2007 (UTC)

Also see erotic sexual denial. FT2 (Talk 01:33, 11 April 2007 (UTC)

yes
I was just watching the movie Jesus Camp, and noticed something a bit strange. Many of the children (and some of the adults) have extremely dilated pupils, like they were on MDMA or something like that. One of my friends recently became a born again christian, and I noticed the same thing happening to him... huge dilated pupils. When people feel this way, I'm thinking it must be the body releasing endorphins that make them feel that way, which allows them to feel like jesus is inside of them, and that leads to the dilated pupils. Has anyone else noticed this, or have any thoughts on it? 128.61.52.213 03:11, 10 April 2007 (UTC)
 * Didn't you ask this question before? Splintercellguy 03:13, 10 April 2007 (UTC)
 * In a word, "yes". On 8 April.  JackofOz 03:16, 10 April 2007 (UTC)
 * We he asked it again because we didn't give him an answer last time. ['Mαc Δαvιs '] (How's my driving? ) ❖ 14:44, 10 April 2007 (UTC)
 * Two answers have been provided, one on the Humanities desk here, and one on this page here. -- JackofOz 00:05, 11 April 2007 (UTC)

Time Dilation
According to special relativity, an observer moving with respect to a clock will observe the clock running slower, i.e., the clock will be subject to time dilation. However, I have some trouble conceptually with this... Here's an example:

If two space ships are moving toward each other at velocities that are a substantial fraction of c, an observer in either ship will observe time dilation in the other ship. I.e., Observer A in Ship A will observe time dilation (time slowing down) for Ship B, and Observer B in Ship B will observe time dilation for Ship A.

However, if Ship A and Ship B were to slow down and dock together (both slowed equally), which observer would have aged more?

To my understanding, both would have perceived the other passing through less time, and it seems that observer A would think observer B is younger, while observer B would think observer A is younger. That's paradoxical, and I don't think it's right. Which would have aged more? Jolb 03:43, 10 April 2007 (UTC)


 * I think you're describing the Twin paradox. It's a thought experiment that has one of two twins travel some distance at the speed of light, and the other stay behind on earth. When the space-traveling twin returns, he will not have aged much, whereas the earth twin will. The (false) paradox arises when we consider that velocity is relative, and we could just as easily have considered the spaceship to stand still, and the earth to move away at the speed of light, causing the space-faring twin to age faster. The resolution lies in the fact that the space faring twin accelerates, which is not relative (even with his eyes closed the twin can feel the spaceship accelerate, while the twin on earth can't feel the earth accelerating backwards). The acceleration of the spaceship changes the reference frame of the twin causing his time to move faster, relative to earth. risk 04:26, 10 April 2007 (UTC)


 * Your understanding is correct. They both see the other's time as moving slower. If they slow down, then they would be accelerating, and what happens there is complicated and not covered by special relativity (I think). --Spoon! 04:32, 10 April 2007 (UTC)


 * That is correct. The Special Theory of Relativity only deals with non-accelerating frames of reference.  Indeed, that's why it's the 'Special' theory.  It took Einstein another ten years to come up with the General theory that could cope with accelerating frames.  TenOfAllTrades(talk) 04:36, 10 April 2007 (UTC)


 * So what if you apply General Relativity? Can that tell us which observer ages more? Jolb 04:46, 10 April 2007 (UTC)
 * Well, yes. It's in the article on the twin paradox, linked above.... TenOfAllTrades(talk) 04:56, 10 April 2007 (UTC)
 * Jolb: The simple answer to your question is that neither observer ages more than the other. This is a perfectly symmetrical situation. They start off (presumably) at the same age they undergo symmetrical motion and accelleration - when they finally get back together, they are the same age.  The details of how this could be is indeed at the heart of the difference between special and general relativity - and in your specific example it comes about because both spaceships accellerate (decellerate - it's the same thing) in order to come to a halt next to each other.  That puts this into the realms of general relativity.  The article on the twins paradox (of which your problem is a simple variation) explains it pretty well - and you should certainly read it if you need more than this simple response. SteveBaker 05:26, 10 April 2007 (UTC)
 * According to the Twin paradox article and my reading of Einstein, User:Risk has it backwards in saying "The acceleration of the spaceship changes the reference frame of the twin causing his time to move faster, relative to earth." Change :faster" to "slower" and it would be correct. The spaceman twin flies around a long time at .9999 C and comes home to find his Earth twin dead and gone and his grandson there to welcome him back. Edison 13:13, 10 April 2007 (UTC)
 * You are entirely correct. I always get these things mixed up. risk 14:04, 10 April 2007 (UTC)
 * A good resource on this is the Usenet Physics FAQ. &#x2013; b_jonas 19:12, 10 April 2007 (UTC)

EMF and p.d
Could someone please explain to me the difference between potential difference and EMF, thank you —The preceding unsigned comment was added by 86.152.69.146 (talk) 10:18, 10 April 2007 (UTC).

Yes our page has it


 * The difference is rather fine, especially if you're looking at things from a circuit point of view. -- mattb

air borne telemetry system
please explain air borne telemetry system with its working..thank u —The preceding unsigned comment was added by Ambuj0542 (talk • contribs) 12:55, 10 April 2007 (UTC).
 * Umm, I've not come across that term before, do either AWACS or GPS fit the description? AWACS isn't really telemetry and gps is not really air borne.. Vespine 22:26, 10 April 2007 (UTC)


 * Have you looked up telemetry? thats a start, but its quite a large subject involving transducer s,multiplexers, radio transmitters RF amplifiers, aerials and such like. Probably now it also includes microprocessors. —The preceding unsigned comment was added by 88.110.240.163 (talk) 00:43, 11 April 2007 (UTC).

spring launch
When a spring is launched vertically up by certain force will its elastic potentil energy is totally converted into gravitational potential energy ?why or why not ? —The preceding unsigned comment was added by 74.107.218.93 (talk) 12:57, 10 April 2007 (UTC).

If we do part of your homework, do we get part of your degree? --TotoBaggins 13:43, 10 April 2007 (UTC)

Think about what else might happen in addition to the elevation of the spring. Would the spring be compressed? would there be any noise or atmosphere in the way to slow it up. Could a tidal force waste energy by moving water around? Would the spring stay at the high point or would it fall over or fall down? If you can answer these questions you may have more of an answer to your problem! GB 07:01, 11 April 2007 (UTC)


 * Heat - there is always heat produced in these kinds of things. Entropy is a harsh mistress. SteveBaker 01:20, 12 April 2007 (UTC)

scales
does lizard and sharks havescales? —The preceding unsigned comment was added by 218.186.9.5 (talk) 13:35, 10 April 2007 (UTC).

Lizards: yes; sharks: sort of. --TotoBaggins 13:47, 10 April 2007 (UTC)

Dew point below freezing
The article dew point doesn't show how to calculate the dew point when the temperature is below freezing. (1) Is there a dew point when it is below freezing? (2) if so, how is it calculated? Thank you, Bubba73 (talk), 15:09, 10 April 2007 (UTC)


 * Because, as the article says near the top:

When the dew point temperature falls below freezing it is called the frost point as the water vapor no longer creates dew but instead creates frost or hoarfrost by deposition.

—The preceding unsigned comment was added by 88.110.240.163 (talk) 15:53, 10 April 2007 (UTC).

In some applications the dew point must be far below freezing. One such is high voltage electrical cable. Some dew point testers for such applications work by taking in some of the gas to be tested, such as air or nitrogen, into a test chamber. Via various means the pressure is suddenly decreased, and one looks for the formation of fog. A dial or table is used to relate the pressure drop necessary for fog to appear to the dew point. Edison 17:04, 10 April 2007 (UTC)


 * Is the "frost point" calculated by the same formula as the dew point (except with a temp below freezing, of course)? Bubba73 (talk), 19:46, 10 April 2007 (UTC)


 * If you were to read the article, you might conclude that it is


 * I did read the article, but the formula says that it is valid only for temperatues above freezing. Bubba73 (talk), 00:12, 11 April 2007 (UTC)
 * Sorry to be unable to cite the operating manual for the device, but I am pretty sure it referred to "dew points" way below freezing, and did not use the terminology "frost point". The device was probably from the 1940's, and even contained a little piece of radium to assist the fog in forming. Edison 04:30, 11 April 2007 (UTC)

Dipole antigravity
How do physicists view the claim in the article Dipole antigravity to have demonstrated "gravitational dipole moment?" in the lab with spinning hemispheres etc. There is one published article from 1999 by Dr. Eue Jin Jeong cited in the article (up for deletion). Surely such a dramatic finding would have inspired some followup. Edison 15:48, 10 April 2007 (UTC)


 * Considering that other physicists have cited Dr. Jeong's article zero times (according to Citeseer), the answer to how physicists view the claim would appear to be "with great infrequency". --TotoBaggins 17:01, 10 April 2007 (UTC)


 * I don't know whether this theory is crackpot or real - but the style of writing in the article is unacceptably unencyclopeadic - so I'd vote for deletion on those grounds alone. A Google search turns up all of the usual nut-job pseudo-science sites - that doesn't necessarily mean that the theory is junk - but it's a bad sign. SteveBaker 01:17, 12 April 2007 (UTC)

scientific brain game
i have questions i need help with.i was produced for the medical proffesion.i know its kinda general.only info i have is that the answer is pretty obvious on anybody smart with googling.i thot i was, and i found stainless steel as the answer but it aint.please i need to gloat to someone.i have spent my whole easter trying to solve this question but nuthin cums up. —The preceding unsigned comment was added by 212.49.87.168 (talk) 16:47, 10 April 2007 (UTC).


 * The question is? Splintercellguy 21:57, 10 April 2007 (UTC)
 * You didn't tell us about the question. And also you're probably safer using "comes" instead of "cums," for future reference :) ['Mαc Δαvιs '] (How's my driving? ) ❖ 22:30, 10 April 2007 (UTC)

the question is -i was produced for the medical proffesion.what am i?
 * A medical degree? The answer could be so many things that have been invented to aid medicine, it's ridiculous... All the drugs, equipment, and even models and other ideas. Capuchin 10:53, 11 April 2007 (UTC)
 * What about the Hippocratic Oath? It was developed long, long before much was known of physiology yet it set fourth the ethical parameters that define modern medicine as a profesion of healers rather than a science for the sake of discovery.AggieAnnieM 06:58, 12 April 2007 (UTC)

Suicide and Mutual assured destruction
Since suicide is now a common means being used by radicals to get what they (or their leaders) want does Mutual assured destruction offer any real deterrance to rougue nations that develop (or acquire) nuclear weapons from using them? Also since Iran has developed industrial scale nuclear weapon production capability does it plan to recover costs by selling nuclear weapons to other rougue nations and terrorists? 71.100.6.150 18:57, 10 April 2007 (UTC)


 * Well, that's been a question that has been asked a lot lately. Noah Feldman recently wrote a cover story in the New York TImes magazine about this: Islam, Terror and the Second Nuclear Age. Some people think MAD doesn't work when you have non-state actors, much less suicidal ones. I've always thought the suicidal bit was a bit overstated — the guys who order terror attacks are not suicide bombers. The suicide bombers are kids who they brainwash into believing they'll get all sorts of rewards and will be a huge hero and all that. The actual leaders, as most wars, are far from the battlefield. They seem to care about the long-term a bit more than is often acknowledged. But in any case, any sort of messianic religion opens you up to an irrationality which is incompatible with the "reason" of deterrence.


 * Iran has not yet developed industrial scale nuclear weapon production capability. They have claimed to installed additional centrifuges, though it is unlikely they have really learned how to use them correctly. The news media has largely misreported the technical details of this story. Jeffrey Lewis, an arms control expert, has a blog which goes over these sorts of claims in more detail than you get in mainstream news, I recommend it heavily.


 * In any case, it would be very much against Iran's short and long term interest to give nuclear weapons to "terrorists". Terrorists are on the whole more unreliable than states and nuclear weapons are powerful — giving out free nukes could easily mean having them go off in your own cities. In any case it would be easy to tell if a nuclear bomb went off where it came from — all production plants have unique isotope signatures so you'd know within hours it originated in Iran, and they would have swift retribution. As for rogue states — it depends on whether Iran really feels it can trust said state. The Soviet Union trusted China for a long time and helped them with some of their nuclear development but balked at actually going all the way with it — Stalin was simply not willing to give Mao the bomb on a platter, he was suspicious of Mao's intentions and whether said bomb would end up being used recklessly. Now when you are talking about irresponsible profiteers — like Pakistan's A.Q. Khan, who happily sold bomb-production materials to Iran, North Korea, and Libya — it's an entirely different ballgame. He has no accountability in comparison to a state, he has no empire that can crumble beneath him. As a consequence free agents a lot scarier, in my opinion.--140.247.250.146 19:17, 10 April 2007 (UTC)


 * The larger issue is that the exponentially-quickening development of technology will inevitably put more power in the hands of individuals (like Mr. Khan). John McPhee's book The Curve of Binding Energy posits that we'll one day have to accept nuclear attacks the way we currently do major natural disasters, which is probably not far from the grim truth. --TotoBaggins 22:42, 10 April 2007 (UTC)


 * ...and the inevitable spread of nuclear weapons and their use against cities will eventually result in more decentralized, underground living. Unfortunately, I don't see people changing their living arrangements until a few nuclear strikes make it clear just how vulnerable large surface cities are. StuRat 03:03, 11 April 2007 (UTC)


 * Underground might at one time have held promise for surviving nuclear attacks originating from airplanes and missiles but nukes that are sneaked into (or constructed in) underground complexes and detonated would probably do far more damage than if civilization were spread out over the Earth's surface or living somewhere in space. Nebraska bob 05:36, 11 April 2007 (UTC)


 * I don't agree. If people were spread out over a large area, and lived underground, it would then take many nuclear weapons to kill the same number as could be killed with one if concentrated in a single location on the surface.  This is because rock absorbs both the blast and especially the radiation far more than air. StuRat 15:17, 11 April 2007 (UTC)


 * Aren't you forgetting something? What about large man made cavern’s such as exist in a Canadian underground hydroelectric complex? Such enclosed areas allow far more damage from high pressure especially if blast doors are closed. If not then the pressure wave spreads through tunnels. Highly secure underground is my choice for tightly secured military complexes and possibly other government operations but not for the general population where size alone would allow many different terrorist plans to be both effective and carried out. World wide control and uncompromising restriction of fissionable and fissionable material is by far the better plan. Including total and absolute destruction of any government that defies such control and restriction by the world power so put in charge. World government versus rogue state sponsored death by suicidal nuclear bomber? I choose world government. Nebraska bob 16:57, 11 April 2007 (UTC)


 * I think we're talking about different things. You're talking about the entire population of a city crammed into one cavern, while I'm talking about them in a million underground houses. StuRat 03:14, 12 April 2007 (UTC)


 * Not really. A million houses would still have to be connected presumably by tunnels to provide water and to carry away sewer waste and gasses. provide electricity and maybe gas plus air. In reality going underground for a whole population just in terms of cost versus eliminating fissionable material production by rogue nations ...the latter seems the more viable option. Nebraska Bob 05:16, 13 April 2007 (UTC)


 * If you haven't noticed, we aren't doing so well at keeping nukes out of the hands of rogue nations. North Korea has them, Pakistan has them (semi-rogue ?) and Iran may have them soon.  Non-rogue nations with nuclear weapons can also pose a nuclear threat to each other, as can terrorist organizations.  While the initial cost of building underground houses is higher, there are cost advantages in the long run, like reduced heating and cooling bills.  I picture the same sewer pipes, water supply lines, electrical lines, and gas supply lines that we currently have working just fine for underground houses.  Air supply and exhaust can go directly to the surface from each house. StuRat 06:44, 13 April 2007 (UTC)


 * I have yet to see evidence that any 'rogue' nation (whatever that means) doesn't care about the future. Most of them in fact care greatly about the future. Some of there leaders may be a bit deluded, but then again so is Bush seemingly. However I think most of them are smart enough to know that getting blasted to smitherens is not in their best interest. Iran for example, may not like Israel, but I have yet to see any evidence many people there really consider it a good idea to get blasted to smitherens just because they can take out Israel with them. Also, no 'rogue' nation is ever likely to attack a bigger country like the US with nukes. At most, they could take out half the country (and that's rather unlikely IMHO) but they will still be wiped off the map.
 * The US has in fact IMHO been one of the biggest threats when it comes to nuclear weapon use. They risked the entire world in the Cuban missile crisis, despite the fact there was no real threat there. The Soviet Union was already well in range of nukes under the control of the US. Despite this, the US decided to risk the entire world, just because they wanted to show they had bigger balls or something. Fortunately, the Soviet Union wasn't as dumb as the US and had no real desire for a nuclear war, unlike the US was seemingly. The US has also been one of the key states which has pushed against any attempts at nuclear disarment and has also a leader in pushing for mini-nukes and the like. The reality is, despite all the outrage at 'rogue' states, they aren't really the biggest threat when it comes to nuclear weapons. They will simply never use them pre-emptively. It's the bigger countries that are the real threat in that regard (as well as some potential non-state actors of course).


 * One issue is that the politicial and social situations in these 'rogue' states may mean lone actors like Khan may be more likely, but this is difficult to say for sure. Russia post Soviet Union for example is perhaps a bigger threat. Indeed, a social revolution in any country with nuclear weapons is probably the biggest threat in terms of lone actors.


 * The primary reason why 'rogue' states acquiring nuclear weapons is of concern to bigger countries is not because they are likely to use them pre-emptively, but because it reduces the power of these countries. The US for example could invade Iran if they wished. It would be a catasphore in many ways for them, but the actual invasion would probably succeed if they tried hard enough. Try that in a nuclear Iran tho and Iran may very well take Israel and whoever they can reach with them (as would any country, 'rogue' or other who are facing perceived eminent destruction). This is the primary reason why 'rogue' states acquiring nukes is of concern and also the primary reason they want to acquire them in the first place (especially post Iraq)


 * Nil Einne 14:14, 11 April 2007 (UTC)


 * P.S. Forgot to mention, the US is the only one to have ever used nuclear weapons of course despite the fact it's highly debatable whether they needed to. Also note in terms of messianic religion and the like, it doesn't matter whether everyone believes their leader is god unless the leader really believes he or she is god and can't be harmed (or it doesn't matter if they die), they are not going to risk their destruction. Even in some doomsday cults the leaders don't commit suicide, only the followers. Of course they could be deluded enough to think people won't retialite but I think this is far less likely then people think. Nil Einne 14:30, 11 April 2007 (UTC)


 * Not to debate but "post Iraq" is post 911. As for the USA its creation and use of nukes goal has always been for the purpose of peace rather than for domination by a particular religion or philosophy other than peace. In fact the USA has so demonstrated this by helping North Korea and trying to help Iran. What makes the possession of nuclear weapons untenable by Iran is not there use as a deterrent for invasion but because Iranian leadership stands fast in its commitment to the destruction of Israel and the West. Nebraska bob 17:12, 11 April 2007 (UTC)


 * Long time later (searching for something else) but . For example when has the Iranian leadership ever said they personally want to destroy Israel or the West (note most evidence suggests the common quote of the president wasn't about his believing Iran should wipe Israel off the map but his preference for what would happen). And how can you say the US create nukes solely for peace when they invaded, support revolutions etc in many governments which didn't agree with their philosphy even during the cold war but leave alone dictatorships etc which did and used their nukes to help ensure the Soviet Union couldn't stop them. (The US given their size not of course really needing their nukes as deterrence for anyone else.) Nil Einne (talk) 05:04, 18 June 2011 (UTC)


 * I think there is also two sides to this - just as the threat of total annihilation might not concern some of the more recent nuclear nations, their nuclear capabilities are not enough to deter the USA or much of Europe. A couple of sub-kilotonne nukes carried on an airplane or the thousand-mile range classes of missiles these guys have simply aren't going to "assure destruction" - sure they can take out a lot of innocent people and provide a serious threat but in any nuclear exchange, the USA and Europe would barely be scratched by comparison.  MAD only worked to the extent that it did because both sides could clearly see that in any exchange, nobody could possibly 'win'.   In an exchange with (say) Iran or North Korea - there is simply no possible way for their chosen targets to lose the war.  So MAD isn't needed - the sheer one-sidedness of the exchange ought to be enough of a deterrent.  What wil work is that when some tin-pot dictator starts behaving badly, the bigger nations of the world aren't going to be able to simply overturn them with an aircraft carrier and a bunch of marines.   The idea that a million civilians might die if you attack is an unbelievably strong deterrent.  Would the US and UK have invaded Iraq if Saddam had just one half-kilotonne missile within range of Isreal?   I doubt it.  Would even a suicidal nut-job fire such a missile if he knew that the consequences would be his entire nation being turned into radioactive rubble...maybe...but if he also knew that at the end of it, the USA and Europe would be greatly upset - but in the end have one less problem to deal with...probably not. SteveBaker 01:08, 12 April 2007 (UTC)


 * You did not sign your comment above and the BOT did not sign for you so I don't know from passed discussions how to read or know exactly what you are saying. As for using nukes it’s a foregone conclusion that geographic area known as Iran would no longer be a livable area on the planet if Iran ever actually used a nuclear weapon. Period. That said the problem the world is concerned about right now is Iran as a source of nuclear weapons for Cuba, Venezuela, and terrorist organizations in general should Iran not end its development program as of yesterday. My guess is that the US and the UK and the rest of the world would rather suffer the losses necessary to shut Iran down and end its existence as a nation rather than deal with proliferation (rather than use of nukes) later on. Just my opinion. Nebraska Bob 20:47, 11 April 2007 (UTC)


 * (Ooops! Didn't mean not to sign it...all better now!) SteveBaker 01:08, 12 April 2007 (UTC)

Kinetic Energy in Wake of Fast Moving Object
Is it possible to be moving so fast that objects in your wake are sucked into an orbit around you, as in the Matrix Reloaded during the minute 154. —The preceding unsigned comment was added by 84.13.132.232 (talk) 19:32, 10 April 2007 (UTC).
 * I don't have the movie at hand to refer to, but yes and no -- yes in general, no regarding the specific (but common) terminology in question. For the "yes", objects at speed (such as, say, cars on a highway) generate air vortices that pick up very light objects and can carry them along.  By way of specific example, leaves easily circulate the interior of my convertible, and I expect that at least a few of them are captured while driving.  On another scale, tornados do what you describe -- granted the tornado itself isn't moving very fast, but consider its winds as a wake of sorts, as an aerial wake is really just a sort of wind.  Moving on to the "no", sustained stable orbits such as those common in discussions of astronomy are not going to arise.  Just a technicality, but there you go. &mdash; Lomn 20:10, 10 April 2007 (UTC)

The question is likely to be answered by looking at how objects get sucked around other objects moving at speed. Setting aside non-speed-related matters (gravity, magnetism, etc), and asuming the only issue is that one object is moving fast, the reason other nearby objects are affected is vortices and eddies. The fast moving object moves, and this has two effects: the space ahead of it, air or fluid is "pushed" out of the way, and the space behind it is at the point of movement, empty. Air pressure (see bernoulli effect) causes air to rush in from the sides to fill the space behind, whilst ahead of it there will either be a high pressure area, a shock wave (if moving fast enough) or various other fluid effects.

We can now look at how this affects objects nearby. A nearby object will be swept along by the vortices which are the air/fluid rushing in to fill the low pressure space left in the fast moving object's wake. But there is little chance it will gain enough energy to swing around the fast moving object that I can see, under normal circumstances. It is solely moved due to the inrush of air or fluid, and this is simply moving into the low pressure space left behind and then dissipates, and there is no obvious effect operating to give it momentum that moves it forward faster than the object itself was moving. The catapult effect used in speeding up spaceships relies on gravity or other forces, not fluid effects, and doesn't play a role here.

Hope this helps. FT2 (Talk 01:04, 11 April 2007 (UTC)

Differences between human and other lifeforms
Are there, according to you, fundamental and qualitatives differences between us, Homo sapiens, and the rest of the biosphere? Or do we see us so much different from it only because of our anthropocentrism? —The preceding unsigned comment was added by 62.48.110.205 (talk) 22:50, 10 April 2007 (UTC).


 * Who do you mean by "according to you"? (And is "us, Homo sapiens, and the rest of the biosphere" two categories or three? :-) )
 * Certainly, many believe (as do I) that human life is qualitatively the same as the rest of biology (with the notable exception, of course, of our alleged "higher intelligence"). But anthropocentrism casts a long shadow, indeed, and if we're merely quantitatively different from the other animals, you'd probably not get a lot of argument if you were to claim that we're more different than, say, an elephant and a giraffe. —Steve Summit (talk) 00:00, 11 April 2007 (UTC)


 * Although I'm also not sure exactly what you're asking here, if we think solely in terms of the biochemical basis of our bodies, we are all the same. While different organisms are made of varyingly different macromolecules, the vast majority of the molecules in every organism are constructed from the same monomers.  We all contain genetic information in the form of nucleic acid, we are all internally bathed in water (most of us, anyway), the bulk of our dry mass consists of proteins constructed in nearly identical processes across the whole of the biosphere, and our energy is stored in the form of sugar (usually...for most of us).  Basically, take any organisms and grind it down to its monomers, and we'll all look pretty much the same with a few perturbations here and there.  Someguy1221 00:16, 11 April 2007 (UTC)


 * By "according to you", I'm asking you your opinion because i'm not sure it's possible to be objective about all that... Or we have to define the criterions arbitrarely. By "us, Homo sapiens, and the rest of the biosphere", I just mean two categories :)
 * I was thinking maybe the area where people could invoke the best arguments for the dissociation between human and other life is space exploration, the hability to leave the planet were we've grown... But again this is arbitrary since thousands of species are able to do things that we can't. —The preceding unsigned comment was added by 62.48.110.205 (talk) 00:29, 11 April 2007 (UTC).


 * I don't mind answering, but it's worth pointing out that there are those who feel pretty strongly that the Reference Desk should not be used for opinion-gathering questions like this, precisely because the answers are all so subjective. —Steve Summit (talk) 01:02, 11 April 2007 (UTC)


 * There are differences between Homo sapiens and the rest of the (non-human) biosphere. But there is also differences between Mus musculus and the rest of the (non-mouse) biosphere and differences between Fugu rubripes and the rest of the (non-pufferfish) biosphere. Species are, by definition, different from each other. Whether human differences are more fundamental than any other species' differences is a matter of opinion that will incorporate elements of philosophy and religion. But from a reductionist's point of view, humans differences are simply a result of a different pattern of nucleotides from any other living thing. No better no worse, just different. Rockpock  e  t  01:24, 11 April 2007 (UTC)

Aside from our higher intelligence (and specifically, the ability to use symbolic logic), there are a few other physical differences. Humans are fully bipedal, which is quite rare, not counting birds. Still, humans are unique in having the two feet and two hands configuration, as birds have two feet and two wings, other primates have four feet/hands (each being about midway between our feet and hands), and kangaroos use two legs and their tail when standing. Humans also have less body hair than most other mammals, and a longer childhood as a percentage of life span. Humans are also one of the most widespread species on land. So, there are a few things which make us unique. StuRat 02:39, 11 April 2007 (UTC)


 * How about the domestication of fire and combustion? The author Stephen J. Pyne, a "fire ecology historian", makes a good case for controlled fire as being one of humankind's most ancient tools (predating Homo sapiens themselves, dating back to other Homo species), very deeply embedded in nearly every other technology (eg, making steel requires fire, most electricity comes from coal-fired power plants, etc), having had a major impact on most of the planet's environments (from slash-and-burn to global warming), and being apparently unique to humans -- if you don't count things like the Bombardier beetle, whose "domestication" of combustion is like skunks' domestication of stinky smell (pretty limited). Pfly 07:17, 11 April 2007 (UTC)


 * I heard an interesting theory that we humans are "more special than most other species" because we kill off everything that is similar to us. Neandertals, the Flores Hobbits, etc. I'm no expert, and this could be a crazy quack theory. Aaadddaaammm 07:45, 11 April 2007 (UTC)


 * I believe any successful species will tend to cause some species which compete with it for resources to become extinct. Note that this doesn't have to take the form of species A physically killing species B.  Instead, species A just eats the food and occupies the habitat that species B would need to survive. StuRat 15:08, 11 April 2007 (UTC)


 * I think there is a difference. It's not that we're so different from other animals in biochemical or structural ways - it's what our behavior is causing to happen to us that is the difference.  With our big brains and our science (especially computers and medical science) we are able to fight the effects of evolution in a way that no other species can.  When we have certain adverse genetic traits (such as infertility or something that causes a disease that would ordinarily be fatal during childhood) that could normally be eliminated from the gene pool very quickly, we now work hard to 'cure' the person and let them live a normal life - which includes having children and passing these genetic traits onto the next generation.   This means that genetic defects that would ordinarily be selected out fairly quickly are going to start building up over the coming generations.  On the other hand, couples frequently have their unborn child's genetic makeup screened and may choose to abort the ones with certain genetic traits.  The result of this is that we've taken the reins away from 'natural' selection and taken control of the decisions ourselves.   This may be disasterous - total genetic collapse (as predicted in science fiction for years where the whole of humanity becomes infertile and you have to have baby factories) or it may be that the wider diversity of genes and our eventual ability to detect and correct these problems could turn out to be beneficial.  But what's clear is that our idea of what is beneficial is now dominating evolutionary pressures.  If there were a gene that produced (say) immunity to AIDS but caused 100% infertility as a side-effect, then that gene would stand a good chance of surviving - where in the past it would have been elminated in a single generation.  Hence, we've effectively ceased evolving biologically and have switched our collective futures over to the evolution of ideas.  Brains and computers - not nature red in tooth and claw.  Our ever-changing ideas of morality rather than the brutal death of those who can't outrun a Tiger when called upon to do so.


 * Pushing this trend to the limit - sooner or later I think we'll either produce effective artificial intelligence that will be our 'offspring' and will gently replace us (hopefully not as in Terminator!) - or we'll enhance our brains with computer implants and eventually end up with all of our knowledge and intelligence inside the machine - making the body a bit of a pain to deal with. If we do that, we can have effective immortality - we can slow our system clocks down and travel between the stars within an acceptable subjective time - we can add more memory and more CPU cycles as technology improves.  That's the natural path for a creature for whom ideas are in the driving seat rather than biology.  The line between human and cybernetic intelligence will blur - then vanish and we'll cease to be animals at all.


 * OK - that was a bit 'out there' - but it is the natural progression of things. SteveBaker 17:39, 11 April 2007 (UTC)


 * In addition to bipedalism, "humans evolved a derived brain allometry in comparison with chimpanzees and early hominins" (Allometry). Some of the brain size changes in humans compared to other apes are related to altered timing of brain development events (heterochronies). Most human brain growth happens after birth (allowing more neural nets to be shaped according to experience) and human children have extended developmental windows for synaptic plasticity that allows humans greater social learning such as complex language learning. --JWSchmidt 14:58, 12 April 2007 (UTC)

Complication vs. side effect
What exactly is the difference between a side effect of a medication and a complication of using the medication, or is there any difference? -Joelmills 22:53, 10 April 2007 (UTC)


 * A side effect is a naturally occuring effect of the medication. That is, the drug itself causes the side effect.  A complication typically refers to an effect not directly caused by a medication.  Simple examples would be a drug interacting with some other chemical (Alcohol, or another drug, or an unrelated medical condition) to produce a new effect neither would produce on its own.  Complications can also include bacterial and viral infections that were made more likely or more severe by a drug one is taking (common with immunosuppresant drugs). —The preceding unsigned comment was added by Someguy1221 (talk • contribs) 00:08, 11 April 2007 (UTC).

Makes sense. Thank you. --Joelmills 00:32, 11 April 2007 (UTC)


 * Usually one hears of complications of a disease, not a medication. --Anon, April 11, 2007, 01:48 (UTC).


 * Yeah, that's what I thought, too. The reason I asked is because I'm writing a protocol for work on pain management, and the standards set forth by the powers that be require a list of both side effects and complications for meds we use.  I was having trouble deciding if prolonged recovery from anesthesia would be a side effect or a complication of a medication.  It seems from what Someguy is saying that a complication would be a compounded effect secondary to an adverse reaction or drug interaction.  --Joelmills 02:08, 11 April 2007 (UTC)

And, on rare occasions, side effects can actually be beneficial. I don't know that complications ever are. StuRat 02:30, 11 April 2007 (UTC)


 * One drug has the side effect of causing spontanious orgasms every time a patient on this drug yawns! I can't remember what it is, but I think it was a antidepressant or something like that. Aaadddaaammm 07:50, 11 April 2007 (UTC)


 * Maybe that's how it cures depression. :-) StuRat 15:03, 11 April 2007 (UTC)


 * Our article on Clomipramine cites the yawning/orgasm side effect which in some situations cound be quite a complication! ~ hydnjo talk    15:24, 11 April 2007 (UTC)

Maybe it's true to say that all relevant complications are side-effects, but not all side-effects are complications. JackofOz 03:01, 11 April 2007 (UTC)

Unknown Costa Rican lizard
I recently took a trip to Costa Rica and got a shot of lizard one morning. I'd like it to be used in some article, so does anyone know what it could be. FYI, the lizard was seen at a beach resort in Guanacaste at 8:something AM local time. - AMP&#39;d 22:54, 10 April 2007 (UTC)


 * I'm tempted to say look here but unfortunately it doesn't even look remotely like a compsognathus :) Brammers 20:39, 12 April 2007 (UTC)

Anti-Hydrogen
If you take 1 positron, and 1 antiproton, put them together, and you get antihydrogen. Suppose you could create an entire cloud of antihydrogen, would it have the same physical properties as normal hydrogen? and yes, we do have an article on the Gravitational interaction of antimatter -- VectorPotential Talk 23:04, 10 April 2007 (UTC)
 * To my knowledge, this hasn't been proven yet. If certains types of symmetry hold, the chemical properties (aside from the annihilating bit) will be identical.  However, said symmetry is not proven to exist in the case of antimatter, and an asymmetry of the properties might be a nice way of explaining why matter exists at all.  (I should have payed more attention in quantum.)  Someguy1221 23:55, 10 April 2007 (UTC)
 * Are you suggesting that the Big Bang resulted in a divergence of matter and antimatter? Nebraska Bob 19:20, 12 April 2007 (UTC)
 * But we are close to study precisely that. Antihydrogen has been produced already more than 10 years ago. Unfortunatly, antimatter is produced from highly accelerated particles and so rather flies at high speed than sitting still, waiting to be analysed. A few years ago, people at CERN, using CERN's Antiproton Decelerator Ring managed to slow down and collect antihydrogen in a Penning trap, see e.g. this Physics News Update from 2002 saying that first very rough measurements of the energy levels (i.e., chemical properties) of antihydrogen were made. If you search on Google Scholar for "antihydrogen" and either "gravitation" or "spectroscopy", you will see that in the recent years, a lot of proposals have been made for experiments aiming to see whether antihydrogen really and exactly behaves as hydrogen with respect to gravitation and chemical properties. I suppose some of these experiments are now in preparation, and we will know more quite soon. Simon A. 20:04, 11 April 2007 (UTC)

Nose question
I am a male who had rhinoplasty to change the shape and size of my nose. I am now married and thinking about having kids. My wife has a small normal nose. My question is this. If I have kids, will they still have the possibility of inherting a large nose. Even though my new nose is now of normal size, I still don't know if through the genes they can inherent that trait. I just do not want them to be teased at like I was for having a large nose? —The preceding unsigned comment was added by 205.157.110.11 (talk) 23:06, 10 April 2007 (UTC).

As a firm believer in Lamarckism, I know that your kids will have normal size noses. My belief is so strong that you can be sure that what I said is true. Of course, 99.999999% of the learned scientists says I'm totally wrong but my invincible faith sustains my beliefs and so I can say to you in complete confidence that you have nothing to fear. 202.168.50.40 23:22, 10 April 2007 (UTC)


 * What User:202.168.50.40 is saying in a roundabout way is that your genes have no way of learning about your surgery, so the chances of your passing this trait on to your offspring are exactly as they were before. (The opposing view -- that environmentally-acquired traits can be passed on to your offspring -- is called Lamarckianism.) --Steve Summit (talk) 23:27, 10 April 2007 (UTC)

As Steve Summit says. Here is more explanation. Your genes (and anyone's genes) are acquired at conception, and short of some fairly exceptional circumsrtances(9nuclear war, genetic engineering etc) are an integral part of you throughout your life. They act as the blueprint for your body. Your body itself may be modified (trim a nose, lose a limb) but the genes which dictate your blueprint remain untouched. When you have children, it is your genes and your wife's which combine to provide a new blueprint for the baby, and those genes are unaffected by whether your body has changed or been deliberately or accidentaly modieid during your life.

There are two important aspects of this that count for your own children. First, they gain genes from both parents, not just one. But far, far more important, what they grow up being sensitive to or as their "life issues" may well not be what yours were. You may have been scarred by teasing and rightly not want them hurt by it. But they may be only slightly teased, but suffer from other things. The best you can do for your children therefore, is above all, not to push your own life's fears onto them. Teach them they are fine and have value, and tp believe they are good and worthwhile human beings. teach them to try and find what's best, do what's good, and to understand some people will say hurtful things to try and feel better themselves and this is something every child has, and daddy had it too. Teach them its not nice, but if they trust themselves and have fun you will always love and believe in them. And then -- stop worrying as much and enjoy parenthood yourself! :) FT2 (Talk 00:20, 11 April 2007 (UTC)

How Intelligent Is Alien Intelligence?
The day we find life forms on alien worlds, how 'intelligent' will they have to be to be considered "intelligent"... similar to an ant? a dog? a daulphin? a chimp? a human? my mother-in-law?--JLdesAlpins 23:42, 10 April 2007 (UTC)


 * A human, because humans are the only life form considered "intelligent". --Bowlhover 23:51, 10 April 2007 (UTC)
 * If any species is advanced enough to travel all the way to our little corner of the galaxy, then they might be so far above us that they may see us roughly the same way we see a common chimpanzee, so perhaps a less human centric definition of intelligence may be appropriate (: VectorPotential Talk 23:55, 10 April 2007 (UTC)
 * You could also use as baseline intelligence whatever is necessary for the aliens to build a radio transmitter that can reach Earth from their own planet. Someguy1221 00:27, 11 April 2007 (UTC)


 * Really? − Twas Now ( talk • contribs • e-mail ) 02:23, 11 April 2007 (UTC)


 * Humans are the only known life form considered intelligent. I'm pretty sure everyone will agree with that; chimpanzees are too dumb to follow logic, communicate effectively, and develop complex technology.  --Bowlhover 02:30, 12 April 2007 (UTC)


 * Known to whom? I would counter that I know chimpanzees are intelligent.  Your criteria for intelligence seems to be that an animal must have at least human-level intelligence, which effectively precludes the possibility that any other known species may be considered intelligent.  Why must the technology be complex to be the product of intelligence?  Does this mean the first simple spearheads were not made by intelligent beings?  Also, chimpanzees are capable of language (see Great ape language), and I recall some research that showed the logical capabilities of chimps.  Really, I know that humans are more "intelligent" than chimps and gorillas, but that doesn't not mean that chimps and gorillas are absolutely not intelligent. − Twas Now ( talk • contribs • e-mail ) 05:15, 12 April 2007 (UTC)

I'm fairly certain human intelligence is being used as the reference frame. But it's highly likely that any life forms we meet will either be billions (American usage) of years behind in technological advancement, or billions of years ahead. Given the improbability of even finding life, I say that the chances of finding a form of life with a dispute over whether or not it's "intelligent" as highly unlikely. And to be honest, I'm more worried about trying to find intelligent life right here on earth =P-- Ķĩřβȳ ♥  ♥  ♥  Ťįɱé  Ø  23:57, 10 April 2007 (UTC)


 * According to dolphin, they "are considered to be amongst the most intelligent of animals". JackofOz 00:00, 11 April 2007 (UTC)


 * Dolphins are actually the second most intelligent species on the planet, behind mice. -- mattb


 * It has been suggested that we may be more likely to find alien life via SETI if they are at about our current tech level because as we advance, stray signals (leakage) tends to reduce for a variety of reasons. Of course, it has also been suggested that we may in fact be more likely to find a purposely sent signal rather then stray signals and these we may get easier to detect the more advanced the civilisation is Nil Einne 13:41, 11 April 2007 (UTC)
 * But it's also been said that our best current radio receiver technology would be incapable of detecting our own most powerful broadcasts at the distance of the nearest star (4 light years).  That means that we are relying on the hypothetical alien civilisation transmitting at us with vastly more signal strength than we currently know how to generate.  The only way we could transmit over those kinds of distances with present technology would be by putting all of the energy into a narrow beam (a powerful radio-frequency laser perhaps) - but if that's what the aliens are doing then that would imply that they would have to be aiming their transmissions directly at us...which means that they'd have to know we were here...which means that they must have vastly more sensitive radio receivers or telescopes than we do.  Whichever way you slice it - if we got a message from another civilisation tomorrow then the very fact that SETI could hear them would be conclusive proof that (at least in the discipline of communications and telescopes) they are vastly more advanced than we are.   Furthermore, unless by some amazing flook they live on one of the handful of nearby star systems, the radio message we'd be getting from them would be decades, centuries or maybe even millenia old.   If they were even close to our present technological level when they sent the signal to us - they'd probably have a few hundred years of advances beyond that by now.  If you imagine where humanity was in (say) the year 1800 - you'll realise that things will have changed a lot by the time we get their message!  So - if we detect aliens just by listening for them - the only ones we find will be much smarter than we are.  The stupid ones won't be able to talk loud enough for us to hear them over interstellar distances - and they certainly won't have the technology to get much closer to us! SteveBaker 17:11, 11 April 2007 (UTC)


 * The more I read about SETI, and look at who studies it and who funds it, I find that SETI falls into two categories: 1) People who are unscientific and have unrealistic expectations about communication with extra-terrestrials; and 2) People who are very scientific about the prospects, and have (essentially) zero desire to successfully communicate or detect "aliens." The first category are operating irrationally and will probably be unsuccessful because their methods are simply unsound.  The second category recognize the difficulties and analyze why such methods are inherently unsound - and they use this "search for extra-terrestrial intelligence" as a philosophical and anthropological rhetorical question, sort of a launchpad to study human society and civilization.  What characteristics make our society "intelligent" anyway?  What "footprint" does our existence leave on the universe, compared to non-biological/non-"intelligent" processes?  What processes and phenomena separate "us" from "geological processes," why is our own planet "special?"  In summary, before we find "alien" intelligence, we first have to find intelligent life on earth, and explain what it is and how we found it.  Nimur 18:17, 11 April 2007 (UTC)


 * I agree - at the beginning I was very enthusiastic about the SETI initiative - but I'm beginning to think that we would be better off using that energy and equipment to hunt for extrasolar planets with atmospheres that show spectral signatures that demonstrate the existance of life (intelligent or otherwise). If they succeeded in identifying strong candidates for planets with life, we could attempt to beam tightly focussed messages at them. —The preceding unsigned comment was added by SteveBaker (talk • contribs) 00:58, 12 April 2007 (UTC).


 * The trouble with such an approach is it doesn't inspire the same level of interest. Given that in all likelihood it will be many hundred years at a minimum before we actually receive a response, it's an extremely long term concept. Then there is also controversy about whether it is even wise to send out a signal. While SETI mayy not achieve anything in 1000 years, it could very well achieve something within the next 2. We just don't know and have no way of knowing at this time. Anyone who claims to be able to conclude one or the other sounds dubious to me. Also, it seems to me that SETI is more complementary to any such ideas than competing. Remember that SETI does not operate completely randomly. As our level of tech and our knowledge advances and we begin to detect extrasolar planets with good signs of life then it's likely a fair amount of the SETI work will be concentrated on looking for signals from these planets. At the same time, we may decide to send signals ourselves. I don't therefore think that SETI should be thought of as competing with these other ideas but complementing. Personally, as a biologist I think there are much more worthwhile projects in the biological sciences then most of the 'crap' space stuff and even arguably things like the LHC. On the other hand, I am biased and nor do I understand the projects well enough to comment fairly. Also, these projects can sometimes have unexpected benefits which aren't expected otherwise. Perhaps most importantly however, these projects (especially space ones) can be quite important in inspiring people in science as I've already remarked. Personally I don't partake in any distributed computing and if I did I doubt it would be SETI@home. I think there are other projects much more worthwhile (although what's going to happen to the results seems a bit dubious in some cases). But SETI@home has attracted more interest then many of these projects and this is probably because for better or worse, the potential results, even if rather difficult to achieve, seem particularly inspiring and interesting to many people. In the end, while I wouldn't say SETI@home is necessarily the best use of time and money, it seems a much better use then many other things like Iraq war for example. But then again, I'm not an American so I can't speak for them as to whether SETI is a worthwhile use of their money. Nil Einne 09:12, 14 April 2007 (UTC)


 * Forgot to mention, remember of course if SETI or something does detect life, if that life is at our current level when we detect it, this will of course mean they are probably much more advanced by now (since it seems likely anything we will detect will probably be hundreds light years away at a minimum) Nil Einne 08:46, 14 April 2007 (UTC)


 * Considering intelligence to be the speed with which an entity can reduce to minimum form the largest number of multiple state logical equations made up of the largest number of variables and states, human intelligence might be easily surpassed by something with simply a larger noggin. Nebraska Bob 19:32, 12 April 2007 (UTC)