Wikipedia:Reference desk/Archives/Science/2011 June 27

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June 27

What is the biggest Humpback whale ever found?

What is the biggest humpback whale ever found? Neptunekh2 (talk) 00:46, 27 June 2011 (UTC)

According to this, "maximum reliably recorded adult lengths are in the 16-17 meter range". ~ Mesoderm (talk) 01:29, 27 June 2011 (UTC)

life and reproduction

Would it be scientifically accurate to say that by having a child, I am perpetuating 3.5 billion years of successful reproduction, and therefore extending a 3.5 billion year long lineage by one generation? The Masked Booby (talk) 02:49, 27 June 2011 (UTC)

That's probably roughly right, although the lineage conceivably might have been a lot longer than that if life on Earth started here via exogenesis. Note that in any event, exactly how many generations it took to create you isn't precisely defined, because sexual reproduction can mix the genes of individuals of widely different ages. There's presumably also a little vagueness in the generation count due to it being a little vague as to when during the process of abiogenesis there began existing clearly defined cells, with clearly defined parent cells. However, the vast majority of generations of your ancestors since life began involved asexual reproduction of single-celled organisms, so the vagueness in the number of generations wouldn't be that large of a percentage. Red Act (talk) 03:57, 27 June 2011 (UTC)

The simple answer is "Yes". Now, if the OP is trying to figure out how many generations that translates to, it gets slipperier. Just among my own 16 great-great-grandparents, there is 37-year gap from oldest to youngest. That's more than the average length of a "generation" (20-30 years) just by itself. ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:24, 27 June 2011 (UTC)

Actually more than one: your mitochondria have their own proud parentage. But if we credit that, we should also consider horizontal gene transfer which, in a sense, means that we could have parentage through many small bits of many different microbes in the billions of years past - before at last converging on some common ancestor(s) of all life in yet earlier generations. Wnt (talk) 04:30, 27 June 2011 (UTC)

A microbe called Adam? :) ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:43, 27 June 2011 (UTC)

Don't forget Y-chromosome DNA. ~AH1 ^(discuss!) 01:33, 30 June 2011 (UTC)

I get the impression from the above discussion that a great many of my ancestors were probably single-celled organisms and thus incapable of creating written genealogical records. If so, this explains why I have been unsuccessful in tracing my family tree back further than about 10,000 years (as well as other issues I have puzzled over). This is a huge relief! Thank you very much. Wanderer57 (talk) 20:16, 2 July 2011 (UTC)

Rock-hard stools and fake fruit juice

As a child I learned by experience that drinking too much fake fruit juice led to terrible stools so rock-hard I could only pass them by pulling them out piece by piece with my fingers. So I've long since avoided anything but real fruit juice - though on two or three occasions at hotels or social events I've forgotten this precept until unpleasantly reminded that it still applies even as an adult. But looking over the web it seems like fruit juice is commonly recommended to people with fecal impaction (which sounds like a more serious version of this), and it seems like advertisements for stool softeners have grown very common in the U.S. in recent years. (the effect of home budget cutbacks...?) So in the interest of all the kids who haven't learned by trial and error yet I'm curious - can someone think of evidence that might link this problem to some ingredient in fake fruit juice? The first guess that comes to mind is high fructose corn syrup... yet I get exposed to so much of that in other forms without any similar effect ever happening. Unfortunately, because of when and how I was exposed, I don't know the ingredients of the products involved, though one of the worst culprits vaguely resembled orange juice. I couldn't find anything on PubMed in a few basic searches... but I'm not sure what I'm looking for. Wnt (talk) 05:56, 27 June 2011 (UTC)

For making that discovery I'd like to shake your hand ... or maybe not. :-) StuRat (talk) 06:23, 27 June 2011 (UTC)

But, seriously, if everyone who drank such drinks had that reaction, it would be widely known already. You must have had an allergy or unusual reaction. Also, I would bet that parents who give their kids fake juice also don't tend to give them enough fiber and provide a generally poor diet, overall, so any of those factors could contribute. StuRat (talk) 06:23, 27 June 2011 (UTC)

I don't see anything on PubMed about allergy causing fecal impaction. While it may not be a universal reaction I somehow doubt it's all that rare, judging by the prevalence of hard stools. Wnt (talk) 06:31, 27 June 2011 (UTC)

As a past participant in the F-plan diet, I can tell you that juicing oranges removes the fibre from them and leaves you with the water and other bits. If you want to get the benefit of the orange you need to eat the whole flesh (OK you can leave as much as the white pith as you wish to) and not to juice it. So real fruit juice could have the same effect, particularly if you're not drinking a great deal anyway.--TammyMoet (talk) 12:36, 27 June 2011 (UTC)

Interesting. When I get real orange, grape, or apple juice, it's not uncommon for me to run through 1-2 liters in 24 hours, but it never caused this effect. But I'm getting the impression the underlying biology is more variable than I thought. Frankly, I'd been thinking that the reaction might be universal and widely known, since after all there are things like olestra (and I think adulterated olive oil...) which are widely sold and which have equally disturbing effects. Wnt (talk) 15:04, 27 June 2011 (UTC)

Fruit juice containing pulp contains dietary fibre. ~AH1 ^(discuss!) 01:31, 30 June 2011 (UTC)

WIMPs

There is a huge amount of conjecture and speculation about weakly interacting massive particles in the literature, going back to mirror matter hypotheses in the 1950s. Has there ever been any evidence for their actual existence? 76.254.22.47 (talk) 07:13, 27 June 2011 (UTC)

Have you read Weakly interacting massive particles#Experimental detection? Red Act (talk) 07:21, 27 June 2011 (UTC)

Neutrinos are WIMPs so the answer is yes! But so far no smoking gun evidence for other kinds of WIMPs has been found. Dauto (talk) 07:54, 27 June 2011 (UTC)

That's not true and the Wiki-articles on this subject are out of date. The DAMA-Libra results which were originally received by a lot of scepticism have been confirmed by the COGENT results, and very recently COGENT has also reported an annual modulation. These are consistent with light WIMPS of a mass of about 8 GeV to which other DM direct detection experiments are not sensitive to. There are a lot more physicists taking these results serious than a few years ago. Because you first had the DAMA results, then the confirmation of these results by DAMA-Libra and then later the completely independent experiment COGENT. Count Iblis (talk) 15:08, 27 June 2011 (UTC)

Thanks for that information. I had heard of the DAMA results but wasn't too impressed. I will definably look into the COGENT experiment which I hadn't heard of before. Dauto (talk) 16:28, 27 June 2011 (UTC)

After reading about CoGeNT (Which seems to be part of the CDMS II experiment), I have to say that I don't think that is the smoking gun evidence just quite yet, though we may be getting tantalizingly close to it. Dauto (talk) 19:01, 27 June 2011 (UTC)

Just read an article in Science about WIMPs yesterday. It's in their news section, so it should be pretty accessible to the lay reader. Bhattacharjee, Y. (2011). "Possible Sighting of Dark Matter Fires Up Search and Tempers". Science. 332 (6034): 1144–1147. doi:10.1126/science.332.6034.1144. PMID 21636756. NW (Talk) 15:46, 29 June 2011 (UTC)

Difference between curd and yoghurt

difference between curd and yoghurt... their nature and formation..... acidic nature.... — Preceding unsigned comment added by Simplyds (talk • contribs) 12:13, 27 June 2011 (UTC)

Have you read the Wikipedia articles on curd and yoghurt? The differences are easy to discover. Oddly, the acidity of these foodstuffs seems harder to determine. After a bit of a look round I found this which is a bit heavy but has info on yoghurt, and this one has info on milk curd. Richard Avery (talk) 12:55, 27 June 2011 (UTC)

Capturing CO2

Could the CO2 expelled by a car be captured? Wikiweek (talk) 12:18, 27 June 2011 (UTC)

Sure, by attaching a hose to the exhaust pipe and routing it somewhere. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:57, 27 June 2011 (UTC)

Yes Buggs, I'm thinkin' the "somewhere" leaves your response a bit open-ended, and not even clever. Caesar's Daddy (talk) 13:13, 27 June 2011 (UTC)

I've seen this done in garages, when the mechanics have to run the engine for awhile to test something. The hoses presumably route the CO, CO2, soot, and whatever else, to the outside of the building. Given that, it ought to be possible to capture it. Although, as noted, it's not "pure" CO2 emitting from a car, but a variety of things. So it might be possible to capture the contents of the exhaust, but by what process would you separate the various products from each other? ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:37, 27 June 2011 (UTC)

Somewhere to a CO2 parallel universe, where it disappears? But would it be practical? You'll still need some way of compressing it... — Preceding unsigned comment added by Wikiweek (talk • contribs) 13:14, 27 June 2011 (UTC)

You can bubble the CO2 through lime water which sequesters it as Calcium carbonate. This is a simple kind of carbon dioxide scrubber which I will let people read and follow links from on their own time. Attaching such systems to cars, however, is impractical and expensive, which is why it isn't done. --Jayron32 18:30, 27 June 2011 (UTC)

Several by-products of combustion are already captured in a catalytic converter, but CO2 is not one of them because out of all the by-products, CO2 is one of the least harmful. Vespine (talk) 00:42, 28 June 2011 (UTC)

Catalytic converters work by reducing nitrogen and sulfur oxides to less harmful gasses. Such oxides make up a miniscule amount of the exhaust, which is still mostly carbon dioxide; so to deal with the CO2 would require a MUCH larger system. Furthermore, the primary danger of CO2 is as a greenhouse gas, and its not clear that a reduced product (in this case likely methane, CH4) would be any less harmful. The problem with carbon sequestration in calcium carbonate is that you have to, very frequently, change out the chalk and replace the lime. Quite messy business for something you want to just "work" without any outside help, like a catalytic converter does. --Jayron32 02:55, 28 June 2011 (UTC)

Note that a catalytic converter does not 'capture' anything. As the name implies, it contains one or more large-surface-area catalysts that encourage the conversion of certain exhaust components into less-noxious chemicals. (This generally includes the combustion of unburned or partially-burned fuel, the oxidation of carbon monoxide into less-toxic carbon dioxide, and the breakdown of nitrogen oxides into nitrogen and oxygen.) TenOfAllTrades(talk) 14:56, 28 June 2011 (UTC)

It's not very practical to capture the carbon dioxide from the tailpipe as the car is being driven down the street, for the reasons listed above. A more practical approach may be to use carbon credits and carbon trading. Under such a system, anyone driving (or perhaps manufacturing or selling) a car or, better yet, refining or selling gasoline for the car, would have to pay a company to extract the equivalent amount of carbon dioxide from the air and sequester it. This approach has the possibility of being far more efficient, but requires the political will to pass the legislation to make it mandatory. I believe there are existing companies which will currently do this on a voluntary basis, but, of course, most drivers won't participate. StuRat (talk) 17:29, 28 June 2011 (UTC)

Lithium hydroxide is one of the few substances that can capture CO2 at the source. ~AH1 ^(discuss!) 01:29, 30 June 2011 (UTC)

But it still wouldn't be very practical to haul a tank of it around with you, with the need to replace it at each fill-up. StuRat (talk) 17:07, 30 June 2011 (UTC)

General Fusion

What are the main reasons it will fail? 20.137.18.50 (talk) 12:33, 27 June 2011 (UTC)

Well, it might fail to solve some of the technological challenges required to make fusion happen in the first place. Or it might achieve a repeatable fusion reaction that consumes more energy than it releases. Or it might solve all those problems, but still not be an economically feasible process. Gandalf61 (talk) 12:49, 27 June 2011 (UTC)

Private companies based on fusion have failed in the past because the capital R&D costs are very high and the guarantee of economical success is nonexistent. They have an additional downside from government or university work in that they are reliant on investment funds but they are trying to develop proprietary technology. So generally they need hype but have difficulty providing the details about how they made it happen, which is a sure recipe for suspicion. There was an ICF company in the early 1970s that failed after cycles of this sort — it turned out that ICF was hard, and that generating sustained research funds from private donors was hard. Universities and governments have typically dominated in this field because their funding mechanisms are not profit-based. You can still get useful results even if you don't get closer to getting a profit in those contexts, but that is not a good business model.

This is a separate question from the specific technical one. The general difficulty with fusion is that the tolerances for imperfections (either in keeping the plasma off of the walls in MCF, or compressing it in ICF) are very low, for any imperfection rapidly leads to either incredible inefficiency or rapid cooling, both of which make generating a gain in net energy unlikely. Now I don't know much about Magnetized target fusion but it seems to be an attempt to average out the difficulties of both. Whether it actually works to that end, or whether it simply means you are trying to solve two different and difficult problems at the same time, remains to be seen, I think. The track record for fusion is not great: every problem solved usually results in the discovery of two more problems. This is why the two current most favored efforts (NIF and ITER) are basically based on the idea of scaling it up to monstrous sizes so that hopefully the imperfections become less important. --Mr.98 (talk) 13:52, 27 June 2011 (UTC)

I don't like your will there. That's very pessimisitic. It could fail, for a variety of reasons from physics to politics, but that's far from certain. i kan reed (talk) 17:05, 28 June 2011 (UTC)

I think the OP is just expressing the fact that so far every attempt at commercializing fusion (much less getting even net energy) has failed over the past five decades. There are little reasons to be optimistic with fusion — the history of fusion research is filled with people saying "this shouldn't be too hard — give us 5 years!" again and again and again and again. It turns out that controlled fusion is genuinely hard. --Mr.98 (talk) 18:44, 28 June 2011 (UTC)

What's so hard about putting a star in a bottle ? :-) StuRat (talk) 19:13, 28 June 2011 (UTC)

Five years? Everyone knows commercial fusion power is twenty years away -- and has been for the past half-century. --Carnildo (talk) 00:40, 29 June 2011 (UTC)

University/lab scientists say 20 years. People wanting to commercialize it say 5 years. Which is a nice reflection of the different funding forces playing on both of them — one says "fund more basic research and you'll get this cool technology," the other says, "invest today, earn money soon!" --Mr.98 (talk) 00:44, 29 June 2011 (UTC)

bond angles

how "flexible" are bond angles (or equilibrium bond angles, because they can move)? I mean in large molecules like polymers, they can easily bend (such as polyethylene) and we see a lot of images showing structures like DNA bending as if its a simple rope or something.also, the covalent bonds in liquid glasses such as SiO sre still present but apear to be somehow looser than the solid form.. if the bond angles (or equilibrium bond angles) are more flexible when the olecules are larger,why is it that way. is everything about molecular geometry only true for smaller molecules? thanks.--Irrational number (talk) 12:44, 27 June 2011 (UTC)

• Some bonds are free to move as a swivel. allowing large molecules to bend.
• Large molecules have many bonds. The slight flexibility of each of them can add up to a large flexibility for the larger molecule.

Dauto (talk) 17:14, 27 June 2011 (UTC)

Do these materials(large molecules) naturaly tend to bend too?-Irrational number (talk) 18:26, 27 June 2011 (UTC)

There are two conflicting things here. First, a long simple alkane is indeed very floppy, and bends quite alot. However, that bending only works if the molecule is dimensionally constrained; essentially long straight chains are the "floppiest". When there is a network of bonding within a molecule in three dimensions, it can constrain the bonding. The carbons in an alkane are in the same hybridization as the carbons in diamond, and yet diamond is very much NOT flexible. In DNA, the three-dimensional structure constrains the DNA chain into a relatively rigid double helix, though the entire chain does have some flex to it. Look at other macromolecules like proteins. Some proteins are very flexible, while others are not. The difference is the presence of large numbers of cysteine bases, which form disulfide bonds and constrain the structure of the protein; proteins with lots of disulfide crosslinking (like keratin) tend to be relatively inflexible. --Jayron32 18:28, 27 June 2011 (UTC)

There are cubane, propellanes, cyclobutane at 90 degrees ... even cyclopropane at 60 degrees. It's hard to think of a molecule that forces C-C bonds at a smaller angle than that, but if you do ... odds are someone's done research on it. ;) The bonds have a preferred angle, yes, but generally carbons seem to prefer association of any sort over none at all. But the strain on such structures is enormous - of course, in a long piece of plastic, the deformation of any one bond is absolutely miniscule by comparison. Wnt (talk) 18:46, 27 June 2011 (UTC)

Cyclopropene beats 60° :). DMacks (talk) 12:51, 29 June 2011 (UTC)

Cyclopropyne doesn't appear to be an energy-minimum, but if you're willing to look more broadly (simple octet/4-bond main-group atoms other than carbon), silacyclopropyne does exist and the C–Si–C angle is around 41°.(doi:10.1021/ja960762n) DMacks (talk) 13:50, 30 June 2011 (UTC)

how did biblical figures probably walk on water

if not by magic, then what is the most likely mechanism biblical figures used to walk on water? — Preceding unsigned comment added by 188.29.96.144 (talk) 13:38, 27 June 2011 (UTC)

There is not universal agreement that Jesus was literally walkig on the water. ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:40, 27 June 2011 (UTC)

They probably didn't... AndyTheGrump (talk) 13:42, 27 June 2011 (UTC)

The could have used floating sandals, as in the illustration in our article on Walking on water.--Shantavira|^{feed me} 13:49, 27 June 2011 (UTC)

The article Jesus' walk on water gets into specifics of the Bible story. ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:52, 27 June 2011 (UTC)

I think Jesus walked on water using the same levitation mechanism by which Yoda levitated, i.e., the levitation was enabled by the imagination of the storyteller. But see levitation for real levitation mechanisms, and levitation (paranormal) for other mythological levitation. Red Act (talk) 14:08, 27 June 2011 (UTC)

A sandbar close to the surface of the water could give the appearance of walking on water especially if seen from another water-going vessel—perhaps at a distance, and perhaps with the lower portion of the body blocked from view by the water-going vessel upon which one finds oneself. Bus stop (talk) 19:37, 27 June 2011 (UTC)

Maybe they thought life is a state of mind. Richard Avery (talk) 19:48, 27 June 2011 (UTC)

Modern magicians use a clear plastic support, just below the water. Plastic wasn't available then, so perhaps glass was used. Unlike the sandbar, this can fool people right there, as clear objects can become virtually invisible, once submerged, especially with waves at the top. Also note that in Biblical times it was common for religious figures to use magic tricks to convince people they had God(s) on their side. The magic contest between Moses and the Egyptian high priest, where each turned their staff into snake(s), shows this nicely (some Christian fundamentalists might argue that Moses' trick was the real thing, but who argues that the Egyptian priest was really using the power of Egyptian gods ?). StuRat (talk) 19:54, 27 June 2011 (UTC)

You have to be careful with that trick. The nature of waves in shallow water is different from deeper water. In Superman II there was a scene that showed the evil General Zod walking on water. They got a little too close with the camera, and although you couldn't see the platform he was walking on, you could see its effect in the rippling of the water. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:39, 27 June 2011 (UTC)

But, of course, you were merely seeing the effect on the waves from the supporting force field. StuRat (talk) 04:21, 28 June 2011 (UTC)

Egyptian fundamentalists of course. If Wikipedia had been around in Old Testament times, there might have been a heated debate. Wanderer57 (talk) 21:28, 27 June 2011 (UTC)

If the internet had been around in O.T. times, God would simply have posted the Ten Commandments in His blog. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:35, 27 June 2011 (UTC)

If it was a wiki, I'd hate to think of all the edit wars on that one. StuRat (talk) 04:21, 28 June 2011 (UTC)

He would probably have added "Thou shalt not annoy others with your constant twittering." Googlemeister (talk) 13:21, 28 June 2011 (UTC)

And his Admin policy would have been strict. "Disemvowellement? No, I think you misheard." {The poster formerly known as 87.81.230.195} 90.201.110.117 (talk) 17:18, 28 June 2011 (UTC)

There are two ways that humans today can walk on water: either by walking on ice, or by running very quickly on floating substances such as lily pads or thin wood. ~AH1 ^(discuss!) 01:27, 30 June 2011 (UTC)

In Jesus the Man, Barbara Thiering presents an interesting idea about the origin of "walking on water". According to her, it was routine for priests to perform a certain ceremony on a boat that involved people wading from the shore to the boat. By contrast, the priest, dressed in robes and needing to maintain dignity, could not wade through the water, and so a low-lying jetty was built solely to allow the priest to walk out to the boat. To the onlookers from the shore, it looked like the priest was walking on water, and they used that phrase to joke about priestly superiority. A certain event involving Jesus and the jetty led to the phrase being adopted for Jesus (and embellished in documented form, according to Thiering). Johnuniq (talk) 03:43, 30 June 2011 (UTC)

painkillers for waxing

What would be more effective pain relief for waxing of intimate areas? Paracodal or ibuprofen? I've been advised to take something before my appt and these are the two options in my drawer! Thanks. (just so you know, I take both occasionally and am not allergic to either and have never had any adverse reactions in the past and this is not a request for "medical advice", you can just give me science!) 195.27.52.146 (talk) 15:15, 27 June 2011 (UTC)

It really is a request for medical advice, actually. Who advised you? In many countries only a medical practitioner would be able to advise. In others, perhaps a pharmacist. Itsmejudith (talk) 15:51, 27 June 2011 (UTC)

I feel that this is a specific question about the action of the two drugs. In this case, there is a very clear answer. Ibuprofen primarily reduces inflammation and fever. Neither of those will be of much help in reducing upcoming pain in sensitive nerve endings. Paracodal contains paracetamol, which specifically reduces pain by reducing the sensitivity of nerve endings. Both are "pain relievers", but they relieve different kinds of pain. If this doesn't completely answer the question, please delete it and mark this as a true request for medical advice. -- kainaw™ 18:41, 27 June 2011 (UTC)

This sounds like a request for medical advice to me. I have no idea, for example, whether the practitioner might be relying on your yelps and screams as feedback about whether he/she is pulling too hard, and by suppressing them you could make something gruesome happen. IMHO if something is so painful you need a drug to suppress the pain, your body is trying to gently hint to you that perhaps it is not a good idea. Wnt (talk) 18:50, 27 June 2011 (UTC)

I don't think you need a medical license to suggest cosmetics, so I would go with a skin cream or shaving cream containing menthol and/or eucalyptus and/or aloe. The menthol a pain-killer, the eucalyptus is an antiseptic to prevent infection, and the aloe is a painkiller and will help you heal after. The advantage of a topical cream is that it's much stronger where you need it, while anything you take orally is distributed around your body, so very little of it will actually go to the skin in question. I do agree with Wnt, though, that if they advise stronger painkillers, they aren't doing it right. It shouldn't be that painful. StuRat (talk) 20:08, 27 June 2011 (UTC)

Why not use Lidocaine/prilocaine?

The lidocaine/prilocaine combination is indicated for dermal anaesthesia. Specifically it is applied to prevent pain associated with intravenous catheter insertion, blood sampling, superficial surgical procedures; and topical anaesthesia of leg ulcers for cleansing or debridement.[3] Also, it can be used to numb the skin before tattooing as well as laser hair removal.

Count Iblis (talk) 22:32, 27 June 2011 (UTC)

Kainaw is right, that's just what I wanted to know. To the rest, waxing is notoriously painful and taking a couple of painkillers before doing it is pretty much standard advice from the practitioners. Wnt—there's no such thing as "pulling too hard" when it comes to waxing! That's the whole point.  :) Thanks for all the responses! 195.27.52.146 (talk) 06:44, 28 June 2011 (UTC)

communication over vast distances

Is it in any way possibly to send information over vast distances (in a reasonable amount of time). Even better, is this also applicable to traveling? 66.229.227.191 (talk) 15:19, 27 June 2011 (UTC)

The question is vague. By typing this comment, I'm sending information to people in distant countries, if they happen to be looking at this page. By using my cell phone, I can talk to those people. Did you mean vaster or faster than that? Michael Hardy (talk) 20:43, 27 June 2011 (UTC)

No form of communication or transportation is faster than the speed of light, which severely limits interstellar travel. Red Act (talk) 15:39, 27 June 2011 (UTC)

A wormhole would be useful but there is no reason to believe that they actually exist. Dauto (talk) 17:19, 27 June 2011 (UTC)

The speed of light is fast enough if you transmit yourself using the message. Ultimately, we are just information stored in the brain and all that can in principle be transmitted. If the message that defines you travels 10,000 light years and upon arrival you are recreated using the received message, you would not experience the 10,000 years. Count Iblis (talk) 17:32, 27 June 2011 (UTC)

You wouldn't experience anything. If such technology existed, allowing a copy of a human brain's "state" to exist, it would be reasonable to describe it as a fork(). A copy of the state would be created and begin new processing. But it does not change the processing-state of the original copy. Needless to say, hypothetical technology to serialize the complete state of a human brain, transmit it by any method, and restore functionality by running it on a "virtual machine" is still science-fiction. Much work remains to precisely define the type of "machine" and its "instruction set" or "state." Even once these tasks are complete, building a replica and designing a "scanner/copier" will be additional, complex tasks. Nimur (talk) 17:43, 27 June 2011 (UTC)

Add to that the fact that you would only be able to travel to places that have a receiver. Dauto (talk) 19:28, 27 June 2011 (UTC)

If it takes 10,000 years to get there, they might have a receiver built by then. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:33, 27 June 2011 (UTC)

Indeed, so if e.g. the Earth were to face some disaster, we could transmit signals that contain the information to recreate our civilization elsewhere. That would be easy to do if we have transformed to a machine civilization. If the signal is powerful enought it can be picked up millions of lightyears away in some nearby galaxy. They can then download our programs and eventually our entire civilization can be rebuilt there.

A limiting factor here is the data rate. Perhaps the best strategy is to have a radio beacon repeatedly transmitting an easy to decode message that tells listeners to look out for a laser beam. Using a visible light laser, one can transmit more than 10^14 bits/second. So, more than 10^21 bits of information can be transmitted per year and if we use higher frequency beams much more than that.

The power of radio transmitter and the laser beam must be large, but that's not a problem for a machine civilization capable of using all the power that the Sun emits. The laser beam can be split into separate parts that are aimed at many of the nearby galaxies. The beam divergence can be made small enough such that the beam's width is exactly the size of the galaxy upon arrival (the brighness of the beam would then be similar to the apparent brighness of a star at a distance of the order of the diameter of that galaxy, so it would be easy to detect).

Our survival then depends on there being just one civilization capable and willing to recreate us among the many hundreds of nearby galaxies. Count Iblis (talk) 00:16, 28 June 2011 (UTC)

If Earth received instructions on how to fabricate individuals of some dying alien species, along with DNA sequences (or the alien equivalent) of numerous exemplars of the species, and especially if they were cute and nonthreatening (dolphins, seaturtles, pandas, Love birds), some humans would feel sorry for them, or want to adopt and raise them, or would hope to gain financially or militarily from their special abilities, or to publish articles about them in scientific journals, or exhibit them in zoos, or whatever. It is quite likely that someone would build the machine and feed in the DNA sequences, producing some living exemplars of the species. Of course their civilization might really be be aggressive and flourishing rather than dying, and the cadre of synthesized individuals might be genetically coded such that when they are grown they exterminate, enslave or replace the native population or open a port of some sort to allow a wholesale invasion. Such unintended consequences are a likelihood if a civilization does what someone in a distant star system tells them to do. On Earth, people have carried out malicious instruction from random phone callers such as putting Vaseline and alcohol on their hair and setting it on fire, cutting off their hair, [1] or cutting off someone else's hair, soaking the phone in the toilet, or strip searching a teenage employee at a fast food restaurant. The "call from space" might also be malicious or a prank. Even if the authorities suspected it was not on the level, that the senders might be con artists, pranksters or hostile militarists, they would be likely to build it for fear that otherwise the "other side" or terrorists will build it and gain some competitive or military advantage from the new technology. Those who send out technological information to other stars might be idealistic and altruistic benefactors, or they might have ulterior motives, such as a xenophobic wish to exterminate all other intelligent lifeforms. An "interstellar hoax message" comparable to the ones which got the women to cut or ignite their hair might tell us that there is some "peril from space" (alien invasion or bacteriological weapon coming from space) and that we need to launch a crash program to protect ourselves, or that we need to kill all marine mammals, or modify the DNA of the next generation of humans, or vaccinate ourselves with some bogus vaccine they helpfully sent instructions for. The basic interstellar hoax message would tell us to build some gadget which will make us happier, healthier, wealthier, or more powerful, complete with demo video showing the "cornocopia" will feed everyone, or the "filter" will unpollute the air and water, or the machine will eliminate infectious diseases, or the "antigravity device" will make it easy to get around, or the "energy machine" will eliminate powerplants. Industrialists and governments could convince themselves that it would be "Ok to build a small demonstration model" and that they could "turn it off at the first sign of trouble." Hilarity ensues: "IT'S NOT STOPPING! IT'S GETTING BIGGER! AIEEE!" Many classic con games could be modified to be motivating. Most Earthly hoax messages seem to just be intended less to provide actual gain to the sender than to make people look silly, run around and waste resources, like fake distress calls from nonexistent sinking vessels, or fake bomb threats. Edison (talk) 16:25, 29 June 2011 (UTC)

If light-speed communication is too slow for you then superluminal communication is the page to look at for more information. Apparently the prospects are not good. --Antiquary (talk) 19:21, 27 June 2011 (UTC)

Biology

Why do some birds migrate even though they are warm blooded ? — Preceding unsigned comment added by Ssmagic (talk • contribs) 16:27, 27 June 2011 (UTC)

It doesn't have anything to do whether an animal is warm blooded or cold blooded. Many species of all kinds migrate. See animal migration for details. --- Medical geneticist (talk) 16:32, 27 June 2011 (UTC)

Humans are warm-blooded, but we still find it desirable to take many steps in order to avoid being cold. Why should it be any different for animals? There are many different adaptations to cold, including migration and hibernation. Dragons flight (talk) 17:01, 27 June 2011 (UTC)

Humans also migrate, at least in their older years... --Jayron32 18:21, 27 June 2011 (UTC)

Apart from seeking more comfortable temperatures, some bird species have to migrate because the availability of their preferred or obligatory food sources are greatly affected by the changing seasons. If, for example, a bird lives on insects, it would likely find very slim pickings during a Northern European winter, making migration to, say, North Africa, advantageous. Our article Bird migration describes in detail this and several other reasons for the phenomenon. {The poster formerly known as 87.81.230.195} 90.197.66.204 (talk) 19:46, 27 June 2011 (UTC)

Another frequent reason for migration is reproduction. They often migrate from a wide area to a small one, where their greater population density helps them find a desirable mate. Then, there is sometimes "safety in numbers" where they raise the chicks, or perhaps they breed in an inaccessible area to deter predators. StuRat (talk) 20:29, 27 June 2011 (UTC)

In general, birds migrate because of the reasons above, not because it's cold. There are plenty of birds that hang around in winter when there's a food source. You might say the cold and snow are indirect reasons for the migration. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:31, 27 June 2011 (UTC)

I suppose you could argue that those species which migrate to warmer climates in winter never developed (or lost) the adaptations that would allow them to survive cold weather (right up to penguins that can survive winter in Antarctica). So, at this point, they do need to migrate to avoid the cold, among the other reasons. StuRat (talk) 04:17, 28 June 2011 (UTC)

Penguins migrate to a degree too though, don't they? Googlemeister (talk) 18:35, 28 June 2011 (UTC)

Yes, but for other reasons, not to stay warm. StuRat (talk) 22:15, 28 June 2011 (UTC)

"The swallow may fly south for the winter, yet it is no stranger to our land..." Albval (talk) 19:36, 28 June 2011 (UTC)

Be amazed by the journeys of the arctic tern, typically about 2 million km in a lifetime, commuting from the arctic to the antarctic. Mikenorton (talk) 19:45, 28 June 2011 (UTC)

hello (identifying #7 plastic)

how do they tell #7 plastics apart at recycling centers — Preceding unsigned comment added by Tsp12345 (talk • contribs) 19:38, 27 June 2011 (UTC)

That's a good question. The plastic recycling article is rather hazy on the subject, simply saying that they're separated based on their resin identification code. This article says the manual sorting process is too expensive and isn't sufficiently reliable, and talks about two technologies that can identify some plastic types. It's not clear if these automatic methods are in widespread use. In my own area, it seems they only want drinks bottles; everything else (tubs, trays, lids, caps, films, bags, etc.) they don't take. I imagine that if (or when) most retail products contain RFID tags, the separation of some post-consumer waste (bottles, tubs, trays at least) may become more easily automated. -- Finlay McWalter ☻ Talk 19:51, 27 June 2011 (UTC)

Some recycling programs will only accept properly marked (i.e. with the correct code) plastics for recycling. Some plastics, if kept with the same type, can be melted down and reused in the same application; however this requires proper sorting. While "pure" plastics can fetch greater prices on resale, they are also much more labor intensive to ensure proper purity; some cheaper reuses (for example, shredded and used as mulch) fetch much less on the open market, but then again are much cheaper to process. Plastic recycling has more information, and the economics of recycling are quite complex, especially when coupled with the "social pressures" to recycle even when it is not financially feasible to do so. --Jayron32 20:22, 27 June 2011 (UTC)

I added to the title to make it actually useful. StuRat (talk) 20:25, 27 June 2011 (UTC)

I found a few sources via Google Books. Several of them say that Near Infrared (NIR) and Middle Infrared (MIR) spectroscopy can be used with some success, but that it doesn't work with plastics that have black/grey dyes in them, because those absorb the NIR wavelength; also MIR cannot be used for high-speed processing.[2][3][4][5] Other techiniques measure the density or melting point, or use chemical markers.[6][7]] ... Anyways, I would suggest searching Google books for identifying plastics recycling, and you'll probably turn up quite a bit more information. Cheers. ~ Mesoderm (talk) 20:36, 27 June 2011 (UTC)

Some plastics labelled as recyclable are indeed not. Those with very low rates of recylcling include #3, #6 and #7. ~AH1 ^(discuss!) 01:24, 30 June 2011 (UTC)

weird plastic taste in coffee

Hi, I'm a total coffee philistine, but one thing I can't handle is the plastic taste that you get from some containers. Basically I brew up several cups, and store them in my plastic container (Sistema brand, in Australia), but of late, I've noticed the ghastly plastic gunky taste is getting in the coffee, even though it didn't originally. I've been using them for several months without incident, and now, suddenly, nearly every coffee comes out awful. Why does this happen? Surely plastic is inert, so it shouldn't get into food. Has this problem ever been investigated with plastic containers? Also, is there any cure? It's been emotional (talk) 21:04, 27 June 2011 (UTC)

I used to drink coffee out of various plastic and foam containers and noticed the same thing. Given that many plastics (or byproducts of burning/heating them) act as endocrine disruptors or mutagens, I didn't feel like taking any chances and started drinking out of ceramic, glass, or metallic containers. I no longer have to deal with the unpleasant plastic taste (which I notice every time I drink out of plastic containers now), and I don't have to worry about the health effects of drinking a hot liquid out of a plastic container. ~ Mesoderm (talk) 21:13, 27 June 2011 (UTC)

I agree with glass (not leaded crystal) or ceramic (unpainted ceramic, that is). Metal, however, can also react with beverages, so they often coat this inside of metal containers with plastic to prevent this, and we're back to the original problem (unless you have a gold or platinum bottle :-) ). I use glass, myself. Specifically, I buy Everfresh juices and reuse the glass bottles: [8]. StuRat (talk) 22:32, 27 June 2011 (UTC)

To answer your question, there are several chemicals that can leach out of plastic bottles into the contents. More leaching is expected with more heat, more flexing of the bottle, more time, and more acidic content (a highly alkaline drink might be a problem, too, but there aren't many of those). In your case, pouring hot coffee into it might be the problem. StuRat (talk) 22:35, 27 June 2011 (UTC)

Thanks, very astute of you, StuRat. Thanks to all of you. It's been emotional (talk) 23:11, 27 June 2011 (UTC)

Don't they have ceramic coffee pots coffee pots in Australia? Or even teapots? (I see that "coffee pot" re-directs to "Coffeemaker", which are of course not coffee pots. Coffee pots are similar to tea pots, but designed for coffee. Usually taller and more cylindrical than teapots in my experience). 2.97.219.42 (talk) 10:15, 28 June 2011 (UTC)

In US English, at least, a coffee pot (that's 2 words in US English) is the container into which the freshly brewed coffee pours from the coffee maker (also 2 words), and a tea pot (also 2 words) is where the tea is steeped. So, neither is the storage container asked about here. StuRat (talk) 13:14, 28 June 2011 (UTC)

The US is not the whole wide world, and people often do things differently in different countries. 92.29.120.26 (talk) 20:28, 28 June 2011 (UTC)

And I never said that it was, did I ? If there's a country where a "coffee pot" (as 1 word or 2) or a "tea pot" (as 1 word or 2) are used for storage of beverages, then I'd like to know that. StuRat (talk) 20:42, 28 June 2011 (UTC)

Well, Britain, Europe, India, China, and many more. Cofffee pots are particularly used in Arabia I understand. Its called an "X"-pot because its got "X" in it. Perhaps you are confusing them with kettles, which are only used for heating water. 92.29.120.26 (talk) 21:04, 28 June 2011 (UTC)

No, I'm not confusing those. See below. StuRat (talk) 22:13, 28 June 2011 (UTC)

Typical UK coffee pots - here  Ronhjones  ^(Talk) 21:28, 28 June 2011 (UTC)

That's what I'm thinking of. Those are for serving coffee, not for storing it. My reading of the Q is that they want to store the coffee, and possibly transport it to another location, and therefore need a container which can be sealed for that purpose, such as a thermos. StuRat (talk) 22:10, 28 June 2011 (UTC)

Perhaps they serve coffee in a coffee pot in the US, but on this side of the Atlantic it is considered uncouth to put the spout of the coffee pot in your mouth: over here the coffee is always served in a cup or mug. Something to remember if you ever visit our sceptered isle. 92.24.141.227 (talk) 21:08, 1 July 2011 (UTC)

Does "serve" have a different meaning there, too ? Here a coffee service or tea service includes everything placed on the table, such as the pot, cups, and saucers. StuRat (talk) 03:04, 2 July 2011 (UTC)

You can do whatever you like in the US, but over here such behaviour is frowned upon. 92.29.127.122 (talk) 13:04, 2 July 2011 (UTC)

is it any easier to catch a bullet at the top of its arc if you throw it up than if you shoot it up?

If I take a bullet in my hand, and throw it up a couple of feet for you to catch, is it any easier for you to catch it than if we repeat the same thing, but, in a very still place, you happen to be on top of a cliff and the arc of the bullet I shoot from somewhere far far away looks, relative to you, exactly the same on paper as when I threw it up to you from a couple of feet below? I mean, because the top of the parabola should look the same. — Preceding unsigned comment added by 188.28.68.234 (talk) 22:10, 27 June 2011 (UTC)

From a pure physics standpoint, velocity is velocity; the round has no memory that it used to be going very fast; and so, near the top of a parabola, vertical velocity approaches zero. "Engineering details" may confound this simplistic viewpoint: a round fired from a gun will be hot; it may be wobbling; it may have deformed during firing or flight. It will also be hard to aim very precisely due to error propagation (a longer time in flight means that tiny error in aim will result in large error in position). The safety factor should be considered, too - if you miscalculate, or if wind, non-ideal turbulence, or any other parameter changes the expected peak location of the trajectory, your experimenter will be in a very dangerous position. Nimur (talk) 22:18, 27 June 2011 (UTC)

Well, the bullet still wouldn't be going very fast, even if your calcs are off a bit. However, the variability is enough that you couldn't reliably get the bullet to reach the peak of it's trajectory within reach of the target person on top of the cliff. So, it would be easier to catch if hand thrown. StuRat (talk) 22:25, 27 June 2011 (UTC)

Also if the bullet is shot out of a rifle it might be spinning pretty fast, which might make it harder to grab. Rckrone (talk) 23:15, 27 June 2011 (UTC)

I think what the OP meant by "easier" is purely the act of nabbing the bullet, given that you just happen to be in the right place at the right time. At the very top of its arc, at least for one moment, it will have zero or near-zero vertical velocity, before it starts to fall again. So if you were next to the bullet and had a butterfly net or something, grabbing it should be just as "easy" as if it were thrown up in the air. Obviously, this only works if you've thrown or shot it pretty much straight-up. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:26, 27 June 2011 (UTC)

The difference that comes to my mind is that you couldn't see it if it originated at a distant point. In one instance you could maintain eye contact for the length of the trajectory. In the other instance you would only be able to establish eye contact at a fairly late point in its trajectory. This would introduce an added difficulty. Human vision is inadequate to the task of tracking a fast-moving small object especially at a considerable distance. While the object would still be small if tossed from only a few feet away, the tracking of such an object by the eyes of humans is still within normal operating range. Bus stop (talk) 23:33, 27 June 2011 (UTC)

You might, if it were painted international orange or something. Maybe the OP needs to clarify what he means by "easier". My concept of this would be that you could fly like Superman and be able to spot the bullet and to be at the top of the arc and grab it. However, Superman could grab it as soon as it leaves the rifle without doing himself any harm (unless it was made of kryptonite). So the OP needs to comment further. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:49, 27 June 2011 (UTC)

Let's formulate this as a problem. Let's say we have a .38 Special, with a muzzle velocity of about 600 feet per second, which is pointed upward and fired. How accurately must the muzzle velocity and direction be controlled in order to produce an error of less than 1 foot in any direction in the location of the trajectory peak? Extra credit: how does the necessary directional accuracy compare to the maximum possible accuracy of a .38 Special? Looie496 (talk) 23:49, 27 June 2011 (UTC)

No one has specifically said it so I'll add it. Both bullets will be experiencing a constant downward acceleration of 9.8m/s² . So yes, the "top" of the parabola of the fired bullet will be identical to the parabola formed by a thrown bullet from the point where the thrown bullet's velocity matches that of the fired bullet. As stated above however, this is only given "perfect" conditions of no friction or turbulence (etc...) which of course don't exist in real life. Vespine (talk) 00:30, 28 June 2011 (UTC)

A bullet shot straight up will still travel a few thousand feet. If a bullet travels 5000 feet, then to be accurate to within 1 foot (assuming there is no wind or other atmoshperic effects) you will need accuracy of .01 degrees to be within a foot. I don't think most handguns would have that level of accuracy and even a sniper rifle would be tricky. Of course a sniper rifle would probably go a lot higher then 5000 feet since it has a much higher muzzle velocity. Googlemeister (talk) 13:13, 28 June 2011 (UTC)

miami

do they have central heating in most houses in miami and what kind — Preceding unsigned comment added by Superhands99 (talk • contribs) 22:40, 27 June 2011 (UTC)

It does get chilly enough in winter to need some form of heating, but, due to the relatively low amount of heating needed, electrical heating is common (the cost of electrical heating is prohibitive in colder climates). Electric baseboard heating is one common form. StuRat (talk) 22:56, 27 June 2011 (UTC)

Miami recently set a record because 10 straight days failed to reach 65 F in January.[9] I think little heating is required. Miami has a climate of 149 heating degree days versus Detroit (6224) or Duluth (9371). Rmhermen (talk) 00:58, 28 June 2011 (UTC)

Even 65°F is a bit cold, especially for the elderly. But, of course, those are the highs. The record low is 27°F: (pick "Record Low" check box). At those temps you can die without some form of heat. StuRat (talk) 04:10, 28 June 2011 (UTC)

It's my understanding that many homes in Miami area, especially the older ones, don't have heating systems. Presumably, on really cold days (by their standards), they use space-heaters or blankets or something. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:13, 28 June 2011 (UTC)

Or they could just use their aircos as heaters :) . Count Iblis (talk) 02:36, 28 June 2011 (UTC)

That's right. I live in Florida (Not in Miami, though) and every house I've ever lived in has has a AC/heating unit, with one single exception. Dauto (talk) 03:21, 28 June 2011 (UTC)

By AC/heating unit do you mean Air source heat pumps? Rmhermen (talk) 21:19, 28 June 2011 (UTC)

Yes that correct. Dauto (talk) 18:39, 29 June 2011 (UTC)

You could just turn a small window AC unit around and it would provide heat to the room while cooling the outside right? Googlemeister (talk) 13:26, 29 June 2011 (UTC)

Yes, that's also correct. A heat pump is nothing more than an AC. Dauto (talk) 18:39, 29 June 2011 (UTC)

But if it's too cold outside, and the A/C is operated continuously, ice would build up on it. StuRat (talk) 01:01, 1 July 2011 (UTC)