Science desk
< November 20	<< Oct \| November \| Dec >>	November 22 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

November 21

Yet another "identify this bug" question for the entomologists out there

OK. I didn't get a picture, so please bear with me. Today I spotted a butterfly which displayed stark mimicry; when it was landed, it looked almost exactly like a brown grasshopper or a locust, however when it took to wing, it was obviously a butterfly with black and yellow wings. When it landed again, it folded its wings, which were brown and it looked rather locust-like again. It even flew a bit like a grasshopper. Any ideas? --Jayron32 00:55, 21 November 2009 (UTC)[reply]

Leafhoppers (as well as some other critters within Auchenorrhyncha) look somewhat like a cross between a moth and a grasshopper; see images on google [1] and let me know if my guess is even close. This is just a guess, though. In general, there is something like a rule 34 of the arthropod world: "anything can be mimicked". If you find out what that critter is, let us know. Sorry. All the best, --Dr Dima (talk) 02:02, 21 November 2009 (UTC)[reply]

I don't think those are it; but since none of the pics in the google image search show the animal take to wing, it is hard to tell. I only saw it for about 30-60 seconds, and only in flight for about 5-10 of those, but the wings definately looked butterfly-like. While flying, it had butterfly shaped wings, and it flapped them like a butterfly. When it was lit on the ground, however, it looked grasshopper-like. Any other ideas? --Jayron32 02:33, 22 November 2009 (UTC)[reply]

Grasshopper? Bus stop (talk) 02:55, 22 November 2009 (UTC)[reply]

Back when I was in Camp Moshava (Indian Orchard, near Honesdale, PA), I used to find exactly what you are describing on the obstacle course -- large, grasshoppers that, oddly enough, had extremely bright orange/yellow wings that obviously could only be visualized when the insect was in flight. DRosenbach ^{(Talk | Contribs)} 04:57, 22 November 2009 (UTC)[reply]

That sounds like it! These wings were black with brilliant yellow border around the lower rim. I have seen grasshoppers in flight before, and this was NOT it. When it was in flight, it looked obviously like a butterfly of some sort. It was just on the ground that it looked like a grasshopper. BTW, this was in North Carolina that I saw the weird grasshopper/Butterfly thing. --Jayron32 05:49, 22 November 2009 (UTC)[reply]

Well, Sciurus carolinensis seems to find its way to the NY metro area, and they can't even fly. As soon as I read your post, I knew it was the same thing -- isn't science wonderful like that? DRosenbach ^{(Talk | Contribs)} 13:51, 22 November 2009 (UTC)[reply]

At the risk of being repetitious, it was probably a grasshopper; their underwings are often black with a yellow border. See here. They may also have the opposite as in this picture. Matt Deres (talk) 04:16, 23 November 2009 (UTC)[reply]

Thanks! That looks like the color I saw! Maybe it was a grasshopper after all! Next time I am at that park, I will keep an eye open for more specimens. --Jayron32 04:31, 23 November 2009 (UTC)[reply]

CAN matter be split into any arbitrarily small quantity?

Hello,

Where does scientific consensus stand on this question? I did a thorough read of Atomic theory, and I see that the lede characterizes this notion as "obsolete", but I don't trust that claim since nothing in the article supports it. Thanks. Andrew Gradman ^talk/_WP:Hornbook 05:02, 21 November 2009 (UTC)[reply]

No. Once you get down to the molecular scale you can't split it any further without changing what it is. Once you get down to elementary particles, you can't split it any further at all. --Tango (talk) 05:22, 21 November 2009 (UTC)[reply]

How about down to strings ? Even if we can't currently do such a split, that in no way means that it's impossible to ever do it. StuRat (talk) 05:41, 21 November 2009 (UTC)[reply]

Strings aren't a splitting of elementary particles, just another way of interpreting them. In String Theory, each elementary particle is made up of one string. --Tango (talk) 21:06, 21 November 2009 (UTC)[reply]

Thanks, Tango; I am enjoying the elementary particles article.
StuRat raises another question. I notice that our articles offer no description of the "radius" of any of the elementary particles (Quark, lepton, and Gauge boson) -- in contrast to the "charge radius" mentioned in our proton article. Does this mean that elementary particles do not have a radius?
Or, to ask a different but similar question: if you told me that the radius of the smallest known elementary particle was (say) 10^-20cm, I would ask: Is it unintelligible to think of the universe on scales smaller than that? If I asked you (or my son asked me!) what the universe looks like on the scale of 10^-60cm, would my answer have to be, "The universe simply does not support the question"? Andrew Gradman ^talk/_WP:Hornbook 07:10, 21 November 2009 (UTC)[reply]

Well if you consider a photon of light and try applying the notion of splitting to it, if you halve the energy the wavelength doubles. It becomes bigger if you split it! So splitting is rather a problematic idea. Dmcq (talk) 10:01, 21 November 2009 (UTC)[reply]

Although it works a bit differently than with a proton, elementary particles do sort of have a radius, in that it becomes rather meaningless to talk about a particle's position to a precision smaller than its Compton wavelength. See also classical electron radius.

The 10^-60 cm scale you mention is much smaller than even the Planck length, so it's not really known for sure what happens down at that length scale, or even whether or not the Planck length actually has any important physical significance. The universe may well support the question of what the universe looks like on the scale of 10^-60 cm, but if it does, the answer to that question is unclear at this time. Red Act (talk) 10:43, 21 November 2009 (UTC)[reply]

If I'm not mistaken, yes, matter can indefinitely be reduced into smaller and smaller components. That seems to be the trend in theoretical physics anyway. And really, is anyone stupid enough to truly believe that we could ever get to 'the bottom' of existence. It's a total red herring for more research grants. Vranak (talk) 19:28, 21 November 2009 (UTC)[reply]

I am reminded of a wonderful (and accurate!) hyperbole from Mark Twain on the subject of scientific extrapolation. -- Scray (talk) 20:14, 21 November 2009 (UTC)[reply]

@Vranak, and if I'm not mistaken you are mistaken; or at least know nothing about physics and should not be answering science questions. SpinningSpark 20:40, 21 November 2009 (UTC)[reply]

Vranak is referring to the fact that every time we've thought something is indivisible before we've been proven wrong and therefore it is likely that we will be proven wrong again. It's an interesting point, but I think it is misleading. Quarks were discovered about 40 years ago and the electron about 100 years ago and none have been split in that time (and particle physics has been an extremely active field of study in that time with all kinds of amazing discoveries). That, combined with theoretical reasons, convinces me that we have probably reached the end of the sequence. --Tango (talk) 21:06, 21 November 2009 (UTC)[reply]

Tango, this may be one of the most impressive displays of assuming good faith I've ever seen, but at some point it becomes delusional.... --Trovatore (talk) 21:08, 21 November 2009 (UTC)[reply]

And perhaps we can put a statute of limitations on how long we should wait before declaring the sequence resolved. Fifty years and no new sub-sub-sub-atomic particles? Sound fair? Vranak (talk) 21:42, 21 November 2009 (UTC)[reply]

And I would also submit that that more than one knows about 'physics', whatever that in the last resort refers to, the less one knows about anything that is not physics. Vranak (talk) 22:04, 21 November 2009 (UTC)[reply]

In the words of noted physicist Dave Barry:

I have examined cheese very finely, and as far as I am able to determine, it is made up of cheese. I have obtained similar results with celery.

(Actually I don't remember for sure whether "cheese" or "celery" came first; IMO "cheese" works better so I'm going with that.) --Trovatore (talk) 21:12, 21 November 2009 (UTC)[reply]

One thing that can be said at this time is that there is no experimental evidence at this time that points to there being structures at scales smaller than the particles in the standard model. So the simplest assumption (and hence a favorable assumption according to Occam's razor) is to assume for now that there is no structure at smaller scales.

If there is structure at a smaller scale, the subdivision would certainly have to work very differently than reducing a substance into a set of molecules, or a molecule into a set of atoms, or an atom into a set of electrons, protons and neutrons, or a proton into a set of quarks. In each of those cases, the bigger thing is made up of smaller things that each has a mass that’s less than the mass of the bigger thing. But if, for example, the electron were hypothetically composed of constituent particles, known experimental constraints on the size of the electron would require that the constituent particles would have to be so small, that their masses according to a combination of the Planck–Einstein equation and E=mc² would have to be larger than the mass of the electron. But mass certainly doesn't behave that way in any experiments that have been performed so far. In any experiment performed so far, all objects have at least as much mass as the sum of the masses of their constituent parts. Red Act (talk) 22:38, 21 November 2009 (UTC)[reply]

I would also dispute this idea that we've been dividing up matter many, many times. The ancient Greeks believed in atoms - since then, we've found that atoms are protons, neutrons and electrons - and realised that protons and neutrons contain quarks. That's it. We've revised the model just twice since the ancient greeks! Just once in the case of electrons and not even once in the case of photons. There really isn't evidence that there is anything more fundamental than quarks. String theory doesn't change that - that hypothesis doesn't claim that each quark is made up of multiple strings - it basically says that there is one string per particle - so it's not a third subdivision - it's just another mathematical representation of the same level of subdivision. The idea that science keeps finding ever smaller constituents of matter over and over again doesn't really hold water. SteveBaker (talk) 23:43, 21 November 2009 (UTC)[reply]

Greek atoms would be atoms of say wood, or stone, or other complex things. Those got divided into molecules, and then into atoms, and on. So more than two. Also, if free quarks can not be created, then they might as well be fundamental, since we won't be able to see anything smaller than them. Ariel. (talk) 06:41, 22 November 2009 (UTC)[reply]

I'm pretty sure there was never a time when people believed in molecules but not that they were made up of atoms. So it's not fair to say that we first broke matter into molecules and then discovered that they could be broken into atoms - that's not how it happened at all. The ancient Greek idea that there was a fundamental particle that could not be subdivided is really no different from the the ideas that popped up in the late 1700's. Certainly, the Greeks were mistaken about "stone" or "wood" being a complex mixture rather than an element - but that is a relatively minor detail that they'd have fixed if the chemistry of the situation had been understood. They also (correctly) believed in gold and copper atoms and knew that some substances were mixtures of different atoms. After all, even after Dalton, there were initially quite a few compounds that were initially thought to be atoms - and quite a few molecules (eg O₂ - Oxygen) that were initially thought to be atoms. That doesn't alter the degree of subdivision in the model. SteveBaker (talk) 16:37, 22 November 2009 (UTC)[reply]

I'm not sure it's fair to connect the ancient Greek atomism with our current understanding of atoms. We use the same word for both concepts, but they're not really compatible or interchangeable. APL (talk) 05:35, 22 November 2009 (UTC)[reply]

Still, John Dalton came up with atomic theory (in a real, modern, scientificy way) in the 1780's. Electrons and protons came around some century or so later, and quarks some half century later. Since then, bupkis. Nothing new, really, in terms of structure. The deal is, when you get down to sizes that small, you are reaching the limit of observation. Quarks could be fundemental (not brake-down-able) or they could be made of smaller bits, but unless our understanding of the universe takes a drastic change, there's no way to tell really. The OP could be right, but there is absolutely no evidence that he is. There's no reason to believe it goes down any deaper than the quark level because there is no evidence that it does. Once you leave the realm of "evidence" you enter the realm of "just making shit up", for which science is poorly equiped to discuss. --Jayron32 05:45, 22 November 2009 (UTC)[reply]

I'm surprised that no one has linked preon yet. But I think that if you want to talk about the "ultimate constituents of matter", the whole idea of particles is a red herring. Particles are just a way of talking about perturbations of the vacuum. The nature of matter really comes down to the nature of the vacuum, which is the subject of quantum gravity. -- BenRG (talk) 10:30, 22 November 2009 (UTC)[reply]

Solar fuel generating and storage supertanker

Solar thermal concentrators can be used in an "oil from air" process converting water and atmospheric CO2 to oil and (presumably) methane could be produced by similar methods. The problem is that these devices have to be in sunny areas of the planet, which puts Northern Europe at a disadvantage. Supposing a supertanker was fitted with solar concentrators and sailed to a sunny part of the ocean. There would be no rent to pay to a host nation or Middle Eastern blackmail to worry about, and however long it took (assuming low efficiency until the process can be improved) eventually the tanker could return (using some of its own fuel for power) fully laden with an inexhaustible supply or oil and or gas. Would such a business be economic?Trevor Loughlin (talk) 08:17, 21 November 2009 (UTC)[reply]

"oil from air" is called biofuel or simply firewood. Grows just fine in Northern Europe. --Dr Dima (talk) 08:55, 21 November 2009 (UTC)[reply]

However, if you want to convert air (and water) directly into an energy carrier of some sort, you'd be probably making ammonium nitrate, and not oil or methane. Over 1% of the world energy production goes into making ammonia via Haber process; ammonia is then oxidized to ammonium nitrate. It makes no sense to invest into making oil or methane from ~~air~~ atmospheric CO2 when the oil will then be burned (with rather low efficiency) to make ammonium nitrate. Furthermore, air consists of mostly nitrogen and oxygen (which is what you need to make ammonium nitrate, adding hydrogen from water), but there is very little CO2 in the air. --Dr Dima (talk) 10:02, 21 November 2009 (UTC)[reply]

FWIW it;s actually closer to 2.5%. ~ Amory (u • t • c) 12:27, 21 November 2009 (UTC)[reply]

Fascinating. I wonder what would happen if I tried to run a car engine on ammonium nitrate?Trevor Loughlin (talk) 11:17, 21 November 2009 (UTC)[reply]

Well, it's problematic to put too much of the stuff in a car. But you can run the car on the oil not burned to make fertilizer. Find only 39 more comparable solutions, and we are in the clean - assuming this works, and works to full potential, which I doubt. But every kWh is worth something - we don't need to find the silver bullet, we can very well do with Bronze grapeshot. --Stephan Schulz (talk) 12:38, 21 November 2009 (UTC)[reply]

The problem with bio-fuel if that it takes up land otherwise used for food production. But I have had another idea. Could the ship scoop up oceanic algal blooms or plankton and convert them onboard to biofuel?Trevor Loughlin (talk) 13:10, 21 November 2009 (UTC)[reply]

Or why not use it as food, freeing up the land used to grow that ? (If people object to eating it, use it as animal feed.) Of course, in either the case of food or fuel, you need to remove most of the salt. StuRat (talk) 13:17, 21 November 2009 (UTC)[reply]

Algaculture is your friend :) --Dr Dima (talk) 20:05, 21 November 2009 (UTC)[reply]

And for the OP Algae fuel Nil Einne (talk) 21:21, 21 November 2009 (UTC)[reply]

It depends what you call "Northern Europe" but in the UK there are many coppices that are undermanaged. They could do with cutting more frequently for firewood. And there is land currently used for grazing of horses and other less necessary purposes that could be allowed to grow as secondary woodland and then cut as coppice. The same situation in France. The harvesting of plankton is an interesting idea, which leads me to think about greater use of seaweeds, especially near the coast. In Brittany seaweed was traditionally burnt and used as fertiliser. Perhaps this tradition could be revived. In terms of the efficiency of the supertanker out at sea, it might be more efficient to set up solar power stations at sea, or windfarms at sea, or power stations that generated simultaneously from wind, solar, tidal and wave power. Itsmejudith (talk) 23:05, 22 November 2009 (UTC)[reply]

CFC Project Help

Anyone have information on CFCs, their effect on the environment, etc.? Please give me a list of stuff and the sources from which you got that information, because i'm not technically supposed to use wikipedia for this project. Please help before Dec. 1, which is when It's due. Thanks sooo much! —Preceding unsigned comment added by Carrashlee (talk • contribs) 15:57, 21 November 2009 (UTC)[reply]

Go to Chlorofluorocarbon#External_links, and also view the "References" section right above that. StuRat (talk) 16:09, 21 November 2009 (UTC)[reply]

Using Wikipedia as a source of references shouldn't be a problem - get your information from the references section of the article and you're good to go. SteveBaker (talk) 18:00, 21 November 2009 (UTC)[reply]

Wow! signal distance

What are the best estimates of the distance in light years from the projected origin of the Wow! signal to the Earth? And based on this range, at what approximate Earth date would the signal have been sent? (It was received in 1977). Viriditas (talk) 16:07, 21 November 2009 (UTC)[reply]

Since they weren't able to identify the source, we can't answer the Q. If it was an Earth signal reflected back, then it would have been sent in 1977. If it's from deep space, then it could be any distance in light years/age, up to billions of years old, if it came from a quasar. StuRat (talk) 16:16, 21 November 2009 (UTC)[reply]

Even if we assume it was a source outside of the solar system - there are no stars brighter than 6th magnitude listed anywhere near those coordinates in any of the major star catalogs (check List of stars in Sagittarius for example) - so the source would have to be really distant if it came from the vicinity of a star. The amount of energy that would imply would be truly mind-boggling. Of course if you're speculating on alien intelligences, it could maybe have come from a spaceship. But as with any scientific finding - if you can't reproduce it, you have to suspect simple experimental error. SteveBaker (talk) 17:55, 21 November 2009 (UTC)[reply]

6th magnitude is a pretty bright cutoff (it's roughly the naked eye, ideal conditions cutoff). There could easily be some nearby red dwarfs in that direction that are under 6th mag. There are 65 known stars within 5 parsecs of the Sun, only 8 are brighter than 6th mag. --Tango (talk) 20:51, 21 November 2009 (UTC)[reply]

Chemistry: M.P Test

What is an m.p test? I know it is a form of Chemical Analysis but I am not sure what m.p stands for, so I cannot find any information on it. 86.17.47.85 (talk) 16:25, 21 November 2009 (UTC)[reply]

It might be helpful if you could give us a bit more of a hint regarding context. Organic or inorganic chemistry? Field or laboratory test? Biochemistry and pharmaceuticals, or petroleum geology? Something you did once in class, or something your doctor ordered? TenOfAllTrades(talk) 17:07, 21 November 2009 (UTC)[reply]

Melting point? --Cookatoo.ergo.ZooM (talk) 17:11, 21 November 2009 (UTC)[reply]

Thanks, right on the money :)86.17.47.85 (talk) 21:59, 21 November 2009 (UTC)[reply]

Melting point determination, perhaps. See Melting_point#Melting_point_measurements. Ben (talk) 19:23, 21 November 2009 (UTC)[reply]

Ah brilliant, I think that is what I was looking for. Thanks a lot. 86.17.47.85 (talk) 21:59, 21 November 2009 (UTC)[reply]

Some transistors not used in an FPGA?

Hi- Is it possible that for some configuration of an FPGA some transistors/gates will not be used at all?

Thanks! —Preceding unsigned comment added by 94.159.143.218 (talk) 20:23, 21 November 2009 (UTC)[reply]

Yes. It is rare that every configurable logic block on an FPGA gets used, and it is usually impossible to use all the individual gates in a logic block. Gates are constructed from transistors.Cuddlyable3 (talk) 21:15, 21 November 2009 (UTC)[reply]

Thanks 94.159.143.218 (talk) 00:45, 22 November 2009 (UTC)[reply]