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November 18

Fluoroantimonic acid

Is fluoroantimonic acid only considered the strongest acid because no one has discovered any stronger acid, or is it physically impossible for a stronger acid to exist? --75.50.50.76 (talk) 02:40, 18 November 2009 (UTC)

I;m not sure what you mean by "physically impossible". Acid strength is determined relatively; it is determined by how the acid reacts with other substances. Consider the model Brønsted–Lowry reaction:

HA + B <---> A + HB

The strength of two acids HA and HB are determined relative to each other such that if HA is the stronger acid, then the equilibrium above will favor the forward reaction, while if HB were the stronger acid, the equilibrium would favor the reverse reaction. There is a "standard acid equilibrium constant" known as K_a, which is calibrated for B to be water, and HB to be hydronium; however in practice HA and HB could be any two acids. Thus, to compare acid strength, you just compare how the equilibrium lies, and you can literally "rank" every acid against every other acid based on how well it reacts compared to each other. The acid at the top of this list is fluoroantimonic acid; there is nothing about the structure that would make a stronger acid actually impossible, its just that for every known substance so far, fluoroantimonic acid is the one at the top of the list. Hypothetcially, any number of substances could be discovered/isolated/created which may end up being even stronger; there is no theoretical upper limit to acid strength, since its not an absolute value; it is only a relative value. --Jayron32 04:30, 18 November 2009 (UTC)

The article calls it "the strongest known acid", so that just means nobody discovered a stronger acid. — DanielLC 16:32, 18 November 2009 (UTC)

Another possibility is that at least one of our articles is wrong (since they are mutually exclusive): the article Helium hydride ion also describes its subject as "the strongest known acid". I'm surprised this has not already been raised, since Graeme Bartlett just mentioned helium hydride on this page. -- Scray (talk) 01:59, 19 November 2009 (UTC)

It could be that helium hydride is only being obtainable in near-vacuum gas-phase conditions ("HHe+ cannot be prepared in a condensed phase"), whereas fluoroantimonic acid is something that can exist at "standard" lab conditions. So fluoroantimonic acid is the strongest known acid that you could put in a flask on a lab bench, whereas helium hydride is the strongest acid which exists under any condition. -- 128.104.112.237 (talk) 17:22, 19 November 2009 (UTC)

Different definitions of acid are producing different answers. Most would think of acid as a liquid, rather than a gas. I suspect there may be quite a range of stronger acids yet to be discovered. Some other gas phase ones that are strong but not strongest could be trihydrogen cation CH₅. Perhaps they could exist in the appropriate fluid as well, like liquid hydrogen or methane. And then there is the case of the pure proton. It is the most extreme case, but is it an acid? Graeme Bartlett (talk) 21:07, 20 November 2009 (UTC)

Need derivations of the solar insolation inside earths atmosphere and latitude at any point

Best method of learning about insolation is incoming solar radiation.in-incoming,sola-solar,tion-radiation I need derivations of all insolation related parameters like latitude, declination and insolation itself...please help —Preceding unsigned comment added by 220.225.125.246 (talk) 03:53, 18 November 2009 (UTC)

There isn't much to derive; it's just trigonometry. The insolation is the solar constant times the cosine of the angle that the sun makes with the zenith. That angle depends on both the latitude and the day-of-year/time-of-day. We have a nice diagram of this effect in the insolation article. We also have a formulation for the position of the sun as a function of time and date. (If you want to derive this, it will be a matter of geometric projection of the orbital parameters of Earth - the math is not complicated, but there is a lot of it). Earth's orbit explains these parameters; ironically, they are derived by the inverse process - measuring the sun's declination and reprojecting it back to an orbital specification. So, you might as well take the solar declination formula at face-value, since it is basically an empirical (observation-based) formula.

As far as other parameters - are you working with a more sophisticated atmospheric absorption model? Usually, the effect of longer travel through the atmosphere is negligible compared to the geometric projection (that I described above), but you can read about optical depth if you want to try to apply that formula and estimate the total amount of gas between the sun and a particular location on earth. For this approach, you would also need an atmospheric profile model - you can look at Earth atmosphere to get some background. I believe there are several reference atmosphere profiles published by NOAA and the American Geophysical Union; I will try to dig up some links. Nimur (talk) 04:55, 18 November 2009 (UTC)

The "U.S. Standard Atmosphere" and the Jacchia's thermosphere profile are hosted at NASA Goddard's website; I know people who have used COSPAR parameters for pressure as a function of height; you can use these to estimate atmospheric absorption if you dare... this approach may require some integral calculus... but as I mentioned above, if you actually calculate it out, you will find that the optical depth variation with angle is negligible for most purposes. This is because the "longer paths" traced out end up traversing through the (sparse) high atmosphere. If you don't like these atmospheric profiles, our article has a list of other common atmosphere models; or you can create your own simple gas-density model based on the hydrostatic equilibrium approximation (e.g. exponential fall-off with height). Nimur (talk) 05:00, 18 November 2009 (UTC)

Dog Whisperer

On the Dog Whisperer last night (I'm in Edmonton, Canada), a woman is bound via wheelchair because of a 3 last name disease (Cabot is a name?). It affected her brother, mother and I think their dad. They died. Her leg muscles don't work that well, I think. What is this disease?174.3.102.6 (talk) 05:31, 18 November 2009 (UTC)

Charcot-Marie-Tooth disease? --TammyMoet (talk) 11:02, 18 November 2009 (UTC)

Season 5 (the current season), episode 20, "Mad Dogs", which first aired on September 11, 2009, does involve a brother and sister who live together, who both have Charcot-Marie-Tooth disease. Red Act (talk) 19:47, 18 November 2009 (UTC)

what canadian animal stores apples in the fork of branches ?

This fall, I've found apples (presumably fallen for nearby apple trees) stuck in the fork of branches in trees near my south-eastern canadian home and I'm wondering what kind of animal stores fruits that way ? The apples seem damaged on top, but sides and bottom look undamaged to me. They are placed 2 to 4 meters (6 to 12 feet) high in the forks of main branches of young trees, quite near the trunk. The tree trunks are 5 to 8 cm (2 to 3 inches) in diameter at that height and the branches are about 1 to 2 cm (3/8 to 3/4 of an inch) in diameter at the fork. The apples are all quite solidly stuck. 207.96.217.70 (talk) 05:45, 18 November 2009 (UTC)

Occam's Razor gut reaction - someone is placing those there intentionally to feed birds & small mammals. Just a guess, though. 218.25.32.210 (talk) 07:38, 18 November 2009 (UTC)

I would guess a squirrel. Normally they bury things, but an apple is too big, plus maybe it knows it would rot. I would guess it went to eat it, and got distracted, or in a fight and lost it. If it then got stuck it was unable to remove it, so just ate the top. Just a guess. Ariel. (talk) 09:49, 18 November 2009 (UTC)

A squirrel is a good guess, as they are known to "squirrel" things away. However, I'd guess that the apples were intentionally stored. I agree that they won't last as long as nuts, so they probably eat them within a few days. The damage on top is probably just from where they carried it with their mouths. StuRat (talk) 11:46, 18 November 2009 (UTC)

Knife against bone / nails on a chalkboard

I've read the Misplaced Pages articles about nails on a chalkboard and psychoacoustics, but have another twist I'd like to share/ask about on the SciRefDesk. When I'm cutting apart raw chicken thighs, occasionally the knife will strike the bone at an angle. I find this kinetic sensation even more immediately revolting than nails on a chalkboard. I'm feeling physically uncomfortable right now just thinking about it. Note that I've never had any bad experiences with knives, been stabbed, lost a loved one to a stabbing, or suffered any other sort of event that might provoke an unusual psychological reaction to this particular situation. I've also noticed that at work when I slice the plastic seals off new watercooler bottles with scissors I feel vibrations/textures/whathaveyou quite similar to the knife into bone, and then of course the corresponding involuntary physical reaction is also quite similar. The nails-chalkboard example is an auditory stimulus, but mine with the knife is a kinetic stimulus - is this a personal quirk, or is there an equally well-recognized phenomenon for particular vibrations and such? Thank you! 218.25.32.210 (talk) 07:07, 18 November 2009 (UTC)

I'm not sure if it's related, but vibrations at a certain frequency (the resonant frequency ?) cause me searing waves of pain. One example was when I tried to hit a baseball with a wooden bat and hit it outside of the "sweet spot". StuRat (talk) 11:40, 18 November 2009 (UTC)

Sounds similar to the reason I can't file my nails. It's giving me shivers just to think about it. So, you're certainly not the only one experiencing this, but I don't think it can be universal: it is were, other people wouldn't be able to file their nails. 86.142.231.220 (talk) 15:22, 18 November 2009 (UTC)

Absolutely subjective -- as a periodontal resident, I cut bone, soft tissue and teeth with no revulsion whatsoever -- and it's not like the first 3 times I did it, I was cringing. Pretty much the only thing I can't handle is watching someone vomit -- it makes me gag. DRosenbach 15:45, 18 November 2009 (UTC)

My wife files her nails almost every day, but I can always give her a shiver by giving one of her fingernail a light scratch with one of mine. She says that it makes her teeth hurt. (?!) Kingsfold (talk) 19:39, 18 November 2009 (UTC)

Directed graph condensation terminology

The strongly connected components of a directed graph form a poset. What is the terminology for lesser, greater, minimal, maximal components?

For example, some websites (strongly connected components made of pages (nodes)), can't be reached from the rest of the internet (have no hyperlinks coming back in). So in a sense this site is locally maximal, or "outgoing only". But what is the actual term? -Craig Pemberton 08:41, 18 November 2009 (UTC)

We have a glossary of graph theory which might help you, which suggests k-edge-connected graph may be what you are looking for. This is more a question for the Mathematics desk though. I'm not sure I really understand your question though, a poset does not have to be strongly connected and just because a graph is strongly connected does not make it a poset. They are two different things. SpinningSpark 10:06, 18 November 2009 (UTC)

In the context of Markov chains, one calls the strongly connected components "communicating classes" and calls them "closed" if they are minimal in the reachability ordering (i.e. you can't get out of them) and "open" if they are not. I don't know a term for maximal classes, or anything for minimal classes in more general graph theory. Algebraist 12:41, 18 November 2009 (UTC)

Accuracy of Sonar?

I was just thinking, sonar works by sending out pings and then timing the time it takes to come back from different directions right? Is there a reason why you couldn't make sonar goggles, for seeing in total black conditions or something, or even being able to see through things sound can go through, or is there an inherant low resolution to it? What about radar? Gunrun (talk) 10:46, 18 November 2009 (UTC)

I would think one problem would be sonar-absorbing materials, like cloth, which would look "black". Not sure about the resolution, although bats manage to catch insects with it. On the other hand, they will also go for a tossed rock, so that supports the "inherently low res" theory. StuRat (talk) 11:34, 18 November 2009 (UTC)

See Medical ultrasonography, Gynecologic ultrasonography and lot's of images. The wavelength of 100 kHz ultrasound in air is .343mm. Since you can't see sound, sonar goggles would have to contain a 2-D phased array of microphones, a processor to convert the microphone signals to an image, and a screen to display it on. Include a Wheelbarrow to carry all that stuff. Cuddlyable3 (talk) 11:45, 18 November 2009 (UTC)

There has been research into enabling the blind to form an image through transmitted sound, some of these devices working on a scanning principle. It is called sonification, our article is not very informative, here's a magazine article. The theoretical resolution in the audible band is going to be on the centimetre scale - you could find the beach but not individual grains of sand. SpinningSpark 13:28, 18 November 2009 (UTC)

The Make Magazine blog recently had a link to this : DIY sonar visualizer with Processing + Arduino. But, of course, that's 2d. APL (talk) 15:29, 18 November 2009 (UTC)

8 or 9 abreast seating in Airbus A300 & A330 airliners.

What is the percentage of Airbus A300 & A330 airliners operating with 9 abreast seating, rather than the standard Airbus 8 abreast seating ?

This question is partly to resolve whether 9 abreast seating constitutes an "unusual layout" in A300/A330 aircraft, and therefore that fact should be included on the Monarch Airlines page. --JustinSmith (talk) 14:11, 18 November 2009 (UTC)

Why not just say that the seating is 9 abreast and don't make any commentary on it at all. No need to analyze whether it is unusual or non-standard or anything, just make the statement and let the reader reach his own conclusions about how he should feel about 9 abreast seating. --Jayron32 15:40, 18 November 2009 (UTC)

Some contributors to the Monarch Airlines Talk page do not consider that the 9 seats abreast is relevant, saying it`s not an unusual layout. For my part every other A300/A330 I`ve been on has 8 abreast seating. I`m prepared to accept 9 abreast seating may not be unusual if someone is able to tell me what percentage of these aircraft have each layout. Why argue about an objectively provable fact ? --JustinSmith (talk) 18:36, 18 November 2009 (UTC)

The number of seats is based on the type of seats used. I haven't been on an Airbus, but I have flown very often. Identical aircraft owned by two different airline companies commonly have different seat configurations. The cheaper company will cram in more seats. The more expensive company will use less (wider) seats. It is a normal aspect of commercial aircraft, not an odd feature. -- kainaw™ 18:55, 18 November 2009 (UTC)

For most aircraft models, the way that one airline "crams in more seats" is to reduce the spacing between them (seat pitch). But information of this kind, whether seat pitch or number of seats in a row, seems automatically notable to me as people may find it useful to decide on how to value the price difference between airlines. I like the suggestion to mention the fact without comment as to how rare or common it is. But that discussion belongs on the article's talk page or a general talk page about air travel or similar, not here. The question for the RD was how rare or common it is. This, I can't help with. --Anonymous, 20:15 UTC, November 18, 2009.

I would agree with Kainaw that seat pitch varies significantly between different airlines, but the number of seats abreast doesn`t. Not on most of the airliners I`ve been on, apart from Monarch obviously. For instance on Airbus widebody planes Economy is always 2+4+2, Premium Economy 2+3+2 and Business 2+2+2. As far as I`m concerned variation in this is unusual. --JustinSmith (talk) 09:40, 21 November 2009 (UTC)

Why do you feel more tired after a few hours sleep than when you went to bed?

It seems that people generally feel more tired when they have only had a few hours sleep than when they went to bed. No doubt they would have felt more tired if they hadn't gone to bed at all, but why would you feel more tired than when you went to sleep? I guess it must be simply a perception, perhaps influenced by different hormone levels at night and during the day. QuickSnow (talk) 14:12, 18 November 2009 (UTC)

• REM sleep is crucial to rest.
• The air quality where you repose may be compromised, if you wake up groggy. Vranak (talk) 14:23, 18 November 2009 (UTC)

"No doubt they would have felt more tired if they hadn't gone to bed at all" - actually, with me, that's hardly ever true. Usually after I have gone to sleep, for just a short period, or, for a longer period, I wake up feeling much more tired than if I had actually stayed up, even if I had stayed up a full 8 hours. So I reject this hypothesis :p Rfwoolf (talk) 14:34, 18 November 2009 (UTC)

To the contrary, when I have had to work for more than 24 hours, and get a few hours sleep, I feel far more alert than before the sleep. Even a 1 hour nap helps. Chalk it up to individual differences. Part of it may be how lousy you feel for a short while when you first wake up. Edison (talk) 14:38, 18 November 2009 (UTC)

Ditto. As a chronic insomniac, there is, for me, a huge difference between 4 hours of sleep (which ain't great, but is something) and zero hours of sleep. The former can actually get me through the day; the latter will get me until about 5pm and then I'm zonked (unable to concentrate, agitated, physically and mentally exhausted). --Mr.98 (talk) 22:53, 18 November 2009 (UTC)

It is called Sleep inertia. That article may be of some help. --Tango (talk) 14:51, 18 November 2009 (UTC)

Very interesting. Thanks. QuickSnow (talk) 01:31, 19 November 2009 (UTC)

An object at rest tends to stay at rest unless acted upon by an outside force. — DanielLC 16:28, 18 November 2009 (UTC)

When I had keep crews working for 3 days in an emergency, I would send some home after 24 hours for 8 hours, perhaps allowing them 5 or 6 hours of actual sleep, allowing for travel, family interaction, etc. A worker who got 5 hours actual sleep on 3 consecutive nights was demonstrably more safe and productive than someone who went 36 or 48 hours with no sleep. It may feel rough to wake up after a short sleep, but an hour or two later there is all the difference in the world. In the American Civil War Nathan B. Forrest's smaller Confederate force in one battle pursued a larger Union force for several days. Forrest had his men take turns napping, while the Union forces were constantly at battle stations. In the final battle, after which the Union forces surrendered, the Union forces were falling asleep in combat. Edison (talk) 05:16, 19 November 2009 (UTC)

health care

what type of national health care does New

Zealand have? —Preceding unsigned comment added by 76.210.215.156 (talk) 16:02, 18 November 2009 (UTC)

Have you read our article on health care in New Zealand? — Lomn 16:29, 18 November 2009 (UTC)

Small passive solar water heater

Hi all,

If I wanted to build a small solar water heater for just a gallon or so of water, would there be any reason not to allow the water itself move through the solar collector by convection, looping around and around?

Most of the instructions I've seen suggest using antifreeze in the tubes, and then having tubes loop back inside the tank warming the water, but I wonder if this extra step is necessary for such a small system.

Any thoughts? Thanks! — Sam 63.138.152.155 (talk) 16:12, 18 November 2009 (UTC)

I agree that such a system seems like total overkill for 1 gallon. Instead, just get a 1 gallon glass water bottle and place it on a reflective surface, say aluminum foil, on top of an insulator, like Styrofoam. On a sunny day, this should get the water warm. Don't leave it out when it's below freezing and/or dark, or it could freeze and break the bottle (but then again, a broken 1 gallon glass bottle isn't exactly a disaster). If you can arrange a large inverted cone of aluminum foil with the water bottle at the bottom, you might even get the water hot. If you add some dark food coloring to the water it will get somewhat hotter, but that depends on how you want to use it. Here's some images of solar ovens to give you a few ideas: . StuRat (talk) 16:20, 18 November 2009 (UTC)

You should paint the bottle black so it absorbs heat, rather than put in on foil that will reflect heat. --Tango (talk) 18:44, 18 November 2009 (UTC)

Sounds like Sun tea. 75.41.110.200 (talk) 18:51, 18 November 2009 (UTC)

Take a look at concentrating solar power for ideas about how to build solar energy concentrators, both large and small. The simplest can be built easily by lining a convex-shaped object (like a large bowl or tube) with foil; and placing the object you want to heat (hot dog) at the focal point of this mirror. You can paint that object dark colors to help it absorb heat; the rest of the apparatus can be foil-lined to increase the energy collected and concentrated. If you are good at plumbing, you can run water through the hot-spot and then plumb it to where ever you need the heated water. Here's an article with a photo of such a device. Nimur (talk) 19:20, 18 November 2009 (UTC)

I disagree on painting the bottle black, because this will generate heat at the surface, and much of it will radiate back off the bottle. The goal is to create the heat in the interior. This can be accomplished by having a black object in the center and/or by having the fluid itself absorb solar energy by being a dark color (but not so dark that all the heat is absorbed right at the surface of the bottle). StuRat (talk) 23:08, 18 November 2009 (UTC)

We have a very detailed article on Solar water heating. It describes several schemes of increasing complexity; the simplest one(s) are passive and use just water in a single open loop (no closed loops, no antifreeze, no forced circulation). I think that's what you are looking for. --Dr Dima (talk) 01:26, 19 November 2009 (UTC)

Thermosiphoning will cause cold water to sink and hot water to rise, maintaining circulation through a solar water heating system. A collector might include serpentine (curving back and forth) copper tubing, soldered to a steel back plate, all of that painted flat black. Facing the sun should be a pane of glass. Behind the steel should be good insulation to reduce loss. The assembly should be sealed against air leaks. Expect about 1 kilowatt per square meter of solar energy input in full sun, if the collector is oriented at an angle equivalent to the latitude. If it goes below freezing at night, the collector will freeze and burst after radiating off all the energy you collected during the day, so it would need provisions for draining at night and pumping the water up in daytime. I have collected solar energy with a simpler system consisting of a black garden hose lying on a roof, connected to the top and bottom of a storage tank. Hot water rises, cold water falls, and warm water results. There are actually places in the world where it rarely goes below freezing, and an antifreeze loop would seem to create unnecessary expense and complexity there, but you get what you pay for. Edison (talk) 05:08, 19 November 2009 (UTC)

Aluminum borohydride

When researching sources to create the article aluminum borohydride, I found a source stating that aluminum borohydride reacts violently with water, even reacting with the trace amounts of moisture in the air. However, another source I found states that aluminum borohydride has an NFPA-R rating of 0, meaning that it doesn't react with water. Which source is correct? ----J4\/4 <talk> 17:31, 18 November 2009 (UTC)

I'm pretty sure all borohydrides are quite reactive with water, so I would guess that the source which indicates a reactivity rating of 0 is probably in error. I would find additional sources before proceeding, however, just to be sure. --Jayron32 20:53, 18 November 2009 (UTC)

According to the Riedel/Janiak, Anorganische Chemie, 7. Auflage, de Gruyter 2007, p. 577 Aluminum Borohydride is a covalent compound that is liquid at 25°C. It therefore should hydrolyze quite easily to give B(OH)3 and H2. Regards --91.6.28.130 (talk) 18:46, 20 November 2009 (UTC)

Evolution of separate sexes

Sexual reproduction obviously has a survival advantage, in that it increases genetic diversity, thus allowing species to adapt faster. However, this doesn't explain the evolution of separate sexes. After all, genetic diversity would increase faster if any organism could reproduce with any other organism. Why did separate sexes evolve despite this? ----J4\/4 <talk> 18:26, 18 November 2009 (UTC)

I'm having difficulty comprehending the question. Maybe I'm just dense, or maybe there's a faulty assumption or two contained in the question. Vranak (talk) 18:40, 18 November 2009 (UTC)

If organisms reproduced by a variant of sexual reproduction, where any organism could produce an offspring, which would contain the DNA of both parents, with any other organism, genetic diversity would increase more that under the artificial limits on diversification created by having each organism only able to reproduce with approximately half of the other organisms of that species. ----J4\/4 <talk> 18:43, 18 November 2009 (UTC)

I'm still baffled by the scientific lingo. I used to understand this stuff, but I'm glad I've forgotten. Vranak (talk) 19:42, 18 November 2009 (UTC)

To simplify as much as possible: "Why don't we all have both male and female parts". Some animals do indeed work like this, but they tend to be "lower orders", not mammals and birds, for instance. The advantage of different sexes is that it provides a way to have a division of labor with each gender customized for it's role. Males, not having to carry babies, can be faster and fight more, while females can concentrate on rearing the kids. StuRat (talk) 23:01, 18 November 2009 (UTC)

For a novel, decidedly nonscientific perspective, I would suggest that life would be so boring as to verge on the intolerable if there were no sexes. Video games and comics books just aren't that compelling much past the age of 14. Something needs to keep our interest, so why not a separate gender that is both like yet unlike? Doesn't totally cover it for everyone I know. Vranak (talk) 05:09, 19 November 2009 (UTC)

This is a big question that a lot of evolutionary biologists have worked on. Our article, Evolution of sexual reproduction, should give you a good introduction. --Tango (talk) 18:46, 18 November 2009 (UTC)

Actually, having just skimmed through that article, it doesn't seem to address this exact issue. It probably should... --Tango (talk) 18:53, 18 November 2009 (UTC)

Sexual reproduction allows for specialization. There are further advantages to sexual reproduction than just genetic diversity. Specialization can take on a wide variety of forms. Survival is enhanced by sexually divergent members contributing advantageous characteristics that it would be more difficult to develop by evolutionary means in an all-in-one organism. Bus stop (talk) 19:14, 18 November 2009 (UTC)

I'm pretty sure this ^ is the essence of the answer, although it might help to also ask why the gender balance is roughly 50:50. Let's consider a hypothetical species in which every individual is fully hermaphrodite and can reproduce with any other individual. Assuming they are otherwise mammal, one of these individuals will have to gestate the offspring. Let's say that the normal situation is that individuals both impregnate and are impregnated. While an individual is pregnant, they can still impregnate others although they cannot be impregnated themselves. And towards the end of gestation, they are less capable of impregnating others. Once the child has been born, the individual who gave birth to them has to devote resources to caring for them. The individual who also contributed to this child's DNA can choose whether they invest resources in them or not, but they are also responsible for a child they gave birth to.

Let us imagine that an individual is born who does not allow themselves to be impregnated, or physically cannot be impregnated. They can still pass on their DNA by impregnating others, but they never have to devote resources to a developing child within themselves, nor do they have times when they cannot impregnate others, nor do they have to devote resources to any given child. They might increase some of their children's survival chances by devoting resources to them, but they might equally spend all their resources begetting as many children as possible. This individual has a clear advantage over the hermaphrodites.

But if more than 50% of the individuals in a species use this tactic, it starts to be an advantage to be the one bearing the children. The individuals who have taken the male route cannot reproduce with each other: they need to find a mate who can bear young if they want to reproduce. Those who can bear children can pick their mate more carefully, because they have a choice of willing partners: they need to choose carefully because they invest more in each child. And, to maximise their chance of grandchildren, it's in their interest to bear both types of children: those who can bear children, and those taking the male route. A 'male' should also beget both 'male' and 'child bearing' children to maximise grandchildren. Since the quirk that produced the 'male' individuals is almost certainly carried by the 'males', as long as the 'males' are only passing it on to about half their children, it is in the child-bearing individuals' interest to reproduce with the 'males' rather than with other child-bearing individuals. And thus, we have two genders.

If the males passed on the tendency to be male to every child, or females carried a recessive gene, two copies of which rendered a child male, you might expect some hermaphroditism to remain. But in an XY situation, two genders emerge. 86.142.231.220 (talk) 19:30, 18 November 2009 (UTC)

this old article discusses the evolution of Anisogamy--Digrpat (talk) 19:21, 18 November 2009 (UTC)

It's all about the gametes (sperm and eggs) and finding "a selective advantage of large, immobile gametes (eggs) ... An assumption that eggs produce a pheromone sperm attractant leads, by established physical principles, to a more than sufficient advantage of large egg size. Without pheromones, combinations of increased target size and weaker increased zygote fitness or increased gamete longevity also provide sufficient selection." Also see . Fences&Windows 01:40, 19 November 2009 (UTC)

There are two strategies for gametes: get big so it'll survive longer, or get smaller and try to impregnate the big ones. Imagine Reason (talk) 04:20, 19 November 2009 (UTC)

That's right. There is a division of labor at the gamete level. Some of them are big (female) to provide enough of a head start for the new organism while the other ones are mobile (male) to increase the chances that they will find each other. Dauto (talk) 13:53, 19 November 2009 (UTC)

ATSC standards

I am trying to understand how television channels use the ATSC standards to broadcast their information. The RF channel is 6 MHz wide, but is there usually only one signal that is modulated over the entire 6 MHz? I know that there was two different carriers for video and audio under NTSC, and that DTV is supposed to be able to make possible additional features to broadcast television, like what is available to cable and satellite TV, but I can't make out from the articles whether a TV station would be able to use something like "sub-channels", within their allotted bandwidth. How does ATSC account for this? Thanks —Akrabbim 19:05, 18 November 2009 (UTC)

I have received subchannels over-the-air, so I know they exist. I don't know how it's done. --Jc3s5h (talk) 21:48, 18 November 2009 (UTC)

Specifically, in the US I've seen three subchannels per frequency. StuRat (talk) 22:52, 18 November 2009 (UTC)

I guess my question can be rephrased as this: Does the ATSC have different carriers on the same channel for different content like the NTSC had with audio and video, or do subchannels and the like come from one compressed signal on one carrier, spanning the entire channel. I have hooked up an antenna to a spectrum analyzer, and it looks like there is approximately equal power across all 6 MHz of the channel, but I can't tell if there is information split between more than one carrier or not. Thanks for the responses so far. —Akrabbim 04:57, 19 November 2009 (UTC)

The subchanels are multiplexed in the digital realm, not the rf realm. The rf signal contains a single mpeg transport stream. Inside that stream are the various subchannels and audio for them. There is no separate rf band for audio, or for any of the subchannels. Ariel. (talk) 06:33, 19 November 2009 (UTC)

Fantastic, thank you. —Akrabbim 13:22, 19 November 2009 (UTC)

Vacuum-Forming PMMA (Acrylic)

Can PMMA (Lucite, Acrylic, Plexiglas, Perspex) be heated and vacuum-formed using a partial-vacuum machine?

Will it discolor? Will it separate ("sweat") into subcompounds? Will the addition of semi-transparent aluminum film on the acrylic substrate have an adverse effect on the forming process?

I'm working on forming some custom visors for movie prop helmets and am trying to find a suitable material. The final shapes of these visors precludes the use of commercial tinting after the forming process, and the tint will burn off, discolor or tear if applied to the plastic sheet before heating and forming.

Thanks, Nullexe (talk) 23:03, 18 November 2009 (UTC)

I have heated tinted perspex with a hot air gun until plastic (fairly soft), then formed it by hand/vice etc into the required shape. It did not discolor. It did not decompose. I would put the semi transparent film on after forming if poss. This will avoid wrinkling of the film under heating. I see no reason why it could not be formed on a vacuum m/c. Just be careful you dont get it too hot and dont expect small radii.--79.75.63.71 (talk) 15:15, 19 November 2009 (UTC)

PMMA is used extensively in dentistry and to increase setting rate and quality, pour-ups are placed into pressure pots with warm water. I don't exactly know what you mean by the use of a vacuum in your question, but better setting occurs under positive pressure, so perhaps to a worse extent under negative pressure. DRosenbach 16:52, 19 November 2009 (UTC)

@DRosenbach-I'm referring to vacuum forming, which uses a rigid form to hold a sheet of plastic over a heat source until extremely malleable, then overlays that sheet onto a positive mold (a "buck") and then negative pressure is applied underneath the buck, which pulls the plastic down forceably around the buck. The plastic is then allowed to cool and harden, and when detached from the buck, produces an almost-identical copy of the buck. With the helpful input of you and 79.75.63.71, I'll be attempting some test pulls here soon and will update this topic with results. Nullexe (talk) 20:43, 24 November 2009 (UTC)

Do you expend more energy with intense exertion over a smaller exertion for a longer period of time?

Per the title, say I:

• Run hard ten miles and it takes me thirty-five minutes (seven minute miles); or
• Jog ten miles and it takes me one hour (twelve minute miles); or
• Leisurely stroll ten miles and it takes me two hours and five minutes (twenty-five minute miles).

My impression is that I burn more energy with high exertion even if I complete the same task no matter that at lower exertion I take more time at it. Is my impression correct? Is it wrong? What are the comparisons in energy expended? And why does one burn more energy than another, if indeed that is the case? Purely from musing on it, it seems to me the only reason one would expend more energy than another is efficiency of the movement, breathing, respiration and so on, rather than something inherent about expending energy faster verses slower, but even with that hypothesis, I don't even have a guess as to whether slower verses faster is more energy efficient.--108.1.106.132 (talk) 23:05, 18 November 2009 (UTC)

Bear in mind that you also burn energy when doing nothing (basal metabolic rate), so, the longer you take to travel the ten miles, the more energy will be burnt up that way. So, for that reason I'd say the stroll would burn the most energy total. However, if you add in resting time afterwards to make the total time the same in each case, then that changes the equation. In that case the fastest run (and rest afterwards) would burn the most calories, since running is less efficient. StuRat (talk) 23:23, 18 November 2009 (UTC)

I don't think "time" here is the only factor—muscles use energy differently depending on exertion and time (see the chart on Aerobic exercise), and so I don't think StuRat's reasoning works out. That being said, I have read studies that implied that using up a lot of energy vigorously does trigger your body into seeking out more calories, and thus a lot of people, after hitting the gym, consume far more calories than they would have otherwise, even more than were burnt exercising. For that reason I have heard it recommended that light, regular exercise (e.g. walking regularly, rather than running) can be more productive if the overall goal is weight-loss, as it avoids less over consumption. --Mr.98 (talk) 00:51, 19 November 2009 (UTC)

You'll also burn more calories the longer you keep your heart rate up. That's why swimming or playing squash for 30-60 minutes will likely burn far more calories than a game of baseball. It's also part of the reason why marathoners are thin as paper whereas sprinters actually have some fat and muscle on them (I'm simplifying, there are other reasons as well). ~ Amory (u • t • c) 01:42, 19 November 2009 (UTC)

For a fixed distance, running burns more energy per mile than walking, because the body moves up and down a lot more during running. (The exception is if you're walking really fast -- the movement is so inefficient then that switching to a slow jog at the same speed can reduce energy output.) Also the faster you run, the more energy you burn per mile, but the difference is not all that large until you hit the point where you are getting close to maxed out. Looie496 (talk) 20:08, 19 November 2009 (UTC)

November 19

Photo-electric cells for the home?

a) Will they eventually become cheap enough to cover the roof and walls of your house with, or is there any fundamental reason for them staying expensive? b) If you did cover the roof and walls of your house with them, what proportion of the electricity useage would they provide, for somewhere like London for example? 92.29.45.37 (talk) 00:24, 19 November 2009 (UTC)

Rule of thumb: in moderate climates, one square meter of a roof photovoltaic system provides about 0.5 - 1.0 kilowatt-hour of electric energy per day. Average Domestic energy consumption in UK is about 2000 kg of oil equivalent a year, which is 8.4 gigajoules per year = 8.4x10/3600 kilowatt-hours per year = 2300 kilowatt-hours per year = 6.4 kilowatt-hours per day. So you need something in the ballpark of 10 m of solar panels to satisfy energy needs of an average UK household. Regarding the prices: yes, they will come down, but not dramatically and not very soon. You need 10 m of semiconductor on your roof, for crying out loud. However, simple solar water heaters discussed in one of the previous questions are dirt-cheap (they are essentially copper tubes painted black) and can save some significant bucks / pound sterling / euro / whatever your currency is. --Dr Dima (talk) 03:06, 19 November 2009 (UTC)

10 square meters is not all that large. 3.3 x 3.3 meters square should adequately fit on the roof of a single family home; that amounts to a square about 11 feet on a side. Other configuratiosn, such as 2 meters x 5 meters (6 1/2 feet by 16 1/2 feet) would also work nicely, and may fit better on some roofs. It's a lot of semiconductor material, which is where the cost comes in; the material cost is largely due to supply and demand. If everyone in a large metropolitan area started installing solar electric panels, prices would drop drastically. --Jayron32 03:12, 19 November 2009 (UTC)

Um - technically - the law of supply and demand says that if everyone started installing these things, the price would go UP not down! However, "economies of scale" might push the price down - so I don't entirely disagree with Jayron's point. SteveBaker (talk) 12:52, 19 November 2009 (UTC)

You are both right. Initially the cost would go up, but the increase in demand would very likely cause the people who make the things to raise production levels and increase the supply so prices would eventually drop. Googlemeister (talk) 14:33, 19 November 2009 (UTC)

I think Dr Dima's estimate may be low. If a typical house is oriented with the roof crest East-West, then the entire roof-half facing the sun might, in the future, be covered with photovoltaic solar cells, tied into the grid through an inverter. When the sun is shining brightly, the solar electricity could well exceed the usage, and the meter would "spin backward," or more realistically the homeowner would accrue credit against electricity used when the sun is not shining. Solar energy striking a square meter oriented normal to sunlight, i.e. at an angle appropriate for the latitude(horizontal at the equator, 45 degree angle at 45 degree latitude, vertical at the poles,) receives about a kilowatt per square meter. Then the efficiency of the solar cell (currently still not all that high), and the degree of cloudiness must be factored in, as well as the efficiency of the inverter. I believe that solar shingles will be in common commercial use in a few years. See and . Such companies as Dow and Johns-Manville have tested solar shingles which can be installed by just nailing them down, like regular shingles, with easy electrical connections. A house roof might be 20 square meters on the side facing the sun, with peak solar input of 20 kilowatts. The DC output from the solar installation can be fed through an inverter to one circuit on the normal breaker panel, and a smart meter can credit the homeowner for any generation larger than demand. Generation smaller than demand would simply slow down the spinning of the meter and reduce the electric bill. The Museum of Science and Industry in Chicago presently has on its grounds a "smart house" which has solar panels on the roof and a small wind generator, There is synergy in this combination, because the wind is often blowing when the sun is not shining brightly. On most days, the electrical records show that the house has, for some period during the day, generated more electricity than it has used. If the solar energy striking the sun-facing roof half is not turned into electricity then (in the summer at least) it is just a wasted resource, or it heats up the house (in the summer) and requires more air conditioning. Edison (talk) 04:49, 19 November 2009 (UTC)

There are several efforts to drive down the price of solar panels - and if one of these comes off then perhaps the price might drop significantly enough. However, the big problem with solar panels is with energy storage. You get all the power you need (and then some) during the day (when you're probably out at work) - but zero at night when you mostly need it for lighting, cooking and heating. The amount of batteries you'd need to store that energy would be enormous...far more than most householders have room for. Right now, you can solve that in many parts of the world by effectively selling your excess daylight energy to the power utility and using the money to buy it back at night. Not all electric companies allow that - but many do. However, that model is only sustainable while your 24 hour production is less than your usage. If you are simply using your electricity provider as a large battery without giving them money for the privilage - they aren't going to want your business for long! If this model of borrowing electricity at night and paying it back during the day becomes the norm for 99% of households - then that will require a new pricing model for these utilities - and that's an unknown quantity right now. The utilities might manage to keep things together by selling excess daytime power to factories and such - and using the profits to generate power for homes at night. But there is also a longer term issue in the more extreme latitudes - that your solar production in the winter is much lower than in summer - but the winter has longer nights and colder weather - so more power is needed for lighting and heating. In the summer, there is plenty of power - but warm nights and long days mean less power is needed. While it's possible that storage solutions might cover the day/night problems - there is unlikely to be a solution for storing power in those quantities over 6 months of the year. SteveBaker (talk) 12:52, 19 November 2009 (UTC)

As for long-term storage of energy, one way to do that is by pumping water from a low reservoir to a high one, then later use this gravitational potential energy to run turbines, as the water goes back down to the lower level. StuRat (talk) 13:40, 19 November 2009 (UTC)

@Dima: I think you are off by at least a factor of 10. 100m2 is a more likely estimate for the required area. @Steve: The storage of energy is a problem only if solar becomes our ONLY source of energy. A combination of solar, wind and hydro might solve that problem quite easily. Biofuels and Nuclear power are also likely to remain important components of our energy portofolio even after we run out of fossil fuels. Dauto (talk) 13:31, 19 November 2009 (UTC)

Yeah - Dima is WAY off on energy requirements for a typical US/European home. Our article Photovoltaic_system#System_performance agrees that the best you're going to get from solar panels is 1kW/hr per square meter each day. At worst (and I'd guess that London is close to the worst) you'll get maybe a third of that on average - assuming average cloud cover over the year - and some way to store unused summer power for the winter (tough!). Remember: London is pretty far north (Americans: It's at the same latitude as Southern Alaska) - and it can be cloudy for weeks at a time. So 0.3kW/hr per sq.m is about right for London. The Domestic energy consumption article gives the average energy in a household a year consists of 20,000kW-h (and breaks that down according to usage) - which is close to ten times what Dima estimated. So you need 55kW/hr per day. That means that you're going to need 160 square meters of panels in London. 50 sq.m in Texas/Arizona. Completely covering the rooftop might be enough if you have a large-ish house - but not if you live in an apartment! Covering the walls is less useful because vertical surfaces are at entirely the wrong angle to the sunlight at the times of day (around noon) when the energy is mostly being delivered. The reality seems far, FAR worse. Look here - this is for systems sold in Austin, Texas - where there is a LOT of sunshine. A $17,000 installation comprising 15 one meter panels produces 2,800 – 4,000 kWh per year. Between a fifth and a tenth of what you need...in Texas. So expect to pay $80k to $170k to completely power your home - and expect to need between 80 and 150 square meters of panels to do it...which fits very well with my estimates. This manufacturer claims a 30 year lifespan for the product - but fails to mention that the amount of power they produce steadily declines over the years. But at (say) $100k capital cost - you'll be paying perhaps $300 a month on top of your mortgage to pay for them. So unless your electricity bill is well over $300 a month - it's not a money-making proposition until the price of panels comes way down...and that's in sunny Texas...in London...forget it! SteveBaker (talk) 18:49, 19 November 2009 (UTC)

Steve, careful with your notation - there is a very big difference between kilowatt/hr (a rarely-useful rate of power-per-unit-time) and kilowatt·hr (a unit of energy). I think you have repeatedly used "kilowatt/hr" when you mean "kilowatt·hr". I think your calculations are all square, but other readers may naively misinterpret your notation, especially when trying to calculate energy and power consumptions over average time periods. Nimur (talk) 19:31, 19 November 2009 (UTC)

A couple thoughts:

1) How much electricity a home uses depends greatly on whether you use electricity for heating and A/C. If not, then a small patch of solar cells on the roof and a way to store that energy for night (either with batteries or by using the power company) should satisfy your demand. If you do heat and cool your home with solar energy, then even a house completely covered with solar cells might not be enough.

2) Solar cells are quite inefficient, in that they only change a few frequencies (colors) or light into electricity (this is also true of leaves converting sunlight into chemical energy). Passive solar heating, on the other hand, can change all frequencies of visible light, and even infrared and ultraviolet, into heat. So, you can heat your home much better by just letting light in large, insulated windows than by having solar cells convert it into electricity that you then use to generate heat inside. A/C is more of a problem, though, as any method of using light to cool your home is highly inefficient. StuRat (talk) 13:50, 19 November 2009 (UTC)

I qwonder if a world electricity grid would be theorectically feasible, allowing electricity to be moved from day to night and summer to winter. 78.146.97.208 (talk) 20:14, 19 November 2009 (UTC)

Transmission-line losses would be huge. Take a look, for example, at HVDC. Loss estimates range widely; our article claims "3% per 1000 km" (for example, so says Siemens' marketing brochure); but I think it would be significantly higher (researchers I work with have cited dramatically higher numbers - at least an order of magnitude worse). HVDC Transmission Systems Technology Review is a good overview, but does not quote power-loss estimates for any of the case studies. This dismal but well-sourced policy analysis indicates that it is more efficient (in terms of energy and dollars) to ship energy in the form of rail-cars full of coal, than to turn said coal into electricity and pipe it by transmission lines. Though the proposal for piping solar-electric power via long-range electric transmission lines does not bear the direct carbon-related costs due to the burning of coal, this analysis is helpful in establishing the ballpark kinds of efficiency numbers. This is not to say such projects are never undertaken - the Pacific DC Intertie is an HVDC line largely designed to sell cheaper-to-generate hydroelectricity from the Pacific Northwest to the electricity-starved Los Angeles area. Nimur (talk) 21:14, 19 November 2009 (UTC)

The Nord Pool is the first multinational exchange for trading electric power between Norway, Denmark, Sweden and Finland.. Cuddlyable3 (talk) 12:17, 20 November 2009 (UTC)

What about super-conducting electricity cables? If technology can put several gas piplines from one side of europe to the other and beyond, then a super-cooled conductor inside some liquid gas and insulation is not impossible. 92.27.157.99 (talk) 19:42, 20 November 2009 (UTC)

Definition of “taxon”

Monkeys are a paraphyletic group (because the Old World monkeys are closer relatives to certain non-monkeys than to the New World monkeys). Does it follow that monkeys are not a taxon? Our article taxon says: “Today it is common to define a good taxon as one that reflects presumptive evolutionary (phylogenetic) relationships. But this is not mandatory” (emphasis added). If a taxon can be paraphyletic (such as reptilia, an example given in the taxon article), then our article monkey is wrong when it says “The term 'monkey' is an artificial grouping; it is not a taxon..., but instead it is a paraphyletic group, like ‘fish’.” This question was asked here three months ago but the answer given then is inconsistent with the discussion in the taxon article. —Mathew5000 (talk) 05:22, 19 November 2009 (UTC)

The entire Linnean system is not terribly internally consistant on these issues. The classification of "monkeys" as two seperate taxa, while classifying reptiles (reptilia) into a single taxon is simply a statement of existing practice. Monkeys ARE currently classified under two seperate taxa, and reptiles ARE currently classified under a single taxon. That this is not consistant is moot; perhaps monkeys should be put into a single taxa, OR perhaps reptilia should be removed entirely from the classification system and replaced with more appropriate taxa, however neither of these reflects what is actually being done. Should either of these things be "officially" adopted by whatever body is in charge of officially adopting this stuff? Maybe. Is it inconsistant as it stands now? Possibly. --Jayron32 05:38, 19 November 2009 (UTC)

'Not a clade', might be better than, 'not a taxon'. A taxon is pretty much any name for a group of organisms that has ever been published by a taxonomist. A phrase like "All primates that are not prosimians (lemurs and tarsiers) or apes" hints at a 'ragbag', indicating that further work is required. William Avery (talk) 11:31, 19 November 2009 (UTC)

I've taken a shot at improving the wording in the monkey article; please check that I got it right if you can. Looie496 (talk) 18:27, 19 November 2009 (UTC)

The term '"good" taxon' went through my mind later. I think that's clearer. William Avery (talk) 21:02, 19 November 2009 (UTC)

Thanks; the edit improved the article. It would be good to have a bit more discussion in the Etymology section of that article. I assume that when Europeans first encountered the platyrrhines in the Americas, they called them "monkeys" because they looked more similar to the cercopithecoids than either group did to the apes; then at some point later (but when?) it was realized that cercopithecoids were closer to apes. Or am I wrong about that; maybe it is only in English that there is one term applying to the platyrrhines and cercopithecoids? This goes beyond etymology; it belongs in an encyclopedia article on the broad subject of monkeys. —Mathew5000 (talk) 01:39, 20 November 2009 (UTC)

Out of curiosity I had a look at articles from other-language Wikipedias, and it turns out that the English turn “monkey” is unusual: most other languages have no single term encompassing platyrrhines and cercopithecoids but not great apes. For example, the French article fr:singe says “Les anglophones distinguent deux types de singe, Apes et Monkeys, le premier terme regroupe les Hominoidea et les gibbon, ceux-ci sont donc plus grand et sans queue contrairement aux seconds. Également polyphylétique, ces distinctions anglophones n'ont pas de correspondances précises en français.” (Anglophones distinguish two types of singe, Apes and Monkeys, the first term including Hominoidea and gibbons, which are bigger and lack a tail, in contrast with monkeys. Equally polyphyletic, these anglophone distinctions do not have precise correspondences in French.) The Dutch article nl:apen says “In verscheidene talen wordt een onderscheid gemaakt tussen apen en mensapen (bijvoorbeeld het Engels: monkey (aap) en ape (mensaap)). Het Nederlands maakt dit onderscheid niet, en mensapen worden ook apen genoemd.” (In several languages, a distinction is made between apen and mensapen (for example in English: monkey (aap) and ape (mensaap)). Dutch does not make this distinction; mensapen are also called apen.) The Spanish article es:mono says “Los términos mono y simio son sinónimos, pero en la jerga zoológica suele distinguirse entre ambos por influencia del inglés, idioma en el que los términos equivalentes monkey y ape tienen diferente significado.... Este uso de la palabra simio como traducción de la palabra inglesa ape, restringida a los primates sin cola, es erróneo, y no corresponde al castellano. Se recomienda para este uso la palabra hominoideo.” (The terms mono and simio are synonymous, but in zoological jargon they usually distinguish between the two under the influence of English, a language in which the equivalent terms monkey and ape bear different meanings.... The use of the word simio as translation of the English word ape, restricted to primates without tails, is erroneous, and does not correspond to Castilian. For this use the word hominoideo is recommended.) —Mathew5000 (talk) 03:00, 20 November 2009 (UTC)

Nut

What's the nut inside of peach/nectarine stones? jc iindyysgvxc (my contributions) 11:15, 19 November 2009 (UTC)

As far as I know, they are called pits and are not nuts. The Peach is a relative of the Almond, and Amaretto is flavoured using the pit from inside an Apricot.Popcorn II (talk) 12:10, 19 November 2009 (UTC)

You can call it a nut, just as with the related almond, but it's actually the seed of the peach tree, not a true nut. The "pit" or "stone" is the endocarp of the fruit, a drupe. These nuts are not necessarily safe to eat (in quantity), as plants in this family usually contain some amount of cyanide. See bitter almond and apricot kernel. --Sean 13:18, 19 November 2009 (UTC)

Least Densest Fabric

I don't know if I spelled that right, but what fabric is most like "light as air"? --Reticuli88 (talk) 19:49, 19 November 2009 (UTC)

for clothing? --Reticuli88 (talk) 19:55, 19 November 2009 (UTC)

I would guess that would be paper clothing. You're probably familiar with the paper gowns you get to wear in the hospital, but there was also a fad of wearing disposable paper dresses in the 1960's: . StuRat (talk) 23:27, 19 November 2009 (UTC)

I doubt that paper clothing would be lighter than fine silk. But there aren't any fabrics that are literally "light as air" because the lightest solids known to man are 'aerogels' - those are not quite as light as air (although they come amazingly close) - but they aren't really robust enough to make into fabrics. SteveBaker (talk) 03:14, 20 November 2009 (UTC)

What about a birthday suit? :-) Mitch Ames (talk) 08:10, 20 November 2009 (UTC)

Lace and gossamer are mostly air.--Shantavira| 08:17, 20 November 2009 (UTC)

And a good thing, too! "Boss, I, er, let our, uh, $100,000 slab of aerogel float away. Sorry." --Sean 19:03, 20 November 2009 (UTC)

@Steve: According to the article aerogel, the lightest solid is indeed slightly lighter than air (1 mg/ccm vs. 1.2 mg/ccm).--Roentgenium111 (talk) 15:12, 23 November 2009 (UTC)

Looking for a particular female scientist.

I'm trying to remember the name of a particular female scientist. All I remember about her currently is that her given name started with S and was German-sounding, she was some type of Germanic or Eastern European, and she worked in the early 20th century. Any suggestions? --✶♏‭ݣ 20:35, 19 November 2009 (UTC)

That's probably a pretty big category. Could you be a bit more specific about the scientist? What area of research (biology, physics, chemistry, medicine)? Major award winner of some sort? TenOfAllTrades(talk) 20:42, 19 November 2009 (UTC)

I think it was physics or chemistry (or both). Were there really that many Eastern European female scientists whose given names started with S in the early 20th century? (I mean prior to World War II.) --✶♏‭ݣ 20:53, 19 November 2009 (UTC)

Oh, and she definitely never won a Nobel, since I went over the list of female Nobel laureates. Other than that, I can't speak to awards. If you could point me to lists of female science award winners for awards that were created before 1940, that might be helpful (but I wouldn't know where to start looking for such lists). --✶♏‭ݣ 20:55, 19 November 2009 (UTC)

Hmmm. I thought you may have be thinking about Maria Skłodowska, much better known under her married name Marie Curie, but she has a Nobel (well, she has two ;-). --Stephan Schulz (talk) 20:58, 19 November 2009 (UTC)

How about Sulamith Goldhaber or Stephanie Kwolek, although they did most of their work after WWII I assume. Mikenorton (talk) 21:07, 19 November 2009 (UTC)

It wasn't either of those two. Her given name was very Germanic sounding. --✶♏‭ݣ 23:05, 19 November 2009 (UTC)

Any of these? Gertrude Scharff Goldhaber, Luise Meyer-Schützmeister, Hertha Sponer. Red Act (talk) 00:33, 20 November 2009 (UTC)

I do realize that's it's not the given name that starts with S on those, but they all do at least have a name starting with S. Red Act (talk) 00:38, 20 November 2009 (UTC)

A wild guess, which does not quite satisfy the criteria, but Sofia Kovalevskaya. (Igny (talk) 00:37, 20 November 2009 (UTC))

Lise Meitner does not start with S, but contains an S, and she was a notable Austrian-born physicist working before WW2 who never won a Nobel Prize. --Anonymous, 00:50 UTC, November 20, 2009.

Take a look at:

• List of physicists
• List of women scientists
• Contribution of 20th century women to physics
• and, if you are really dedicated to the task: Category:Lists of scientists or Category:Women scientists

Let us know if you find what you are looking for. Abecedare (talk) 01:09, 20 November 2009 (UTC)

Assuming that you mixed up the given and surname, there's Hertha Sponer, one of the first women to get a PhD in physics in germany. It could also be Stephanie Kwolek, inventor of Kevlar and with a given name which could be pronounced in a very german way. If you recalled what the person was famous for, it would help. There's too many female physicists from the 20th century to easily check them all. Which when you come to think of it, is really great. :-) Too bad most of us can only recall the names of Marie Curie and Lise Meitner. EverGreg (talk) 13:32, 20 November 2009 (UTC)

None of the above is it, but thanks to everyone who contributed. I'll look through the lists more. Now I'm starting to wonder if I just imagined it. Thanks, and I'll post again if I find her. --✶♏‭ݣ 16:20, 21 November 2009 (UTC)

Boating the Amazon River

Has anyone recently, like NatGeo, navigated the whole (or most) of the Amazon river? Strictly for exploratory, scientific reasons? --Reticuli88 (talk) 20:37, 19 November 2009 (UTC)

Navigating the whole Amazon is actually not much of a feat, because at the point in Peru near Iquitos where the Ucayali and Maranon join to form the Amazon, they are both already huge rivers. If you want to go farther upstream, you have to decide which river to follow. Looie496 (talk) 22:38, 19 November 2009 (UTC)

We don't need no steenkin' boats! --Sean 19:11, 20 November 2009 (UTC)

smoke stream

Moved from Computing desk by Falconus

In thomas the tank engine tv show the trains make loads of smoke. how is this done, and where can one make such a device to make smoke —Preceding unsigned comment added by 82.44.55.114 (talk) 15:38, 19 November 2009 (UTC)

This might get a better answer on the science desk. We have an article on fog machines. I would speculate that the tv show uses dry ice and a little water, which spews out steam and condensed water mist (not smoke). Dry ice is cheap and comparatively safe; and the fumes are just carbon dioxide and water mist. However, because the "fog" it produces is mixed with CO2 (which is heavier than air), the smoke often appears to hug the ground. It's possible that other techniques are used, like glycol theatrical fog, or even just a real steam boiler. Nimur (talk) 15:50, 19 November 2009 (UTC)

Is this the same questioner from this archived question? Our article on Thomas and Friends has a section about animation and one about models which talk about some of this. The 1:32 model trains had smoke generators (which are discussed in the archived section I just linked), and CGI seems to be the preferred method now. --LarryMac | Talk 16:23, 19 November 2009 (UTC)

Yes it's the same questioner, and sorry I missfired and posted on the wrong desk. Could you move my question to the right desk? Thanks, and sorry for the mistake —Preceding unsigned comment added by 82.44.55.114 (talk) 16:37, 19 November 2009 (UTC)

November 20

Temperature's Affect on Metabolic Activity

Hello,

I know that as temperature goes up, enzymes become more reactive because substrates move faster and are more likely to bind to the active site. But is temperature proportional to enzymatic activity linearly, quadratically, exponentially, etc? It would help if you can give some kind of justification like a journal article. Thank you. —Preceding unsigned comment added by 69.139.218.4 (talk) 00:30, 20 November 2009 (UTC)

I don't know for sure. But, if the enzyme activity is proportional to the speed of the atoms moving around in the liquid, you can just check how the average velocity of particles is related to temperature. From Maxwell Boltzmann distribution it seems the average speed is proportional to the square root of the temperature. I assume you read Enzyme kinetics, which doesn't cover temperature, but might help anyway. It's possible the speed of the activity of the enzyme itself might change, but I think that it's overwhelmed by variations in when the enzyme comes in contact with the atom, so could be ignored. But it's possible that at low temperature it becomes more important, and at high temperature the atoms move so fast the enzyme has no time to work. So it's probably not a simple relationship over an entire temperature range. Ariel. (talk) 10:30, 20 November 2009 (UTC)

Note that in birds and mammals, attempts to control body temperature may cause us to slow down our metabolic activity when we overheat, so this could figure into it, too. For example, digestion may slow down when we get hot. StuRat (talk) 10:37, 20 November 2009 (UTC)

Your assumption is wrong: Enzymatic activity has no easy and generalizable correlation with temperature. All enzymes have an optimal working temperature, and deviations from this slow reactions down, in general. The exact relationship is different for every single enzyme, and depends an substrate, protein structure and in general the thermodynamics of the reaction catalized. Most human enzymes, for example, would have evolved an optimum around 37°C body temperature (and many start to denature already 10°C above that, so will not be functional any more at this point), but there are enzymes from the archaea which have optimums near the temperature of boiling water, and almost no activity at room temperature. I don't exactly have a journal article for this, but every biochemistry textbook should have a chapter about influence of temperature on enzymes and proteins in general. --TheMaster17 (talk) 10:48, 20 November 2009 (UTC)

The Molecular Basis of the Effect of Temperature on Enzyme Activity. Axl ¤ 13:03, 20 November 2009 (UTC)

Technical question about movie cameras used in traditional filmmaking

Does the film used in motion pictures cameras requires film developing? i found the article lack of such specification.

Any help would be kindly appreciated.

If so, which part of the postproduction process is that related. Film editing perhaps?.HappyApple (talk) 02:49, 20 November 2009 (UTC)

Yes. If you look around Kodak's website you will find information about developing motion picture film. --Jc3s5h (talk) 03:02, 20 November 2009 (UTC)

Yes - the film uses the same chemical processes (more or less) as you find in regular still image film cameras. The film stock is generally sent off for processing as quickly as possible after the end of filming each day - LONG before the editing or post-production stages. There is more information in our article: Dailies - the prints that are made immediately after processing to allow directors and producers to see the footage shot on the previous day. These days, they'll use digital cameras mounted alongside the film camera in order to get instant feedback after shooting - but the dailies are still useful to ensure that exposures, color balance and focus were correct. SteveBaker (talk) 03:03, 20 November 2009 (UTC)

Movie cameras for a long time (incl. before the digital era) have had a video tap for similar purposes. 69.228.171.150 (talk) 03:52, 20 November 2009 (UTC)

Thank you for helping me realize where all those clips on YouTube came from! Cuddlyable3 (talk) 11:58, 20 November 2009 (UTC)

Further, most movies include the name of the company that processed the film at the end of the credits. It is not a trivial task. When processing film, it is easy to have one strip of film be slightly more processed than another strip of film. The difference in color on the overprocessed film is very easy to see. If you compare a very old movie to a modern movie, you can see how the picture quality jumped around in old movies but stays steady in new movies. You can also see how experiments to maintain a constant picture quality have progressed through the ages. Most people can recognize a film from the last 60s/early 70s just by the color of the movie. It was a side-effect of the processing of the time. Now, with digital, there is still a need for the people who color balance the films. So, that part of processing isn't going away. It is just done on a computer now instead of with actual film. -- kainaw™ 06:44, 20 November 2009 (UTC)

There was an interesting problem with a batch of film for Lord of the Flies that caused it to get washed out every few seconds, for a few frames. They traced it down to the developer, who was smoking a cigar while developing the film. When he inhaled, the tip of the cigar got brighter and ruined the film. They had to reshoot. StuRat (talk) 10:32, 20 November 2009 (UTC)

Seeing the effort needed to process a single film strip increases one's respect for what was done for the early multi-strip Technicolor versions. Cuddlyable3 (talk) 11:58, 20 November 2009 (UTC)

Thanks for the answers it helped me a lot. --HappyApple (talk) 14:11, 20 November 2009 (UTC)

I dispute the claims of Kainaw and request a reliable source for the claim of poor quality control in film development in past eras. Craftsmen were craftsmen. Edison (talk) 04:59, 21 November 2009 (UTC)

I've seen old silent movies like that, where the brightness varies dramatically. I doubt if it was due to poor craftsmanship, just a lack of automation. If a machine is used to time every step in the development process, you will get more accurate timing than some guy with a stopwatch, especially if he has to go to the bathroom. StuRat (talk) 05:52, 21 November 2009 (UTC)

Static electricity

When you pull a sweater off in the winter and you get sparks between your undershirt and the sweater, what causes that? I know it's static electricity but how does it get there? Dismas| 04:08, 20 November 2009 (UTC)

That's called the Triboelectric effect, described in that article and more superficially in our Static electricity article. -- Scray (talk) 04:22, 20 November 2009 (UTC)

Static charges build up easily in dry air, which is typically found in a room with electric heating. Cuddlyable3 (talk) 11:44, 20 November 2009 (UTC)

Lunar water

Hi, the Moon is hotter (I guess) than the hottest desert during most of its daytime. Because of this lunar water is suspected only to exist in those cratered areas near the poles which are in permanent darkness. This makes sense because the water is frazzled and evaporates in the searing month-long heat. What is often claimed is that this evaporated water is then lost to, or flys off into, space. How does the vapor reach exit velocity? i.e. wouldn't it be impossible for vapor to find its way beyond the moons gravitational force without a big push? Does what goes up not come down on La Lune? ~ R.T.G 12:00, 20 November 2009 (UTC)

The moon's scape velocity is small enough that water can reach it simply by random thermal movement. That's why the moon doesn't have an atmosphere. Dauto (talk) 13:03, 20 November 2009 (UTC)

That's true - but it also provides another mechanism for water to get into those always-dark craters. When there are a few molecules of water in the lunar soil, they get repeatedly hit by all sorts of particles and photons of various energies and get thrown out of the soil and up, away from the surface. Some, indeed, gain so much energy that they escape the moon entirely. However, lots of them don't - and eventually float slowly back to the lunar surface - ready to get whacked again. You can envisage this as a bunch of molecules bouncing around the surface of the moon - randomly jumping from place to place...until they just happen to end up inside one of those always-dark craters. Once a molecule happens by random chance to end up in one of those places, it's shielded from all of that incoming energy and there is no way for it to get out. Hence water accumulates in those places - even water that wasn't conveniently deposited there in the body of an icy asteroid impact. There isn't much water in the lunar soil - but when the water from the entire surface of the moon is gradually collected in just a few special places, it can add up to a lot. SteveBaker (talk) 13:59, 20 November 2009 (UTC)

Extending that idea, couldn't other particles (dust) gradually cover (fill-in) the bottom of such craters, such that we could envisage most locations on the moon's surface as having once been the site of a crater? If so, couldn't the buried water be more widely-distributed, and not "in just a few special places"? -- Scray (talk) 14:24, 20 November 2009 (UTC)

No, because water that accumulated anywhere else would evaporate when the Sun heats it up again. Thus it would be kept in motion until it finds a stable position, either in a permanently shaded polar crater or by escaping the Moon entirely. Now for an analogy: Have you ever seen a spot in the center of a road intersection where no cars drive, that accumulates debris ? The debris gets knocked all over the place by the cars, until it finds it's way to that spot, then it stays there. This effect also causes debris to accumulate on the shoulders. StuRat (talk) 17:51, 20 November 2009 (UTC)

To an extent, yes, but dust is much heavier than water (by several orders of magnitude, I think). That means it doesn't move about anywhere near as much. You may find Lunar dust#Moon fountains and electrostatic levitation of interest. --Tango (talk) 14:44, 20 November 2009 (UTC)

It's just hard to imagine natural flow being enough to blow vapour into space. The moon as a low gravity thresh-hold but its not as if you could trip and fly off it not by a long shot. Isn't the upper-Earth atmosphere in a lower gravity state but gas blowing away is only a minor event? Of course vapour collection could be such a minor event too but on the Earth, heat affected gas reacts in conjuction with other gas i.e. is bouyant but on the moon there is little to nothing hosting bouyancy. Would the affected by heat rising off the moon not disipate long before escape velocity and distance and wouldn't our upper atmosphere be blowing away rapidly through the hole over the antartica? Bit vague to answer now sorry but just flaoting away doesn't apply to our familiar surroundings. Thanks for answers ~ R.T.G 16:52, 20 November 2009 (UTC)

The solar wind bombards the planets and moons (especially the inner ones) with high energy particles. This can blow loose those molecules in the upper atmosphere (on those planets and moons lacking a magnetic field which would deflect the solar wind). The gravitational attraction at Earth's stratosphere is only slightly less than on the surface, because it's only slightly farther from the center of the Earth (our atmosphere is very thin relative to the radius of the Earth). However, the lightest molecules still escape (via Jean's escape), such as those of hydrogen. That's one reason why we have hardly any H₂ molecules in the air. Here's a diagram of the Moon's interaction with the solar wind:

      ->   ->_____->    -> ATMOSPHERE BLOWN LOOSE
      ->    /     \ 
SOLAR ->  
WIND  ->   | MOON  |
      ->  
      ->    \_____/
      ->    ->    ->    -> ATMOSPHERE BLOWN LOOSE    StuRat (talk) 17:42, 20 November 2009 (UTC)

The process is called Jean's escape and it is one of many processes which can cause a gas particle to reach escape velocity. We have an article on Atmospheric escape. Basically, what happens is that the Maxwell distribution has a long tail - some gas molecules are always statistically going to have much faster velocities; and as those escape orbit, the thermal distribution re-equilibrates. The mechanism of showing that a gas always follows a Maxwell-like distribution is a very complicated derivation of statistical physics and thermodynamics, but it can be done. Nimur (talk) 16:59, 20 November 2009 (UTC)

"First, the water is dissociated into hydrogen and oxygen by ultraviolet light from the Sun, and then the light hydrogen is pulled away in the solar wind."? Maxwell distribution would suggest that water vapour bounces off itself and flys beyond the bow shock region of the moons magnetosphere (no article actually says this and Jeans escape is neither explained or an existing article...) ~ R.T.G 22:21, 20 November 2009 (UTC)

Our article is a bit sub-par. I will work on it over this weekend, and if necessary, create an entire separate article for Jean's escape. Nimur (talk) 08:10, 21 November 2009 (UTC)

That diagram (above) makes it look even more likely that water would accumulate - the 'wind' that is blowing directly downwards at the lunar equator has to either blow around the equator or up or down towards the poles - the velocity of the water molecules as they sweep over the poles would be at right angles to the gravitational vector - resulting in them simply falling into the next available crater that would shelter them from the solar wind. Since the always-in-shadow craters are mostly to be found at, or near to the poles - that would also fit the water-accumulation theory rather nicely. SteveBaker (talk) 23:13, 20 November 2009 (UTC)

Unit conversion

Now, I'm pretty bad with anything mathematical, but it turns out to be quite essential for the work I'm doing with regards to converting units. I've used spectrometry to obtain absorbencies, and I've been given an ε₂₈₀ (constant at 280nm) value to use in the simplified Beer-Lambert law (concentration = absorbency/ε₂₈₀), so I can work out concentration like that.

However, I'm pretty sure that value would give me a concentration in the units of moldm. I need the values in μg cm. I get really confused when trying to convert this values. I can't just multiply or divide the value because it's composed of two parts (the amount, and the volume). How can I convert moles to μg, and dm to cm in the same method? Thanks. Regards, --—Cyclonenim | Chat  12:43, 20 November 2009 (UTC)

I don't think I could improve on our article explaining factor-label conversion of units, but if you have a question after looking at that, please ask and we'll try. I found this by first going to the Dimensional analysis page, which is a more standard, but general, term for this type of math. -- Scray (talk) 14:05, 20 November 2009 (UTC)

I'm not sure I know how to apply that technique to this case. The equation I'm using is concentration = absorbency/a constant. If I put in the units, it'll be moldm-3 = one arbitrary value / another arbitrary value. Regards, --—Cyclonenim | Chat  14:50, 20 November 2009 (UTC)

If you have mol/m and you want to get to μg/cm, then you just multiply in a chain, e.g.: (mol/m)(molar_mass g/mol)(10 μg/g)(10 m/cm). Multiplication and division are Associative. -- Scray (talk) 14:59, 20 November 2009 (UTC)

BTW, this sort of math is VERY important in biomedicine - practice it a lot. -- Scray (talk) 15:02, 20 November 2009 (UTC)

I know it's really important, which is why I'm so pissed that I can't understand it! I think I need to work through an example, so I'll provide one and have a go. If C=A/ε, then I can do 0.088/3.65x10^4 and get 2.41x10^-6 moldm, not mol/m. The problem is that's all I have to work with, I don't have any conversion factors. So to convert moles to mcg, I need to know the molecular mass of BSA. I don't have the molecular mass, sure I could probably find it but something tells me I don't need to. Converting dm-3 to cm-3 is the easy bit because I know how many dm-3 go into cm-3, but I don't know how many moles go into a gram of substance without knowing it's molecular mass. I'm probably missing something, I'm really sorry for me stupidity! Regards, --—Cyclonenim | Chat  15:06, 20 November 2009 (UTC)

If it helps, one of the tables I have actually gives me the volume of BSA in the test tube. For the example above it's 1cm3 of BSA and 4cm3 of H20. It also says the concentration of the BSA stock is 250mcg. Regards, --—Cyclonenim | Chat  15:10, 20 November 2009 (UTC)

This is clear: the conversion from moles to mass is the molar mass, by definition! BTW, I really find it confusing when you write moldm. What's a "moldm"? Yes, I'm pretty sure you mean mol•dm, but I should not have to guess. Ambiguity is the bane of both science and medicine! This is of course meant constructively - best wishes in your studies, -- Scray (talk) 16:25, 20 November 2009 (UTC)

I noticed another point of confusion - you refer to the "volume of BSA". That should bother you a little, since BSA is not a liquid. Therefore, it would not generally be measured by volume, unless the BSA is packed in a reproducible way (like sugar or salt might be, but even then we only measure those by volume in the kitchen). Thus, you're almost certainly talking about a solution of BSA, and the volume would only help (in the problem above) if you knew the concentration of that solution. Of course, if you knew that you wouldn't be using the Beer-Lambert law in the first place. -- Scray (talk) 16:42, 20 November 2009 (UTC)

biotechnology - monoclonal antibody

Respected sir.

why not use sendai virus after started to use PEG in monoclonal production —Preceding unsigned comment added by Marimathan kumar (talk • contribs) 12:30, 20 November 2009 (UTC)

Perhaps a more detailed elaboration of what you'd like to know would help. DRosenbach 12:46, 20 November 2009 (UTC)

aluminium chloride colorimetry

This is the method to determine total flavonoid content in crude drug. I want to know the principle and limitation of this technique. —Preceding unsigned comment added by 161.200.255.162 (talk) 12:49, 20 November 2009 (UTC)

Did you forget to ask a question? Dauto (talk) 19:39, 20 November 2009 (UTC)

I see a clear question there, even if not phrased in the interrogative mood. (I don't know the answer.) --Trovatore (talk) 22:22, 20 November 2009 (UTC)

Fevers and Calories

I had a fever the other day and it got me thinking. How many extra calories does it take to raise an "average" person's body temperature by 1 deg F (or deg C if you want). I know there's all kinds of factors that go into this question, that's why I asked about average, I'm interested in an answer even if it's close to a guess. Also, what's the survival advantage of a fever due to infection? Does it make the immune system more efficient? or is there another reason? Tobyc75 (talk) 14:39, 20 November 2009 (UTC)

Table 3-4 in this book suggests a 12% increase in caloric need for every 1 degree above 37 centigrade, but I don't think that directly answers your question about how much energy it takes to raise body temperature 1 degree. I suppose a direct answer would be to determine the specific heat capacity of an average human body and multiply by average body mass! For the second part of your question, we have a page for that, which provides a number of hypotheses (difficult to prove)! -- Scray (talk) 14:42, 20 November 2009 (UTC)

For a rough back-of-the-envelope sketch per Scray, the human body can be appropximated as a bag of water of the same mass. Since it takes one kilocalorie (exactly, and confusingly, equal to one food calorie) to raise the temperature of one kilogram of water by one degree Celsius, the actual amount of heat energy absorbed by a 70 kg adult is about 70 kcal (70 food calories) per degree Celsius of temperature increase. As noted, actually maintaining an elevated temperature relative to one's surroundings (mostly against the cooling effects of heat radiated away from the skin and carried away by warm exhaled air) will require continuous input of energy. TenOfAllTrades(talk) 15:51, 20 November 2009 (UTC)

You forgot to mention the ugly part. Nimur (talk) 17:03, 20 November 2009 (UTC)

A fever doesn't just work by burning more calories. It uses the same techniques used to prevent hypothermia (just with the thermostat set a little higher). Constricting blood vessels in the extremities to reduce thermal losses, for example. --Tango (talk) 15:59, 20 November 2009 (UTC)

Creationist evolution

I was thinking and not sure, whether this idea exists, but what is the possibility of evolution, which includes the concept of initial intelligent design (thus supporting the existence of God amid self-going, but artificially prepared evolution)? That is, in order to successfully launch the mechanism of evolution, there should be: first, the original evolutioning species (chicken or the egg, where chicken is supposed to be created by the God); second, favourable conditions for the existence of evolutioning life forms, which fall under the concept of entropy and ultimately under the concept of fine-tuned Universe. In other words, such complex process as evolution could not start spontaneously, without some assistance from the outside. Are there any references to that concept? Brand 18:42, 20 November 2009 (UTC)

Well, there is the concept of the "watchmaker God", who sets everything in motion and then stands back and watches what develops. In some versions of this concept, God actually dies after setting it all in motion. StuRat (talk) 19:04, 20 November 2009 (UTC)

It looks like that. I just would like to expand my concerns above. Given that there are much more hostile, rather than life-supporting systems, I tend to think that the concept of fine-tuned universe is essential to keep the self-going evolution running. Imagine initial life forms, thrown into some hostile environment to evolve. They will rather die instead of evolving. And if evolution takes minimum of several thousand years, someone has to maintain the neccessary conditions. This also points to God. Besides, I am not fully satisified with the evolutionist approach to the chicken or the egg dilemma. If mutation must have taken place at conception or within an egg of chickenish animal, as our article says, then what or who may cause the mutation and why? Most likely, also God. Brand 22:02, 20 November 2009 (UTC)

That is a very common religious viewpoint. It is, for example, roughly what is believed by most Christians that aren't Creationists (which is a large portion of Christians, probably a majority). --Tango (talk) 22:18, 20 November 2009 (UTC)

Certainly, evolution isn't incompatible with the idea that an intelligent designer kicked off the entire process from the first self-replicating RNA strand - then stepped back and let evolution take over. However, that isn't a way for Christians and Intelligent design nut jobs to get away with it. This hypothetical designer would have no possible way to know how things would turn out. You absolutely can't convincingly argue that the designer set things up from that first DNA strand and with the knowing intention of getting humans out as a result. That's impossible - there are far too many random variations due to quantum theory and chaos theory happening over billions of years for that to be possible. But that doesn't mean that science can support even that most limited view - really, it can't. There is absolutely no evidence that this happened - and in the absence of that evidence, we have to employ Occam's razor and say that this idea is basically untenable. Extraordinary claims require extraordinary evidence - and there isn't any.

In this form, the argument has nothing whatever to do with evolution and everything to do with the concept of 'abiogenesis'. It seems strongly likely that the first self-reproducing 'thing' that evolved by stages to produce all life was simply an astoundingly unlikely-seeming coincidence. However, there has been plenty of time for that coincidence to have happened, given all of the oceans of the world over billions of years...and even if that seems too much of a coincidence, it could have started on some other world and gotten here via panspermia types of mechanisms - which allows for life to have started (by pure luck) in any ocean of any planet surrounding any star in the entire galaxy - or even beyond. When you figure the odds of that happening - it seems like a certainty that life would spontaneously arise without any magical being being involved. Tossing 100 coins and having them all come up heads is very unlikely - but if every cubic foot of water in all of the world were tossing 100 coins once a second for a few billion years...does it still seem so unlikely that they'd never once all show up heads?

SteveBaker (talk) 23:02, 20 November 2009 (UTC)

I disagree with the uncertainty objection. The initial wave function of the world fully determines the future wave function, and it's true that over billions of years it will have branched into a huge number of possible outcomes. But how we interpret that result is basically a philosophical question, and doesn't necessarily have an objectively correct answer. The Many-worlds interpretation would say that all those possible worlds exist. We're experiencing only one of them, but by the Anthropic principle it would have to be one where intelligent life exists. The Copenhagen interpretation would say it's a dice roll like you implied. Hidden variable theories would say that the specific outcome is determined all along even if we can't know it.

The second part I totally agree with. Rckrone (talk) 23:57, 20 November 2009 (UTC)

It may be that on millions of other worlds, conditions were right for a while but due to bad luck life never got started, or others where life did start, but after a while things changed in a way that killed it off. Even in our own backyard, on Mars, there might be evidence that there was once the very early stages of life, but that things didn't work out. Given enough opportunities (and there are billions, possibly infinite) things are bound to go just right and keep going just right long enough for something to happen like what happened on Earth, regardless of how unlikely. Rckrone (talk) 00:10, 21 November 2009 (UTC)

This is the way I understand it, and I think SteveBaker said this, too. We happen to be on a world where things have worked in a particular way, but that set of events did not require an omnipotent and omniscient creator; we just haven't seen all of the versions that turned out differently from ours, on innumerable other worlds of other solar systems of other galaxies. Who knows what our descendents may discover if we give them a chance. -- Scray (talk) 00:51, 21 November 2009 (UTC)

I don't think we should apply the human knowledge to that designer, so he ought to know how things would turn out. It is impossible that the intelligent designer did not what would occur. May be our science just is not advanced enough to fully explain and support creationist ideas, akin to primitive man, unable to explain the lightning? As far as I know, evolution does not answer why the colour range of the life forms represents an established gamma or why the basic pigment of the majority of plants is green. But in terms of fine-tuned Universe you can say for example, that the green color plays a vital aesthetic role as generally accepted placid color. So it is impossible to imagine the majority of plants being brown, yellow, red or of other color. So why from too many random variations we have in particular the green color? Or the blue sky? Brand 11:00, 21 November 2009 (UTC)

Evolution does explain why the basic pigment of the majority of plants is green. That green pigment is chlorophyll, which plants evolved to contain a lot of because chlorophyll does a great job of providing a crucial role in photosynthesis. In turn, there is an evolutionary pressure on us humans to feel more content being surrounded by a lot of green, because the aesthetic appreciation of the color green helps to cause us to settle in nice, green areas, where plant life is thriving, and hence food is more abundant.

Evolution plays a role in why the sky appears blue, too. The sky appears blue because Rayleigh scattering scatters short-wavelength electromagnetic radiation more than long-wavelength electromagnetic radiation, and the shortest wavelengths of electromagnetic radiation that we can see are blue light. Evolution comes into play here in that evolution determined what range of electromagnetic radiation is visible to us. We have evolved to be able to see the range of electomagnetic radiation that we do, because that's the most advantagous range to be able to see, since that's the range of wavelengths for which there is the greatest solar irradiance. See sunlight, and . Red Act (talk) 12:14, 21 November 2009 (UTC)

I'm pretty aware that there are scientific reasons behind that. But the plants were green before the appearance of humans and most likely even before the appearance of herbivores. And how evolution explains the picturesque properties of landscapes? The core question is why evolution has ultimately set not only useful, but also such pleasant parameters? Many self-going processes are negative, like decomposition or aging, while evolution features the increase of beauty among others. How such process defines and shapes beauty in all of its complexity without external assistance or auspices? Brand 13:25, 21 November 2009 (UTC)

Of course plants were green - because their greenness is not caused by a design for beauty, but by functional parameters. Beauty is in the eye of the beholder. It's very much dubious that we have a sense of beauty that is not in some way connected to a utilitarian purpose (select fit mates, select good settlement places, learn to navigate...). And how is decomposition or aging "negative"? What about natural processes like the formation of a snowflake from water? Or a spiral galaxy from gas and dust? Or even the Mandelbrot set from a simple equation? --Stephan Schulz (talk) 13:37, 21 November 2009 (UTC)

Asking why things "evolved to be beautiful" is to completely misunderstand the process. Plants and animals evolved to be the best fit to their environment - and the wind up looking the way they do because that's the best fit to the environment. We find 'natural' things pleasant because we too have evolved to live amongst those things. We evolved to want to live in the kinds of landscapes that we are best suited to coping with - an idyllic landscape is one where we can find food and shelter - we like there to be a lake or a babbling brook in our landscape because we need water to survive. We find poisonous or otherwise unhealthy things ugly - scorpions look incredibly ugly - so do most other harmful insects - the appearance of rotting fruit is abhorrent - the smell of rotting flesh is repugnant. That's because we've evolved to be repulsed by things that we need to avoid in order to thrive. A barren, rocky landscape isn't something we'd generally find "beautiful". Julia sets, Mandelbrot sets (and especially the super new Mandelbulb set) look beautiful because they mimic the real world things that we've evolved to enjoy. The mandelbrot/bulb set would be ignored as a mere mathematical curiosity if it didn't happen to tickle our sense of beauty. (In fact, if you visit the forums where the Mandelbulb was discovered, they consciously rejected many other fractals on grounds of beauty alone). There are a VAST number of other mathematical systems that generate complex fractals - but most of them are ignored because they are considered ugly by our oddly evolved sense of beauty. Even amongst people - we find people beautiful when they show the outwards appearance of health and normality. Any human form that's out of the realms of the common is "ugly" to us because we've evolved to avoid mixing genes that are very different to our own into the next generation. Discoveries such as the uncanny valley really emphasis that. Our perception of color evolved to allow us to distinguish ripe fruit from unripe - our sense of smell to distinguish wholesome from rotting. Beauty is something WE evolved to make us fit into the world that exists - not something that the world evolved to suit us. This mistake is one of the most egregious that the religious and creationist nuts make. SteveBaker (talk) 18:54, 21 November 2009 (UTC)

Ultimately you cannot keep going to a more complex answer (God, gods, etc.) when responding to a question. Natural selection is infinitely simpler than any god one might conjecture. Creationists refuse to answer the question of where their god came from, but I know the answer: we created God. Imagine Reason (talk) 17:49, 21 November 2009 (UTC)

The sky was also blue before humans. If it is evolution, which determined what range of electromagnetic radiation is visible to us, as Red Act says, then the evolution must have anticipated the appearance of humans (which suggests the external intelligent assistance), who, unlike previous life forms, became the first and the only ones to enjoy and appreciate picturesque color values. We have not evolved to be able to see the range of electomagnetic radiation that we do, because even prehistoric men were able to perceive the sky color. As for the natural processes like the formation of a snowflake from water, all or at least many of such things require certain conditions, while the processes like decomposition or aging are self-going, the same way as disorder, which requires much less efforts to take place than the order. And creationists do not need to answer where the God came from because it is simply beyond all available knowledge, but all monotheistic religions actualy refer to one God. Brand 18:35, 21 November 2009 (UTC)

The sky radiates light in a color that we call "blue" because of Rayleigh scattering - a simple physical process that has nothing to do with evolution. We PERCEIVE the sky as "blue" because we've evolved eyes that take best advantage of the available light under a blue sky - and to help us do the things we needed to do while we were doing most of our evolving. That means spotting animals despite their camoflage - detecting what fruit is ripe, what is unripe and what is past it's best. We evolved to see a blue sky - the sky didn't evolve for us to see it...that's just nuts!

Creationists certainly don't need to explain where god came from unless they intend their hypothesis to explain everything. Science has loftier goals - we aren't content to figure out how animals came to be - or how planets formed - we aim to know how absolutely everything began - what makes every smallest thing do what it does. If scientists ever did find evidence for gods - the very next question we'd have would be: "Where did the gods come from?". By failing to ask that question - refusing to even consider it - the Creationists (and especially the Intelligent Designists) cannot lay claim to be scientists...which (sadly) they all too often do. So - what's the answer? Either they have a hypothesis - or they have to seek a hypothesis - or they give up pretending to do science and settle back into their dark ages beliefs while science gets on with the methodical business of sorting out how things actually happened. SteveBaker (talk) 19:23, 21 November 2009 (UTC)

I don't think science does any better than religion at solving the problem of a first cause or infinite regress. At the moment science appears to be blocked off from anything prior to the Big Bang — there is no candidate for anything that would count as observational evidence of what, if anything, occurred before the Big Bang or (more to the point) caused it. But supposing that were to change, it would just push the problem back a little earlier. Either you have an uncaused cause, or else an infinite chain of causes with no ultimate explanation as to why it's there — this is common to all accounts of causality, whether naturalistic or supernaturalistic. --Trovatore (talk) 20:00, 21 November 2009 (UTC)

Steve, evolved how? Was there any evolutionary shift to blue perception, when our ancestors perceived the sky in some different color? As far as I know, the color vision didn't evolve, it just was, which suggests that either the sky was set to appear in pleasant blue to us or our eyes were set to perceive it as blue by intelligent intervention. The colors are a relative term, other life forms perceive them in different ways or don't distinguish at all. Brand 20:36, 21 November 2009 (UTC)

Many animals have different color perception than us. In fact the number that perceive it exactly like we do is small. Most modern primates have tri-chromic vision very similar to ours, but that's rare among mammals. Presumably at some point in early monkey evolution they gained the ability to distinguish colors like we do. APL (talk) 20:56, 21 November 2009 (UTC)

So here proponents of modern evolutionary synthesis run to darwinism... I support the notion above, that evolution isn't incompatible with the idea of an intelligent designer. But it seems like not only he launched the entire process from the first self-replicating RNA strand, but also provides the necessary background since then. The sky example could be just one particular example, unless I misunderstand something. Brand 21:55, 21 November 2009 (UTC)

You absolutely do misunderstand!

Vision has clearly evolved - there can be no doubt that early animals were completely blind - then there was an evolution of light-sensitive patches - then an opening above those patches to provide a measure of directionality - then lenses and irises and all of that stuff to enable a proper image to be formed - and somewhere along that process, light receptors that are sensitive to different frequencies. There are animals at every one of those stages present even in the modern world. I read someplace that there is evidence that 'eyes' evolved many times and in many different ways in different branches of the animal kingdom. Even some kinds of plants can "see" at a primitive level - they turn their leaves to track the sun. People think that dogs (for example) can't see colors - that's not quite true - they see in two colors. We happen to be sensitive to three frequencies - other animals to two frequencies, yet others to just one frequency - or in yet others, there can be sensitivity to as many as half a dozen frequencies. Some animals see ultraviolet (bees, for example) - others in infrared (owls, snakes). Heck, there are even a very rare few humans who can see four frequencies instead of three (See tetrachromat). The point is that each one of those solutions is optimal for the lifestyle of the creature in question. Dogs don't distinguish green from red because - being carnivores - there is no evolutionary advantage to being able to distinguish ripe fruit from unripe. Snakes and owls hunt at night - when being able to see body heat is useful - so they've evolved natural 'night vision' and can see infrared light. Humans are not nocturnal animals - so we never evolved that capability. Bees have really good color vision - and can even see into the ultraviolet because they need to be able to see patterns in the petals of flowers so that they can figure out the precise timing of maximum nectar production. Again - humans don't eat nectar - so we never evolved that capability.

If there was a "designer" he/she/it was pretty useless at the job. Something I read recently: I like the problem of why giraffes can't make much in the way of vocalizations. You might think that it's something to do with the long neck - and it is - but not how you imagine. Our vocal chords evolved from the gills of early fish. In all fish, there is a nerve that goes from the brain to those gills. The nerve on one side of the body goes over a particular artery - the other side goes under it. No big deal for a fish...but as fish evolved to reptile and reptile to small, furry mammals and from there to giraffes - that pair of nerves have continuously evolved to their new functions - at no point in all that time has the nerve on one side of the vocal chords ever changed it's basic route. In humans, the nerve from the brain to one side of our larynx goes directly from the brain - as an intelligent designer would route it. But the nerve that goes from the brain to the other side loops down into our chest cavity - then back up the neck to the other side of the larynx. A pretty poor piece of design - but a not unexpected bit of evolution. Alas, for the poor giraffe - that means that the nerve for one side of the larynx travels about a foot or so from the brain - the other travels all the way down that L-O-N-G neck - around the artery and all the way back again...a round trip of about 15 feet! Hence, the giraffe has an enormous problem - when it decides to go "Whoot!" (or whatever it is they'd like to say) - the message arrives at one side of the larynx WAY after the other - and all that comes out is a kind of pathetic cough.

Why would a "designer" (especially an intelligent one) design giraffes (and humans, for that matter) to have this peculiar problem? There is absolutely no rational reason - it's utterly crazy. However, evolution is blind to the future. In the fish, this was the most efficient way to pack in that nerve - and in each tiny incremental change the benefit to totally rerouting the nerve was insufficient to overcome the tendency for a baby animal to be very, very similar to the parent. Hence at no point in the gradually decreasing ability of giraffes to vocalize was there ever an opportunity to reroute that nerve. Every single fish-descended animal has that exact same wierd connection to the larynx on one side of the body. An intelligent designer with such perfect foresight to produce humans - who evidently intended giraffes to evolve from fishes would have taken the time to route that nerve over the top of the artery in those fish. Only a blind-to-the-future process could make such a colossal error. You'll probably tell me that the designer didn't WANT giraffes to make melodious love calls - OK - but why are all animals with larynx's afflicted with this same gigantic screwup? See: Recurrent laryngeal nerve

Intelligent designer? No - bloody stupid designer! ... Or evolution - only able to make tiny changes at each step along the way. Blind to the future. It's truly the only sane explanation.

SteveBaker (talk) 00:23, 22 November 2009 (UTC)

It sort of boggles the mind (my mind) when people compare religion to science. The two don't address the same field. It is just a misunderstanding. And it is banging one's head against a wall to try to resolve the two, or to point out their differences. Engaging in this matter points out a misunderstanding — probably of both. Bus stop (talk) 00:33, 22 November 2009 (UTC)

Of course they address the same field. They both try and answer questions like "What is the nature of the universe?" and "Why do we observe the things we do?" and "Where did everything come from?". They try and answer those questions in completely different ways, but they are trying to answer the same questions. --Tango (talk) 00:48, 22 November 2009 (UTC)

They do both address the same concerns — in the extremes. At the limits of their respective capabilities they are the same, yes. But most of what they are both about takes place in what can be called more middle ground. The basis of each field of study is mainly the middle ground, where they are both distinct, and it is always an error, in my opinion, to be cognizant of their differences of opinion on any given subject. Science and religion, in my opinion, have nothing to do with one another in the main grounds where they have their most applicability. Bus stop (talk) 01:05, 22 November 2009 (UTC)

Science doesn't have limits - it probes everything - it seeks to explain absolutely everything. You can't hope to retain these religious theories by simply seeking to declare them off-limits to science. If religion truly didn't have anything to do with science - we wouldn't have all of these religious nuts trying to shut down the teaching of evolution in schools...but they do - so there is clearly a large area of overlap. Not just in theory - but in the practicalities of the lives of our children. It's a very real collision of ideas - they simply can't both be true. It's also not just at the fringes. All of modern biology hinges on evolutionary theory - take away that cornerstone and pretty much the whole thing collapses - without evolutionary theory, we can't predict the implications of things like the spread of H1N1 - that's not "in the extremes"! Ditto cosmology - something like 40% of Americans seem to believe that the world is less than 10,000 years old. That can't be stupidity - it can't be lack of information - it's that they subscribe to some crazy religious theory that's 100% at odds with science. This whole "Can't science and religion just co-exist?" is ridiculous. SteveBaker (talk) 01:58, 22 November 2009 (UTC)

The Universe

a) How fast in mph is the universe expanding? b) what exactly is it expanding into? c) if it is not expanding into anything then how do we know that the older inner parts of it are not just shrinking and giving the illusion that the outer parts are expanding? d) how old is the universe compared with the age of the earth? I've read its only ten times, which does not seem much. 92.27.157.99 (talk) 19:46, 20 November 2009 (UTC)

d) The Universe is actually younger (or the Earth is even older) than that. The age of the universe is currently estimated at roughly 14 billion years. The age of the Earth, meanwhile, is pegged at about 4.5 billion years — in other words, the Earth has been around about a third as long as the entire Universe. TenOfAllTrades(talk) 20:07, 20 November 2009 (UTC)

b) "If the universe is infinitely big, then the answer is simply that it isn't expanding into anything; instead, what is happening is that every region of the universe, every distance between every pair of galaxies, is being "stretched", but the overall size of the universe was infinitely big to begin with and continues to remain infinitely big as time goes on, so the universe's size doesn't change, and therefore it doesn't expand into anything. If, on the other hand, the universe has a finite size, then it may be legitimate to claim that there is something "outside of the universe" that the universe is expanding into. So the answer in that case is that we really don't know what, if anything, the universe is expanding into."

c) Presumably because the distances are physically getting bigger? - Jarry1250  20:57, 20 November 2009 (UTC)

Or your ruler is shrinking without you being aware of it because you are shrinking too. 92.29.18.113 (talk) 21:31, 20 November 2009 (UTC)

That would only apply if all distances increased at the same rate, which they don't. Larger distances increase more than smaller ones. --Tango (talk) 21:35, 20 November 2009 (UTC)

More generally, we can only measure distances by comparing them to other distances. Saying that all distances have increased or decreased across the board doesn't really mean anything. We would have no way to tell. When it's said that galaxies are getting farther apart it can only mean that the distances are getting larger compared to the small distances that we use as measuring standards. Rckrone (talk) 23:05, 20 November 2009 (UTC) Edit: Sorry, didn't see that SteveBaker already addressed this point. Rckrone (talk) 00:54, 21 November 2009 (UTC)

If the universe has finite volume then it is almost certainly still unbounded, that is, it doesn't have a boundary. It might, for example, be the 3D equivalent of (the surface of) a sphere. The Earth's surface is definitely finite, but there is no edge you can fall off. If the Earth inflated like a balloon then we would say it was expanding into outer space, but that's because the surface of the Earth is a 2D space embedded in a 3D space (the universe). While we can think of the universe as being embedded in a larger space it is rarely useful to do so (although see Brane cosmology). --Tango (talk) 21:08, 20 November 2009 (UTC)

a) The universe is expanding at about 70 km/s/mega-parsec (that's the Hubble constant). That is, if two galaxies are X mega-parsecs apart (for large X) they will be receding from each other at about 70X km/s. The farther apart the galaxies are, the faster they recede from each other. --Tango (talk) 21:08, 20 November 2009 (UTC)

c) I don't think we know that the parts close to us aren't shrinking. Surely the two effects are indistinguishable? It is merely convention that we talk about the expansion of the universe - the shrinking of the universe would work also. The idea is that the 'ruler' we're using to compare distances with to is also changing size. All we know is that the ratio between the distance to some distant galaxy and the length of a particular platinum-iridium rod stored in some museum in Paris...is increasing. We can't say that things close to us aren't changing size because the only way to measure them is to compare them to the rod in Paris - and it too could be shrinking. There is absolutely no way to know whether that is because the rod is shrinking or the galaxies are moving further away. However - it really doesn't matter. We can't measure absolute distances - only ratios of distances to standard rulers. However, from a practical perspective - the "big bang" is even harder to get your head around when you think of it that way and the 'inflating balloon' and 'chocolate chip cookie baking' analogies for the expansion get super-difficult to understand when you try to think of them like that...so we stick with the 'expansion' version of the story. SteveBaker (talk) 22:46, 20 November 2009 (UTC)

Ah, yes, of course. We don't use the platinum-iridium rod any more, but I realise that the point holds: most of our units of distance are now intrinsically based on time, and that can change. In the case of a metre, distance covered by light in that fraction of a second can change. Point taken. - Jarry1250  09:15, 21 November 2009 (UTC)

Can anyone identify this plant?

Can anyone identify this plant? The photo was taken in Narbonne, in the south of France. Thanks -- Александр Дмитрий (Alexandr Dmitri) (talk) 20:49, 20 November 2009 (UTC)

Looks like Brugmansia to me. Highly poisonous!. Closely related to Datura. --Dr Dima (talk) 22:08, 20 November 2009 (UTC)

Signs of global warming?

Hi. Recently this November, I've noticed numerous signs that may indicate the signal of global warming in my local area. I'm from Southern Ontario. Please address the categories of indications separately.

Animals and plants

• Earthworms - I saw at least three today, after the rain passed by yesterday and last night.
• Dandelions - Yellow flowers, white seed puffs, and flowers in the closing stage. Many sighted within the past week, saw at least half a dozen just three days ago, along with windblown spores.
• Insects - In the past two weeks, I've seen ladybugs, houseflies, and smaller insects that look like mosquitoes.
• Ducks and geese - On one occasion, I saw a number of ducks or geese flying in a near-V shaped formation, and I've also seen many ducks or geese staying in a small pond.
• Seagulls - In the past week, I've seen many seagulls on some days, flocking close to buildings.
• Squirrels - I've seen both the black and the grey squirrels that are common in this area.

Weather

• Temperature - Some nights have been below freezing and frosty, but many have also been above freezing. The autumn chill of the air is missing on some mornings. Four of the next six days are forecast to have nights above freezing. Foggy days have been abundant, and two such days have occured this November. Many afternoons feel very warm with the sunlight and mild temperatures.
• Precipitation - There has only been one snowfall so far this autumn, and the form of precipitation for the previous two days has been rain.

Global

• Sea ice - Arctic sea ice this November has been the lowest on record for this time of year.
• ENSO - A moderate El Nino is developing in the Pacific.

So, do some of these signs, especially those locally relating to animals and signs, suggest that global warming is responsible? Are any of these particularly unusual for my location and time of the year? Thanks. ~AH1 21:54, 20 November 2009 (UTC)

Short term changes in one place are meaningless as evidence for global warming. There are always fluctuations in weather patterns. You need a large amount of data from all over the world over a long timescale to draw any conclusions about the global climate. --Tango (talk) 22:20, 20 November 2009 (UTC)

Indeed. All of these may become more frequent with global warming, but they may also be coincidence. Arctic sea ice is about the most useful single indicator, as it shows some effect of several years worth of temperatures. But even that varies a lot from year to year, and you need to look at long-term trends. --Stephan Schulz (talk) 22:59, 20 November 2009 (UTC)

Good replies so far. For your "animals and plants" category see phenology. El Niño probably isn't affected much by global warming (and any given El Niño certainly isn't a sign of global warming). Short Brigade Harvester Boris (talk) 05:50, 21 November 2009 (UTC)

I recall it being said by some professor on tv that the average global temperature has in fact been getting colder for the past few years. 78.146.30.105 (talk) 18:39, 21 November 2009 (UTC)

Yes, it has. The experts almost all dismiss that as a short term fluctuation, though. --Tango (talk) 20:43, 21 November 2009 (UTC)

See Temperature record if you'd like to see for yourself what the trend looks like. Rckrone (talk) 21:10, 21 November 2009 (UTC)

OK, but what about my observations in plants and animals in particular? Are they unusual? ~AH1 23:52, 21 November 2009 (UTC)

Are plants able to use Creatine to produce ATP?

Are plants able to use Creatine to produce ATP?174.51.21.137 (talk) 23:29, 20 November 2009 (UTC)

I think the simple answer is most likely "no". One study I found (PMID 11878275) enabled tobacco plants to do so by transforming them with the creatine kinase gene. My sense from that, and some other reading (e.g. our creatine article), is that creatine metabolism is a feature of vertebrate animals, not plants, but I'm no plant expert. -- Scray (talk) 01:37, 22 November 2009 (UTC)

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)

Leafhoppers (as well as some other critters within Auchenorrhyncha) look somewhat like a cross between a moth and a grasshopper; see images on google 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)

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 /_WP:Hornbook 05:02, 21 November 2009 (UTC)

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)

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)

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)

• 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) 10cm, 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 10cm, would my answer have to be, "The universe simply does not support the question"? Andrew Gradman /_WP:Hornbook 07:10, 21 November 2009 (UTC)

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)

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 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 cm, but if it does, the answer to that question is unclear at this time. Red Act (talk) 10:43, 21 November 2009 (UTC)

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)

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)

@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)

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)

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)

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)

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)

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)

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=mc 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)

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)

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)

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

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)

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

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)

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)

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)

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)

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

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

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)

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

Using Misplaced Pages 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)

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)

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)

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)

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)

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)

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)

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

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

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

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)

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)

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)

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

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