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October 7

Fossils in antartica

Are there human fossils or gorilla fossils that have been found in antarctica? How about ruins? — Preceding unsigned comment added by 128.214.166.6 (talk) 09:10, 7 October 2013 (UTC)

No, Antarctica's geographical isolation and glaciation predates humanity's existence. Plasmic Physics (talk) 09:32, 7 October 2013 (UTC)

Elder Things, though—that's a different matter. Deor (talk) 09:59, 7 October 2013 (UTC)

Scarely any more credible that the fictious scribblings on those hellish Archaean organisms is the real Piri Reis map which - if you squint your eyes just so and really really believe - shows a prehistoric Antarctic coast, free of ice, and full, perhaps, of ancient astronauts and maybe Elvis. I mention this only because there are occasional "documentaries" about this, which may linger in the back of one's mind. -- Finlay McWalterჷTalk 11:52, 7 October 2013 (UTC)

Let's take this Q a step at a time:

1) Will there be any fossils in Antarctica ? Yes, because it was once a lush tropical land, in the era of dinosaurs.

2) Will there be any primate fossils ? No, as noted above, because Antarctica was much as it is now during the era of primates, and thus not suitable for primates. However, there might be human mummies, of early explorers, whalers, etc., who died there and were freeze dried.

3) Will there be many accessible fossils ? No, because of the conditions in Antarctica now. Most of it is covered by steadily moving glaciers, making it quite difficult to dig through. There are occasional rock outcrops, though, and excavation could occur there, however, the weather and distance still makes any such mission rather difficult and expensive.

4) Will those fossils be more accessible in the future ? Sure, due to improved technology, perhaps allowing us to scan and find fossils before we start to dig, and also maybe due to global warming, which may melt off some of the glaciers in the way. StuRat (talk) 12:01, 7 October 2013 (UTC)

The British Antarctic Survey website has a database of Antarctic fossils, including some pictures. 'Abundant finds of fossil leaves and wood point to the existence of extensive forestation in earlier geological periods, even to within a few degrees of latitude of the South Pole itself. Dinosaurs, and later, marsupial mammals once roamed across its surface.' AndrewWTaylor (talk) 12:36, 7 October 2013 (UTC)

Note that this doesn't mean the dinos lived within a few degrees of the South Pole, as Antarctica has moved over time, as all the continents have, due to continental drift. StuRat (talk) 12:50, 7 October 2013 (UTC)

See also Geology of Antarctica. Count Iblis (talk) 13:55, 7 October 2013 (UTC)

• Actually the ice cover of Antarctica only dates back about 15 million years, while primates first appeared around 50 million years ago -- so time alone is not decisive here. But Antarctica split off from Africa around 150 million years ago, and its most recent linkages are with Australia and South America. Like Australia, its isolation caused it to never gain land mammals more advanced than marsupials. Looie496 (talk) 16:26, 7 October 2013 (UTC)

• "...OTHER than mammals" may be better language. Words such as "advanced" are problematic when speaking of evolution. And of course the marsupials in Australia continued to evolve after their separation from those places where non-marsupials evolved. HiLo48 (talk) 22:22, 7 October 2013 (UTC)

Yes, the platyrrhine monkeys originated in South America 40 million y/a. It is possible they colonized Antarctica. μηδείς (talk) 16:47, 7 October 2013 (UTC)

What's the likelihood of a disease occuring by means of a french kiss?

What's the likelihood of a disease occuring by means of a french kiss? 140.254.70.33 (talk) 20:47, 7 October 2013 (UTC)

Depends on the disease and the contact. If you've got a specific concern, see your doctor. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:17, 7 October 2013 (UTC)

Oral ecology and more specifically diseases transmitted through Saliva have a partial answer. 23:05, 7 October 2013 (UTC)

Note that diseases can be transmitted from one person to another by kissing, but the act of kissing doesn't create the disease. A person has to be carrying the infection in order to pass it to someone else. thx1138 (talk) 16:11, 8 October 2013 (UTC)

Could we eat grass?

Can we process (break it down) cellulose to make it edible for humans? OsmanRF34 (talk) 22:01, 7 October 2013 (UTC)

No. People eat it when they are starving because it is filling, but you cannot survive on it. See Irish potato famine. μηδείς (talk) 22:30, 7 October 2013 (UTC)

Medeis, I mean could we eat it, after we have processed it biochemically (with some enzyme, bacteria or whatever) outside our body. OsmanRF34 (talk) 22:53, 7 October 2013 (UTC)

(ec) Cellulose is broken down by bacteria in our hindgut, but to a very limited extent. Humans have an ensyme that helps break down starch into sugars, so we derive nutrition from starchy foods. However, humans lack an ensyme to break down cellulose into sugars. In general, animals that can derive nutrition from cellulose are either monogastric using Hindgut fermentation, or ruminants. Cellulose structure does not change in cooking, either. If you were to "digest" cellulose outside the body, using some microorganisms such as Weizmann organism for example, you'd end up with sugar or alcohol molecules (some of which have, indeed, substantial nutritional value).--Dr Dima (talk) 22:34, 7 October 2013 (UTC)

The best way to process grass chemically is with a cow. Fermented cellulose yields wood alcohol, which is poisonous. The problem is you either run into toxins or huge waste--otherwise people would be doing it now, rather than feeding it to their livestock. μηδείς (talk) 23:07, 7 October 2013 (UTC)

And using bacteria to break down cellulose is one method of producing methanol now under research and development. The hope is to provide a car fuel by using farm waste, without the downside of making food more expensive, which happens when you make ethanol from corn, or any other food. StuRat (talk) 00:00, 8 October 2013 (UTC)

No, Medeis, the cow is not the best way to process grass. In fact, it takes 20 pounds of grass (or 7 pounds of feed) to make 1 pound of beef; see Environmental impact of meat production. Most of the grass / feed is wasted as CO2 and methane of cow respiration and flatulence. I cannot find numbers for how much sugar or ethanol can be made out of a given amount of straw or grass, but I really hope the ratio is higher than 1:20. (I'm aware it's not an entirely fair comparison, though, as there are large additional costs involved in both beef and bio-ethanol production). In any case, the grass is not meant for eating; it is meant for playing soccer :) . If you want a better intermediate between sunlight and food, try spirulina. --Dr Dima (talk) 00:20, 8 October 2013 (UTC)

Okay Dima, you can recommend eating fried termites rather than some bovine equivalent if you like, but neither does Spirulina 'eat' grass. In the meantime, I will take my grassfedcowproducts. μηδείς (talk) 00:30, 8 October 2013 (UTC)

I don't think that 20:1 ratio is relevant. It's the calories in the 20 pounds of grass that should be compared with the calories in the pound of beef, not the weight. Or perhaps we could compare the protein or some other nutrient. Now, I agree that feeding cattle with food that humans can eat directly is a poor choice, in comparison with feeding that food directly to the people, but in the case of grass, using animals to convert it into something edible to humans, like milk or meat, isn't a bad choice. Of course, we can choose to grow food crops instead of grass, in some places, but not all places where grass grows are suitable for other crops. StuRat (talk) 00:27, 8 October 2013 (UTC)

You both are certainly right in that beef provides more calories (than grass) and tastes much better than the alternatives; I am not arguing for switching from eating steaks to eating sugar, ethanol, or cyanobacteria :) I do however think that, as far as the answer to the original question goes, fermentation outside the cow is a more promising method of cellulose processing than fermentation inside the cow. --Dr Dima (talk) 00:56, 8 October 2013 (UTC)

Grass carp are much more efficient than cattle for converting cellulose to human-edible nutrients. Roger (Dodger67) (talk) 09:09, 8 October 2013 (UTC)

People might have a beef with that and carp about your plan. StuRat (talk) 14:03, 8 October 2013 (UTC)

Can we process (break it down) cellulose to make it edible for humans?

Yes, in theory. And there are rudimentary efforts to develop an efficient chemical process to convert cellulose to starch for human consumption, as discussed in this paper (non-technical overview: Let Them Eat Wood!). The process though is currently wildly uneconomical:

Zhang estimates that, given the current price tag of the enzymes that his team used, it would cost about $1 million to turn 200 kilograms of crude cellulose into 20 kilograms of starch, about enough to feed one person's carbohydrate needs for 80 days.

Also note that while using cellulose as a food substitute is improbable in the near future, cellulose is already used extensively as an "external energy source" after conversion to Cellulosic ethanol. Abecedare (talk) 01:14, 8 October 2013 (UTC)

I think "extensively" is a bit of an exaggeration when talking about Cellulosic ethanol. Rmhermen (talk) 01:39, 8 October 2013 (UTC)

You are right. I should have said that it is much closer to mass commercial exploitation than cellulose-derived-food but had a brain freeze at some point. :) Abecedare (talk) 02:37, 8 October 2013 (UTC)

Yes, I had mentioned this above. Note that this could increase food production, indirectly, if we return to using corn exclusively as food and cattle feed, rather than to produce ethanol. StuRat (talk) 14:01, 8 October 2013 (UTC)

Many animals besides cattle convert cellulose into tasty meat, and some produce milk and textiles as well. Rabbits eat a lot of grass and other plants and need less management than cattle. I have several in my yard most days managing their own affairs quite well. Edison (talk) 14:36, 8 October 2013 (UTC)

Yes, but try catching them and eating them. First, I bet it will be harder than you think. Second, after you catch 1 or 2, you might find the rest move elsewhere. So, if you actually want to use rabbits as a food source, you would likely need to keep them in cages, which is at least as much work as managing a cattle herd. StuRat (talk) 12:15, 10 October 2013 (UTC)

Brain wrinkles

Why are our brains wrinkled? The standard explanation is that it's to do with size- but this doesn't make sense. Doesn't volume matter more than surface area for the brain? Is there some kind of neural activity that can only take place on the surface? 68.0.144.214 (talk) 23:11, 7 October 2013 (UTC)

[1] Plasmic Physics (talk) 23:18, 7 October 2013 (UTC)

Completely SWAG here: more surface (which implies less volumen), and that's helpful because it can get more glucose or oxygen. OsmanRF34 (talk) 23:29, 7 October 2013 (UTC)

• The appropriate (if not helpful) articles here are gyrus and sulcus. The size explanation does make sense, you just have to see it from an evolutionary/developmental point of view. It's specifically the outer layer of the brain, the neocortex, which expanded the most during human (and other higher mammals) evolution. The embryonic development here is important, like all mammals, the cortex develops in a flat, layered structure during early embryogenesis. The thickness and order of these layers is crucial for the correct functioning of the cortex later on. This is why you can't just make them thicker, rather than fold them up. In lissencephalic animals, the cortex remains flat. In humans however, by the 5th month, the cortex grows too large to remain in a flat layer, in essence it outstrips the growth of the underlying deeper brain structures. Hence the giri and sulci, just a means to fit an excessively large neocortex in a finite volume of skull, without distorting the organisation within the cortex. Fgf10 (talk) 23:39, 7 October 2013 (UTC)

• Surface and volume both matter, but in different ways. The cerebral cortex consists of gray matter on the surface and white matter underneath. The cell bodies of neurons are almost entirely in the surface layer of gray matter, and there is no way of making that layer thicker without massively changing its architecture. So the only simple way to increase the number of neurons is to increase the surface area. The white matter is mainly filled with axons that connect neurons to each other. So, an increase in connectivity would generally imply an increase in white matter, and therefore an increase in volume. The factors that result from all this are pretty complex to work out, but if you would like to read more, you might look at http://www.pnas.org/content/97/10/5621.full for a starting point. Looie496 (talk) 23:42, 7 October 2013 (UTC)

Brains of several types of mammals, with labels in French

• How do you fit a cloth napkin into a wineglass? μηδείς (talk) 00:33, 8 October 2013 (UTC)

Make the napkin smaller than the wineglass, of course. That rationale isn't convincing unless you explain why the napkin needs to be larger than the wineglass. For the cerebral cortex the answer isn't obvious, because the general principle is that the cortex of small-bodied animals such as a rat tend to be smooth, whereas the cortex of large-bodied animals such as a whale or elephant tend to be very convoluted. Looie496 (talk) 01:17, 8 October 2013 (UTC)

Does it not occur to you that making the neocortex smaller means making the processing area less powerful? The chimp's cortex is about 1/4 the surface area of ours, and the difference is largel due to wrinkling. Human brains have a mechanically limited volume, and folding allows more surface within the same volume. The surface structure of the cortex is vital. Jeff Hawkins covers this in On Intelligence. This is all comparative mammmalian intelligence 101, not speculation. Carl Sagan covered it way back in his Dragons of Eden. μηδείς (talk) 01:53, 8 October 2013 (UTC)

Human brain addresses the folding and gives the reason for it. As Fgf10 implies, we don't seem to have any one article that addresses this directly, fully, and concisely. μηδείς (talk) 02:49, 8 October 2013 (UTC)

Of course packing more surface area into a given volume is part of the story, but a full understanding would mean being able to explain the differences in convolution patterns for various species, as in the picture I've added. And that's not so easy to do. Looie496 (talk) 03:59, 8 October 2013 (UTC)

That PNAS reference is really a nice exposition, except.... it argues that a simple scaling law requires the amount of white matter to grow at a 4/3 power law faster than the amount of grey matter. Which means that if an animal were large enough, the existing grey matter ought to be stretched taut, doesn't it? Also, the humans are right dead center on the line they draw through all the species. [2] Which leads me to think that the convolutions actually have nothing at all to do with the grey/white matter ratio, at least within the existing range of sizes; they incorporate both white and grey, as we know from images. And yet... well, something has me badly confused on this point. Wnt (talk) 04:03, 8 October 2013 (UTC)

Hmmm, some more clues: Echidna helpfully points out that its brain is far more folded than that of the platypus, with a thinner grey matter layer; and lissencephaly mentions that some persons with the condition have 'near normal intelligence'. It represents a failure of neuronal migration, but with relatively trivial causes (viral infection). So what we're looking at here is a reorganization of the grey matter to make it thinner (but wider) that somehow is advantageous, which makes it fold up. Wnt (talk) 04:14, 8 October 2013 (UTC)

OK, [3] is a good one. It explains the conventional justification for increased folding with increased size: the head can't scale at the same rate as the body and still be feasible to hold up. So there's this pressure to have a number of grey matter cells proportional to the cells (and presumably sensory cells, muscle fibers, etc.) of the body, versus this other scaling law of grey/white matter. The result is that there are lineages that undergo lissencephaly with miniaturization (mice, marmosets). Then there are sirenians, which apparently have a tendency to this, especially manatees (but then again, those critters are ... not persuasively functional neurologically, as critters go). I didn't quickly find information in NCBI for the claim that lissencephalics can have normal intelligence; I found the claim from Wikipedia at [4] but it isn't clear in this context whether this refers to mild losses of folding as well as mild losses of intelligence. I'll leave this point open for now. Wnt (talk) 04:28, 8 October 2013 (UTC)

October 8

Going to Space

A small group of us are getting together to try and launch something into space, by any means necessary. So far, we seem to have settled on the idea of getting a big helium balloon, but as far as I can tell, that'll only get us 20 miles or so up, rather than all the way into actual space. I'm wondering if there's any better alternatives, maybe a stronger balloon, perhaps if it had a lower pressure of gas to survive the inevitable expansion, perhaps if we could launch a rocket from the balloon once we're up in the thin air there, are any of these ideas actually feasible? Has anyone managed such an amateur launch all the way across the boundary of space before, and how did they do it?

213.104.128.16 (talk) 11:24, 8 October 2013 (UTC)

Outer space is, by definition, a vacuum. No matter what you fill your balloon with, or what you make it out of, it will never be lighter than nothing, so you can't float into space on a balloon. You can launch rockets from balloons and aircraft, but it's only of marginal benefit. Do you really just want to get to space, or to orbit? Of those, only orbit is particularly useful, and to do that you need to get orbital speed, which is thousands of mph, something which can only be attained (with current technology) with a substantial rocket. -- Finlay McWalterჷTalk 11:33, 8 October 2013 (UTC)

As Randall Munroe puts it: "...getting to space is easy. The problem is staying there." — PhilHibbs | talk 15:10, 11 October 2013 (UTC)

Space is, by definition, 62 miles high, where air pressure is low enough to prevent winged aircraft from flying. The aim is to cross that line with some sort of altimeter and return with evidence. Getting into orbit can wait for a later project. 213.104.128.16 (talk) 11:49, 8 October 2013 (UTC)

I think that seemingly precise figure of 62 miles deserves clarification, especially since this is the Science Desk. The link is to the Kármán line, which is actually at an altitude of 100 kilometres, and is very much an approximation. For Americans this gets rounded to 62 miles, which sounds precise, but isn't. HiLo48 (talk) 01:05, 9 October 2013 (UTC)

See rockoon, which outlines launching rockets from balloons. The benefit is off course that you don't spend fuel getting up the first few thousand meters, saving weight and cost. WegianWarrior (talk) 11:57, 8 October 2013 (UTC)

A liftoff from a rockoon sounds like it might be rocky. μηδείς (talk) 01:00, 9 October 2013 (UTC)

See the Brooklyn Space Program, which used balloons to send an iPhone into space, recording the entire trip. For inspiration, see this amazing video of the iPhone's journey to space and back down to earth, with pretty awesome footage of both outer space and our planet on the way down. Zunaid 12:48, 8 October 2013 (UTC)

I support the concept of a rocket launched from a balloon as the best way to get into space and then come right back down. However, you do need to be careful where you do this, as a plane might crash if it runs into the balloon. So, you want to do this far from commercial routes, and also ensure that the balloon collapses and falls right down after the rocket is launched, rather than floating around posing a continued hazard to navigation.

Also, you might want to use hydrogen rather than helium. It's cheaper and has better lifting power. It is flammable, but as this is an unmanned craft, the risk is minimal. StuRat (talk) 13:52, 8 October 2013 (UTC)

Risk is minimal once launched. If you use hydrogen you should certainly consider the risks when filling the balloon, as well as storage and transportation. -- Q Chris (talk) 14:55, 8 October 2013 (UTC)

It doesn't seem any more risky than flammable fuels, like gasoline, to me. Indeed, leaking hydrogen quickly dissipates in the air, while gasoline forms a flammable puddle that persists for quite some time. StuRat (talk) 16:26, 8 October 2013 (UTC)

The current record is 53 km, so just into the mesosphere. Perhaps a two stage balloon would work better. You can put a very small amount of hydrogen gas in a huge balloon so that at sea level it isn't inflated at all. This is then carried folded up on board a helium balloon. The folded balloon is held firmly in its shape to prevent it from expanding as the balloon rises and air pressure drops. Then when some target height is reached (say 30 km), the folded balloon is let to expand. The volume increases by itself because of the low pressure, it's size will be much larger than the balloon that carried it at 30 km. At that height the pressure in the original balloon is no longer equal to the air pressure, but the big balloon won't be completely inflated, the pressure of the hydrogen gas inside will be the same as the atmosheric pressure. This means that the big balloon will be able to rise a lot higher than the original balloon. Count Iblis (talk) 14:33, 8 October 2013 (UTC)

What nonsense is this? A balloon, filled with a lighter than air gas, prevented from expanding, is just harder to lift than one that isn't. 1.122.124.206 (talk) 14:48, 8 October 2013 (UTC)

In fact slightly harder as you would not get the benefit of the increasing buoyancy of the balloon as it expands. -- Q Chris (talk) 14:56, 8 October 2013 (UTC)

And the Kronig-Causius equation (for any gas, the volume occupied is a function only of the number of molecules, the temperature, and the pressure) shows us that a balloon that allows the pressure inside to equall the pressure outside will, if boyant at any given altitude, will be boyant at all altitudes. So no point in having two different balloons. 1.122.124.206 (talk) 15:01, 8 October 2013 (UTC)

No, that's not the point here. You have to release the constraints in the stratosphere, it can't be used at low altitudes, because the aerodynamic forces due to the varying wind speeds over its length will be very large. Count Iblis (talk) 15:11, 8 October 2013 (UTC)

If you carry an uninflated balloon on another balloon, because you have not achieved maximum possible boyancy, the whole assembly has be larger and/or ascend slower, so wind issues are worse, not better. And horizontal drift due to wind is not relevant to wanting to achieve a maximum altitude anyway. 1.122.124.206 (talk) 16:17, 8 October 2013 (UTC)

The problem is to reach very high altitudes where you need extremely large balloons to be able to lift a light object. Then it looks like you could just lift off with such a balloon from ground level. When the balloon hasn't fully inflated, the buoyancy force will approximately stay the same. But this won't work, because at ground level you'll have that enormous balloon that will be compressed into a sheet with an enormous surface area. While the buoyancy force acting on this is indeed able to lift an i-phone of, say, a few hundred grams, that thing likely won't go far. It will be blown by the wind into some nearby obstacle. It cannot lift very fast because the huge surface area will lead to large frictional forces at even low velocities. Also, if there is some downdraft, it won't lift at all.

The buoyancy force, after all, is the integral of the pressure over the surface area, which is equal to the weight of the displaced air, but with that huge surface area, the aerodynamic forces completely swamp this out. So, in practice, you need a better ratio between the volume and the surface area, which means that the thing should actually be inflated more. Obviously you can't start with such a better inflated balloon at gound level as then you won't reach the desired height. So, the best solution is to lift of with a smaller balloon that will carry a larger weight to an altitude of, say, 30 km, where the bigger balloon will both be inflated and where the winds don't pose a problem like they do in the troposphere. That bigger balloon will only lift the i-phone, the buoyancy force acting on it will be much smaller than that on the smaller balloon. Then it will lift from 30 km altitude without problems, compared to ground level the air is much less dense, which means that the aerodyamic forces acting on its huge surface area are less of a problem. Count Iblis (talk) 17:10, 8 October 2013 (UTC)

Balloons won't work. your only option is a sounding rocket.217.158.236.14 (talk) 15:13, 8 October 2013 (UTC)

Balloons ALONE won't work. StuRat (talk) 16:24, 8 October 2013 (UTC)

This could be a really exciting project. I think that key to making it more exciting, and more feasible, would be to do some careful research into what little is known about the mesosphere. There are so-called atmospheric tides and other density variations that could give you a substantial boost in pressure, improving your odds with any space shot depending on balloons or aircraft to get much of the height. I know nothing much about them, but if you can find a way via NASA to get real-time data about these, you'll have a leg up.

Personally, I think it would be especially interesting if you could include a camera module (people have used cell phones, even for modules launched from genuine NASA missions), and try to coordinate your launch in advance of a line of thunderstorms. The area you want to go is prime territory for Sprite (lightning) effects, and the potential, however uncertain, for getting a fairly close up view of the effect would be something that could really drum up interest in your mission and make it more than "just some more kids shooting off rockets", which could also be of help when it comes time to try to get the FAA to authorize your shot, etc. (I don't recommend shooting missiles without doing so, as they tend to be remarkably paranoid about such things) Of course, trying to shoot in advance of a thunderstorm also means trying to deal with or avoid very problematic weather conditions. And I really don't have any idea whether their effect on the upper atmosphere would help or hinder you; my assumption is that updrafts ought to improve the density at a high level, but...

You already propose having one sensor (an altimeter), presumably run off the cell phone; you'll also want to look into what other sorts of sensors would be useful to explore atmospheric phenomena. If you get anywhere near really trying this, you ought to write some mesosphere/sprite researchers, send them an attachment with your plans, try to get professional feedback and collaboration.

I should also point out that even much less ambitious ideas have gotten huge publicity: see http://www.wired.com/gadgetlab/2009/09/the-150-space-camera-mit-students-beat-nasa-on-beer-money-budget/ . I'm sure I actually saw footage from this in a TV ad at some point, which presumably means somebody made some serious money out of it.

Come to think of it, you might even manage to get some commercial sponsorship before the launch, if you can come up with a good enough plan. The manufacturer of the cell phone is one possibility... also, it dawns on me that you need to get the absolute thinnest possible weather balloon that is sturdy and reliable - maybe you should talk to a condom manufacturer and see if they'll fabricate you a prototype in exchange for having their logo on it. :)

Also... please, set up an account here so people can correspond with you! If you're going for this project, set up a page with your plans as you develop them (maybe Wikiversity is the best WMF project for it, but advertise it here), get more input and involvement. Wnt (talk) 17:03, 8 October 2013 (UTC)

LOL @ condom idea. However, they might find off-the-shelf weather balloons to be far cheaper. Here's info on a 17-mile high launch using weather balloons: [5]. You could use that as a starting point, then make it a cluster of weather balloons supporting a launch fixture for your rocket. BTW, you will likely need a multi-stage rocket to go as far up as you have in mind, even starting from 20 miles up. Also, assuming the rocket launches sideways to avoid hitting the balloons, you will need a guidance system that can turn it upwards once it clears the balloons. As for the camera, you might want to only put that on the balloon, as it's far simpler to have a camera functioning there than on the rocket. Of course, this means you wouldn't get pictures from the highest point. This video shows the type of rocket I have in mind: [6], and they did manage to attach cameras to theirs. StuRat (talk) 17:43, 8 October 2013 (UTC)

Heh, I'm back looking at this again. It has a fascination about it... To begin with, the best balloon altitude so far is still only 53 km, though the manufacturers aspire to 60 km [7] (based on [8], which I'll admit doesn't actually have anything to do with condom manufacture that I can see) -- which, unfortunately, suggests that one heavy-assed rocket is going to be needed, which means a really gigantic balloon, and the amount of helium involved, with the prices going up and up -- yipes! Nor is the notion of playing with huge amounts of hydrogen with such a rocket appealing either. But Orbital airship indicates that some people are dreaming of getting to the mesosphere this way, presumably by factoring in some kind of propulsion... Wnt (talk) 18:07, 8 October 2013 (UTC)

Notice that the Rockoon article doesn't have much to it - I think the mass problem you mentioned explains a lot. Making the rocket bigger to get through 20 extra miles of air is probably a lot cheaper and simpler than engineering a reliable design for a combination rocket/balloon platform. However, I know balloons are a common hobbyist method of getting things "near" space and getting some rather incredible photos from cell phone cameras. I don't know if there are more restrictions (or what the cost is) for launching sounding rockets outside of a research institution. Maybe we could find some resources on what options there are for a hobbyist sounding rocket launch. Katie R (talk) 18:16, 8 October 2013 (UTC)

One option is to lower your aspirations - even getting to/near 50 km, if you can score an elite balloon, might give good sprite viewing. Competing to make an orbital airship seven times the size of the Hindenberg is not an option. And then... there are the weird ideas. After racking my brain for an hour, the best I can come up with is, "what if you could make some kind of device that can ionize air (at 40 km or so) or capture the right kind of ions (from the lower edge of the ionosphere) and use electrical charge to propel them off at high velocity, thereby creating a rocket thrust from stored or captured energy without needing to carry the propellant with you". With the desired add-on that you use some kind of infrared laser beam locked onto the cell phone's GPS and altitude telemetry to provide the power, because batteries are heavy. So far the only thing I found on Google was a description of something like this means of "electromagnetic propulsion", apparently designed for lower altitudes, in a kid's AP Physics paper [9] but the diagram looks remarkably good to be his own, I think. We need a real rocket scientist, dammit! Wnt (talk) 18:47, 8 October 2013 (UTC)

Wouldn't that be an ion engine ? A laser from the ground wouldn't work, as it would dissipate in the atmosphere. A nuclear power source might provide the needed energy, so long as you skip the pesky safety shielding.  :-) StuRat (talk) 23:23, 9 October 2013 (UTC)

There has been one suborbital hobbyist launch already - see Civilian Space eXploration Team. Rmhermen (talk) 19:13, 8 October 2013 (UTC)

| The Straight Dope explains how to make your own spaceships, including Civilian Space eXploration Team's project above. Such a project could cost Between $500 to $2.5 billion, depending on your pocket. OsmanRF34 (talk) 21:46, 8 October 2013 (UTC)

1999 gmc yukon slt

specs on 1999 gmc yukon slt — Preceding unsigned comment added by 184.34.89.19 (talk) 18:45, 8 October 2013 (UTC)

You mean besides what you can find with just a cursory search on Google? Sebastian Garth (talk) 21:27, 8 October 2013 (UTC)

I have a chemistry question: If you mix hydroxycitric acid and Atropa_belladonna together in a bowl what will happen?

I have a chemistry question: If you mix hydroxycitric acid and Atropa_belladonna together in a bowl what will happen? Venustar84 (talk) 22:05, 8 October 2013 (UTC)

You will have a wet, sour plant. Please sign your posts, and refrain from nonsense, as you have repeatedly promised to do so. μηδείς (talk) 21:51, 8 October 2013 (UTC)

Mixing that acid with atropine, which is derived from the Atropa plant, might have some chemically interesting results. It would need to be in pure form and roughly proportional. I would think that a small quantity of Atropa wouldn't have enough juice to do anything. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:30, 9 October 2013 (UTC)

Forgot to sign and log in. Sorry about that. I fixed it. Venustar84 (talk) 22:06, 8 October 2013 (UTC)

And you forgot to indent. Don't forget to indent. OsmanRF34 (talk) 22:20, 8 October 2013 (UTC)

Is that better? Venustar84 (talk) 22:22, 8 October 2013 (UTC)

Yes. OsmanRF34 (talk) 22:23, 8 October 2013 (UTC)

We should treat this as an honest question. Hydroxycitric acid does have a whole lot of oxygens in positions that allow for the possibility of interesting reactions. I'm seeing commentary online about various "reactions" it undergoes with other substances such as DMSO and various herbs - one source is [10]; I haven't really made a serious search though. The OP may be under the impression he is taking Atropa belladonna if it is being marketed as a homeopathy formulation, even though such formulations often contain no actual atoms of the herb (and I'd bet money they're dispensed using a water tap and a label printer!) Wnt (talk) 02:49, 9 October 2013 (UTC)

And a good thing too, because the actual herb is dangerously toxic! Anyway, when you react hydroxycitric acid with atropine, you could get a whole bunch of competing reactions -- acid-catalyzed hydrolysis, Fisher esterification, even polycondensation (not to mention more mundane reactions such as acid-base reactions). It all depends on the relative concentrations of the reagents and on the reaction conditions (and perhaps on the phase of the moon as well). 24.23.196.85 (talk) 03:01, 9 October 2013 (UTC)

I just heard about the mixing of these ingredients from an old Halloween episode in the 90's: http://myrottingbrain.wordpress.com/2013/09/30/halloween-review-the-tale-of-the-sorcerers-apprentice/

The teenage boy in the story was mixing these elements and I was merely curious. Have people ever mixed those ingredients before?Venustar84 (talk) 06:09, 9 October 2013 (UTC)

IF it's from a work of fiction, especially a TV show episode, then it's meaningless. The script writers took some random scientificky sounding words and put it in the script. It has no basis in fact, and it's quite amazing they actually went through the trouble to pick words that describe real things as opposed to completely made up words, but that's of little consequence. As others have indicated above, there's no valid reason to mix that plant with that particular chemical, and nothing of consequence comes of such a mixing. --Jayron32 01:54, 11 October 2013 (UTC)

The question, to my mind, is if you had half a bowl of the acid, what volume of the plants would be needed to extract roughly half a bowl of atropine? The articles don't seem to speak to that question. If the concentration in a given plant is fairly low, it seems unlikely that you'd get very much of a chemical reaction. As regards the Halloween episode, keep in mind that fiction writers come up with all kinds of bizarre stuff. Such as the notion that placing a fairly small cake of dry ice in a sealed bedroom would cause the sleeper to suffocate. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:18, 9 October 2013 (UTC)

Good alcohol, bad alcohol

Is there a difference in the alcohol of cheap beverages and expensive beverages? I know that fermenting and distilling alcohol are two different processes, but what else can be different? Is the link cheap wine/headache just fiction? OsmanRF34 (talk) 22:28, 8 October 2013 (UTC)

You might be interested in the article on fusel oil (though that's primarily about distilled spirits, not wine). --Trovatore (talk) 23:51, 8 October 2013 (UTC)

Also congener (alcohol). --Trovatore (talk) 23:54, 8 October 2013 (UTC)

Ethanol is ethanol is ethanol is ethanol. Unless you're going so cheap that you've got methanol contaminating your drink, the nature of the alcohol doesn't differ between beverages. As others have noted, it's the other stuff in your drink that causes issues. --Carnildo (talk) 00:19, 9 October 2013 (UTC)

Penny -- Whad'll ya have?

Sheldon -- Alcohol

Penny -- Could ya be more ... specific?

Sheldon -- Ethyl alcohol.

--Trovatore (talk) 00:42, 9 October 2013 (UTC)

Note that it's not the type of alcohol which differs from cheap wines to expensive wines, it's everything else. Specifically, the presence of sulfites can cause headaches, and they are often added at an inappropriate level to give cheap wines a longer shelf life. StuRat (talk) 17:37, 9 October 2013 (UTC)

Actually, the 'sulfites in wine cause headaches' story is mostly urban legend. It is more likely that other naturally-occuring components of wine – particularly the tannins and histamines in reds – cause most wine-associated headaches. From here, for instance:

The "typical allergic reaction to sulfites," says Dr. Mary C. Tobin, director of the Division of Allergy and Immunology at Rush University Medical Center, "is hives, itching, flushing, swelling, nausea, diarrhea and low blood pressure." All bad, but no headache.

People who think they are reacting to sulfites with a headache are probably reacting to something else in the wine—or suffering from an unfortunate nocebo effect. TenOfAllTrades(talk) 19:30, 9 October 2013 (UTC)

Some of that "everything else" (especially the sweet stuff) can cause bonus gutrot and nausea, which can lead to indigestion headaches. All alcohol generally dilates blood vessels, so that factors in. But the price of all kinds of booze is mostly dependant on image. Crown Royale sounds so much snazzier than hooch, and a French bottle of wine from 1761 has a certain je ne sais quoi that an American box from Tuesday doesn't. InedibleHulk (talk) 19:13, 9 October 2013 (UTC)

Suppose the entire observed and extropalated universe

that we're fairly sure of, some 40 billion light years across, were just a tiny mote near the event horizon of a black hole with schwarzchild radius of about 10^(zillion^zillion) light years. If we observed that the expansion of the observed universe was speeding up(as we actually did observe in the 1990s), could the fact of being near this very large black hole explain the speedup? Like from tidal forces or from time dilation, say. Thanks, Rich Peterson199.33.32.40 (talk) 23:37, 8 October 2013 (UTC)

And just where do you s'pose we'd get enough matter for such a huge black hole, eh? 24.23.196.85 (talk) 02:54, 9 October 2013 (UTC)

by resorting to deficit spending, heh.76.218.104.120 (talk) 08:03, 9 October 2013 (UTC)

i apologize for my thoughtless silliness above. My original question was meant seriously.76.218.104.120 (talk) 08:48, 9 October 2013 (UTC)

There are ideas about the universe where it is all a "black hole" in the sense of being closed rather than open, but for the observable universe to be a mote falling into one just out of our field of view should imply some anisotropy in observations. We should see some differences when looking toward or away from the center, I think. (I'm not sure how that scales as you start thinking about an infinitely large hole infinitely far away, and a more knowledgeable answer is still needed here) Wnt (talk) 15:34, 9 October 2013 (UTC)

The acceleration is consistent with mass/energy that fills the visible universe uniformly (the dark energy). As far as I know, it's not consistent with the long-distance gravitational field of any distant object. Among other things, any such field would cause tidal distortion (often called "spaghettification" when talking about black holes) which would be visible as anisotropy in the sky, as Wnt said. -- BenRG (talk) 20:12, 9 October 2013 (UTC)

• Here are a whole bunch of recent articles on 4D black hole speculation. Probably all trace to one paper. μηδείς (talk) 21:43, 9 October 2013 (UTC)

How do you know it isn't already? ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:27, 10 October 2013 (UTC)

October 9

Does anyone know of philosophers or physicists who've discussed turtles all the way down vs.

"a deeper, more general explanation at each new level, consistent with the narrower conditions at previous levels; all the way down"? I have favored the second view, but i've been wondering if turtle preferrers argue that the second view isn't that much different. Thanks, Rich199.33.32.40 (talk) 00:14, 9 October 2013 (UTC)

A physicist who would take seriously the "turtles all the way down" story might have chosen the wrong career. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:26, 9 October 2013 (UTC)

• You seem to be conflating our deepening explanation over time with the more metaphysically fundamental layers themselves. But our order of discovery is just historical accident. Or am I misunderstanding you? μηδείς (talk) 00:36, 9 October 2013 (UTC)

Maybe order of discovery depends on accidents of our particular history and life form, but how do we know for sure, and would it necessarily be a greatly different ordering anyway?-if it were a countable set of discoveries i'm betting the orderings would coincide on a cofinite set... Deeper explanations are assumed by most, not just by me, to be more metaphysically fundamental. But say we're talking about the more metaphysically fundamental layers-then what i mean is replace the word "turtles" with the words "more metaphysically fundamental layers". Couldn't someone "looking" at the column of layers from "outside" argue that "turtles all the way down" is no more and no less reasonable than "more metaphysically fundamental layers all the way down"? Isn't it the same? Thanks again. P.S. I don't mean turtles literally.76.218.104.120 (talk) 00:58, 9 October 2013 (UTC)

Paul Davies in Stephen Hawking have discussed this in their popular books. Also, you can think of the now debunked Bootstrap model as a sort of "turtles all the way down" where you then can't distinguish between which turtels are supposed to be further down than others, so you have one big soup of turtles. Count Iblis (talk) 01:55, 9 October 2013 (UTC)

I am confused by the grammaticality of the two statements above this, to say the least. But "How do we know for sure that not X" is not a rational argument. It places the burden of proof on the challenger, where it does not belong. μηδείς (talk) 02:01, 9 October 2013 (UTC)

Chemistry

I want to know that Why cations are arranged in groups in salt analysis and on what basis they are arranged? — Preceding unsigned comment added by Vgvineetgoel (talk • contribs) 16:29, 9 October 2013 (UTC)

Sounds like you are talking about qualitative inorganic analysis? The groups are based on their properties...which ones all have similar behavior in terms of solubility, etc. The article I linked has lots of details. The deeper why ("why do they have these properties?") depends on which property you want to consider. DMacks (talk) 16:37, 9 October 2013 (UTC)

Saturated fat research

Why is there conflicting research about saturated fat intake in humans? Some say its linked to heart disease, others say its beneficial to the body. Clover345 (talk) 21:28, 9 October 2013 (UTC)

Such studies are almost always statistical, rather than physiochemical. There's little discord nowadays over things like chemical configuration, while "links" directly imply statistical analyses of various groups under various conditions and based on various assumptions. μηδείς (talk) 21:41, 9 October 2013 (UTC)

There could also be confounding factors. Perhaps all saturated fats are not the same, health-wise, or they are only harmful in conjunction with other dietary, lifestyle, or genetic factors. One obvious problem is that foods high in saturated fats may also contain trans-fats, so, if you don't account for that, and one study of saturated fats includes trans fats in the diet, while another excludes them, the first study might well conclude they are unhealthier than the 2nd study. StuRat (talk) 23:14, 9 October 2013 (UTC)

And these usually aren't "controlled" studies: you can't prescribe a strict diet to healthy volunteers and register the results years later, the best you can hope for is people keeping track of what they eat, and hope they do it accurately. And even those studies are rare, most results will come from epidemiological longitudinal studies like the Seven Countries Study, or more basic like the mediterranean diet where it was noticed that cardiovascular disease rates were lower than in the rest of Europe despite the typical diet containing much fat.

One likely explanation is mentioned in Epidemiological study: Advocacy: the results are exagerated and the uncertainties and caveats aren't mentioned in public health campaigns because it's easier to get the message across if the message is black and white.

Some studies may only have had data about the high or low intake of saturated fat, not about what replaced the fats in the low intake group: in one population it may be mostly unsaturated fat, in another mostly carbohydrates. But why speculate when we have an article about it: Saturated fat and cardiovascular disease controversy Ssscienccce (talk) 05:54, 10 October 2013 (UTC) edit: looks like I'm a bit late with that. Don't understand why I didn't get an edit conflict with Red Acts post, wasn't there when I edited... Ssscienccce (talk) 05:59, 10 October 2013 (UTC)

The overwhelming consensus among medical, nutritional and governmental authorities is that saturated fat is a risk factor for cardiovascular disease. Contradictory findings tend to be funded by the meat and dairy industries, which don't like the mainstream consensus because their products are full of saturated fat. See Saturated fat and cardiovascular disease controversy. Red Act (talk) 05:03, 10 October 2013 (UTC)

Are you serous ? Or are you trying to wind us up? You appear to misunderstand the root of Contradiction.This controversy did not exist until the Canola industry lobbed and financially supported prominent individuals of medical professions and lawmakers. Look at their 'logical' justifications. Why do they ignore any references that the Inuit had a diet 'very high' in saturated fats.

I put it to you that you don't mean 'consensus' but mean 'industrially paid for' apologists who are indoctrinated to accuse all dissenters of being 'fringe”.

Have you noticed that on Forums promoting Canola questioning this, The threads mysteriously comes to a halt. “This thread is ended” They can't answer why the Inuits did not have heart disease, cancer, and diabetes. The best they can do, is point to resent studies, by which time the Inuits have adopted Western diets and taken up smoking tobacco. That might satisfy sheeples in (say) the US of A but in Europe we also have the Norwegians, Swedes, Finish and Northern Russian Nenets people --- same story.

Due to climatic extremes, they require a high calorific food stuff (guess what – its fat) to survive the winter. If you don't quite understand this then question an Arctic explorer. They will inform you, that when they start feeling cold they put a large lump of butter (or similar fat) into their mouths. People in Detroit, thinking that they are further north than Canada might like to think they know what a cold winter is like. Yet, think about it, they're in a modern city. It is not the quantity of 'studies' that the Canola industry distributes that one should consider but the quality. --Aspro (talk) 19:27, 10 October 2013 (UTC)

My post was totally serious, and not done to wind people up. I'm going by Wikipedia's reliable source policy. As per the article I cited, the World Health Organization, the American Dietetic Association, the Dietitians of Canada, the British Dietetic Association, the American Heart Association, the British Heart Foundation, the World Heart Federation, the British National Health Service, the United States Food and Drug Administration and the European Food Safety Authority all say that saturated fat is a risk factor for cardiovascular disease. Those organizations all count as reliable sources. I think you'd have a hard time coming up with much in the way of reliable sources to support the claim that those organizations all succumbed to some canola-funded conspiracy. Red Act (talk) 21:13, 10 October 2013 (UTC)

OK. Let us take the wonderful, independent, consumer safeguarding FDA. Fist thing that Google shows is: FDA admits lobbyists influenced knee device approval. Your mistake is one of argumentum ad auctoritatem--Aspro (talk) 22:42, 10 October 2013 (UTC).

Well, you're using the poisoning the well fallacy by discrediting the FDA on an unrelated matter. And I would only be using appeal to authority if I claimed that it was true that saturated fat was a risk factor for cardiovascular disease because all of those authorities said so, which I didn't actually do. What's true is irrelevant here; it's not our job to determine what's true. On Wikipedia, what's important is verifiability, not truth. And giving a source that points out that ten authorities say something does make what they're saying verifiable. Red Act (talk) 00:20, 11 October 2013 (UTC)

L-Carnitine could be a confounding factor here. Count Iblis (talk) 14:23, 10 October 2013 (UTC)

October 10

Compulsive disorder

Is there such a thing as a compulsive disorder where an indivisual needs to isolate themselves from others? Pass a Method talk 09:47, 10 October 2013 (UTC)

Topics like agoraphobia and social anxiety and Hikikomori may be of interest to you. -Jayron32 11:09, 10 October 2013 (UTC)

I don't like the term "agoraphobia", since it seems to include both the fear of open places and crowds. To me those are two different things. There's also the term "enochlophobia", but I'm not sure if that just means the fear of crowds alone. Of course, some dislike of crowded areas is quite common, so I wouldn't call that a phobia unless it rises to the level where it becomes disabling, for example when someone can't go to work because it's too crowded there. StuRat (talk) 12:32, 10 October 2013 (UTC)

Misanthropy and Asociality may also interest you. 196.214.78.114 (talk) 12:24, 10 October 2013 (UTC)

Asperger syndrome can involve social isolation. And of course, merely being introverted causes people to avoid the company of others. StuRat (talk) 12:36, 10 October 2013 (UTC)

Also note that people who often go off by themselves may have a completely different reason than you expect, like gas. StuRat (talk) 12:37, 10 October 2013 (UTC)

Types of Iodine?

Does non-radioactive Iodine affects differently on the Thyroid gland? (heard such a thing somewhere, don't know how much it's accurate). Thanks for a clearing. Ben-Natan (talk) 10:19, 10 October 2013 (UTC)

Yeah, it doesn't give you cancer. The reason that people are supposed to take megadoses of (non-radioactive) iodine during nuclear fallout is that it saturates the thyroid gland so your thyroid won' t take up and incorporate radioactive isotopes of iodine which may be present in the nuclear fallout. this explains it fairly we'll. --Jayron32 11:05, 10 October 2013 (UTC)

Note that radioactive iodine is also used to treat thyroid cancer. Fortunately, the radioactive iodine is then concentrated in the thyroid tissue, where it kills the cancer. It also destroys the thyroid, but the patient can live without one, as long as they take synthroid, or some other med, for the rest of their life. This makes thyroid cancer one of the most survivable types. My brother had this treatment some 30 years ago, and is still quite healthy. StuRat (talk) 12:10, 10 October 2013 (UTC)

Fluorine planet

Would it be possible to have a life-supporting planet where fluorine would take on all the roles oxygen takes on on Earth? E.g. HF being the water analogue, atmosphere of mostly N₂, F₂ and small traces of noble gases. Double sharp (talk) 12:35, 10 October 2013 (UTC)

The would alternative biochemistry X be possible question is very difficult to answer with much confidence, as our total experience with life-bearing worlds is just one, and our total experience with the chemistry of even potentially life-bearing worlds is only a small handful. Our article on Hypothetical types of biochemistry lists a number of systems that have at least been considered; using hydrogen fluoride as the solvent in place of water is one of those hypothetical systems.

Cosmically speaking, such a system seems very unlikely ever to arise naturally; fluorine is vastly less abundant in the universe than oxygen. Seriously vastly—because of the way heavy elements in the universe are produced by stellar nucleosynthesis, oxygen is the third most abundant element in the universe, right after hydrogen and helium. Fluorine, with its odd (rather than even) atomic number, is way down the list. It doesn't come near the top ten. It's outnumbered about a hundred thousand to one by oxygen, in fact. To be fair, there are processes at work in planetary formation that can concentrate it – there's only about a thousand-fold excess of oxygen over fluorine in the Earth's crust – but that's still a long way from being able to have a fluorine-dominated planetary chemistry. TenOfAllTrades(talk) 13:52, 10 October 2013 (UTC)

From abundance of the chemical elements you can see fluorine is down by a factor of 10,000 from oxygen in overall abundance, so it is hard to come up with such a planet other than in the astronomical laboratory of some advanced species. Even then, there are challenges. Consider a carboxylic acid -C(=O)OH, which can be ionized to lose H+, or react with an amine to form a peptide bond -C(=O)NH- linking two amino acids. Now with fluorine you can have... -CH2F, -CHF2, -CF3 ... no double bond. You can still have a nucleophilic substitution, but it's no longer actually an acid, and it no longer can form an extra bond to the carbon during a transition state. Whether you say this is "the same role" becomes questionable. Of course, that's not to say you can't have life in this system, but it would be a different kind of life with very different biochemical possibilities. Wnt (talk) 16:19, 10 October 2013 (UTC)

There's also the fact that, being as highly reactive as it is (it even sets snow on fire!), fluorine cannot naturally exist in the free state in any significant quantity -- it would react with everything! 24.23.196.85 (talk) 22:41, 10 October 2013 (UTC)

If you've got enough fluorine that the planetary surface is passivated, much like how just about everything on the Earth's surface is oxidized, having free fluorine in the atmosphere isn't a problem. You won't have much else in the atmosphere, though (noble gases, and maybe some fluorine compounds if the temperature is right). --Carnildo (talk) 01:52, 11 October 2013 (UTC)

• Once again I'll recommend The Elements: Their Origin, Abundance, and Distribution by P. A. Cox, which addresses the relevant subjects in detail, and is hands-down one of the best books I have ever read. μηδείς (talk) 00:13, 11 October 2013 (UTC)

I'd like to submerge my hands in boiling water...

...without burning them. Something that just looks like boiling water would be good, too. One thought I had was water at a low pressure, but would that damage my hands ? Also, I'd then need some type of seal between my hands and the rest of the room, or the low pressure in the room would presumably interfere with breathing, etc. Ideally I'd like the heat from my hands to make the "water" boil. Any thoughts ? StuRat (talk) 12:58, 10 October 2013 (UTC)

You're going to need an aircraft, or a pressure chamber. This page shows the boiling point at altitude, meaning even at the summit of Everest the boiling point is ~70°C. This page says scalding risk begins above 44°C. Naively exterpolating the graph in that first ref would suggest you'd need to be at about 20km to be below 44°C. -- Finlay McWalterჷTalk 13:21, 10 October 2013 (UTC)

To use the heat from your hands to make the water boil would require even lower pressure since you body temp is about 37°C. You need to get the water to very close to that so that the heat from your hands would take it past the "boiling" point. Be prepared to stand there for a while.196.214.78.114 (talk) 13:33, 10 October 2013 (UTC)

It sounds like you want to put your hands in what looks like boiling water. Why not something that can generate the bubbles that we normally associate with boiling, like a hot tub might? Chris M. (talk) 13:23, 10 October 2013 (UTC)

Ordinary water with some dry ice in it looks a bit as if it's giving off "steam", and putting your hands in it (carefully) might increase the effect. AndrewWTaylor (talk) 13:27, 10 October 2013 (UTC)

Diethyl ether is a clear liquid with a boiling point of 34.6 °C at standard pressure. The snag is that it is a narcotic, and "harmful to the skin". Definitely not a good idea. AndyTheGrump (talk) 13:39, 10 October 2013 (UTC)

Diethyl ether is THE best way to cause an explosion in a lab, even when not boiling. No, definitely not. Wnt (talk) 16:08, 10 October 2013 (UTC)

Provided you take safety precautions (because it's flammable), you might use pentane, a clear liquid that boils at 36 °C, just below body temperature. It is also non-toxic and not a skin or eye irritant (source). - Lindert (talk) 13:43, 10 October 2013 (UTC)

Hmm, isopentane looks like it has an even better boiling temp of 27.7°C, so it should boil more when I submerge my hands. Does either have an odor ? StuRat (talk) 13:48, 10 October 2013 (UTC)

According to Wikipedia, both are odorless, but this page says isopentane has a "mild gasoline odor". I considered isopentane, but didn't include it in my post because I couldn't find whether it is safe to the skin. It looks like it is: [11] "Skin Contact  little to no effect". - Lindert (talk) 14:00, 10 October 2013 (UTC)

To expand on Chris M's answer, a visual effect similar to boiling water might be achieved with a fountain bubbler (from hobby shop components used in table-top fountains) or perhaps from fish tank or koi pond components. ZMBrak (talk) 14:08, 10 October 2013 (UTC)

The OP asks: Quote: Something that just looks like boiling water would be good, too.

Liquid nitrogen is very cheap and it looks more impressive. Dip some flowers in first and crush them in you hand into fragments. Once audience is impressed, dip lights, cue drum-roll, and dip your hand in. This is Wikipedia, so don't blame me if it goes wrong. However, I can give you a link to an expert (who warns you to not do this at home - suppose he means, you ought to go out into the woods to try it?). Hand vs. Liquid Nitrogen --Aspro (talk) 21:53, 10 October 2013 (UTC)

If you can't get your hands on liquid nitrogen, so to speak, then a good substitute, is acetone with dry ice in it. Plasmic Physics (talk) 01:04, 11 October 2013 (UTC)

Now I know acetone stinks to high heaven, so it would be hard to convince an audience that was water. As for dipping my hands in liquid nitrogen, no thanks, I would rather that none of my fingers break off. So far, isopentane is looking like the best option. StuRat (talk) 05:27, 11 October 2013 (UTC)

Ancient years

Were the revolutions of the earth faster during ancient times? Like would a 50 year old dinosaur be actually only 30 years old if compared to the years of today? Could decreasing speed of revolution be the solution to why people in the bible lived so long? — Preceding unsigned comment added by 128.214.166.7 (talk) 15:09, 10 October 2013 (UTC)

For the rate of the Earth's rotation slowing, see our article on tidal acceleration. It tells us that 620 million years ago the day was 21.9±0.4 hours - and explains why. Dinosaur 'days' would have been shorter, but not by as much as you suggest. Dinosaurs first evolved around 230 million years ago, and (excepting the birds, which evolved from dinosaurs) died out about 66 million years ago.

And in answer to the second part of your question, I'd point out that this is the science desk - and there cannot be a scientific answer to a question predicated on the premise that the bible is correct in reporting the age that people lived to. AndyTheGrump (talk) 15:20, 10 October 2013 (UTC)

See File:Geologic Clock with events and periods.svg for a diagram showing the age of the earth according to science. The whole circle is since the earth formed. Th little red line on the top left is the age of the dinosaurs. The thin black line up at the top encompasses the whole evolution of man from a coupe of million years ago till now. The time since the Bible was written would be a thousandth of the width of that. Dmcq (talk) 15:27, 10 October 2013 (UTC)

The Earth would still be going around the Sun in the same amount of time (1 year) - there would just be more days in each year. Or am I interpreting this incorrectly? Rmhermen (talk) 17:39, 10 October 2013 (UTC)

Oops! Right you are. The days were shorter, but the years weren't. AndyTheGrump (talk) 17:47, 10 October 2013 (UTC)

Long ago someone told me that the alleged extreme ages of guys like Noah, Methusaleh, etc., were somehow connected to the "numeric value" of their names. Has anyone here ever heard of that theory? ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:36, 10 October 2013 (UTC)

See gematria. -- Jack of Oz ^{[pleasantries]} 00:21, 11 October 2013 (UTC)

The theory I heard was that those people measured their ages in months (cycles of the Moon), not years, but that it got mistranslated at some point. Many of the lifespans seem to be about 13 times longer than they should be, so that would explain it. StuRat (talk) 05:31, 11 October 2013 (UTC)

Non-flammable explosive

Is there any known chemical or mixture of chemicals that can detonate but not burn? Roger (Dodger67) (talk)

It would seem that burning chemicals that can detonate causes them to detonate under standard conditions. So I am not sure how you would tell. μηδείς (talk) 21:38, 10 October 2013 (UTC)

No. C-4 (explosive) burns "slowly, like a piece of wood". -- Finlay McWalterჷTalk 21:45, 10 October 2013 (UTC)

That's interesting. But doesn't the ability to detonate imply the existence of free energy? Or is there an explosive that will explode but not burn in oxygen? μηδείς (talk) 21:54, 10 October 2013 (UTC)

The motive for my question is: I was watching a documentary on TV in which a there was a fire in a large munitions storage area. The fire resulted in various bombs and other explosive weapons detonating causing a lot of death and destruction. Then I thought to myself - what if the explosives couldn't burn? Then there wouldn't be an intense fire resulting in explosions. I know a lot of work has been done to develop insensitive munitions in recent years but that seems to be aimed at making ammunition of various types safer to drop out of helicopters, expose to heat, and other "abuse". The inability to sustain fire would add to the safety of such explosives. Roger (Dodger67) (talk) 22:18, 10 October 2013 (UTC)

Since the ability to detonate implies the existence of free energy with very finely mixed components, and sufficiently high temperature will inevitably result in chemical energy barriers to be exceeded, the problem would at first sight appear to be intractable. The only mechanism that I could imagine is that at some intermediate temperature, at least one component of the chemicals should disperse (through sublimation, say) at a temperature below that at which they will ignite, e.g. if they mix with surrounding air and dilute, all below their flash point. If this works at all, it would require a well-ventilated storage area. Perhaps one of the reagents in a caged molecular structure (buckyballs?), mixed with another that is moderately volatile or that will dissociate at moderately high temperatures? — Quondum 22:55, 10 October 2013 (UTC)

Ammonium nitrate is an nonflammable explosive. Plasmic Physics (talk) 23:03, 10 October 2013 (UTC)

Nonflammable? The article says Heating or any ignition source may cause violent combustion or explosion. — Quondum 23:16, 10 October 2013 (UTC)

Well, that would be a matter of definition, I suppose. Ammonium nitrate is a powerful oxidizer, so it can make other things combust, at least if you take the position that what "combusts" in a redox reaction energetic enough to be called by that name is the reducer. But it's unlikely to be oxidized itself. --Trovatore (talk) 23:49, 10 October 2013 (UTC)

Oh dear. One should not use Wikipedia as an authority. It is edited by all sorts or experts and non expert alike. There are many explosives that deflagrate to give the technical term. For instance, during the second world war, many marine mine were washed up upon the beaches of Gt. Britain. The Royal Navy personnel simply opened them up, removed the explosive, then burn them on the sands. It was mostly ammonium nitrate. Unconfined, it just burns. To fill a bomb casing with TNT, girls (and I mean very young women) poured bucketfuls of hot molten TNT in to them. Ignite it and it burns like paraffin wax. However, hit a lump with a sledge hammer and it might be the last thing you ever do. Mind you, Torpex was supposed to be stable too but the plane Joseph Kennedy Junior was flying on his last mission with this stuff just blew up.--Aspro (talk) 00:03, 11 October 2013 (UTC)

You used a key word: "mostly". I'm talking about the pure substance. Plasmic Physics (talk) 01:28, 11 October 2013 (UTC)

I don't see any fundamental reason why you can't have an explosive that detonates but doesn't burn. Combustion generally refers to a runaway oxidation reaction; if you've got an explosive that's already fully oxidized, and releases its energy through a decomposition reaction, it wouldn't burn by any reasonable definition of the word -- but that doesn't mean it's safe to stick in a fire.

One of the design criteria for modern explosives is that they should only detonate in the presence of both pressure and heat: set it on fire, and you simply get an energetic blaze; hit it with a sledgehammer and you just get squashed explosives. --Carnildo (talk) 02:02, 11 October 2013 (UTC)

Let's try to answer the intent of the OP's question, rather than getting lost in the specific definition of words used. Are there any explosives that will remain safe from a self-sustaining exothermic reaction, when exposed to extremely high temperatures, given a physical configuration that would support detonation? — Quondum 02:29, 11 October 2013 (UTC)

While many explosives usually won't explode by burning, there's apparently some room for surprises - there is a new generation of munitions like IMX-101 being developed that are even more resistant to exploding by this means. Wnt (talk) 03:09, 11 October 2013 (UTC)

How about an explosive where 2 parts are combined together to get the explosion ? For example, sodium and water. Or how about a fuel-air bomb ? If you just ignite the fuel, it should burn normally, but needs to be disbursed as an aerosol to become explosive. Then of course there are nuclear weapons, which should't explode if subjected to fire, but could leak radiation all over. StuRat (talk) 05:17, 11 October 2013 (UTC)

Efficiency of a thermodynamic cycle

I'm given a cycle that consists of an adiabatic process, an isobaric process, and an isochoric process. To get the effiency, I know that I need to calculate the work done in each process, but I don't know where to go from there nor do I know what the value of $\gamma$ is for a diatomic ideal gas. — Melab±1 ☎ 22:59, 10 October 2013 (UTC)

gamma = 7/5 for a diatomic ideal gas near room temperature. Count Iblis (talk) 00:40, 11 October 2013 (UTC)

To solve the problem, you can use that the internal energy of an ideal diatomic gas is given by E = 5/2 N k T. You know how to compute the work done by the gas, that's simply the integral of P dV, the abosrbed heat minus the work done is by the First law of Thermodynamics (conservation of energy) equal to the change in internal energy, and using E = 5/2 N k T, you know what this change is. So, you also know the absorbed heat for each of the processes. Count Iblis (talk) 00:46, 11 October 2013 (UTC)

Rain in Midwest United States

What is the traditional amount of rainfall in Midwestern United States? If you cite a figure, please add the hyperlink for it. --98.88.155.114 (talk) 23:13, 10 October 2013 (UTC)

Pick any random city in the Midwest and look at the Wikipedia article about it. Indianapolis is as good as any. --Jayron32 23:19, 10 October 2013 (UTC)

Thanks. I just noticed "Climate data for Indianapolis (Indianapolis International Airport), 1981–2010 normal" table. It was helpful. I wish the Midwestern United States article had a similar table with references.--98.88.155.114 (talk) 23:32, 10 October 2013 (UTC)

The Midwest covers too broad an area to make a stat like that very meaningful. Although you could take the sum of each states' annual rainfall and divide it by the number of states, for an approximate regional average. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:15, 11 October 2013 (UTC)

Georgia's water shortage

Can you tell me about Georgia’s water shortage in the last few years. What is the basis of Georgia’s argument with Florida, Alabama and Tennessee?--98.88.155.114 (talk) 23:30, 10 October 2013 (UTC)

See Tennessee-Georgia water dispute. Duoduoduo (talk) 01:06, 11 October 2013 (UTC)

October 11

Have people really fused with their own sofas?

It always sounded like an urban legend to me, but it has been reported (a couple of times, that I can recall over the years) in the mainstream media that people have actually sat on their sofas for so long that their flesh had actually grown into and fused with the fabric. Now, it wouldn't be the first time that some random piece of bullshit that circulated on the internet was picked up and reported as news in one of the less reliable newspapers - but seriously, is there even any way that this could even work in reality?

If you were literally never moving from your sofa for 'x' number of years (that always seems to be a common element in these stories) and therefore inevitably pissing and shitting all over yourself where you were, then surely you'd die of an infection or get eaten by bugs long before you could actually grow into your seat - and your home would become so much of a biohazard that the local authorities wouldn't stand for it? --Kurt Shaped Box (talk) 01:12, 11 October 2013 (UTC)

I think more realistically that someone with an open sore, such as a bedsore, could have the clot/discharge stuck to the fabric in a way that made it painful or perhaps even damaging to move him without considering the issue. Wnt (talk) 02:45, 11 October 2013 (UTC)

Googling "skin fused to couch dies" gets you a lot of hits, although some seem to be recycled stories. Google news gets no hits. This detailed story was published in the Mail. Obviously the skin is not going to grow blood vessels into the couch. But a several year old callous would be pretty thick and not easy to remove in place. We're not really in a place to question the sources. μηδείς (talk) 02:56, 11 October 2013 (UTC)

I happened upon Nip/Tuck while channel surfing one night, and saw an episode about a woman who was so impossibly, grossly, disgustingly, insanely obese that she had lost the ability to move and had totally merged with her sofa, where she had remained for some years. Still mentally alert and talking volubly. Still eating (she had a helper) and eliminating waste products (the helper didn't go there). The smell was apparently indescribable. The plastic surgeon's job was to somehow separate her from the sofa. After they achieved this, the house had to be demolished. How true to actual real life this dramatisation was, I cannot say, but I really hope it was uber-exaggerated. -- Jack of Oz ^{[pleasantries]} 03:13, 11 October 2013 (UTC)

Well, so long as we're citing fiction, here's the pièce de résistance of all skin fusing. μηδείς (talk) 03:33, 11 October 2013 (UTC)

This Tetsuo also has fusion problems. Akira's way better though. Effovex (talk) 04:18, 11 October 2013 (UTC)

Why do light rays bend while passing from one medium to another (during refraction)?

Why do light rays bend while passing from one medium to another (during refraction)? Scientist456 (talk) 04:04, 11 October 2013 (UTC)

See Refraction#Explanation. Bubba73 ^{You talkin' to me?} 05:00, 11 October 2013 (UTC)

This article does not explain the bending of light deeply. Scientist456 (talk) 06:16, 11 October 2013 (UTC)

Per Lagrangian mechanics and Hamiltonian mechanics, the path taken by a particle is such that the action (the difference between the particle's kinetic energy and its potential energy, integrated over the path) is stationary (which usually means it's a minimum), i.e. the first-order variation of the action is zero. In layman's terms, you could say the path taken is the most efficient one. The analogy my professor used is this: imagine you're on the beach, and someone is drowning. To get to them, you have to run across the beach for some distance (easy) and swim some distance (harder by a factor n). The extreme paths are one where you minimise the swimming part but have to run a lot, and the one where you minimise the running but have to swim a lot further. As it turns out, the quickest way to get to the drowning person is the path where $\sin \theta _{1}=n\sin \theta _{2}$ -- i.e., it is given by Snell's law. If you recall that the refractive index n is the factor by which light in a medium travels slower than c, that means light bends simply because it's the quickest path. See also: Hamiltonian optics. --Link ^(t•c•m) 09:18, 11 October 2013 (UTC)

Metal used in hard disk drive chassis?

What kind of metal alloy is used in a hard disk drive chassis? any sources? Electron9 (talk) 04:10, 11 October 2013 (UTC)

I'm almost certain it is just aluminum. But I'm not having luck finding a good source. 203.110.235.8 (talk) 05:39, 11 October 2013 (UTC)

I can't see why aluminium would be used. All the HDD's I have examined have a diecast chassis. Diecasting is (at high production volumes) cheap, and produces a strong accurate product with a vety good finish. The HDD's I have examined have the typical light grey finish of diecasting in alloys that are mainly zinc. Not that it is common for lay men to mistake zinc diecastings for aluminium. 121.221.33.239 (talk) 11:12, 11 October 2013 (UTC)