John Cuthber

If you look at the earth's atmosphere there are lots of things that are a long way from equilibrium. The presence of oxygen, nitrogen and water (rather than dilute nitric acid) is one of the reall biggies. Any of the 3 components on their own doesn't tell you a lot, but the mixture certainly indicates something very odd is happening. If someone analyses the atmosphere of a distant planet and tells me that there is, for example, oxygen and methane or oxygen nitrogen and water present they have got more than half way to convincing me that there's life there but just finding methane doesn't prove anything.

If the person running the sacanner sees something on the screen that the Xrays don't get through he may chose to up the energy and exposure until he gets an image. Is this what you want to happen to your film?

You also need to look at the journal in which the article is published. http://en.wikipedia.org/wiki/Sokal_Affair

Re "I discovered that the moving photons produce gravitation. " What experimental evidence do you have for this assertion?

Is this any help? http://en.wikipedia.org/wiki/Space_blanket

AN is a perfectly adequate explosive at least in the presence of impurities. http://en.wikipedia.org/wiki/AZF However it is normally difficult to initiate an explosion in it.

Given the current definition of the meter, the speed of light (in m/s) is a constant (in vacuo) whether anyone like it or not.

That was going so well until you forgot the capital G in "German". Please stop feeling a little smug. The use of u rather than µ dates from the times when reports were typewritten and the Greek characters were not an option. The u was put in as a place marker and the tail added to it later with a pen before the report was photocopied or whatever.

"On Earth, Methane is primarily produced by Biological processes*. So strong is that link, that Methane in Mars' atmosphere strongly suggests the presence of sub-surface Methanogen micro-organisms:" On Earth, iron is primarily produced by blast furnaces. So strong is that link, that iron in meteorites strongly suggests the presence of blast furnaces in space. Discuss.

There seem to be any number of ideas about am. nitrate. The stuff is slightly hygroscopic. It's a useful (and fairly cheap) nitrogen source so it gts used as a fertiliser. Unfortunately, as a powder, it gets damp then forms into solid lumps that are difficult to handle. So someone came up with the idea of coating prilled AN with wax. The wax stops the grains sticking together. Even more unfortunately this was found to accidentally generate a fairly good explosive (albeit, one that's quite hard to detonate). Further refinements of this gave rise to the low density prill based ANFO used as an explosive. Since the decomposition of AN is exothermic, it's easy to see how the reaction could get out of control. In particyular, the reaction is catalysed by impurities so, as the AN decomposes and leaves the tube (as H2O/N2O) any impurities left behind get more amd more concentrated. This would increase the effective reaction rate. That raises the temperature. I guess you can all see the punchline now.

Sorry, I hadn't realised that was ambiguous. I meant a painful death that was slightly more drawn out.

OK, I'll bite. What compounds generally present in the body will react with hydrogen at any meaningful rate under physiologically relevant conditions? (and I mean real chemical reaction, rather than hanging out with a really unselective receptor; xenon can do that) BTW, you had better tell these people about it. http://en.wikipedia.org/wiki/Hydrox_(breathing_gas) Breathing hydrogen (or He for that matter) is a fairly dumb thing to do. On the other hand saying things like "it will kill you instantly" is irresponsible too; did you ever hear of the boy who cried wolf?

If Moore's law continues for 2^64 minutes how much better will our computers be?

I still think this is a more elegant solution. http://en.wikipedia.org/wiki/Electric_eel#Physiology

Any bets on how long it will take to boot up?

Margel, don't just read that policy; read the dates too. I wonder if the guy who asked the question a couple of years ago is still studying chemistry.

You would have a slightly more drawn out painful death.

I will go on the record to say that an exabyte of ram will soon be the minimum required to install the new version of windows.

"Is the heat of vaporization constant 540Kcal/litre also under vacuum ? " I'm not sure but I don't think the latent heat changes much with pressure. "How do I calculate the amount of heat the 1 litre will yield at a given starting temperature?;" from the heat capacity of water and the temperature drop. Once you get a little bit below 0C the water will freeze and that won't help. If the water started at 100C it could drop its temperature by 100C before it froze. The heat capacity of water is pretty close to 1 cal/g/c (it's exactly 1 at 15C by definition). 1 Kg of water cooling by 100C will liberate 100KJ of heat. Clearly that's not enough to evaporate it because it's less than the 540KJ/litre letent heat. You would need to superheat the water to something like 540C in order to have it all flash to steam when exposed to a vacuum. (actually things get more complicated; you can't assume that the latent heat and heat capacity are constant over that big range also the stuff would turn into a supercritical fluid and the question of evaporation gets poorly defined, but the problem is still there.) Even with a vacuum, you still need to supply extra heat to evaporate off the water.

There's a hint written just below here

The helium supply in our lab has a declared purity of 99.99% What difference will the extra 0.01% make? For a person at rest the blood circulation time is about a minute. There's no way that anything in the lungs could remove the oxygen in the blood faster than that because that's how long it would take for the blood to get back to the lungs. So, if you filled your lungs (which is very difficult) with pure helium (which you can't get) and waited for at least a minute the oxygen in the blood would come to eqm with the gas mixture in the lungs. The usual ballpark figure given for the brain (the most sensitive organ) to fail due to lack of oxygen is about 3 minutes so it's not unreasonable to supose that the body has reserves that are equivalent to about 3 minutes use (feel free to come up with a better estimate). Normal breathing rates are of the order of 5 to 10 litres/ minute so, you have the equivalent of something like 15 to 30 litres of air stored in your body. The total volume of the lungs is 1 or 2 litres so, when this gas all gets mixed most of it is air and only about 1/7 of it is helium. The maths, as well as plenty of experimental evidence, show that you really can breathe a lungfull of He and survive.

Whatever size word you use, with n lines you can address 2^n of them (at a time). If the 64 bit system that the OP asks about is 64 bit (ie uses 8 byte words) then the capacity given is wrong, it should be 8 times more.

With one bit I can adress two locations, one called "0" and the other called "1". With another bit I can addres 4 places "00", "01", "01" and "11" Another bit lets me put a "0 or "1" on the start of those 4 names so I get twice as many adresses again. Each bit of address length doubles the number of possible combinations and, therefore, the size of the memory that can be addressed. The total number of possiblilities is 2^n for n bits so an n bit adress can uniquely identify 2^n possible adresses. Each one hold one byte so it can address 2^n bytes. That's not an arbitrary convention on the maker's part; its a limitation of the bus design. You could do more with a different number base but virtually nobody does that .

The rate at which the water evaporates is largely determined by how fast heat is supplied to it. If you put some water in a Dewar vessel (which is very well insulated) and connected it to a vacuum pump the water would initially boil and get colder, soon it would freeze. The ice would then sublime and get colder still. Eventually the ice would reach a temperature so low that the vapour pressure would be the same as the limit of the pump's performance and the system would just sit there; very cold and not evaporating.

Last time I checked only the UK had the penny as a unit of currency. The US has cents which they coloquially call pennies but it doesn't say that on them. I think we used to have Taco Bell, but they disapeared. At some stage we could have done the experiment, but not any more. There's probably a facebook group devoted to getting them back. Incidentally copper is a noble metal- it only reacts with oxidising acids. Copper oxide will react with any reasonably strong acid to form a salt. That's why you can clean the copper oxide of coins etc. with dilute acid.