h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Wow, you don't want much do you!

I'll keep your questions in mind for various articles, although I doublt I'm qualified to answer all of them.

All I want is a room somewhere. The cold night air's fine as it's better than sitting feeling stuffy. The chair can be any size, though if it sits before a large TV, PC running Descent or decent-quality stereo so much the better. Two rooms might be better, so that any cooking I do won't cause my clothing to smell of beef until it's next washed.

I wish the answers to these questions to be stated merely to get physicists to stop talking from a portion of their body that they cannot identify from their elbow. One of the reasons why I feel that continuing my studies into research, even in Biology, is that any work would not be accessible to most of the people of the world, something all work should do if it wishes to be justified in a world where every effort needs to be made to prevent a population crash, mass revolution or other catastrophe.

H is perpendicular to E because that is the way it comes out in the algebra = uses a cross-product. A spiral is a combination of two perpendicular waves with a phase difference of 90 degrees - hence circularly polarised light. You can resolve any wave form into a series of waves with different intensities and phase differences, so the perpendicular E-H combination is the building block from which one synthesises any other waveform.

Bugger! Missed it. And I could have told you all about electrons in magnetic fields too. Well, provided they were acting in an at least semi-classical way. Ah well. If you need any information on such things, or indeed Gravitational Waves (I have a friend down the pub who is helping build a detector) then I shall be glad to help.

You have a point...I know of many physicists who try very hard to make the subject accessible by writting books, etc. However, I'm not sure that I agree that if something is not generally accessible it is of no use...most people have no understanding of how their car/VCR/etc. works, but it doesn't stop the item from being useful. There are, of course, dangers associated with the general public not understanding (they can have highly dangerous things foisted on them, etc.), but the knowledge we have today is so vast that no-one can understand everything. Really, it behoves those who do understand to consider the public good and act as watchdogs - of course, having bunches of scientists bickering in public doesn't help with funding, however neccessary the arguement is.

There are, however, certain areas of science that do need explained. i.e. food hygiene, where an ex-flatmate of mine has worked for a while, and therefore finds most of the stuff said on television blatantly ridiculous. Also, this liquid nitrogen spill that happened in Edinburgh. I don't know the details, but recken (sp?) the papers branding it a "Death Gas" can't really help.

By the time we understand how the universe was formed and what it is for we will no longer be here.
As for adverts, I learnt what pro-vitamin B5 really does (I've forgotten since, but it's something to do with some sort of cellular metabolic process and nowt to do with hair) and found out that Taurine (of red bull fame) really does do things to the brain and the sex drive. I find that I get moaned at by my girlfriend whenever I announce that something said on the television is utter crap, simply because "they wouldn't say it if it wasn't true and anyway they're trained scientists and must know what they're talking about". You can even see the reason in isolated French farmers feeding cows on human waste - we can't digest cellulose (and it thus forms a large volume of our stools) whilst cows can. Providing all the beasties are eliminated to not upset the balance of the cow's enteric bacteria and to prevent super-beasties breeding therein it seems quite sensible. There is merit in letting the public know of things that are going on but pigeon-science seems to do more harm than good - there's far more to nervous tissue in which the BSE prions might be than the spinal cord; meat is muscle and muscle is innervated.
When was the liquid nitrogen spill? I daresay it froze the arses off all the bacteria, insects, plants and suchlike that it encountered but it's hardly dangerous, seeing as we can inhale upwards of 16 litres per minute of it when exercising. They should concentrate more on the emissions of the tanker that was carrying it.

There certainly is a lot of rubbish spoken (especially in advertising) that is supposed to be 'science fact'. One of the problems is is that the general public do not realise that there is very little scientific FACT - science simply says that, from what we have so far observered, we think things are like this, but one day we may have to change our minds. In some branches of science, the likelyhoods are very small and/or anything that does come along will not make any difference to everyday life (e.g. Newtonian Physics is fine for most things on Earth and Relativity can often be ignored because its corrections are too small to notice). However, in other branches, we are meerly children...

Re the liquid nitrogen spill...I don't know anything about the event but I can imagine that a large spill could be a bit of a problem. There is lots of nitrogen in our atmosphere and it is generally inoccuous. I deal with liquid nitrogen quite often as we use it to cool vacuum pumps...the only thing to ensure is that you don't accidentally pour it all over yourself.

The problem, I suspect, with spilling lots of liquid nitrogen is that it will rapidly boil off in large volumes. Being quite cool, the gas will be denser than the air around it (you get great "clouds" of the stuff rolling along the ground) and will displace that air and, of course, the oxygen in it. Thus, if you find yourself in the middle of an enormous cloud, you will be somewhat short of oxygen with which to respire.

The liquid nitrogen thing: Happened in a hospital in Edinburgh, one guy died, four were injured. News reports claimed it was a spill, but one guy was treated for cuts. Sounds like a dewar might have exploded to me. The thing that annoyed me was the tabloids calling it a Deadly gas when it makes up (approx.) 80% of the atmosphere. I also use it all the time and thus was also annoyed that the blokey in charge had to rush to assure people that no Nitrogen had made it into the atmosphere!

If you are interested, the story is here http://news.bbc.co.uk/hi/english/uk/scotland/newsid_484000/484813.stm

Sensationalism in the name of selling papers strikes again!

Too true. Very sad that someone died, but this sort of mindless reporting does not help anyone. Condolences to his family - sounds like a Dewar breaking.

What has just dawned on me, and I don't think, but don't have the time to check, that no-one has mentioned is, EVERYTHING is magnetic, too some degree. It is all to do with the individual magnetic field of the atoms lining up to create a large one you can measure. This is affected by a large number of factors, including temperature and how the substance is made up. That is where it gets complex. Iron is just more overtly magnetic.

Yes true - diamagnetic, paramagnetic, ferromagnetic, ferrimagnetic, antiferromagnetic. There is a different mechanism however between dia- and paramagnetism (no electron spin involved - it's just due to an applied electric field) and ferro/ferri magnetism, where the electron spin is important and the effect is much greater. 'Permanent' magnetism is ferro/ferri magnetic and exists in the absence of an electric field, hence the name, and only a few transition elements (Fe, Cr, Mn) exhibit it.

Perhaps we should instead concentrate on the question "Whay are magnets ironic?"

first. i bet you my last dollar that magnets are going to be the big think of the next millenium.

just for those of us that are laymen.
if the earth creates this bowl in space, you guys say that the earth is between you and this bowl right?

well what happens if you are on the bottom of the planet, because you dont fall up.
or is there several of these bowls all exactly opposite each other, that sounds like a lot of dimensions?