Severian

The current administration is cutting fundamental science funding and instead channeling that funding into the space programme.

All we Severians have found human cloning very useful. It certainly cuts down on our teaching load.

I regard myself as quite intelligent, and would regard myself as anti-war (though I am not a member of the US electorate). However, I would probably agree with McCain's stance on Iraq, because as well as being anti-war, I am also anti-isolationist. The US (and allies) invaded Iraq, which was a bad call in my opinion, but now they are there they need to do everything in their power to ensure a strong democratic government that can survive when they leave. The worst thing they can do is pull out now, because Iraq will go down(up?) in flames. And since I am anti-war, I don't want another war erupting in the middle east.

Presumably the military will soon be adding wind turbines to all battleships to make them invisble to radar?

To be fair, if the military want special treatment it should be them who provides the evidence. And "no we can't show you the evidence for reasons of national security" just isn't good enough. The same applies to the airlines and hospitals - if they want to ban mobile phones because they interfere with equipment, where is their evidence?

The LHC is what I do for a living by the way.

I am awesomely intelligent, but the cool thing about me is that I am a nice guy with it. Not arrogant at all, and very modest and unassuming.

I have a blu-ray on my pc, but I don't think I will bother for the TV. Even though I have a 42" plasma, I am not sure I could really tell the difference.

But that is only because it is something the general public can understand, or at least that is the perception from the media. No-one who actually does LHC physics really thinks their motivation is undeerstanding the Big Bang. Actually, I think a lot of physicists in the UK were rather ctritical of the programme because it gave far too much emphasis on astronomy and not enough on particle physics. That would be true if our governments would give us support rather than trying to undermine our work at every opportunity. See: http://www.scienceforums.net/forum/showthread.php?t=30198

You could divide your symmetry breaking into explicit and spontaneous symmetry breaking. Then you have http://en.wikipedia.org/wiki/Spontaneous_symmetry_breaking to fall back on two. Notice that there are lots of different sponstaneous symmetry breaking phenomena in physics (look at 'example' in the link and the pages it links to) so you could describe each of these in turn, emphasising the different features. One of the most interesting examples, in my biased view is electroweak symmetry breaking and the Higgs mechanism: http://en.wikipedia.org/wiki/Electroweak_symmetry_breaking

The idea of the two arms is that they change relative lengths compared to one another. With no wave, the arms are the same length so the two laser beams remain in phase. When the wave passes through the arms are of a different length so the waves become out of phase. When you put them back together you will get an interference effect which is very very sensitive to the relative lengths.

The physics teachers thing is a bit stupid too. The reason there are no physics teachers is because the government insist that physics should be grouped together with chemistry and biology (as 'science'), and therefore physics teachers have to teach low level chemistry and biology classes. On the other hand they are not allowed to teach maths, which is under a different heading. So most prospective physics teachers will choose to teach maths instead rather than be forced to teach all of science.

You also need two arms for an interferometer to work (since you are actually interfering the two laser beams). So unless you can come up with a second moon....

Here is the latest news story to emerge. The UK will be pulling out of Gemini, leaving us with no top-rank telescopes in the northern hemisphere. It looks like UK Astronomy will be irreperably damaged. http://news.bbc.co.uk/1/hi/sci/tech/7210342.stm In response, MIST has made some "resolutions": http://www.mist.ac.uk/mistres.html

You would need to decide what you were protecting from first. For example, a magnetic field wouldn't stop a ceramic shell.

Hmm... I don't like Rae's book at all (although it is sitting on my shelf). This is mainly because I think it makes quantum mechanics seem too complicated. In reality, QM is pretty simple if you stop thinking of things as particles and think of everything as a wave instead. Particles are really just very tightly focused wave-packets.

It is a sad statement about modern politics that we are 29,000 signatures behind the petition to make Jeremy Clarkson Prime Minister.

The conservation of angular momentum is a direct consequence of the laws of nature being rotationally invariant. Now, when Dirac invented the Dirac equation to describe electrons, to his surprise he showed that it didn't conserve angular momentum unless the electrons themselves had an additional source of "intrinsic" angular momentum. Since the laws of physics are obviously rotationally invariant, and thus angular momentum is conserved, the electrons must have this extra angular momentum, called 'spin'.

In principle, there is an interaction which can turn an electron and an up quark into a neutrino and a down quark. This interaction could in principle turn an electron and proton into a neutron and neutrino, and this is what happens in neutron stars. But there are two difficulties with the interaction. Firstly, it is a weak interaction, so very short range. Secondly the neutrino and down quark combined are heavier than the up quark and electron, so you need to put quite a bit of energy in to make up the difference (E=mc2). But if you push the electron really close to the proton (like in the formation of a neutron star), eventually they are close enough together to overcome the range problem and the energy of the electromagnetic interaction (or in other words, the energy required to push them so close) is enough to make up the mass difference, and whoosh, they convert to neutron and neutrino (and since both of these are neutral the electromagnetic repulsion, and its associated energy, is no longer there). Incidentally, it is a good job that there are these two difficulties with the interaction, otherwise you would have rapid proton decay, which could be rather catastrophic to the entire universe.

I said true. But if you had phrased the title of the thread as "The universe could be finite in spatial volume and matter content" I would also have said true.

They used to throw salt on the roads here to stop ice forming. But there were lots of environmental concerns about adding salt to the soil, so they stopped the practice.

I must admit, I don't understand that. I can see the point of penalising them for polling too early, but you would think that Michiganites(?) would rebel given that New Hampshire wasn't penalised at all. And basically the only reason New Hampshire wasn't penalised was an appeal to tradition. Seems a bit unfair to me.

I think the word 'combine' is just fine in this context. Two photons annihilate to an electron-positron pair via a t-channel electron exchange. It is this diagram rotated by 90 degrees anticlockwise http://upload.wikimedia.org/wikipedia/en/5/59/ComptonScattering-s.svg You can't do it with one photon since it wouldn't conserve energy.

Sorry, I am getting my terms mixed up. W isn't the work done - it is the disapative force. The integral over it is the work done.

That is not how you should be doing it. You cannot write a disapative force in terms of a potential - in fact, iirc that is the definition of a conservative force, that it can be written as a potential. The Euler-Lagrange equations as [math]\frac{d}{dt} \left( \frac{\partial {\cal L}}{\partial \dot{\theta}} \right) - \frac{\partial {\cal L}}{\partial \theta} = 0[/math] are not valid for your system. Instead you need to write [math]\frac{d}{dt} \left( \frac{\partial {\cal L}}{\partial \dot{\theta}} \right) - \frac{\partial {\cal L}}{\partial \theta} = W[/math] where [math]W[/math] is the work done by the disapative force, in your case [math]W=-A \dot{\theta}[/math], where [math]A[/math] is a positive constant.