Severian

It depends on what you mean by 'relativity'. Special relativity (the can't go faster than light stuff) and QM are most definitely not incompatible. General relativity (which is theory of gravity) is not compatible with QM.

I presume you are refering to this paper? http://arxiv.org/abs/hep-ph/0603106 Flavour changing neutral currents have always been know to be a problem for supersymmetry. But they do not rule it out - just restrict the parameter space.

Anyone can call themselves a phenomenologist, but unless they actually make predictions that can be tested in an experiment, they are not.

Quantum mechanics replaces Newtonian mechanics when things get really small. Relativistic mechanics replaces Newtonian mechanics when things get really fast. If you want to do both at once (small things going going really fast) you need a relativistic quantum mechanics. There is nothing wrong with this. In fact, I teach a course called Relativistic quantum mechanics to grad students. Everything works fine. The problem is when you try too describe gravity. General Relativity describes gravity at large distance scales but doesn't work (it just makes wrong predictions) at small distance scales. Attempts to make a quantum version have so far failed because we find infinities crop up all over the place and aren't under control. I would regard this as a technical issue though. I don't think that they are incompatible per se. It is just that we haven't got it working yet.

WIMPS are sometimes called 'cold dark matter'. The other traditional dark matter possibility was 'Hot dark matter' which has indeed now been ruled out. Whether or not something is 'hot' or 'cold' is dependent on whether or not it is in thermal equilibrium with the universe. If a particle is very light, then the temperature of the universe (ie. the average energy of the photons floating about from the CMBR) is high enough that they can be created (usually in matter-antimatter pairs) and annihilated at will. They are in thermal equilibrium. If the particle is very heavy, then it takes so much energy to create them that it basically never happens. So they are out of thermal equilibrium. Experiments like WMAP have now shown that Dark Matter is cold. The most favoured candidate these days is the "neutralino" which is a stable particle of about 100GeV in many supersymmetry scenarios. This can account for dark matter pretty well. We should find out next year when the LHC switches on (assuming the Americans don't blow it up again).

There is no physical law that says you can't bend space-time. Indeed, I do it all the time . I have mass (my wife claims too much) so my body warps space-time around it according to Einstein's GR. The reason why this doesn't help with warp drives (a la Star Trek) is that I can't warp them faster than the speed of light. I have to do something to the space in order to warp it and the distance I can reash after deciding to do it is restricted by the speed of light.

Why not make some predictions first?

I can't even find a way to see how many points I have in the User CP section. Maybe I am being thick though. I am glad that you don't allow bad marks, since I seem to bring out the worst in people... Edit: Though clicking on the scales does tell me.

They had just put them in. This was the first test I think.

No. There are two electrons in the first orbital because they have different spin. They are allowed to occupy exactly the same state as long as they differ in some other quantum number, in this case spin. You could think of spin as being another dimension is you like (since it is another degree of freedom) but you need to keep in mind that it is discrete, and there is no concept of distance (no metric).

I don't think that is true. String Theory is alive and well. There is plenty of research being done on it and I see no move by the funding agencies to curb it. That is the 2001 BUSSTEPP course. I was asked to tutor at that one, but had other commitments, so couldn't go.

Yes, that's right. It is exactly the same idea. So in principle one could imagine compressing a quark, but one has to be careful in defining what we mean. For example, the observation of a quark's position in some sense compresses it because the previously spread out wave collapses to a point (technically this is what is really meant by point particle - it has a position eigenstate). Alternatively one could define the 'size' of a quark as the volume in which its effects are felt 'strongly'. A quark is surrounded by a cloud of gluons which are emitted and reabsorbed. One could imagine changing the siz of this cloud by changing the properties of the interaction: for example, breaking the SU(3) symmetry would make the gluon heavy and restrict its motion, thus making the effective size of the quark smaller. (This may actually happen in certain dense stars.)

To be honest, I think CMS will be rather happy this happened. They are quite a bit behind schedule and this will give them a chance to catch up. CMS's delay may not delay the switch on now. Also, since the explosion was in the tunnel, the work to repair it is decoupled from the work assembling the experiments (the things in the pic bascule showed - that is CMS I think). So it shouldn't delay the switch on much. And Fermilab really need a long time to build luminosity for a Higgs discovery (unless they are very very lucky) so I don't think a few months will give them it. For the official explanation of what happened see: http://user.web.cern.ch/user/QuickLinks/Announcements/2007/LHCInnerTriplet_1.html (Its a bit technical though)

College-wise, I would recommend Churchill. It is the most Science orientated, and will have (I think) the largest proportion of your fellow science students. Also, because it is not as old as te other colleges, it is not so stuffy and is possibly slightly easier to get in (since the arts types like the old pretty colleges).

Why would you assume that? High school is also a UK expression.

The most obvious thing would be to predict the masses of the known particles. Of course, this would really be a 'postdiction' rather than a prediction, but it would be a start. Usually String Theory also contains supersymmetry. So a prediction of the supersymmetry breaking scale would be nice. While we are at it, they could provide a mechanism for supersymmetry breaking which allows us to calculate their masses. This would then be a genuine prediction. Or how about the Higgs boson mass...? The real reason that they don't do this is because they can basically get any answer they please. More recently there has been a suggestion that there are 101500 different string theory vacua, each of which contains different low energy physics. Certain string theorists suggest that the only way of choosing one over the other is to apply the Anthropic Principle. If that is true, then it is not science.

This thread has somehow developed into a parody. The entire point of the original post was that people should stop presenting theories that they have not thought through. New theories need to come with reasons why they are better than the old theories. I don't see that here.

Considering that it has been studied now for about 30 years, one would be forgiven for thinking that we should be beyond the early stages. The real problem with string theory is that it makes no predictions.

If you order a pint, isn't it more natural to give you one pint, rather than 0.88028169014084507042253521126761 pints? That would just be insane!

The matter all around us is make up of up and down quarks and electrons. But the smallest particle (in terms of spacial spread of its wavefunction) is the top quark.

I agree with Mokele that determinism is a red herring. It makes no difference. But before you ask if free-will is compatible with science, you had better define 'free-will'. I generally find that philosophers who believe free-will is compatible with science have a somewhat odd (in my opinion) definition of free-will.

I think you are misunderstanding what is meant by 'non-local'. It doesn't mean that there is information flow from other points. I means that there is information flowing faster than the speed of light. So there needs to be communication between events which are causily disconnected. I don't see that (a priori) in your setup (although I suppose you could make it so just by insisting that the distande between cells is very large).

This is producing a psuedo-random number - it appears random because you are restricting information. If the observer could know everything about the system (including the state of the previoud cells) then you could predict the 'random' number and it would appear deterministic. As such, this is a hidden variable theory and is ruled out by Bell's Inequality (unless you make it non-local).

Gravity is a Force. Acceleration due to gravity is not a force - it is an acceleration. As Cap'n asked, it would be good if you defined 'constant'. Constant with respect to what? I presume you mean mass? If so, then you are correct, the gravitational force on a mass is not a constant with respect to the mass - objects with higher masses get a larger force under gravity. It is the acceleration which is constant. In other words you seem to be confusing the term 'gravitational force' and 'gravitational acceleration' (the latter of which is the 9.81m/s^2 on the surface of the Earth).

Making his 'death squad' completely composed by shi'ites and then allowing them to publicly taunt him seconds before his death seems like a very bad idea. He came over looking rather dignified. On the other hand, it was good that they allowed a small public funeral. That gives some sense of closure rather than martyrdom and conspiracy theory.