Severian

Old Chinese Proverb says: 'Wise man never chastises fool on first post, especially not with bad spelling'

I would certainly continue to study physics, so the answer to your question is 'yes!'.

I'm sorry, but none of these sentences make any sense. 1. What do you mean by 'an electron doesen't have a dimension'? Are you trying to say that it is a point particle? If so, I agree, but I fail to see the relevence. 2. An electron is a particle so it always acts like one. 3. I have no idea what your last sentence is trying to say!

That doesn't mean that they have to be complex. As Aeschylus said, taking the wavefunction as complex is just a matter of convenience. One could describe your situation equally well using a 2 companent wavefunction A (cos(kx-wt), sin(kx-wt)) with a rule on how to take products, without an 'i' in sight. (This is of course formally identical to using complex numbers....) You see this sort of thing quite often in particle physics. For example a Higgs boson doublet is usually described by a 2d vector (in SU(2) space) where each component is a complex field, but it can equally well be defined as a 4d vector with each component a real field.

1. No. (I presume you mean that the centre of the wheel has the same velocity as the ship?) The wheel has extra kinetic energy from its rotation. 2. No. Why would it? If you crash your car, is the car heavier afterwards?

It all comes down to semantics, just like the question of whether the universe is infinite or not. If you are willing to accept that the space-time is infinite (I would fall into this camp) then there can be no limitation on size because the universe itself is of infinite 'size'.

What has that got to do with whether or not quarks are fundamental?

I have read all three. I'm sorry, but they are possibly the most boring and pretentious SF books I have ever read.

Or to put it another way, we know that momentum is proportional to mass times speed (well velocity...). And speed is measured in metres per second. So momentum must be kilogram x metre / second. Now in relativity, energy and momentum are related in the same way as time and distance. Clearly time and distance are related by a speed (a distance per unit of time), so energy must be momentum times a speed, ie. E = p c. But since momentum is energy times speed we must have E = mc2. [There was some very vigorous hand-waving there. For those who are happier with things a little more complex, the correct mass energy equation is [math]E^2 = m^2 c^4 + p^2 c^2[/math]. When m=0, this reduces to E=pc, while with p=0 it reduces to E=mc2.]

Obviously! But a mass-energy equavilance equation in relativity would have to be of this form since c is the only fundamental constant you have got to play with.

cabriosaurus sounds like a cool open-topped dinosaur.

I think in the UK it is technically illegal for police to break the speed limit, even with their sirens on - the sirens are just supposed to tell traffic to get out of the way. It is obviously not enforced though. You should have asked for the policeman's name, or taken down his reg number and sent in a complaint. Police abuse their powers all the time. They can pull you over for speeding and fine you even if you are not speeding just because they don't like your bumper sticker. It is your word against theirs and their word wins every time.

When it hits an object' date=' light will usually be absorbed by the material but some wavelengths will be reflected (which wavelengths are reflected determines what colour you see the object as). The reflected light will move off (again at the speed of light) until it hits something else, where it is absorbed or reflected. This goes on until the amount of light left is undetectable. The reason that it goes dark 'instantly' when you turn off the light, is that light travels so fast that the time taken for the 'last' photons which leave the light bulb to bounce about the walls being absorbed is so small that you can't distinguish it. Yes, in fact many of the stars you see at night are no longer there. They are so far away that it takes lights years and years to travel to us, and in the mean time the star may have died.

For E=mc2 the 'c' needs to be squared to make the dimensions balance. If you remember from your Newtonian dynamics that kinetic energy is 1/2 m v2 (for non-relativistic objects), since velocity (v) is measured in m s-1 (where here 'm' is metres) then energy must be kg m2s-2. You can see that if we had E=mc, we would not have an energy on the right-hand-side of the equation - c has to be squared. The inverse square law is a little different, since in principle there is somthing to stop us having a 1/r or 1/r3 law (or something completely different). It is interesting to note though that the 1/r2 force produces stable orbits (or to be more exact, orbits which are stable to a small perturbation) - the 1/r, 1/r3 (or any other power) do not, so if gravity had been one of them there would be no formation of planets and no life as we know it.

Encrypted: I think it is much more likely that you are heavily filtering your servers. Take a look at your filter settings. It is possible that they were reset with the patch.

There has to be one somewhere, otherwise we would be unable to have 'energy'. Any statement about energy which science makes is always with reference to another energy, so at least one fundamental energy scale must be in (or be generated by) the final theory.

Your 'model' would imply that there should be no pattern to the universe because a single number in your sequence is not derivable from the others. We know this to be wrong - we can predict physical processes and thus (some of) your numbers. In other words, all of the manifest numbers in the sequence are not independent. It the job of physics to determine what these dependences are and exploit them.

Well, a string theorist would say they are made of strings... For my purposes I think of them as being a representation of a symmetry group (SU(3)).

Why not take the zero at absolute zero, like Kelvin?

Sometimes I worry about you people....

On one level this is a good idea, but on another a really bad one. It is good, because this is exactly what we are doing when we use mathematics to describe physics. We seek to mathemetically describe everything in the universe. It is bad, because your theory would be very non-predictive and inelegant. By describing the universe in this way we gain nothing. What we want to do is have some mathematical laws which tell us how to 'work out' what your numbers should be. In your setup, if you have all the numbers except the last one, you cannot predict what it is - you have to measure it. If you have a law, then you would be able to predict that number, and test it with experiment.

I am more interested in comments on the actual machine itself. Does it look OK (spec-wise)? OS wise, in the past I have always gone dual boot windows/linux, but this time I don't think I will bother with linux, and just put cygwin on top of windows. I can't stand Macs... (it is a funny thing about macs - they are like marmite: you either love them or hate them)

You pretty much have it already. The big question is how we break the electroweak symmetry. Most people seem to be expecting the Higgs boson but it is not clear if it will be the minimal Higgs model or something a little more complicated. The problem is that fermion mass terms in a Lagrangian always look like [math]m \bar \psi_R \psi_L[/math] so they basically mix left (L) and right ® handed particles. But in our very good theory of electroweak interaction, left and right handed fermions are in different representations. This is analagous to the left-handed particle being a vector in SU(2) space while the right handed is a scalar. As you all know (I hope) a scalar times a vector is a vector and not an invariant - it changes with your coordinate system. So the mass term above is not allowed in our theory, at a fundamental level. The only way that it can be put in is to add another SU(2) vector 'H' to make an invariant: [math]Y \bar \psi_R H \psi_L[/math]. Then the (dot) product of two vectors is a scalar, times a scalar is another scalar and therefore the term is SU(2) symmetric and allowed (Y is just a coupling constant). Then one has to imagine that 'H' does not oscillate about zero but oscillates about a finite value 'v'. Then the dynamics of H 'breaks the SU(2) symmetry': we shift H to its minimum [math]H \to H_0 + v[/math] and we are left with [math]Y v \bar \psi_R \psi_L+\bar \psi_R H_0 \psi_L[/math]. Now H0 oscillates around zero as usual and we have given a mass to the fermion of [math]m=Y v[/math]. As you probably realised, H is the 'Higgs boson'. The difficulty is that this is pretty much the only way to do this. Any theory of electroweak symmetry breaking has to provide a fermion mass, so any theory is going to have to provide an SU(2) vector to balance the mass term out. It may be that the new vector is not fundamental, but they all have it. So in technicolor models, for example, the vector is a techniquark bound state. Therefore everyone with any sense expects to see a 'Higgs boson like particle' at the LHC. The real question will be: what is it really? That will take a few years to sort out I imagine. Of course, if they find supersymmetry (susy), the Higgs mechanism for breaking electroweak is pretty much a given since it is so intimately linked to the Higgs mechanism. There are prently of different variations of Higgs mechanism to sort out then though. If susy is there it will be really easy to see. The challenge then is to measure all the masses and couplings of the new particles and try to figure out some mechanism for breaking supersymmetry. This would most likely provide a GUT model too. If susy is not there, the Higgs mechanism becomes a little bit uncomfortable. Quantum corrections to the Higgs boson mass become very large and it is hard to get a physically reasonable theory. In that case, I would imagine there would be some other mechanism like Strongly Interacting Ws or Large Extra Dimensions. The latter would be nice because it might mean that we could probe gravity at the LHC too....