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swansont

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Everything posted by swansont

  1. The latent heat is how much energy you need to add, per unit mass, to melt the ice at 0 C. The specific heat is the energy required, per unit mass, to change the temperature. You know the final mass and temperature and that energy is conserved.
  2. I think perhaps you meant 30,000 km/s, which is approximately light speed. You couldn't actually travel that fast, but at whatever speed you actually were going, light would still travel at c relative to you - you can't tell that if you are moving or if everything around you is moving, if you're in an inertial frame of reference. As far as you can tell, you are stationary, so there's no problem there. As YT said, the mirror isn't moving relative to you, so that's not an issue. The strange stuff happens for other inertial observers. They see you movong fast, and they also see light travelling at c, but they will see the frequency of that light change, as well as lengths contracted and time running slow for you. A lot of strange things become apparent once you realize that c is invariant.
  3. I do physics research, and my job requires a PhD, simply because you can't currently get the relevant exerience anywhere else. But lots of research establishments have internships; it depends on the specific job. I know of programs that take in high school students and others that take college students to do work for a semester or for the summer. College internships often don't pay much (or anything) but you get course credit for it.
  4. I don't think you'd get an explosion, per se, for a gas, because the relevant effect is diffusion. Any given molecule doesn't "know" if it's in a gas at atmosphere or in a vacuum. It just travels and maybe undergoes a collision after a bit. The trend is to diffuse from high density to low density - the effect is nowhere near instantaneous. When you vent a vacuum system to atmosphere it takes a while, depending on the size of the hole you've made, for the system to equilibrate.
  5. Chances are the gammas would ionize electrons rather than excite the nuclei, though the nucleus will recoil slightly when the atom is ionized. The electrons then cause secondary ionizations and emit Bremsstrahlung as they scatter, all the while any given electron has less and less energy. But you're right in that it all eventually shows up as an increase in temperature. Plus, lead attenuates according to an exponential; you wouldn't shield all of the original radiation. Some would escape.
  6. Deuterium + Deuterium = tritium + proton + 4 Million electron-Volts
  7. No, if you were exposed to vacuum for a length of time, you would most decidedly NOT explode. Some tissue damage might occur from your compulsion to exhale, but that's not the same thing. You's asphyxiate after a short while. Your body is mostly water, the coefficient of expansion for water is really, really small, and it's only a 1 atm difference in pressure. Diving to 30 ft doesn't crush you for similar reasons.
  8. Holding your breath would be tough, and possibly cause damage. I don't think it would be particularly bright - not much different than a moonless night away from light pollution here on earth.
  9. I'm Tom, and I'm a geek. I get to play with really expensive toys that someone else pays for, i.e. I'm an experimental physicist.
  10. Or you could store that info in an emulsion or charge-coupled device, and print the likeness out on a sheet of paper. Nah, it'd never sell.
  11. Laser light isn't parallel. It converges and diverges, depending on the optics involved. It can be made to diverge slowly, i.e. over a fairly long distance. But it's never parallel.
  12. Yes, that's the EIT stuff I mentioned earlier. It's a vapor - gas, not a solid, certainly not glass - and be sure to note that "In each experiment, the information about the light pulse can be stored for about a thousandth of a second before it starts to decay."
  13. Virtual photons are the carriers of the force, and used in Feynman diagrams
  14. Yes. General relativity says that gravity is a geometric effect on space rather than a product of having mass.
  15. You have to actually know the laws and variables. There are systems that are chaotic, and so very sensitive on initial conditions and correctness of the model. Processing power doesn't really extend the capability solve those equations, because a wrong answer diverges rapidly as you iterate or add terms to the model. Everybody thought that bigger and better computers would help us predict the weather, but it hasn't really - I think better observations and better data have done more than more computer power.
  16. I'd like to see a reference for the "slow glass." I know that people have slowed or "trapped" light using coherence properties of vapors, and electromagnetically induced transparency. But 1 cm/year in a solid? I need a cite. But, in addition to there being no perfect reflectors, it's also true that nothing is 100% transparent - light will get absorbed.
  17. There is no such thing as a perfect reflector, so any pulse will quickly dissipate. Even .999n goes to zero when n=ct/L gets large. (L is the size of the device, c is the speed of light) In one dimension, using two mirrors (typically confocal), you can do this - if you keep adding light the power grows much higher than in the incident beem. It's called a "power buildup cavity."
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