There are several methods.
Liquid nitrogen gets you sort of cold.
Liquid helium gets you down to 4.2K.
You can use a dilution refrigerator to get to tens of milli-Kelvin. It works by immersing your sample in a mixture of liquid He3 and He4. You then pump really hard on the vacuum above...
I go to UBC and am in the physics/astro department. There are a lot of very bright faculty here. The main focus in physics is probably condensed matter theory, mainly superconductivity with some quantum information thrown in as well. Of course there are researchers in almost every field though...
Not very many people do astronomy anymore. Historically, astronomy was more charting stars and cataloging magnitudes etc. There's not too much of that going on anymore. Most "astronomers" are really astrophysicists. Astrophysics is basically physics that you can't do on Earth :)
Balance a book on your finger. The centre of mass is a point in the book just above your finger. It's the point where the mass of the book seems to be located.
Now all binary systems have the bodies orbitting the common centre of mass. In the limit that one body is large (sun) and the other...
The thing with this is the method used has a huge effect on the sattelites' positions due just to the fact that the Earth isn't a sphere. They're looking for a very small deviation in the sattelites' orbits when they have already been perturbed greatly by other factors. The accuracy of their...
Because dark matter is weakly interacting with other dark matter. It doesn't act like normal matter.
Take two large masses of normal matter, separate them, and let them go. They will gravitate towards one another and hit, eventually forming a large single mass.
Take two large masses of...
From what I can tell so far, schools look good sure... Princeton, CalTech, etc, but your degree will mean much more to you if you get with a good supervisor who is interested in the same things you are. Doing cosmology at Princeton might look good, but if you really want to do micro black holes...
I'm also interested in this. I'm Canadian, and will soon have a B.Sc in Astronomy (with a heavy emphasis on physics) from a Canadian university. I'm considering a lot of options, and one of them is Germany/Denmark/Sweden.
Nothing will happen. The force of gravity will be constant until you start getting into relativisitic velocities. I'm assuming a universe with nothing in it but an infinite massive plane and your box. The force of gravity will just be constant. You can push the box as fast as you want up to...
That's a great question and one I'm going to ask my GR prof when I see her this week :)
Photons slow down in a medium because of how they interact with the electrons (mostly) in the atoms. The photon group velocity is still c through the medium, but the phase velocity slows down (IIRC)...
Most people don't work in the observatory. You get a degree and get a research grant. You then write a proposal to a committee asking for research time on a telescope and if they deem you worthy, you get some time. CERN is basically the same thing.
Of course there are techs and engineers at...
I've talked with a dean at Princeton about admissions into grad school and he said that all they care about for marks is to see that you've taken a rigorous course load and have done well. A few bad grades here and there aren't a big deal. That counts for relatively little though. Almost all of...