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Physics, Astronomy & Cosmology / Can we "see" a proton?

« on: 17/01/2011 10:56:45 »

Hey.
A double question...

From what I understand, we "see" something because light, or a photon, hits an electron in an object, thus exciting it to a higher orbit, and when the electron "falls down" it gives away a photon that we then interpret.
What if we shoot photons at a single proton, or neutron? Will they bounce off of it, or what happens then?

Secondly, what if you shoot a single photon at, for example, an uranium atom that has lots of electrons and lots of shells. What if the photon (being so fast) does not excite the electron in the outmost shell, but hits one "further in". Would that turn the photon into some sort of pinball frenzy in there, or is it always the outmost electron that is affected. If so, why?

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General Science / What would be the radius of a sphere made of many smaller identical spheres?

« on: 22/06/2010 08:51:48 »

Hey,

If i have a sphere of r=1, and take 1000 of those and arrange them into a larger sphere (for example if i let those go in an empty region of space and let gravity do the work) - what will the radius be of the larger sphere?

//Thanks

[MOD EDIT - PLEASE ENSURE THAT POST TITLES ARE FORMATTED AS QUESTIONS IN FUTURE. THANKS. CHRIS]

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Physics, Astronomy & Cosmology / Would a huge star be invisible?

« on: 22/10/2009 15:08:24 »

When an object increases in mass, the grav. field grows. How big would a star have to be for its escape velocity to exeed the speed of light? If these huge stars (I presume) exists, then we wouldn't be able to see them... no?

[MOD EDIT - PLEASE ENSURE THAT YOU PHRASE YOUR THREAD TITLES AS QUESTIONS, IN LINE WITH FORUM POLICY; THANKS, CHRIS]

4

Science Experiments / Acceleration and water

« on: 21/09/2009 15:09:38 »

I read somewhere in a science-fiction book that in order to withstand huge acceleration (in an interstellar craft) you would probably have to be floating in a liquid of sorts, as the liquid is hard to compress, you would feel less stress as the craft accelerated.
The question is then : If you here on earth are swimming in a huge fishtank that is suspended from a crane, and then the tank is dropped from a distance down into any body of water, would you feel the drop? or the impact?
I would want to say yes, but i'm not sure.
What do you think?