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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 / Re: What would be the radius of a sphere made of many smaller identical spheres?

« on: 22/06/2010 14:38:08 »

Thanks.
What got me started is that I have always disliked the notion of singularities.

And just as a personal mindgame, (if we presume that stringtheory is correct) and a string has a length of 10^-33m (and we presume that they are spheres and not one-dimensional)
And that there are about 1*10^57 H-atoms in an average star.
And since electrons are strings, and there are (just by playing roughly with numbers) three quarks in each proton, that would make (just approx.) 4*10^57 strings in a star.
Then if we crush the star to a neutron star, then to a quark star and finally to a string star (where strings are practically touching one eachother, and they according to theory can't be compressed more -
I don't have a good calculator - then how large would that ball o' strings be?

I guess it would be fairly equal to a black hole, but the singularity has been avoided...

Thanks for your time anyways... []

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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 / Re: Would a huge star be invisible?

« on: 23/10/2009 13:37:58 »

Ah, no. A black hole comes from when the internal pressure of a star due to nuclear reactions looses to gravity, mostly due to that the star is "dying".

What I had in mind was the really really huge stars, when they reach a certain mass, would the wink out of existense and become black holes, with no shrinkage before, even though they are "healthy" burning stars?

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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]

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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?

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Physics, Astronomy & Cosmology / The Big Bang and the "Horizon Problem"

« on: 01/09/2009 13:10:23 »

John, I answered this in another post, but think of the cosmic background radiation as the surface of the big bang. So anywhere you look far enough will show you the marble. Its like an (analogy here) inverted balloon. Our boundary in space is the frontier of the big bang...

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Physics, Astronomy & Cosmology / Is the point of origin still present in the Universe and will we ever find it?

« on: 01/09/2009 13:03:05 »

But we see the surface from the inside. Like we would be inside a balloon, no?

Well, no, the surface would still be a sphere and we are looking "down" on it. Problem is that it's all around - there is no up and down. Like and inverted balloon.

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Physics, Astronomy & Cosmology / Infinite Density Within A Black Hole !..Why does It Not Destroy Itself ?

« on: 01/09/2009 10:41:20 »

If neutron stars can collapse even more to quark-stars, then in theory (and if string theory is correct) quark-stars could collapse to string-stars. Anyone able to do the math here? If you take the size of a string and pack a whole stars' worth all up tightly - how big would it be? I suppose such a star would not be very much different from a black hole, without the singularity-problem...

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Physics, Astronomy & Cosmology / Is the point of origin still present in the Universe and will we ever find it?

« on: 01/09/2009 10:34:17 »

I'd like to think of the cosmic background radiation as the "surface" of the point that banged.
So everywhere we look, in any direction, we see the surface of the big bang...