the force?

[mr. piper]

mr mitchell, has asked about gravity. and it has been explained that it is due to a little understood force between atoms. OK. but what i have just realised that i cannot grasp is by which medium is force of attraction channelled? if you think about conductivity, convection, radiation. they are energy sources travelling via a mass of matter. but what on earth is gravity moving through? it travels in a vacumn with no matter also. it is a source of kinetic energy that apparently does not run out. i know my explanation is a bit muddled, but if someone can decypher it, i would be very grateful!

[slimfandango]

Isn't there a perspective on it which explains it in terms of the lattice of space/time? If you think of the fabric of spacetime as a big rubber sheet, then having an object on the fabric causes a distortion on the fabric. Just like placing a ball bearing on your thin rubber sheet. This causes a distortion in the spacetime fabric (actually propagated in 'waves') which obviously has an effect on the way other objects then behave in their locally modified spacetime. In extreme situations, you have a huge local mass in a neglibible space (eg blackholes) it's like having a very very heavy but small ballbearing on your sheet. It doesn't affect much of the fabric, but it does drag it down an awfully long way, and other objects in the vicinity appear to vanish in its locale.

I love this quote from MIT Professor Alan Guth "Space tells matter how to move. Matter tells space how to curve."

[newtron]

I'm not sure I completely understand your question, but I don't think I would call gravity a force between atoms.  At the atomic scale, gravity is an insignificant force.  Gravity is usually only a significant force between large bodies of matter.  As for the rest of your question, I thnk you are confusing a "force" with the transport of energy or mass.  A force generally causes the attraction or repulsion between two or more objects.  A force may cause the movement of mass or energy, but it is not the movement of mass or energy.  I'm not sure if I am making sense or not.  Does this help?

[jake-the-peg]

Matter moves in a straight line, however matter distorts space. This sounds odd  but think about two ants, one lives on a flat plane and another lives on the inside of a huge sphere - they both want to know if what they live on is "flat" or "curved" so they each draw a huge triangle and measure the angles - one ant find that the internal angles add up to 180 degrees the other finds that it does not - he realises that the space he occupies is curved into a dimension he cannot see.

This is the basic general relativity approach to gravity - we see these effects of curved space time in many ways. The most famous was predicted by Einstein and observed shortly after as light from a star skimmed the sun during a solar eclipse and appeared in the wrong place as the sun's gravity warped space/time.

Most gravitational fields we see are nothing like strong enough for us to see the effects of warped space time in our daily lives and so we find it hard to understand. In astronomy though there are numerous examples of it happening - gravitational lensing is a good one where light from a star gets split by an object and makes one star look like 2 or more

see here: http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html

However I think what you are groping towards is what Einstein called "Ghostly action at a distance" Nobody really like the idea of "force fields" be they electrical, magnetic or gravitational. We now use the concept of "virtual particles" that carry these forces ( the gravitons mentioned elsewhere ). This does circumvent action at a distance as a problem but it's a rather inelegant model substitutng ghostly particles for ghostly action.

[landie]

I guess it must be like the Answerbank, it just keeps drawing you toward it and there's no retro rockets on my PC.