Gravity on a Planet Sized Ring

DaSi14

Hello,

I was wondering what the effect of gravity in a planet sized ring would be. If any of you have played the Halo game series, the ring structure is what I have in mind.

-Would you be able to walk on the inside of the ring, and what forces will or will not permit you to?
-Would you be able to walk on the outside of the ring, and what forces will or will not permit you to?
-And can you explicitly identify where the center of mass and gravity are and how they are involved with the forces above?

My line of reasoning is that center of mass and gravity would be in the center of the ring, which would mean that you are able to walk on the outside of the ring, provided that it rotates fast enough.
However, I'm not sure what would happen if you were to try to walk on the inside of the ring. My intuitions compares it to a centrifuge, where if something was spinning fast enough, the contents on the inside would be pushed against the wall, but it conflicts with how I think about the scenario where I walk on the outside of the ring. I hope this makes sense.

Thanks!

rcgldr

Unlike a hollow sphere where the field is zero inside the sphere, the field inside a thin cylinder or ring is not zero and is strongest near the surface of the cylinder or ring. Previous thread on this:

http://www.physicsforums.com/showthread.php?t=586813

phinds

do a forum search. This topic was beat to death here recently. Probably searching for "ringworld" or "larry niven" will turn it up since they were mentioned incidentally in the thread.

EDIT: I see rcgldr beat me to it.