How do I Rotate around a circle

So I was wondering the best way to get a character to go right and left, but the platform is a circle or a half circle so it stays on the platform, but the gravity is toward the center.. I'm not sure how to tackle this at all

I don't understand clearly but as a starting point, if you want to recreate an orbit for an object, you can achieve it with a bullet behavior and a rotate behavior

I think what he wants to create is basically Earth. Having an object that is on a round object and that is able to move around on the round object without falling off, even if the object is upside down. I can visualize what you want to create, and experimented with joints but that did not work well at all.

we started a trend!

http://indiemegabooth.com/project/cosmochoria/

Make Planet Solid

Set Player.Platform.angle of gravity to angle(Player.X,Player.Y,Planet.X,Planet.Y)

Seriously tho don't do it. It's the worst type of game ever.

you mean like this

thanks for the replies people! I'm busy atm but I'll be sure to try it out