It's kinda scary.
In the movie the belt got very close to earth and earth got very much hotter and at some point it would burn up...I think at 175 degrees F? In the movie.
Now in reality could they get hotter and closer to the planet? At what point do things begin to melt? Boiling water gets up to 212 F right? AT what point would water get too hot for humans to endure? At what temperature would human life cease to exist?