What's the scariest theory known to man?

[FuZyOn]

I've been wondering if you guys know some scary theories that you can maybe share. I'm really interested in finding more information about those mind-bending theories.

 

[Rainman]

There's this story about a boy who was reading about stars. The "birth of stars" how they grow into red giants and then die. The little boy upon learning that at some time the sun would be so hot that no life would survive on earth "lost interest in life." What was the point of living the sun would . . .

I think this certainly is one of the most scariest theories. Inhabitants of earth know that eventually the sun which has been sustaining life for so long will destroy it all.