This is a recurring dream I have - I've been having it since August 2008 I think, and it appears randomly during my REM phase - there are two versions of it.
The dream starts with me - I'm fluctuating in Space. No Astronaut suit, nothing. I'm in common clothes. In front of me, very far, Earth, the Sun, the Solar System y'now. Everything. While I'm looking around to try to know what's going on, I hear a horrible woman scream. This scream is not a normal scream, it's... unnatural, in the dream I had the feel that a woman couldn't do that. Then, right next to me, flashes a ginormous Meteor that is fastly and inesorably going to crash on Earth. The thing is so enormous that right before it collides with Earth, I could see it was at least half of it. When it collides, Earth explodes on impact and I'm overwhelmed.
I awake.
As said, there's another version, in which I hear the scream not before the Meteor, but when Earth explodes.
Jee, I always awake full o' sweat when I dream this.