万花筒 2009-06-14&06-15 地球将如何毁灭？（在线收听）

French researchers are predicting doom for Planet Earth.

They believe neighboring planets could stray out of orbit and collide with the Earth billions of years from now. The BBC's David Shukman explains their theory.

A view of Earth from orbit and a strange question "how long would it last?" Scientists have long known about the violent events that formed solar system.   But now they have studied the movements of our nearest neighbors.  Mars, they reckon, could drift uncomfortably close or do this.  If we are really unlucky, it could actually collide with us. Literally, the end of the world.

"So what exactly is this research saying? Well,one key thing that the orbits of the planets which look steady aren’t all that regular. Over the years, some start to move pretty wildly. These are the projected tracks. And the odds are that will lead to a very big collision in about three billion years’ time."

With that long to go, the researcher involved doesn’t look too worried. But amid the old instruments of the observatory in Paris where he works, he has a doom-laden message about the future and what a collision would eventually mean.

"It would be totally devastating because the relative speed is very high. They go at ten kilometers per second. So it’s ten times the velocity of a bullet .   And the impact is enormous. Everything will be destroyed on Earth."

Until now, the worry has been one of these, an asteroid. It's thought one of them finished off the dinosaurs. Think what a planet would do. But this is just a computer graphic. The calculations may be wrong. The only people who need to react to this research are film producers in Hollywood. David Shukman, BBC News.

We are gonna have to say those might be the most menacing graphics we’d ever used. Watching things collide on the planet that I live on? Can’t say I like that very much.

It’s almost Biblical-financial meltdown, swine flu and now this. What’s next, the rain of frogs?

But still watch the news. We want you to keep watching.

Yeah.  Please do. You'll still be here as long as that doesn't happen.

Yeah.