Published February 26, 2008
Scientist have nailed down how and when the Earth will cease to exist.
The sun will slowly expand into a red giant, pushing the Earth farther out into space, but not far enough.
Our home planet will be snagged by the sun's outer atmosphere, gradually plunging to its doom inside the fiery stellar furnace.
"The drag caused by this low-density gas is enough to cause the Earth to drift inwards, and finally to be captured and vaporized by the sun," explains astronomer Robert Smith of the University of Sussex in southern England.
Previous projections had all figured that the Earth would avoid falling into the sun, even during our star's red-giant phase.
The good news: This won't happen for another 7.6 billion years.
The bad news: Life on Earth will end long before then.
In fact, we've only got a billion years left before the slowly expanding sun boils off the oceans and reduces our planet to an uninhabitable cinder, says Smith.
That may sound like a long time, but in fact life on Earth's been around a lot longer than that — a total of 3.7 billion years, according to the latest estimates.
For those first three billion years, true, we were nothing but pond scum. Still, the new figures indicate the long story of life on our fair blue-green planet may be entering its last act.
Is there any way our future descendants can save themselves? Why, yes, explains Smith.
He cites a recent study emanating from the University of California, Santa Cruz. It proposes taming an asteroid to swing by the Earth every few thousand years, slowly nudging the Earth into higher solar orbit, enough to outpace the sun's own outward growth.
"This sounds like science fiction," says Smith. "But it seems that the energy requirements are just about possible and the technology could be developed over the next few centuries."