Astronomers at Britain's University of Sussex have calculated that the earth could be vaporized by the sun unless the planet's orbit can be changed.

Apparently, the sun is expanding and - because its outer atmosphere extends a long way - earth would start orbiting in that low-density outer layer, researchers theorize. Drag caused by the sun's low-density gas would then trap the earth and vaporize it, the scientist believe.

A team at the University of California at Santa Cruz has come up with a plan to alter the earth's orbit, however.

The team says if a large asteroid passed near the earth, the gravitational effects of the mass could be used to "nudge" earth's orbit away from the sun.

If that fails, not to despair. Humans have over seven billion years to come up with a solution. Scientists figure that's how long it will be before the sun warmly welcomes the earth into its world.