What Will Happen to Earth When the Sun Dies?

The sun is 93 million miles (149.6 million km) away from Earth. View full size image

The sun is dying, and when it finally kicks, it will take Earth with it. We probably won't be around to see it, though: The sun's death throes will have taken out life here well before it swallows the planet.

The good news? We've got a very, very long time before any of this happens.

A panel of scientists at the annual meeting of the American Association for the Advancement of Science described the situation in 2000, and it still holds true. Astronomers generally agree that the sun will burn up its hydrogen fuel supply sometime in the next 5 billion to 7 billion years. As it does, gravity will force the sun to collapse into its core, which will ratchet up the heat on the remaining hydrogen and cause the sun to expand into a red giant.

At this point, the sun will swallow the Earth.

"Earth will end up in the sun, vaporizing and blending its material with that of the sun," said Iowa State University's Lee Anne Willson. "That part of the sun then blows away into space, so one might say Earth is cremated and the ashes are scattered into interstellar space."

By then, the sun will be hot enough to burn all its stored helium and the sun will fluctuate in size. The sun isn't quite massive enough to explode in an awesome supernova, so it will merely collapse into a relatively cool white dwarf.

Perhaps a moot point, though, because we'll most likely be long dead before this occurs. As the sun revs up to its red giant phase, it's getting about 10 percent brighter every billion years. At that rate, scientists estimate that all the water on the planet will evaporate in the next billion years.

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