The Sun Will Eventually Engulf Earth

In Scientific American, on September 8th 2008, there is an article about how the sun will end up engulfing the earth and all life on it, sometime in the future. It says,

The future looks bright—maybe too bright. The sun is slowly expanding and brightening, and over the next few billion years it will eventually desiccate Earth, leaving it hot, brown and uninhabitable. About 7.6 billion years from now, the sun will reach its maximum size as a red giant: its surface will extend beyond Earth’s orbit today by 20 percent and will shine 3,000 times brighter. In its final stage, the sun will collapse into a white dwarf.

Although scientists agree on the sun’s future, they disagree about what will happen to Earth. Since 1924, when British mathematician James Jeans first considered Earth’s fate during the sun’s red giant phase, a bevy of scientists have reached oscillating conclusions. In some scenarios, our planet escapes vaporization; in the latest analyses, however, it does not.

But all is not lost. The article also gives a little message of hope.

Could Earth be saved if someone is still left at home? In a bold piece of astronomical engineering, Don Korycansky of the University of California, Santa Cruz, and his colleagues have proposed nudging Earth with a large asteroid arranged to pass nearby periodically. It could take one billion years to move our planet out to somewhere safe, like the orbit of Mars. Our moon, though, might have to be left behind, and any miscalculation could mean extinction. Needless to say, more study is required.