After that it is expected to become a red giant, as the hydrogen that presently comprises it is exhausted and the sun switches to burning helium instead.

之后，据推测太阳会成变成一颗红巨星，因为到那时候现在构成太阳的氢气燃烧殆尽，太阳转而燃烧氦气。

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When a star similar to the sun fuses most of its hydrogen into helium, then the helium into carbon, the star becomes unstable and puffs out into a red giant.

当一颗类日恒星大部分的氢聚变为氦，氦又聚变成碳的时候，它就变得不再稳定，而膨胀成一颗红巨星。

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Of course, in about five-billion years, our Sun will become a red giant and likely will swallow up the inner planets and the planets' accompanying moons.

当然，在大约50亿万年内，我们的太阳将会变成一颗红巨星，并且很可能将吞噬掉内行星和这些行星的卫星。

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Dr Adams has found that there is one chance in 100, 000 that this would cause the earth to be ejected from the solar system before the sun becomes a red giant.

ECONOMIST: To the ends of the earth

The Sun will then become a red giant, swamping and obliterating Mercury.

BBC: Date set for desert Earth

After that it is expected to become a red giant, as the hydrogen that presently comprises it is exhausted and the sun switches to burning helium instead.

ECONOMIST: Is there anybody out there?