Future Neighbor 
If not for its path across the sky, the star Gliese 710 would draw scant attention. It’s only about two-thirds as big and heavy as the Sun, and only a few percent as bright. So from its distance of about 65 light-years, it’s far too faint to see without a telescope. And even with a telescope, it’s nothing more than a tiny orange pinpoint.
In about a million-and-a-half years, though, Gliese 710 should be one of the brightest stars in the night sky — about as bright as Antares, the orange “heart” of Scorpius, which is low in the east as night falls. In fact, Gliese 710 is off to the left of Antares, in the constellation Serpens.
Gliese 710 is moving toward the Sun. There’s a good chance it’ll pass about one light-year from the Sun in 1.4 million years. That’s less than a quarter of the distance to our nearest neighbor today. And there’s a tiny chance that it could pass within one light-week.
Even at such close range, the star wouldn’t have much direct effect on Earth — it’s too small and faint. But it could have an indirect effect. It will stir up the comets that orbit far from the Sun, sending some of them plunging toward the Sun. The closer the star gets, the more comets it’ll send our way. And there’s a chance that some of those comets could hit Earth. Depending on how big they are, that could trigger global catastrophes — wiping out much of the life on Earth.
More about close encounters with other stars tomorrow.
Script by Damond Benningfield, Copyright 2012