Monday, January 5, 2015

Stellar Near Miss?

Apparently we're heading for one. In about 240,000 years, that is.

The star, HIP 85605, should pass our solar system at a distance of 0.04 parsecs and no, it won't knock the Earth out of its orbit. It might, however, disrupt the Oort cloud and send comets and other fragments hurtling towards the inner planets.

If we're still around then, that might be a bit of a problem.

Such cosmic near misses are pretty rare. But it's a definite reminder that the stars, while "set in their courses" by the forces of gravity, are definitely not sitting still. That includes the sun. At our best guess, the solar system is orbiting the center of the galaxy at a speed of about 200 kilometers per second, with an orbital period of 240 million years...

We just don't notice because everything's moving at the same speed.