“If there’s a shining center of the solar system, you’re on the planet it’s farthest from.”
— with apologies to Luke Skywalker
Astronomers have figured out how to find the center of mass of the solar system. And that in turn will help them use überdense stars spinning faster than the blades on a kitchen blender to find gigantic black holes across the Universe that are eating each other.
Right. As you might expect, there’s a bit of a backstory here.
OK, first of all, you might think the location of the center of mass of the solar system is obvious: The center of the Sun. It has 99.8% of all the mass in the solar system, after all!
But that’s not correct. If the planets had no mass, then yeah, the center of the Sun would be the center of mass. But planets do have mass, and that means their gravity pulls on the Sun as well, changing the location of the center of mass, what we call the barycenter.
Two objects of different masses orbit each other; the more massive one makes a little circle and the lower mass one a bigger circle. Credit: NASA/Spaceplace...