Wednesday, August 6, 2014

The Earth Does Not Orbit the Sun?

It's a technicality, but yeah, actually the earth doesn't revolve around the sun -- it revolves around the center of gravity of the solar system.  However, that center of gravity almost always falls in the middle of the sun, thus the earth's orbiting around the sun.  Here's an excerpt from a really interesting article:
Every single object in the solar system, from the gargantuan sun to the tiniest speck, exerts a gravitational pull on everything else. The solar system is basically a massive game of tug of war, and all of the yanking balances out at a specific point: the center of mass, or "barycenter." Everything in the solar system orbits around that point. Sometimes, it's almost smack dab at the Sun's center. Right now, the barycenter is just outside the Sun's surface. But it's constantly changing depending upon where the planets are in their orbital paths.
There's a lot of more of interest including several interesting diagrams at the link above.