How to Find the Basics of Binary Orbits

Most stars we see are actually two stars in orbit around each other. Technically, all orbiting systems are binary orbits, so understanding the basics of these is important in physics. Let's see how these work and get the basic concepts down, especially in terms of finding how fast things must be moving in order for these orbits (which we will assume are circular) form.

Einstein's View of Gravity in General Relativity

We know a bit about gravity, and the fact that all masses attract all other masses. Newton figured this out in the 17th century. However, Newton never understood where gravity came from. We had to wait nearly 300 years before Einstein proposed the General Theory of Relativity, and the notion of 'warped space-time.' Check out this clip from Brian Greene's Elegant Universe.