Can You Tell When a Star Is Not Spherical?

We can study these things, and we can tell sometimes when they are barnee t our systems. We measure the velocity of a star relative to the earth by looking at how it shifts the wave length of the light that's getting to us. If two stars are orbiting each other, then their velocity relative to the earth is constantly changing. And so we can deduce that a star that looks just like one actually has this pattern of two stars moving back and forth.