LIGO's success in detecting gravity waves was one of the great physics achievements of our lifetime. The LISA project will employ three spacecraft orbiting the Sun in an equilateral triangle formation, with sides about 1.5 million miles long. Moshe Fader: I'm unclear how LISA will work but surely it can't be by the subtle length variation in laser beams used by LIGO. Can you explain the method they'll be using? Well, I can explain it at the level of a theoretical physicist, which is not very deep. There's other kinds of science that we're going to learn about, but that's okay. Let's discuss something as big andexciting