Astronomers have been watching pulsars for a long time. The periods change slightly. It looks like they have enough data to detect gravitational waves from super massive black holes colliding. LIGO is audio. The pulsar work will be nano-Hertz. How is that for a neat unit unit? Astrophysicist explains big GRAVITATIONAL WAVE discovery! Are they NEW PHYSICS or merging SMBHs? https://www.youtube.com/watch?v=BUmJxZ7PQzw 24 minutes. Time sink warning. She's good. -- These are my opinions. I hate spam.