In this week's live QA, I talk about Elon Musk's hope of establishing a free Mars, the future of gravitational wave detectors, and what do I think about trying to live in other places in the Solar System? 00:08:10 Should we declare a Free Mars? 00:11:43 How sensitive will gravitational wave detectors become? 00:17:05 More damage at Arecibo00:19:20 Why is the Moon the same visual size as the Sun? 00:25:48 Any hard sci-fi00:28:30 Why doesn't Elon talk about nuclear propulsion or artificial gravity?