Dr. Kelly Fast tells us about the Planetary Defense Coordination Office, which finds asteroids before they find us. She talks about a recent exercise involving the tiny asteroid 2012 TC4, where asteroid hunters across the world coordinated to observe this object on a recent fly-by. We also talk about ‘Oumuamua, the first interstellar asteroid ever discovered.

Dr. Mark Panning tells us all about “earthquakes” on other worlds. He talks about the InSight mission to Mars, which carries a seismometer to detect Marsquakes. He also explains how a seismometer on Europa could teach us about the interior of that icy moon.