Tags Dr. Jay Melosh geologic violence dinosaurs impact cratering asteroids Comets planetary tectonics solar system earthquakes Chicxulub crater Earth craters killer asteroid size planetary protection Planetary Defense Mars global extinction extension event nuclear weapons kinetic energy asteroid deflection Titan Europa Venus Pluto lunar base inflatable habitat risk microorganisms hazard to inflatable structure robotic exploration comet impacts dinosaur cause of death Yucatan Peninsula dinosaur DNA Lunar GRAIL mission Lunar Exploration lunar gold or other ores Late Heavy Bombardment Guest Dr. Jay Melosh Tagline craters and more View the discussion thread.