Prof. Christine Hartzell tells us about the bizarre ways dust and rock behave on asteroids. She explains, "asteroids are complicated because our intuition fails." Tools like shovels become useless, forcing spacecraft designers to innovate.

Dr. Bill Bottke stops by the show to talk about ancient craters on the Moon and Earth. He tells us about how you can figure out crater ages by looking at the nearby rocks, and how that led him and his colleagues to figure out that the impact rate on Earth changes with time.

Dr. Jeff Rich returns to the show to talk about the night sky. He explains how astronomers used constellations to communicate. He also tells us that anyone can invent their own constellation. In a time when people can create "universes inside a computer," we talk about ways to go outside and experience the cosmos.

Dr. Carolyn Ernst tells us about DRACO, a camera on the DART mission. DRACO will take critical images in the final seconds of the mission. Dr. Ernst talks about how heritage is important in spaceflight and explains how DRACO is designed to endure harsh conditions.

Dr. Mark Boslough describes what happens when an asteroid enters Earth's atmosphere. He tell the story of how he learned of the historic 2013 Chelyabinsk impact. He also shares what it was like to see the effects of the Shoemaker-Levy 9 Jupiter impact.

Professor Cristina Thomas talks about NASA's first planetary defense mission: DART. DART is a spacecraft that will impact a tiny asteroid moon. She explains why ground-based telescope observations are key to the mission's success.

Dr. Matthew Knight tells us about a discovery that excited astronomers all around the world. 'Oumuamua is the first minor planet from outside our solar system that we have found. Dr. Knight describes what it was like to observe this speedy object, and explains how it compares to local asteroids and comets.

Dr. Terik Daly talks about his experiments, where things hit other things at tens of thousands of miles per hour. These experiments create pressures greater than that at the center of the Earth, and temperatures hotter than the surface of the sun. Dr Daly tells us what it is like to design and witness these experiments, and how he uses them to learn about the solar system.

Sarah Kaplan of the Washington Post talks about science reporting. Reporters often tackle topics that are outside their expertise. Sarah explains the methods she uses to get at the truth. She also shares where she would send a billion dollar spacecraft, and tells the story of how a small bird caused a big newsroom debate.

Dr. Nancy Chabot returns to the show to talk about iron meteorites. Iron meteorites, she explains, are cores of small planets that you can hold in your hand. She describes her laboratory experiments which use furnaces, glass tubes, and tiny hammers.