Dr. George Privon talks about what galaxies are and what happens when two galaxies merge.

Dr. Dan Petrizzo explains what isotopes are, and what isotopes in water can tell scientists about ancient climates. He also explains how he made Mars rocks in the lab.

Professor Amy Lovell talks about listening in on radio waves coming from comets, as well as the particular challenges of using the world's biggest radio telescopes.

Professor Bethany Ehlmann discusses how to pick a landing site for NASA's next Mars rover, Mars 2020. Over a particularly good beer, we also cover looking for life on Mars, and she answers the thorny question: why look for life on Mars, which has little

Dr Bonnie Buratti talks about Pluto's big mystery: What is the source of energy that is causing all the active geology seen by New Horizons?

Dr. Jessica Watkins talks about enormous landslides on Mars that are millions of years old.

Dr. Michael Busch talks about the strange, low gravity surfaces of asteroids, and the challenges a visiting astronaut might face.

Dr. Britney Schmidt tells us about how she can learn about they icy, watery moon Europa by exploring giant Antarctic ice shelves with submarines.

Dr Jeff Rich talks about where elements come from, and the famous phrase, "We are all made of star stuff".

Dr. Linda Spilker discusses the Cassini Spacecraft; what it looks like, what it has discovered, and plans for the conclusion of the mission.