Dr. Sarah Parcak explains how she uses satellite images to locate archeological sites, and how it's her job to be a detective, piecing together clues to uncover the past. She also talks about GlobalXplorer, a non-profit that lets everyone be a space archeologist.

Dr. Jeff Rich returns to the show to talk about the interstellar medium— all the rocks, dust, and particles that exist between the stars. After some beer, we end up talking about black holes and how Jeff studies nearby galaxies to learn about the early universe.

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.

Mario Cabrera tells us about the specialized detectors used in professional telescopes. He talks about how he's helping to develop new detectors that don't require coolant and provide more science for less money. He talks about the ways a detector is tested, and how he's walked through miles of waist-deep snow (both ways!) in the name of science.

Dr. Jonah Kanner talks about LIGO's spectacular detection of two neutron stars merging together. This merger was not only detected by gravitational wave detectors in the US and Europe, it was also seen by many telescopes across the world and in space. This new discovery will help unlock many longstanding mysteries in astronomy and fundamental particle physics.

Cassini's spacecraft operations team manager, Julie Webster, stops by the show to reflect on Cassini. We chat about the time Cassini dove through Titan's atmosphere, how Julie monitored thousands of channels of telemetry at once, and how she's happy that she doesn't have to spend her time thinking through worst-case scenarios (or "awfulizing") now that the spacecraft is no more.

Dr Morgan Cable returns to the show to chat about the end of the Cassini Mission. We find solace in the fact that there's still a tiny bit of Cassini in orbit around Saturn. Dr. Cable also describes Cassini's discovery of hydrogen, "the easiest food for a microbe to digest," in Enceladus' plumes.

Sagan Prize winner Dr. Henry Throop tells us how scientists look for micron-sized dust that's millions of miles away to protect the New Horizons spacecraft. This search involves computer modeling, occultation observations, and plenty of teamwork.

Dr. Fengchuan Liu talks to us about an international project, the Thirty Meter Telescope (TMT). He describes the telescope, it's many mirrors, and how he helps manage such a complex project.