Dr. Christiansen stops by the show to talk about exoplanets and the Kepler Space Telescope. We share an Australian beverage and she explains how astronomers look for exoplanets, and how the discovery of "hot Jupiters" was a huge surprise to astronomers.

Dr. Lisa Storrie-Lombardi talks about the Spitzer Space Telescope. She tells us how Spitzer made the first observation of light from a planet outside our solar system. She also describes how engineers are constantly innovating, letting Spitzer make better and more sensitive observations.

Dr. Don Yeomans, head of JPL's Near-Earth Object office until his recent retirement, describes how the field of asteroid discovery has changed over the decades. He recalls when early data indicated that asteroid Apophis had a small chance of hitting the Earth (spoiler alert: today, with more data, we know that Apophis will not hit the Earth).

Dr. Kimberly Litchtenburg explains what it is like to explore Mars with the Curiosity rover. It involves daily discussions with scientists, careful programming, and sometimes, fantastic discoveries, like the discovery of a stream bed that once had enough

Professor Yan Fernández tells us about several baffling comets, including one comet that has a nearly circular path around the sun. He also talks about comet Hale Bopp, which we've got to study now, because it won't return to our part of the solar system until 7000 AD.

Dr. Kelsi Singer and I drink an unusual beverage while she shares some of the incredible discoveries that she and the New Horizons team are making. We also discuss a contentious issue— should Pluto be called a planet?

Dr. Robert Hurt stops by the podcast to talk about his job making visuals to explain complicated astronomical concepts. We chat about multiverses, gravitational waves, and Cameron Diaz's love for NASA.

Dr Andy Rivkin and I drink gin and tonics, and Andy explains what spectroscopy is and what it can teach us about minerals on asteroids. He also describes what it's like to use some of the world's most powerful telescopes.

Dr. Tim Sphar, CEO of NEO Sciences and former director of the Minor Planet Center, stops by the show to talk about how asteroids are cataloged and monitored. He also talks about his experience the day tiny asteroid 2008 TC3 impacted Earth.

Dr Cable returns to the show to talk about why scientists often assume that water is needed to sustain life. She explains why most life, like us, likely is carbon-based, and talks about where she'd look for lifeforms beyond our planet.