This week, we talk to Dr. Kirsten Siebach, a Martian geologist from Rice University, talking about her work uncovering secrets of the climate of ancient Mars.But first, we study a newly-discovered system of exoplanets featuring an extreme planet of molten lava. Next, we learn about a so-called cotton-candy planet with a density so low it wasn't thought to be possible. Finally, closer to home, we take a look at a new study revealing that Gale Crater on Mars may have once resembled Iceland, before talking to one of the lead researchers on that study.Next week, we talk to Dr. Lauren Weiss, astronomer at the University of Hawaii, on her work studying the TOI-561 solar system and extreme exoplanets!--- Send in a voice message: https://anchor.fm/the-cosmic-companion/messageSupport this podcast: https://anchor.fm/the-cosmic-companion/support Get full access to The Cosmic Companion at thecosmiccompanion.substack.com/subscribe