Caleb Scharf, the director of Astrobiology at Columbia University, talks with Recode's Kara Swisher about the under=discussed dangers humans would face in space and the rise of private space exploration, as championed by billionaires such as Elon Musk and Richard Branson. Scharf wrote a piece for Scientific American earlier this year, "Death on Mars." about the hazards of the Martian environment for humans, and explains what we know — and don't know — about how human explorers might be able to survive. Plus: Is space tourism actually a good idea? Featuring: Caleb Scharf (@caleb_scharf), director of astrobiology, Columbia University Host: Kara Swisher (@karaswisher), Recode co-founder and editor-at-large More to explore: On Reset, Arielle Duhaime-Ross explores why — and how — tech is changing everything. On Recode Media, Peter Kafka interviews business titans, journalists, comedians and podcasters about the collision of tech and media. On Pivot, Kara Swisher and Scott Galloway talk about the big tech news stories of the week, who's winning, who's failing, and what comes next. And on Land of the Giants, Jason Del Rey chronicled the rise of Amazon. Season 2 will focus on Netflix and is coming soon! About Recode by Vox: Recode by Vox helps you understand how tech is changing the world — and changing us. Follow Us: Newsletter: Recode Daily Twitter: @Recode and @voxdotcom