Daniel and Kelly answer questions about the expanding universe, how sleep aids impact sleep quality, and what characteristics might make aliens better adapted for interstellar travel.

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Daniel and Kelly welcome Dr. Scott Solomon back on the show to talk about his new book Becoming Martian: How Living in Space Will Change our Bodies and Minds.

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Daniel and Kelly discuss Elon Musk's recent announcement that SpaceX has shifted focus from a self-sustaining settlement on Mars to a self-growing city on the Moon.

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Daniel and Kelly answer questions about how it can both be true that humans share 98.7% of their DNA with bonobos and that fraternal twins share 50% of their DNA, why black holes don't have color charges, and whether or not you could treat a fever or let it ride.

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Daniel and Kelly revel in the amazing multiplicity of moons in our solar system and what they reveal about our cosmic history.

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Daniel and Kelly talk about the evolution of cooperation, and why humans struggle so much with isolation.

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Daniel and Kelly answer questions about sentience, chicken eggs, and the early Universe!

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Daniel and Kelly dive into one of the most important but mysterious principles of physics: least action.

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