How do we measure the gravitational constant?

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.See omnystudio.com/listener for privacy information. 

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.See omnystudio.co ...  Show more

As far as weight goes, Earth is a pretty hefty celestial body. But exactly how heavy? And how does one measure something so massive? Find out in this podcast from HowStuffWorks.com.

La recherche d'une vie en dehors de la Terre occupe les scientifiques du monde entier mais enflamme aussi l'imagination de nos contemporains. Pour encadrer cette quête avec une plus grande rigueur, la NASA a mis au point ce qu'elle appelle une échelle de "confiance".

Once more, it's time for a weekly dose of Stuff to Blow Your Mind and Weirdhouse Cinema listener mail...See omnystudio.com/listener for privacy information. 

Why is it so hard to get a picture of the Milky Way? How much of our galaxy have we mapped? What the heck is a "barred spiral" and what does that have to do with our core? I discuss these questions and more in today's Ask a Spaceman!