Our big, beautiful sky stretches all the way from the ground beneath our feet to about sixty miles above the Earth. It’s made up of countless air molecules, pinging around like tiny, invisible pinballs. And even though we can’t feel the weight of each individual air molecule, all together they weigh a lot! But how much does the sky actually weigh? (spoiler alert: it involves lots and lots of farting cats…) Molly and co-host Felix learn more by talking with a band of singing walruses and a pretty wacky weatherwoman. And don’t miss this week’s extra mysterious Mystery Sound!This episode was sponsored by:Indeed (Indeed.com/BRAINS - Terms and conditions apply. Cost per application pricing not available for everyone.)Thrive Market(Thrivemarket.com/brains - Click for 30% off your first order, plus a FREE $60 gift.)*****Do you have your Smarty Pass yet?? Get yours today for just $4/month (or $36/year) and get bonus episodes every month, and ad-free versions of every episode of Brains On, Smash Boom Best, Moment of Um, and Forever Ago. Visit www.smartypass.org to get your Smarty Pass today!