41: Cosmic Microwave Background (Scopes on a Balloon!)

When Chris found out in episode 36 that there was a telescope on an aeroplane, he was joking when he suggested they should try putting one on a balloon. Turns out, that's a real thing — and it leads to a deep-dive into one of the most fascinating discoveries in all of astronomy, the fingerprint of the Big Bang itself: the Cosmic Microwave Background.