What's a Blazar? A Galactic Bakery for Cosmic Rays
b'In 1911 and 1912, an Austrian physicist named Victor Hess took to the sky in a series of risky hot air balloon trips\\u2014for science. Down on land, researchers had been registering signals of mysterious energetic particles on their instruments. They didn\\u2019t know what the signals were or where they came from. So in progressively thinning air, more than three miles off the ground, Hess performed experiments to figure out if the particles came from above or below.\\nLearn more about your ad choices. Visit podcastchoices.com/adchoices'