There was a time before planets and suns. A time before oxygen. You could say there was time, even, before what we think of as light. Back in 1989, the Big Bang theory was still in question. But that year, a NASA team led by cosmologist John Mather launched a mission to probe the earliest moments of the universe.

Mather won the Nobel Prize in Physics for his work on the Cosmic Background Explorer (COBE). This work dramatically confirmed the Big Bang theory — and, as part of it, Mather and his team took a picture of the very first light escaping into our universe. In this episode, Dr. Thaller visits Mather to talk about these discoveries, which transformed scientific understanding of the universe. We also hear about Mather’s current project: an orbiting space telescope twice the size of the Hubble. It promises to capture the first light of galaxies and stars, and even distant planets not unlike our own.