Looking through a telescope is like being inside a time machine -- you are seeing light from the past. And some space telescopes allow astronomers to see light that is billions of years old and existed before there was an Earth or sun. Astrophysicist Michelle Thaller introduces us to scientists who started two of the most powerful telescopes, the Hubble, which launched 25 years ago, and the James Webb Space Telescope, being built right now.

Photo caption: Drs. Jane Rigby (L) and Michelle Thaller gaze up at a giant piece of machinery at NASA’s Goddard Space Flight Center that will be used to test the James Webb Space Telescope before its launch in 2018.

More behind-the-scenes from this episode: http://transistor.prx.org/2015/04/the-ultimate-wayback-machine/

This episode was produced by Lauren Ober. Mix and sound design by Whitney Jones. Photo by Lauren Ober.