Sunlight filtering through Earth’s atmosphere makes beautiful colors at sunset, and it also broadcasts evidence of photosynthetic life on our planet out into the Cosmos. Many of the billions of other stars in the Milky Way Galaxy have planets similar to Earth. Astronomy professor Zach Berta-Thompson explains how we might search for life outside our Solar System by observing the colors of sunsets on some of these alien worlds. Every star in the sky is a Sun, just like our own, and astronomers recently determined that most of those stars have planets. Some of these “exoplanets” eclipse their stars as seen from Earth, causing momentary dips in the stars’ brightness. Zach Berta-Thompson uses small telescopes to search for new exoplanets by watching for these dips (he helped find a few!), and he uses big telescopes to study these exoplanets’ atmospheres (particularly, the color of their sunsets). He is a professor of Astrophysical and Planetary Sciences at the University of Colorado at Boulder.