David Pogue sets out on a worldwide quest to find the key molecules and chemical reactions that have paved the way for human civilization, life, and even the universe as we know it. Stream all three episodes of NOVA l PBS' “Beyond the Elements” now on the PBS Video app. | PBS

Do you believe in the existence of extraterrestrials? 👽 For decades, UFOs have captivated the public, but many scientists saw them as too taboo to investigate - until now. So what does the science say? Explore the evidence as astrophysicists and engineers use new technologies to investigate the strangest objects in our skies. Don't miss What Are UFOs? from NOVA l PBS on the Cascade PBS app. https://bit.ly/3P1fF0Y | Cascade PBS