In a galaxy filled with a billion stars, in a universe filled with a hundred billion galaxies--are we alone? SETI--the Search for Extraterrestrial Intelligence--is a privately funded project using radio telescopes and optical telescopes to scan the stars for signals. See more in this marathon from The Universe. #TheUniverse Subscribe for more from The Universe and other great The HISTORY Channel shows: http://histv.co/SubscribeHistoryYT Find out more about the show and watch full episodes on our site: http://www.history.com/shows/ Check out exclusive The HISTORY Channel content: History Newsletter - https://histv.co/newsletter Website - https://histv.co/History Facebook - https://histv.co/Facebook Twitter - TikTok - http://bit.ly/4kZKjXi HISTORY® is the leading destination for award-winning original series and specials that connect viewers with history in an informative, immersive, and entertaining manner across all platforms. The network’s all-original programming slate features a roster of hit series, premium documentaries, and scripted event programming.