The Universe: Explore the Alien Worlds of Outer Space *3 Hour Marathon*

Which planet is the most controversial? Why is Pluto not considered a planet by some? See more in this 3 hour marathon from The Universe. #TheUniverse Subscribe for more from The Universe and other great The HISTORY Channel shows: Find out more about the show and watch full episodes on our site: Check out exclusive The HISTORY Channel content: History Newsletter - Website - Facebook - Twitter - 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.