The fate of our solar system could have turned out so different.
http://www.cnn.com/videos/us/2015/03/06/orig-pkg-nasa-discovers-mars-ancient-ocean-5-things-to-know.nasa/video/playlists/five-things-you-should-know/
http://www.cnn.com/videos/us/2015/03/06/orig-pkg-nasa-discovers-mars-ancient-ocean-5-things-to-know.nasa/video/playlists/five-things-you-should-know/