In 2005, Kaku appeared in the short documentary film "Obsessed & Scientific" about the possibility of time travel and the people who dream about it. It screened at the Montreal World Film Festival; a feature film expansion is in development talks. Kaku also appeared in the ABC documentary "", in which he suggested that while he believes it is extremely unlikely that extraterrestrials have ever actually visited Earth, we must keep our minds open to the possible existence of civilizations a million years ahead of us in technology, where entirely new avenues of physics open up. He also discussed the future of interstellar exploration and alien life in the Discovery Channel special "Alien Planet" as one of the multiple speakers who co-hosted the show, and Einstein's Theory of Relativity on The History Channel.