So are we alone in the universe? The most rational answer is we don't know. This is of course if you are to provide an answer without the influence of religion. Christianity in particular clings to the concept of creation by a deity as written on the Bible when explaining the origins of man and the universe. As the Christian evangelist Ken Ham once pronounced in a debate with the science educator Bill Nye, intelligent life can only be found on Earth and that the rest of the universe was created by God as proof of his greatness. Obviously, with this position, it follows that Ham and his ilk don't believe in aliens. This is a Christian worldview which is completely different to what you are about to watch.
At least 80% (and this is a conservative figure) of the scientific community believe in the theory of evolution. One of these scientists is Richard Dawkins, a well-known evolutionary biologist and author. In a short video shown at the World-Changing Ideas Summit in New York last October 21, Dawkins explored the idea that there's intelligent life out there and that they may have come to existence in a way that's different from how we on Earth came to be.
The evolutionary biologist Richard Dawkins. (bbc.com)
You can watch the video clip on BBC here. For more information on the World-Changing Ideas Summit, go here. They have a ton of really interesting speakers which include Dr. Jeffrey Hoffman, an aerospace engineering professor from Massachusetts Institute of Technology and Alexis Ohanian, one of the founders of the social bookmarking/networking site Reddit. Hopefully, they'll be uploading their talks soon for free viewing.