Are We Alone? | How the Universe Works

There are billions of stars in our galaxy, with billions of planets circling them. But, as far as we know, only one planet has life: Earth. But are we really alone? Stream Full Episodes of How the Universe Works: https://www.sciencechannel.com/tv-shows/how-the-universe-works/ Subscribe to Science Channel: http://bit.ly/SubscribeScience Like us on Facebook: https://www.facebook.com/ScienceChannel Follow us on Twitter: https://twitter.com/ScienceChannel Follow us on Instagram: https://www.instagram.com/ScienceChannel/