Title: How many planets in our universe could support life? | HowStuffWorks
Headings: How many planets in our universe could support life?
How many planets in our universe could support life?
Citation

Content: Or maybe there are 60 billion planets in our galaxy alone that could potentially harbor life. That's right -- we're not as special as we thought. It turns out that in the Milky Way, scientists now believe that there are 60 billion planets in the habitable zone. The habitable zone is located where a planet is warm enough to keep water on the surface in liquid form without it turning into gas [source: Gannon ]. The planets must be near a star or have cloud cover that keeps moisture locked in. With hundreds of billions of stars in the Milky Way, there are a lot of habitable zones out there. So that's the most recent answer we can give about our own galaxy. Which, lest we forget, is one of hundreds of billions of galaxies in the universe. Each galaxy is chock-full of stars, each of which could potentially neighbor a not-too-hot, not-too-cold planet.