Astronomers have recently estimated that there are 50 billion planets and 300 billion stars in our galaxy, the Milky Way. With the Kepler Mission, scientists have been able to identify exoplanets in the Milky Way and so far have identified 1,235 planets. Based on this information, Kepler Science Chief William Borucki has said that they have extrapolated from that data that there are 50 billion planets. Scientist believe that of these 50 billion planets, 500 million could be located in the “habitable zone” of their stars, meaning that they could support life.
How much is 500 million? If you took 500 million 3rd graders and placed them touching finger-tip to finger-tip, those kids would make 50 and half circles around the Earth1. 500 million is an awful lot of planets that could potentially support life!
1) Assumes each 3rd grader has an average arm span of 52 inches. Five hundred million kids touching finger-tip to finger-tip would reach 26,000,000,000 inches. The Earth has a diameter of 7,926.41 miles or 504,357,468 inches. 26,000,000,000 inches divided by 504,357,468 inches is 51.55 times.