Planets Abound

A new study suggests there may be 100 billion or even 200 billion planets in the Milky Way.  That averages out to a planet or two per star.

The sttudy looked at the system of an M-type dwarf star; about 75 percent of all stars in the galaxy are small, cool M dwarves.  The Kepler planet hunting spacecraft has discovered perhaps five planets in that system.  Extrapolating those numbers out, and doing some other fancy figuring, gives a huge number of worlds in our galaxy.