Billions and Billions

You know you did it: went around intoning in a grave and deep manner Carl Sagan's unlikely catch phrase "billions and billions." Although he never officially said it, he did use the word "billions" when talking about the simple mathematical possibility of the number of planets in our galaxy.

Now, scientists have come up with an estimate based on the number of planet-like objects that have been discovered by a telescope named Kepler. And that estimate is pretty much what Sagan thought all along: billions. In fact, about 50 of those billions -- of which about 1 percent (about 500 million) fit into the not-too-hot not-too-cold segment that could conceivably harbor life in some form.

The numbers start getting really massive when you consider that ours is only one galaxy, and scientists estimate there are 100 billion galaxies. How many habitable worlds would that indicate? You do the math.

You can read more about the new estimate here.