For years Astronomers have tried to guess how many planets exist within the Milky Way Galaxy? Millions? Billions? Since I was a child I was always fascinated by Carl Sagan and his famous saying of billions and billions when talking about extrasolar planets and even inhabited alien worlds. And even though I always wanted to believe it, it still seemed like a high estimate to me. Not even when extrsolar planets started being discovered by the handful, and later by the bucket full when Kepler was launched, did I ever believe that the actual number could be that much.
Now, however, two independent groups have done the math and both agree that the real number is almost certainly above 50 billion planets beyond our solar system, with one saying the number is likely above 100 billion.
This is still by no means proof that our galaxy is teeming with alien worlds, but the recent discoveries of planets of ever smaller sizes, and even planets around non-sol like star systems, seems to point to a galaxy where worlds will form under just about any kind of environment.