An international team of astronomers have reached the most definitive conclusion, one with profound implications: our galaxy contains a minimum of 100 billion planets. Of those, most are small planets like ours. Statistically, every star would have at least one planet.
This means that the chances of life and habitable planets in our galaxy alone is overwhelmingly high. So high that it's impossible to deny that it's out there. The only question is how much of that is little dumb critters* and how much is civilized.
According to Stephen Kane—at NASA's Exoplanet Science Institute at CalTech in Pasadena and one of the authors of the study—"not only are planets common in the galaxy, but there are more small planets than large ones. This is encouraging news for investigations into habitable planets."
Kane is being too conservative when he says that this is "encouraging news". This is amazingly great news! The number of Earth-like planets is much higher than Jupiter-sized giants. The rough estimate is that there are at least 10 billion terrestrial planets across our galaxy alone.
That is a mind-blowing number.
Couple this number with the latest calculations that have extended the goldilocks zone, the area where life could happen around stars. And then add the fact that life happens spontaneously, even under the most extreme conditions, and the idea of a Milky Way thriving with life is impossible to deny.
There's no doubt that, statistically, there's life out there (and let's not even talk about the other 500 billion galaxies in the Universe).
Intelligent civilizations
Of course, how much of this life is smart enough to build computers, communication dishes or Imperial Star Destroyers is another matter altogether. As far as we know, all those habitable worlds may be full of killer snails and dozy fish
But the fact remains that, until now, we could only guess much of this stuff. Now we know. That makes a big difference.
The fact that there are at least 100 billion planets in our Milky Way alone has profound implications for our understanding of the Universe. These discoveries, made using Hubble and Kepler, are finally putting some real numbers in the Drake Equation.
The equation—created by Frank Drake, Emeritus Professor of Astronomy and Astrophysics at the University of California, Santa Cruz—is used to estimate the number of extraterrestrial civilizations in the Milky Way galaxy.
Now we are starting to replace the guesses with solid information and things couldn't look better. Soon it will not be "we want to believe" but "we know." [Hubble]
* Some may argue that advanced alien civilizations would see us as little dumb critters, rather than a civilization.