I have long wanted to put forth the point that there are more planets than stars in the Universe. This goes to my contention that it is reasonable, even necessary, to believe that there is copious life in the Cosmos. After all, from the time when Earth’s surface cooled to when life began to appear was relatively short. It appears that all it takes for self-replicating molecules to get going is the right conditions. With so many planets, the opportunities are so vast; it has surely happened over and over again.
But I haven’t been able to make this exact point. I have still made the same effective point, but I had to rely on the trillions and trillions of stars. Of course, plenty of people have inferred over the years, especially the past decade, that there must therefore by billions, maybe trillions of planets. But we need something more concrete. We need observation. And now it looks like we’re there:
Three studies released Wednesday, in the journal Nature and at the American Astronomical Society’s conference in Austin, Texas, demonstrate an extrasolar real estate boom. One study shows that in our Milky Way, most stars have planets. And since there are a lot of stars in our galaxy — about 100 billion — that means a lot of planets.
It could be that the Milky Way is a weird outlier, a galaxy where planets are easy to make. But there isn’t any reason to suspect that. The observations show that we are an average galaxy with an expected array of stars. What’s more, we are seeing what happens around stars. It isn’t just that these giant gas balls form in space and that’s that. No, it’s much more. Most of them come with their own planetary pals. An accurate average of the star-to-planet ratio remains to be seen (they say 1.6 planets per star, but that is probably extremely low), but it is clear that we’re talking about trillions and trillions out there.
None of this changes the thrust of my argument about exo-life, but it does allow me to be much more specific. This is very nerdexciting.