But if you had to put odds on it, what would you give the proposition that any life lives on another planet? 1-in-100? 1-in-a-million? How about 1-in-a-billion? Is that a fair number? If there were a billion planets, that means you think life would exist on at least one, yes?
Astronomers at the University of Auckland believe claim there are actually around 100 billion habitable, Earth-like planets in the Milky Way. If we use the odds in the aforementioned example, that would mean 100 of those planets have life on them. And that's just in our teeny tiny Milky Way.
Thinking of revising those odds because it seems too easy now and maybe you're scared? OK, let's go with 1-in-a-trillion. There are roughly 500 billion galaxies in the universe, meaning there is somewhere in the region of 50,000,000,000,000,000,000,000 habitable planets. And that's just habitable planets, not regular old ice giants or gas giants, plus these numbers are in the OBSERVABLE universe.
Here's the math for you: 50 sextillion planets have the right conditions for nurturing alien life, and if you divide that by a trillion, that gives us 50 billion planets that have life on them if we use our adjusted odds.
Are we really so arrogant as to think we are the only ones in this infinitely sized universe? Just because we haven't found them, and they haven't found us, doesn't make us special.