One in 10^24 seems like really easy odds to beat. Basically anything should happen more often than that, right? But if we choose a random 17 letters of the alphabet, the odds that they spell "probabilistically" is less than that. If we gave 17 letters to each of the 10^24 planets, we expect the word to happen on only one star (actually less than one). It's not too hard to argue that life is more difficult to get by random chance than the word "probabilistically."
So before taking this article to mean that life is actually pretty likely, consider that an event having to occur at least one in 10^24 odds is actually extremely difficult for complex probabilistic phenomena. Who knows how likely life is, but we can't just assume it's higher than one in 10^24.
You're obviously coming down on the pessimistic side of the line but what's cool about this paper is that we now have a line in the sand to argue about!
I deliberately tried not to come off as pessimistic. I'd just seen a pop science article on this paper that went along the lines of "OMG, 10^-24? That's so small! Aliens are basically guaranteed!" It was totally exploiting people's lack of intution about numbers. I just felt the need to point out that 10^-24 is much more run-of-the-mill than it seems. The crazy thing is that probabilistic things are multiplicative, so it's all exponential. The difference between 10^-3 and 10^-4 is a single extra flip of a 10-sided die. The odds of life on a habitable planet might be 10^-10, it might be 10^-100, but you can be damned sure our uncertainty spans many orders of magnitude above and below 10^-24.
(edit: I just looked up the pop article I was complaining about. It was in the new york times and the title was literally "Yes, There Have Been Aliens." Hence my crankiness.)
Comments
One in 10^24 seems like really easy odds to beat. Basically anything should happen more often than that, right? But if we choose a random 17 letters of the alphabet, the odds that they spell "probabilistically" is less than that. If we gave 17 letters to each of the 10^24 planets, we expect the word to happen on only one star (actually less than one). It's not too hard to argue that life is more difficult to get by random chance than the word "probabilistically."
So before taking this article to mean that life is actually pretty likely, consider that an event having to occur at least one in 10^24 odds is actually extremely difficult for complex probabilistic phenomena. Who knows how likely life is, but we can't just assume it's higher than one in 10^24.
You're obviously coming down on the pessimistic side of the line but what's cool about this paper is that we now have a line in the sand to argue about!
I deliberately tried not to come off as pessimistic. I'd just seen a pop science article on this paper that went along the lines of "OMG, 10^-24? That's so small! Aliens are basically guaranteed!" It was totally exploiting people's lack of intution about numbers. I just felt the need to point out that 10^-24 is much more run-of-the-mill than it seems. The crazy thing is that probabilistic things are multiplicative, so it's all exponential. The difference between 10^-3 and 10^-4 is a single extra flip of a 10-sided die. The odds of life on a habitable planet might be 10^-10, it might be 10^-100, but you can be damned sure our uncertainty spans many orders of magnitude above and below 10^-24.
(edit: I just looked up the pop article I was complaining about. It was in the new york times and the title was literally "Yes, There Have Been Aliens." Hence my crankiness.)