johnnoble90

No. The mean of 1 is the value where the likelihood of 1 planet having life is the highest. We have no evidence for the actual mean. Assuming the mean is 1 then yes it would be equally likely we "should have" had 0 planets with life. There is no evidence for what the actual mean would be though. A mean of 1 in this distribution was simply a worse case scenario. All i was trying to do with this was show that the law of small numbers makes it unlikely that when life forms by chance, it is unlikely to form only once, rather than never or more than once. It is impossible at the moment to work out an actual probability of life on other planets. It is possible i don't know enough about this distribution but i don't see how it wouldn't apply, as it seems to apply to everything else with a probability and we use it in our own logic as well considering you yourself stated that life seems likely on other planets, despite the fact that we don't really understand much about how life formed.

Hi. I'm a new member so if i have completely misunderstood this then please don't laugh at me. I was having a discussion on another forum about the likelihood of life on other planets, and i thought about applying the poisson distribution to workout the highest probability that only 1 planet would have life on it (i.e us). I had to assume the mean was 1 and it came out at 36.7879%. Now this only shows the probability of only 1 planet forming with life, prior to knowing that 1 planet has formed with life, but it would at least show that if we are alone, it is a pretty big coincidence because even having an average designed to make it as unlikely as possible, it is still almost a third of a chance. Can someone please explain whether this is correct or explain where i have gone wrong?