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Comment by mr_mitm | Hacker News Reader

What if the probability of life emerging on a random planet is less than 10^-40? All we can say for certain is that this probability is strictly between 0 and 1.

The number of galaxies is mind boggingly large (around 100 billion in the observable universe), and the number of planets even larger, but there is no reason that the probability of life couldn't be even more mind boggingly small.

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Indeed it doesn’t even need to be that small — even a 10^-28 chance makes it unlikely to have arisen anywhere else in the observable universe.

Newer observations suggest 200 billion with an average of 100 million stars per galaxy and 3-10 planets per star. 60,000,000,000,000,000,000 planets on the low end? Yeesh.

Yes these are huge numbers, but quantities associated with physical space (# of objects) are nothing compared with quantities in combinatorial spaces (# of possible 256 bit passwords or # of possible games of chess).

It seems plausible that getting the sustained chain reaction of life going in a soup of organic molecules and not immediately interrupting it may be at least as unlikely as randomly guessing a 256 bit password, in which case it will certainly never have happened a second time in the volume of space time we call the “observable universe”.

So what? 40 zeros after the decimal point should make you go "Yeesh" even harder.

It honestly did after I thought about it more.

For some perspective 70b sandgrains in one cubic meter sand… so they found 100x3x6 cubes of sandgrains…

The time aspect is important.

Life on Earth took 10 billion years from the Big Bang to emerge. No evidence indicates any other planet did it before us.

I think most galaxies we see are younger than that.

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