Replies

Even an ordinary, intelligent person could probably make a half decent guesstimate on the *possibility* of life elsewhere, with a limited set of variables. Comparing life elsewhere with Earth is problematic, though, because of our “extinction events”, that result in evolutionary “reboots”.

“In the past 540 million years there have been five major events when over 50% of animal species died.” And while human beings breed *a lot*, this cannot be assumed to be a common quality of intelligent animals. Humans have never had to endure an extinction event.

Another down factor are “cosmic” extinction events, like supernovas, that can sterilize a large sector of space to the point where there are no surviving microorganisms.

There is also a good theory that in a galaxy, life can only exist about 3/4ths of the way away from the galactic center. Not too near and not too far away. Like us, on a branch of a spiral, in a quiet enough part of the galaxy to thrive for a while.

In any event, assuming the life of the Milky Way galaxy is about 14 billion years, if you plot where the supernovas have been in say the last 500 million years, to eliminate them from where life is likely to be, then adjust for about 3/4ths of the way away from the galactic center, you have likely eliminated 99 out of 100 places to look.

Then you get to the intelligent life problem, basically, how long to intelligent species last before they either revert to a more primitive state, or just die out? This is the 14 billion year problem.

If intelligent species only last 100,000 years on average, they are biological “flashes in the pan”. But if they are as durable as horseshoe crabs or coelacanth fish, at 450 and 400 million years, respectively, then they have a good chance to at least make their mark in the universe.

About a 1 in 35 chance, that it. 400 million into 14 billion.

f intelligent species only last 100,000 years on average, they are biological “flashes in the pan”. But if they are as durable as horseshoe crabs or coelacanth fish, at 450 and 400 million years.

I don’t see any specifies, no matter how intelligent at their peak, making it past 20M years. Stuff happens. To me, the most compelling scenario comes from Arthur C. Clarke (who was no slouch). After some period of “intelligence” (supposing the civilization does not destroy itself). It evolves to a point where it basically becomes one with the cosmos. That is, it transcends the need for biological or even mechanical bodies to hold their consciousness. Such an advanced consciousness would probably care nothing about the concerns we primitive biologicals hold so dear (eating, sex, the pursuit of wealth & power, etc). In short, it would be as if an ant tried to communicate with us.