“Most astronomers today believe that one of the plausible reasons we have yet to detect intelligent life in the universe is due to the deadly effects of local supernova explosions within 100 light years that wipe out all life in a given region of a galaxy.”
Well, in a practically infinite universe, there must be some parts that escape supernova effects long enough for intelligent life to evolve, if that is what actually happens. If some parts must escape, in a universe of this size, even if only a tiny fraction escapes, we should still see intelligent life all over the place. So they’re going to need to come up with a much better excuse to explain the paradox.
If there is one every hundred years (on average) in a galaxy the size of the Milky Way, that’s a million every hundred million years, easily enough to suppress evolution and keep organisms at the single-cell level.
The simple biochemistry of the notion that life is inevitable is absurd. The truth is that for all the (false) claims of “scientists discover life in a bottle!” we still can only explain spontaneous production of a few of the wrong nucleotides, and some idea how a lipid layer could be formed. It’s like saying you know how fully-functioning, self-replicating robots formed because you found some traces of metal ore.
We haven’t even found a single planet anything like Earth. I was reading about a supposed “super-Earth” in the “habitable zone.” The estimated temperature on this planet was 70 degrees below zero, so if there ever was any water, it would be locked tight in ice. And it was bathed in infra-red. They explained why it may not be bombarded with deadly radiation at regular intervals, but the point is that there was almost no available visible-spectrum light for photosynthesis.
And here’s the kicker no-one talks about:
We are in the exact center and the exact oldest part of the universe. Yes, it’s a quirk of relativity that we’d have to be. But the point is that when we look 3.6 billion light years away, we’re seeing a universe that is EVEN NOW billions of years YOUNGER.
I don’t mean that’s because it took light 3.6 billion years to get here. I mean that as an effect of temporal distortion of high-speed travel, there’s been less time for stuff to happen.
Years ago, I calculated the Drake equation and estimated less than 10^1 (in other words, less than ten) worlds with intelligent life in the universe. I had badly underestimated the number of planets in a typical galaxy, but I also badly overestimated the likely habitability of life on a given planet.
Correction: I wasn’t using the Drake equation as Drake wrote it. The original Drake equation calculated intelligent life in the galaxy. What I did added terms for the number of galaxies in the universe, a number billions of times greater than the actual Drake equation.