There are two ways to look at how life on earth arose.
You can say that since it clearly did arise, that could mean that the process is easy and
likely happens anywhere it can in the universe.
Backing this viewpoint are things such as the moment earth could support life, life
arose, suggesting that the process is straightforward.
The problem is, that process has never been repeated in the laboratory, nor do we have
a complete understanding of it.
Experiments such as the Miller-Urey work show that the building blocks of life can be created
under laboratory conditions mimicking what scientists believe earth’s atmosphere was
like when life arose.
But, so far, that’s as far as it’s gotten.
To date, no living organism has popped out of a test tube during experiments of this
kind, and there are still many mysteries surrounding just how biology emerges from organic chemistry,
such as just how molecules that can self-replicate come into existence in the first place.
In other words, we don’t yet know if life’s genesis is easy or hard, so the other way
to look at how life arose on earth is the say that it was only by pure chance, and highly
improbable to have happened at all.
And, it’s worth noting that as far as we know, life arose on this planet only once
in its entire history.
Thankfully, this is a question seems likely to be answered in the coming decades, unlike
the detection of intelligent alien civilizations, which could happen tomorrow or never.
Between the biochemists trying to figure out just how life arises, to the numerous examples
of liquid water bearing ice shell moons in the solar system, and of course possibilities
at both Venus and Mars, that all could hypothetically host life, we stand a good chance of getting
a good handle on the prospects for simple life in the universe fairly soon.
But that life did arise on earth so rapidly is suggestive that the process is not too
hard.
But within all of this there is a further problem and also a potential solution to the
Fermi Paradox.
Once life did arise here, it seems to have hit a developmental brick wall of sorts and
spent a full 1.8 billion years as simple, prokaryotic single-celled life.
That’s a very long time to go from life’s genesis on earth, to complex single-celled
life, the eukaryotes, which is also something that’s happened only once on this world.
That suggests that moving from the simplest form of life to a more complex single-celled
form is extremely difficult at best, and at worse might be highly unlikely to the point
it may have only happened here and nowhere else in the universe.
Within discussion of the Fermi Paradox, there is always talk about great filters, some brick
wall that prevents life from advancing to become technological civilizations and heading
off into space.
If a failure of evolution to reach a level beyond simple single-celled life is a great
filter, then the universe might be teeming with simple microbes but rarely anything else.
But that in turn would make us highly improbable, having passed either of these potential great
filters.
And even then, there was no guarantee that intelligence would come out of the mix here
on earth, with a number of very specific factors contributing to our development.
This might not just make intelligent life in the universe rare, but potentially unique
to us.
That would make for a very lonely universe indeed.
Thanks for listening!
I am science fiction author and futurist John Michael Godier currently viewing myself as
highly unlikely.
I’ve said those words in regards to alien life at least a hundred times on this channel
whether it was Tabby’s star or the Wow!
Signal, and now it’s my turn.
Serves me right and be sure to check out my books at your favorite online book retailer
and subscribe to my channel for regular, in-depth explorations into the interesting, weird and
unknown aspects of this amazing universe in which we live.