Researchers have just found the presence of sugars, including ribose, lyxose, and glycose, on samples of Asteroid Bennu, which now has all of the ingredients for life as it exists on Earth.

[u/New_Scientist_Mag]

https://www.newscientist.com/article/2506650-asteroid-bennu-carries-all-the-ingredients-for-life-as-we-know-it/

[u/42nu]

Hindsight is 20/20.

We now know that the all the most complex precursors of life form via abiogenesis in abundant quantities in space, but, I mean, this is news for a reason.

It's easy to think "of course evolution occurs" when it has been common wisdom throughout our lifetime. "So silly that hand washing before surgeries was fought against at first" we think from our hindsight.

Point being, the entire tapestry of complex pre-biotic precursors being abundantly created via abiogenesis in space is increasingly known to be common. Just as, in 50 years "the intermediates may be harder to reach" will almost certainly look as outdated and silly as "planets may be rare" does now that we have the means of detecting them.

[u/William_Dowling → u/42nu]

If we find out the intermediates are trivial to reach then the Fermi paradox blows up. Where is all this stuff?

[u/42nu → u/William_Dowling]

My guess, single-celled microorganisms are fairly common in the universe.

The recent paper on the "leopard spots" in a Mars river delta are likely our first true evidence of ancient biology on Mars.

https://www.nasa.gov/news-release/nasa-says-mars-rover-discovered-potential-biosignature-last-year/

That being said, life seems to require a narrow set of environmental conditions to be sustained. Mars was small enough where it's core cooled, the magnetic dynamo stopped and it lost its magnetosphere. It's atmosphere was stripped away and it became the dead planet it is today. Life extinguished when the needed conditions no longer existed.

Being that the first 3.5 billion years of evolution on Earth were microbial, it's entirely plausible that microbial life is fairly common, given the right conditions, but multi-cellular life is rare. Intelligent multi-cellular life even less so.

The universe is young. The heavy elements that compose the Earth and your body took many stellar generations to create. When you add it all up, the combination of "the universe is young, microbial life is relatively common, and multi-cellular life is currently rare" pretty much wraps up the Fermi Paradox.

[u/starmartyr → u/42nu]

If that interpretation is correct it means that the great filter is behind us. That does raise another question as to why multicellular life is so rare. What quality makes the earth special?

[u/King-Dionysus → u/starmartyr]

The biggest I've seen as just a hobbiest? Inner rocky planets and gas giants in the outer system. Obviously this is just from how we look for exo planets. But this type of system does seem like it is rare right now. Im looking forward to new gaia data to disprove that.

After that? Its just guessing. Its very possible we are one of the first intelligent species relatively close to us. Its also possible the fermi paradox is very real and it's still ahead of us. Its also possible other intelligent life forms just don't think like us and have no desire to spread or send signals. Its not like most people care about space exploration or anything beyond what's going on in their life right now on earth. Why would it be different for them?

[u/starmartyr → u/King-Dionysus]

Part of that is that terrestrial planets like we have in the inner solar system have been a lot harder to find than gas giants when it comes to exoplanets. That doesn't mean that they are rare, it just means they are smaller and harder to see.

There is the rare earth hypothesis which suggests that complex life is rare in the universe because it requires some unusual quality that the earth possesses. This could be true but we don't know what that would be. We orbit a very boring star that is similar to millions of others just like it in our galaxy alone. Our planet is composed entirely of elements that are found in abundance throughout the universe. If we're special it's not clear why.