Do you think complex life could develop (perhaps by moving backwards) in a way that they rely on an anaerobic metal-rich environment?

I guess the oxidation event maybe was necessary for life to develop enzymes (since there wasn't sufficient evolutionary advantage for it to develop in an anaerobic environment?) but maybe something could go backwards? I'm just curious if there might be advantages for live in that sort of environment.

The surfaces of clay particles in these lakes have been dubbed "the primordial sandwich".

The early protocells were 'alive', they were self-replicating, but they required nutrients and metabolic processes that only existed near mineral surfaces and would starve if they drifted away. They had to evolve new enzymes to become 'free-living'.

So it looks like the LUCA was one of these early protocells with an incomplete metabolism.

Probably this. How would we know what such 'proto-life' (perhaps even just some self-replicating soup of chemicals, no cell wall) would look like? Where to find it? How rare its occurence? Etc etc.

Scientists might not even recognise it if happened right in front of them.

I'd put my money on coming up with a more general definition of "life", and then looking for short(est) pathways from "soup of random chemicals" to "something in there that replicates (parts of) itself".

Doesn't need to look like life as we know it, as long as some elements of "self-organising structures, something being replicated" are there.

Indeed, all species branch out from that one universal common ancestor that was the first free living successful cell.

Put another way: forming life isn’t easy at all. And once it forms it changes conditions to suit its continuation, not to allow new life to form.

It's possible OoL requires some exponentially unlikely step. We wouldn't realize that because of observer selection: had the step not occurred, we wouldn't be here to be thinking about it. There's a huge complexity gap between the stuff produced in OoL experiments and the simplest known life.

It's also possible OoL requires conditions that no longer exist on Earth, or that only existed in the early Earth (or wherever life got started in the Solar System). For example, if it depended on the existence of short lived radioactive isotopes or free ammonia.

Anything that's so agreeable to abiogenesis that life might spontaneously manifest, is actually pretty tasty for things already alive. They swoop in and eat it before it gets started. So, I suspect that even what the article says isn't that they both arose in the same place, but in different places separated by distance, time, and/or environmental barriers.

The fact that it doesn't is a pretty simple solution to the Fermi Paradox.

https://en.wikipedia.org/wiki/WASP-39b

There are astronomers actively working on minor component, more biologically interesting spectrographs like chlorophyll rather than spectrograms of carbon dioxide. That'll be harder to detect and limited to shorter ranges.

At some point, probably very soon, like less than a decade, we'll be able to definitively state that we have atmospheric data in an onion layer shaped shell where we have unequivocable proof that out to X lightyears from Earth there's no planetary scale chlorophyll higher than a minimal level aka there's no earth-like plants on that planet. That shell will likely expand over time. Or, perhaps we will find a forested, or at least algae covered, planet, some light years away, which would be very interesting indeed.

The question is rapidly changing from a purely philosophical belief to scientific observation, like right now, in real time, in the 2020s. What a cool time to be alive!

This follows old, old stuff from radio astronomy along the lines of how far away could a 1960s radio telescope realistically detect life on earth. The answer IIRC was not very far LOL. But there's been a lot of progress in radio astronomy, etc.

With respect to fermi filters etc people need to pay attention to how far away the Earth can be detected using radio telescopes. That distance has imploded since the end of analog UHF TV broadcasts. We still broadcast absolute swill, in fact more than ever, but digital detection range is much lower than analog AM carrier detection range from analog TV. The Earth has, to some extent, recently gone radio-quiet, which is interesting because we are still here, in fact more of us than ever. So WRT fermi filters of not being able to detect civilizations, disappearance of 1950s/1960s signals does not necessarily imply disappearance of civilization. Another example, if any aliens are watching the high altitude freon contamination of our atmosphere they're likely really confused right about now.

What is the basis for this assertion?

What we learn from these philosophies is that God is necessarily the author of life and love, but as well hatred and destruction. Worth noting that the latter are most (but not exclusively) expressed in human conduct. Among all animals humans have the most developed ability to decide how to act. That ability is not absolute, often enough logic and reasoning is bypassed and emotion rules.

Naturally cognition is not unbounded, we are limited by constraints of our construction. It means aspects of the universe are unknowable, we can't know what we're missing.

But knowing what we can know is an obligation of our privileged existence. As knowledge expands it exposes the utter complexity of all things emerging from common fundamental processes.

Seeing what is seen, a human may for a moment get a glimpse of the hand that binds everything together. That's a gift if there ever was one.