[azeemba]

The funny thing is that an oxygen-rich environment is a hell-hole! Oxygen is insanely reactive and will corrode anything. Even early life on earth found oxygen toxic. It was released as a waste product by early life and they were so successful that all that oxygen accumulated resulting in the Great Oxidation Event (https://en.wikipedia.org/wiki/Great_Oxidation_Event).

That likely resulted in many species going extinct!

[eru]

Yes, first everything rusted, and then the excess oxygen collected in the atmosphere.

Many of our iron ore deposits we still mine today are from that rusting. (That iron used to be mostly dissolved in the oceans.)

[dredmorbius]

And the concentration into BIFs, banded iron formations, was all but certainly the result of biological activity.

Our present technology based on iron and steel owes itself to early life on Earth, from 1.6 to as much as 4 billion years ago. As with petroleum and coal-bed formation, a process unlikely to repeat in Earth's future. Iron ores are abundant, but still a finite resource.

<https://en.wikipedia.org/wiki/Banded_iron_formation>

[gorgoiler]

I once heard a similar point and it has fascinated me ever since: an alien observing human culture would be appalled at how dangerous our lives are.

Everything around us is bathed in warm oxygen, just waiting to catch fire! Our homes, our clothes, our fields, our possessions, …our hair. Ready oxidation brings vitality to Earth but it’s also ridiculously dangerous.

[brazzy]

It's very unlikely the aliens would not have something very similar going on in their own biosphere. Life needs energy to operate, after all.

[Terr_]

I often like to quip that the [21%] corrosive gas is pretty nice today, and I think I'll go consume a big container of industrial solvent to help counteract the radiation from the uncontrolled nuclear [fusion] explosion in the sky.

[acron0]

Industrial solvent? Does this mean "inside air"?

[dredmorbius]

An oxygen-rich environment is so thermodynamically unstable (it would lead to oxidation and rusting of virtually every other prevalent element) that it would be exceedingly short-lived without the presence of oxygen-liberating biological metabolism. To that extent, a high-oxygen atmosphere is one of the very clear and detectable indicators of probable life which we are capable of detecting even on extra-solar planets (via spectroscopic analysis of reflected or filtered light).

Far more an Eden, then.

[freedomben]

Definitely true, but oxygen is also immensely useful for life evolved to benefit from it, enabling much more complexity. I'm fascinated by the giant insects that got huge back when the oxygen level was much higher.

Related: highly recommend Robert M. Hazen Great Courses and book

[cactusfrog]

I hope humans are like Cyanobacteria in that in destroying the environment we create the substrate for something grander.

[sl-1]

I fear that