Oh boy! So, this all takes place around 2.3 billion years ago. Up until then, life had been pretty much chilling for a billion or so years. Pretty much everything was a single-celled organism back then. Also, the planet was a whole lot different. There was no ozone layer, so UV radiation was constantly reaching the surface. That kills stuff, by the way, in high concentrations. Methane gas was also being spewed into the air by various volcanic eruptions. So, not a very nice place. Most importantly, oxygen wasn’t much of a thing. The little there was existed in the ocean and bonded with the iron molecules that were floating around to make rust.
The organisms that were alive got along just fine without oxygen, for the time being. These are called anaerobic organisms, and some of them still exist today. A lot are in your stomach right now. Anyways, along comes this little thing called a cyanobacteria. It’s unclear how they evolved, but the point is, they can do this neat trick we like to call photosynthesis. As you probably know, a byproduct of photosynthesis is oxygen.
Cyanobacteria were incredibly successful - they could make up to 16 times as much energy as anything else. So, they started multiplying. Pretty soon, there was a bunch of extra oxygen floating around, and not enough iron to bond with it. Then things started dying. See, to a lot of anaerobic organisms, oxygen is incredibly deadly. And now there were billions of cyanobacteria constantly spewing it out.
Long story short, almost everything besides cyanobacteria died. The survivors either adapted to be able to live with oxygen, or went and lived in places without it, like underground or in sulfur vents (those guys are still around today!). The cyanobacteria were literally so successful that they changed the chemical makeup of the atmosphere. This also led to a decrease in greenhouse gases and started the longest ice age the world has ever seen. Go cyanobacteria!
Life cannot exist in perfect, sterile, unchanging balance. The only time the universe will be in complete balance is during its heat death, when all reactions have reached equilibrium and there is no longer any free energy. Chaos and entropy are terrifying conceptually, but necessary.
I refuse to believe that a perfect world is a stable world. A stable world is a dead world. A world without change is a stagnant, decaying, wretched world. Maybe in an afterlife, this is different, but in our current, living one? Hard pass.
There is, however, a limit to the amount of change and chaos that life can cope with before it gets overwhelmed. We typically refer to an excess of chaos as a “catastrophe” or a “cataclysm.” When natural disasters strike and cause a massive loss of life, when species are hunted to extinction or ethnic groups are slaughtered en masse, when oil spills ruin a patch of water and sand for years to come, when plagues sweep across the land… these things can overwhelm life, beat it down, and perhaps even destroy it.
And we see this in Egyptian mythology as well. The land of the gods is said to be the land of pure ma’at, perfect balance and justice and order. The land of mankind contains both isfet and ma’at, and a balance must be struck between the two. An excess of isfet, chaos, will lead to the fall of our world and ourselves.
I mean sure, theoretically, aliens could have noticed any time from the Great Oxygenation Event 2.3 billion years ago onwards that life was probably happening here, which might be reason enough to investigate, and sure, in principle, if there were aliens who were significantly longer lived than us, visiting more-or-less nearby places around the galaxy might be a very possible thing to do even with, yknow, currently-known-possible-by-earthlings technology;
And sure, hypothetically, given a few thousands or maybe millions of years head-start in technical development, they would probably find it easy to, like, biosynthesize human or other animal bodies to drive around and explore this weird rock, and sure, it’s possible that some of them might have come here with weird ideas about what are better or worse ways of arranging this world that have nothing to do with the views of its current inhabitants, and i mean sure, in principle, those who wouldn’t have come with those ideas would be really really sorry about what those other people did.
But there’s no aliens on Earth, people! You do not need to suspect anyone of being a nearly immortal alien! Such people cannot be found on Earth and do not need to be searched for!
My botany professor just called the appearance of an oxygen-rich atmosphere “the greatest case of pollution in Earth history” and honestly this is the best description of the Great Oxygenation Event I’ve ever heard
This is not the end of life, just the end of humanity. Sure a LOT of other species will die with humans, but at least the Earth’s population will get a new beginning. Something similar already happened with the Great Oxygenation Event.
New species adapted to the ‘polluted’ atmosphere will appear, evolve, live, without another self-proclaimed 'superior’ specie either destroying their environment; or forcing them to spend their lives in cages (Circus, Zoos…) and in some cases kill them after (farms, slaughterhouses…); and a lot of other mistreatments I’m not thinking of right now. I’m not against eating meat, but not in this unnatural way. Not when a big part of the produced meat is wasted because of the industrial countries’ consumption system.
In a few years, Earth will finally be rid of the parasites -no offense to actual parasites intended- that humans are. I can’t wait.