It took about a billion years of photosynthesis on earth before all the ferrous iron dissolved in the oceans was oxidized and atmospheric oxygen concentration began to take off.

... and it probably killed most of the then current bacteria/archea, because they were adapted to an atmosphere without oxygen https://en.wikipedia.org/wiki/Great_Oxidation_Event

Fascinating

great questionprobably not poison it directly, but you'd lose a significant chunk to oxidation reactions before reaching any stable equilibrium. the surface is essentially a massive reactive sink. mars has a similar problem, the perchlorate in the soil would react badly with a lot of things we'd want to introduce. the optimistic read is that oxidation reactions release energy and eventually reach stability. the pessimistic read is the timescale is geological.

Isn't Mars red due to oxygenation of the rocks? Is that ancient oxygenation or is there some quantity of oxygen in Mars atmosphere today? Does the atmospheric CO2 sometimes break down (maybe under sunlight) and release some small quantity of O2 or might there be another source? Might something underground be respirating atmospheric CO2?

The realistic read would then be, we'd be better off just blowing a giant bubble of water in any number of lagrange point and having ourselves a brand new water park to play with, bring dolphins to, etc ...

Oh wait no that's a different kind of read.

Terraforming is an exceptionally energetic endeavor. Even if you had the perfect combination of icy asteroids with just the right amount of water, nitrogen, oxigen etc. and the means to hurl them towards Mars, this kinetic event would be so energetic that it would take centuries to millennia before the surface would cool to habitable temperatures. it's not physically possible to do it ex in the span of a human lifetime.

Ar the scale terraforming entails, the crust reactions with the new atmosphere are closer to a rounding error.

Just put a parachute on the asteroid.

;-)

All that kinetic energy needs to go somewhere. It's irrelevant if the asteroid burns up in the atmosphere or if trillions of tiny parachutes heat the atmosphere.

I guess you could devise some scheme where kinetic energy is shed or transformed into useful tasks; for example, delivering to Venus an amount of water similar to Earth requires an icy ball half the diameter of the Moon - and the kinetic energy of this mass traveling at 10km/s is about half of the energy required to spin up Venus to a 24h cycle. So some space elevator like contraptions could hypothetically catch the snowballs and lay them on the surface while at the same time spinning up the planet.

But if you have the required clarketech it's unclear why bother with planets instead of creating exponentially larger and better habitats.

You must have missed the smiley emoticon. Yes, I am well aware that parachutes on asteroids won't work. It was a joke. (I used to work for NASA.)

Well, oxygen _is_ poison. It's eager to react (sometimes violently) with almost everything. It rusts and oxidates perfect shiny metals and silicon making everything an oxide!

No. "Poison" refers to a substance toxic to humans, but we can be exposed to pure oxygen and breath it very fine. But yes, oxygen is dangerous.

"Poison" can also refer to a substance toxic to other animals. We say that chocolate is poisonous to dogs for instance. And a good fraction of Earth's biosphere was killed off by oxygen poisoning in the first of Earth's great mass extinctions.

Also, the dose makes the poison and excess oxygen actually can poison humans. Deep sea divers have to worry about excess oxygen inducing seizures if they mess up their breathing gasses enough. And even 100% oxygen at regular pressure will slowly damage the lungs, something ICUs have to worry about.

Nick Lane had a great book about oxygen, Oxygen, which maybe isn't as good as his book about mitochondria but is well worth reading.

if the moon will be settled it will be settled by AI embodied in some kind of (nano) robot or artificially created life.

Terraforming anything looks really expensive. Ask a finance guy to run numbers on terraforming places with gravity too weak to hold onto a useful atmosphere for any length of time*, and give you his opinion.

*say, Earth's moon

There was a time (1930 - 1960) when Futurism believed we could do great things. Now I imagine a Moonbase or Mars base, and then it gets bought by Private Equity who cancel the maintenance budget, double the number of tourists, and when it OceanGate Titans with the loss of everyone, they shrug and the courts don't give them so much as a slap on the wrist.

That would never happen to the Starship Enterprise. Even in Total Recall, where the baddies wanted to kill the poor, they cared about the integrity of the base keeping everyone alive.

Maybe I'm not reading the right techno-utopian stuff - but I've never seen a Moon Base or Mars Base proposal which claimed to both have an actual business plan, and to project sustained profits.*

Having no prospect for sustained profits is pretty good for keep PE away.

(OceanGate Titan was a money-losing obsession project, not a viable business.)

*Except maybe the O'Neill Space Colony idea - where the Moon Base is just a Lunar strip mine, plus mass driver to throw the "ore" into orbit. IIR, they used a load of NASA's 1970's "lies we must tell Congress" numbers in calculating their transportation costs. And their whole scenario is about half a century out of date now.