I concur - the thing is that Mars is often spoken of as a "lifeboat" for humanity. It will take an awful lot of hard and determined work for us to ever make Earth less hospitable than Mars. Similarly it will take centuries of hard and determined work to ever make Mars as good as the worst possible Earth. Short of a full on nuclear war (small, but nevertheless non-zero probability) we're better off improving what we've got.
Note, I'm only addressing the "lifeboat" justification, I still think sending folks to Mars would be cool as hell.
Even after a full-on-nuclear war, or run-away-global-warming, or a Chicxulub asteroid impact, the overwhelming majority of the Earth will remain infinitely more habitable than anywhere on Mars.
Not really; a large asteroid is fundamentally incapable of making Earth less hospitable than Mars. For example, it would need to be so large that the impact blew away the entire atmosphere.
It doesn't need to make it just like Mars, to be as inhospitable. An asteroid big enough to crater to the mantle, sending out massive waves of lava and darkening the sky for years would do. It might wipe out all humans on Earth. Of course, unlike Mars, Earth would recover. Not that humanity would care.
> It doesn't need to make it just like Mars, to be as inhospitable. An asteroid big enough to crater to the mantle, sending out massive waves of lava and darkening the sky for years would do.
No, it wouldn't. That would make the Earth much less hospitable than it is now, but still much more hospitable than Mars.
> It might wipe out all humans on Earth.
This is not evidence of being less hospitable than Mars, since humans cannot survive on Mars. Even at the worst point of this disaster, human life would be easier on Earth than on Mars under normal Martian conditions.
This concept always feels slightly strange to me. Earth does not "recover" from anything, nor does anything that we or an asteroid could do "damage" Earth. Make it less hospitable for us, sure!
But Earth itself has always been constantly changing due to external and internal forces, sometimes at a rapid rate and always at a slow rate, and none of that change is fundamentally positive or negative to Earth itself.
Agree, except earth after full on nuclear war is still likely better than best possible Mars.
Especially considering timeframes needed to improve Mars, vs timeframe to get past initial post nuclear war issues, which are likely not as bad as the worst case scenarios we've been taught about.
Also, I always found it interesting that the people that are so scared of us changing/destroying the world with nuclear war, are the same ones that don't think twice about basically doing the same thing (drastic manmade change) to another planet.
Or that they think it would somehow be easier than a similar feat of geo engineering to repair earth, either post climate change or nuclear war.
Note, I'm only addressing the "lifeboat" justification, I still think sending folks to Mars would be cool as hell.