I'm perplexed by this statement as the journey would be the exact opposite of what you purport. Are you saying that, unless we can travel to someplace that is very hospitable to life, that we shouldn't bother? How are we ever going to develop the technology to go to such a theoretical place if we're not working on the technology already and constantly iterating on it?
Let's say we're going to be hit with an asteroid that will kill all / most life on Earth. There is no way we can stop it. Having colonies on other planets and moons within our solar system means all of those people, in their self sustaining habitats, will live through the extinction event. Humans would not go extinct.
> If we can manage to survive on Mars, certainly we can manage to survive on the most life-friendly planet known to man.
Are you saying there is no such thing as an extinct level event for humans simply because we can live on Mars? I'm not sure what the point is that you're trying to convey here.
If we can build a sealed habitat on mars capable of recycling water and growing its own food, we can do the same here on earth. Just give it a dedicated fission reactor to keep the greenhouses running, distribute half a dozen of them around the world so that they can't all die to direct impacts, and fortify them heavily to keep the starving masses out.
It is thought that Chicxulub may have produced global firestorms, before a period of global cooling. The point still stands: it's not hard to build structures that can survive fire. Building out of concrete, with thick walls, a self-contained air supply, and away from any vegetation (or simply underground) should suffice, and will still be much easier than colonizing Mars.
No. I'm saying that if the threat of human extinction is the GP's concern, a mission to Mars is very low on the list of solutions that will effectively mitigate that threat.
> How are we ever going to develop the technology to go to such a theoretical place if we're not working on the technology already and constantly iterating on it?
I never said or implied that we shouldn't work on such technology, what I'm saying is that there are more immediate problems to deal with if one's primary concern is the continued existence of the human race. Colonizing Mars does not scale as a defense against an extinction event, and human colonization outside the solar system will remain impractical for the foreseeable future, and possibly forever.
>Let's say we're going to be hit with an asteroid that will kill all / most life on Earth.
I'd take my chances on a post-apocalyptic Earth before attempting to tough it out on Mars or the moon which are even more susceptible to celestial collisions considering their atmospheres.
> Are you saying there is no such thing as an extinct level event for humans simply because we can live on Mars? I'm not sure what the point is that you're trying to convey here.
No. I'm saying that Mars as an environment is already an existential threat to humanity in its natural state, and any problems we might face on Earth will certainly be present on Mars, except Mars is also hostile to life.
Why is that low on the list? What threat are you referring to? Extinction level events can't be generalized because there are a huge amount of them many of which could leave the planet uninhabitable so I'm not sure why you're not only generalizing them but making it sound as if it's an unlikely solution against an unknown list of problems.
> Colonizing Mars does not scale as a defense against an extinction event
Care to explain why? Considering there are a large list of known (and probably a larger list of unknown) possible extinction events, many of which could wipe out the entire human race almost instantly, off world makes the most sense as part of a system designed to ensure the human race can stay around forever (or at least past an extinction level event).
> any problems we might face on Earth will certainly be present on Mars
False depending on what this extinction level event is. There are a great many things that could make Earth less habitable than Mars (though most of them most likely temporary).