He believes that the biggest risk to humanity is that we're currently all on one planet. This means global warming, nuclear war, pandemics, zombies, etc, could basically wipe out humanity.
If he can get humans living on Mars, that means that destroying life on a planet no longer destroys humanity, and that is a very significant levelling up to human survival. Getting people to Mars, to learn how to settle permanently there is a first step. Getting re-usable rockets is a first step even before that. Most things related to SpaceX that Musk does are essentially steps on the path to making this happen.
He may or may not be on the right track, and even if it's a good idea he might be doing it the wrong way, but everything is consistently focused around making this happen. For this, further developing the mid-west, terraforming Arizona, or colonising the bottom of the sea are all insufficient to achieve the goal.
Nuclear war might wipe us out, but that is looking less likely than in the past. And if it does happen I think it's arguable that the universe might be better off without us.
Of course not. In fact, our eventual extinction is inevitable. But it seems to me exceedingly unlikely to happen any time soon.
GRB or Asteroid are also ELE that the GP did not mention.
That is, if we assume a GRB intersects Earth, what is the probability that it won't also hit Mars?
Very Big Asteroids are definitely one event it would serve us well for though.
https://en.wikipedia.org/wiki/Gamma-ray_burst#Energetics_and...
Yes, of course. I even think it's worth while putting some of that effort into looking into colonizing Mars (though I think there is a lot more low-lying fruit that is being neglected in terms of improving our overall odds of survival). All I'm saying is that we're nowhere near ready to talk about actually doing it yet.
Can you elaborate? You talking politically?
Beyond that, I just don't see any credible existential threats.
No, Earth won't be _as_ hostile as Mars.
Biological warfare, a large asteroid strike, etc.
Simply surviving on Earth, however isolated, is hardly helpful though. You need to simulate things like the lack of an atmosphere to teach you anything useful.
Yes, and not a single one of them has ever sustained a mission for more than a few months (AFAIK). If we're going to colonize Mars we need to be able to sustain these kinds of efforts for years.
We're trying to run a marathon before we've even learned how to crawl.