The thing being defended against isn't the sun blowing up. It's a species-ending impact or some other localized global catastrophe that would cause the loss of 100,000 years of culture, art, and history.
Everything we've worked for during the entire history of the human existence can be erased in an instant. All other benefits of being interplanetary aside, redundancy is important.
> The thing being defended against isn't the sun blowing up.
It was in the post I was replying to.
> It's a species-ending impact or some other localized global catastrophe that would cause the loss of 100,000 years of culture, art, and history.
Do you plan on building museums on mars or something? Whatever you plan on doing on mars in order to preserve "culture, art and history", you can do it for much, much less money on Earth.
> Everything we've worked for during the entire history of the human existence can be erased in an instant.
