It has been argued that humanity is just one asteroid strike away from extinction. Scientists look at the Cretaceous-Tertiary extinction event, an asteroid strike that wiped out the dinosaurs, and most other land vertebrates, as a major incentive to diversify our habitats as a species. According to this view, humanity needs to colonize another planet before an extinction event, be it an asteroid impact, virus outbreak, or nuclear war, threatens our survival as a species. SpaceX founder and chief engineer Elon Musk has stated that this is a major impetus for his Mars exploration and colonization efforts. "It's important to get a self-sustaining base on Mars because it's far enough away from earth that [in the event of a war] it's more likely to survive than a moon base [...] If there's a third world war we want to make sure there's enough of a seed of human civilization somewhere else to bring it back and shorten the length of the dark ages," Musk responded in an interview. (The Guardian, 2018)
image by J. Contant
image by US Navy
We live on a fragile planet in a highly dynamic Universe, so manned exploration of space is not just about our quest for knowledge but also an insurance policy for the future." (BBC, 2012)
This possibility is not out of the question. NASA discovers hundreds of new near-earth objects every year, some of which are large enough to cause an extinction event. Asteroid 99942 Apophis made headlines in 2004, after it was calculated to come uncomfortably close to Earth in 2029, 2036, and 2068. All three possible collisions have since been ruled out, but it emphasizes the fact that this planet is not above civilization-ending events on short notice (O'Neill, 2021).
Colonizing Mars is a good way to hedge our bets against a tragic ending to our human story.