Asklemmy

And you have your head stuck so far up your ass you think climate change is the only threat to the habitability of the Earth when one solar flare gone wrong or object striking the Earth or black hole travelling at the speed of light passing sufficiently close could erase humanity from existence and we would never see it coming. None of these things are fiction and all of them are completely within the realm of possibility. Modern astronomy has documented examples of all of these things happening. In fact the leading theory right now is that the Earth and moon existing as they do is the result of the collision of two objects typically referred to as Gaia and Theia. Theia broke off pieces of Gaia and those eventually came together to form the moon while the rest became the Earth.

As of right now the only thing preventing our species from going extinct due to any of a very large number of astronomical events is luck. But you have no guarantees that that luck will last forever and humanity needs a backup plan.