A big rock will hit Earth eventually. We currently have no defense.894
If you think truly long term, you realize eventually there will be some natural disaster—even if it is not made by humans—that destroys all life on Earth.895
Most people are probably aware of Halley’s Comet. Slightly under once per century, Halley’s Comet comes near us. There are probably many objects, many comets that have long periods we simply don’t know exist. There are billions, maybe trillions of objects in the outer solar system. Some of them are super-long-period comets.
For example, when the comet Shoemaker-Levy hit Jupiter, it made a hole in Jupiter the size of Earth. If that hits Earth, that is game over. Dead. Everything is dead.896
For all of history, Earth did not have any ability to stop asteroids. Now with Starship we have some ability to stop small asteroids. Large asteroids and comets are still a danger.
There’s always some risk of this occurring. The probable lifespan of all forms of life is much greater if we’re a multiplanet and ultimately a multistellar civilization.897