I was looking at this chart, enter image description here

which shows that an order of magnitude increase in asteroid impactor diameter roughly corresponds with two orders of magnitude increase in it's rarity. So if the K-T Impactor at 10km diameter is a 100 million year rarity impact, then a 100km diameter impact has a 10 billion year rarity (on the order of the lifetime of our planet). On a large time scale, orbital perturbation allows for some chaotic orbits, so it might not be vanishingly likely that one of the big asteroids eventually hit earth. The asteroid 16 Psyche orbit overlaps in distance to the sun with Ceres, so it could potentially get a natural gravity assist into another orbit.

What would happen to Earth if it got hit by the asteroid 16 Psyche at, say, 40 km/s in the Pacific off the coast of Japan?

I am specifically looking for an answer to one or more of the following questions: How big would the crater be? How much kinetic energy would be released? What portions of that would be transferred into heat, ejecta, and deformation? Would there be a secondary antipodal mountain formation like the Caloris impact on Mercury? Would it cause magma oceans? Would life on earth survive to reclaim the surface before the Sun went red giant?


Using the impact effects calculator

The energy before impact (making a some reasonable assumptions) is $3.35 × 10^{27}$ Joules = $7.99 × 10^{11}$ MegaTons TNT, most of which would be deposited in the Earth.

The impact effects calculator doesn't discuss the formation of antipodal mountains (this is not a well-understood process) but it certainly seems possible that there could be major antipodal effects. The initial crater would fill with lava, but there would not be a planet-wide magma ocean.

Would life survive? perhaps, life is surprisingly resiliant. This would cause mass extinction, and probably wipe out much or all of complex life. But "until the sun expands to a red giant" gives us millions of years for evolution to find a way. But any answer would have to be speculative.

The average interval between impacts of this size is longer than the Earth's age.


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