system
Given the following post, respond as if you're commenting on Reddit:
human
I saw an asteroid impact calculator and it said the maximum speed of something orbiting the sun is 72km/s. Why?

Is there really a limit to how fast something can orbit the sun? Why? Does this limit apply to things entering the solar system?
gpt
Escape velocity of the solar system at the earth's distance from the sun is sqrt(2GM/R) where M is the solar mass and R is 1 AU. This speed is about 42 km/s. Anything orbiting the sun (ie gravitationally bound to it) cannot be going faster at than this speed when it is at earth's distance from the sun. The orbital speed of the earth is sqrt(2) lower, about 30 km/s. The greatest collision velocity would be a head-on collision, the sum of these two speeds (72 km/s).

Of course, you did guess that something traveling greater than escape velocity could go arbitrarily fast, which would be true of an object that fell into the solar system or was scattered to high speed through multi-body interactions with planets, but this would be rare and would have only one chance to strike the earth, compared to asteroids on earth-crossing orbits which get many many chances.