What is the fastest known speed of an asteroid in the Solar System?

The laws of physics provide an answer to the given question. If the body of the Solar System is to be on a more or less stable trajectory, there must be a balance between the gravitational force – which increases towards the Sun – and the centrifugal force. The second mentioned is the larger the faster the body orbits. It logically follows from the above that bodies orbiting closer to the Sun reach higher orbital speeds. So if we are going to look for a planet with a high orbital speed, we have to look inside our system, not at its periphery.

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Astronomers last year discovered an asteroid with a diameter of about 1 km, which circles the central star with a period of 113 days, following a highly elliptical path crossing the trajectory of Mercury and Venus. An object with a label 2021 PH₂₇ approaches up to 0.13 AU at perihelion then it “whistles” around the Sun at a speed of 106 km/s – which is the current known record for an asteroid in our solar system. At the same time, it is not entirely clear how the object got on the described trajectory: It could be the result of a close flyby (perhaps collision) of two asteroids in the main belt, or perhaps it is a stray comet.