The Asteroid Belt and the Kuiper Belt are relics from the formation of our solar system .
Understanding the size and spin distribution of the two belts is crucial for a deeper understanding of the formation of our solar system and the dynamical process that govern it .
In this paper , we investigate the effect of collisions on the evolution of the spin distribution of asteroids and KBO ’ s .

We find that the power law nature of the impactors ’ size distribution leads to a Lévy distribution of the spin rates .
This results in a power law tail of the spin distribution , in stark contrast to the usually quoted Maxwellian distribution .
We show that for bodies larger than 10 km , collisions alone lead to spin rates peaking at 0.15-0.5 revolutions per day .
Comparing that to the observed spin rates of large asteroids ( R > 50 km ) , we find that the spins of large asteroids , peaking at \sim 1 - 2 revolutions per day , are dominated by a primordial component that reflects the formation mechanism of the asteroids .
Similarly , the Kuiper Belt has undergone virtually no collisional spin evolution , assuming current day density .
Collisions contribute a spin rate of \sim 0.01 revolutions per day , thus the observed fast spin rates of KBOs are also primordial in nature .