Why are asteroids observed at the distances of the gaps in the asteroid belt?

Answer 1

A gap is located at an average orbital distance, and asteroid orbits often have large eccentricities.

Edit:

These are the "Kirkwood gaps" and they are caused by the effect of Jupiter's gravity on the asteroids. I've not deleted the previous answer, but I don't think

it helps much.

The gaps are in the distribution of the values of the semi-major axes of the

orbits of asteroids rather than particular places in space.

So orbital eccentricities can't be the explanation.

I think it's simply because asteroids stray into the Kirkwood gaps under various gravitational forces. But these orbits are not stable and asteroids will tend to be cleared away again, eventually.

Answer 2

Asteroids are observed at the distances of gaps in the asteroid belt because those are positions where the gravitational pull of Jupiter affects their orbits, creating regions where asteroids are more likely to either accumulate or be scattered. These gaps result from gravitational resonances with Jupiter's orbit that help shape the distribution of asteroids in the belt.