2. A wide disparity or difference in attitudes or opinions: The generation gap is the subject of many books and articles.
Through the gap in the stage curtain, Willian could gape unnoticed at the audience. He noticed a significant gap between the afternoon, the matinee, and the evening audiences.
There was a large gap in the wall where the artillery shell exploded.2. A pass or access through large steep hills: When Tim and his friends were exploring a geographic region, they were able to walk through a gap in the mountains so they could see what was on the other side.
3. A space between objects or points; an aperture: Shirley had an abnormal gap between her two front teeth.
4. A conspicuous difference or imbalance; a disparity: There was a big gap between Sue's income and her spending during the last month.
The reason for this activity is that in such positions any minor planet would be repeatedly perturbed by Jupiter's gravitational field until it was forced out of the "forbidden" orbit.
The gaps are an example of gravitational resonance.