However , in the real world , many bodies rotate .
This introduces oblateness and distorts the gravity field , and gives a quadrupole moment to the gravitational field which is significant at distances comparable to the radius of the body .
However , in the real world , many bodies rotate , and this introduces oblateness and distorts the gravity field , and gives a quadrupole moment to the gravitational field which is significant at distances comparable to the radius of the body .