It is gravity that keeps planets, stars, solar systems and even galaxies together. The orbits of planets, while nearly circular, are in fact . Comets have a far more exaggerated elliptical orbit, which takes them close to the and then very far away again When objects are in orbit they are continually around a larger one. Two objects together will fall at the same rate and therefore appear to next to each other.
When objects are in orbit they are continually around a larger one. Two objects together will fall at the same rate and therefore appear to next to each other.