explain gravity to me? Let's start with a definition ... When matter is collected in one place, it forms a center of mass ...

The gravity holding these galaxies exists because of this invisible mass. For decades ... large gravitational force pulling it towards the center of the shell,” Lieu explained.

Gravity close gravityThe force of attraction between all objects. The more mass an object has, the larger the force of gravity it exerts. is a force that attracts objects towards each other.