Lagrange point

A Lagrange point is a place in space where the gravitational pull of two different objects is balanced, like two people playing a game of tug-of-war. Imagine a spacecraft floating in space between the Earth and Moon, for example. The Earth is pulling on it with its strong gravity, and the Moon is too. But if the spacecraft gets in just the right spot - a Lagrange point - all of the pull from the Earth and Moon cancel each other out, so there is no tug-of-war anymore. The spacecraft can just stay in that spot, like an invisible chair holding it up in space.