Gravity

Gravity is a law of nature where all objects of mass attract each other. Gravity holds the planets of star systems together and basically holds the whole universe together. Sir Isaac Newton developed the theory of gravity.

Referenes

 * The Tractators are a insect-like race that can control gravity with their minds. (DW: Frontios)
 * In the year 100,000,000,000,000 when all the stars had burned out, planets were found through a graviational field navigational system. (DW: Utopia)
 * During a crisis in midflight the TARDIS locks onto the nearest place of Gravity and lands there.