Gravity Gravity was , as Leela repeated from the Fourth Doctor ' s teachings , " the force that stops us from flying us into space " . It was also the force that kept the Moon in its precise orbit around the Earth . ( AUDIO : " Energy of the Daleks " ) According to the Twelfth Doctor , " everything " had mass , including light , heat and radiation , which meant " everything [ had ] gravity too " . ( COMIC : " The Eye of Torment " ) According to the Fifth Doctor , the gravity of a celestial body was dependent on its mass , not necessarily how big it was . Peri Brown added , " And how fast [ it was ] spinning and what the core [ was ] made of . " ( AUDIO : " Red Dawn " ) Gravity was measured in gees . ( COMIC : " Terrorformer " ) 4 . 6 billion years BC , rocks were pulled towards a Racnoss webstar , creating the Earth . ( TV : " The Runaway Bride " ) The Dalek s planned to counteract gravity and make the Moon leave Earth ' s orbit on 31 January 2025 , making the planet ' s axis shift wildly , causing natural disasters and severe climate changes . ( AUDIO : " Energy of the Daleks " ) Sir Isaac Newton developed the theory of gravity . The Fourth Doctor once claimed that he sat in Newton ' s tree dropping apple s onto his head , then explained gravity to him over dinner . ( TV : " The Pirate Planet " ) In the year 100 , 000 , 000 , 000 , 000 when all the star s had burned out , planets were found through a gravitional field navigational system . ( TV : " Utopia " ) During a crisis in midflight , the Tenth Doctor claimed his TARDIS would lock onto the nearest place of gravity and land there . ( TV : " Voyage of the Damned " ) Many celestial bodies had gravity that was significantly lower that of Earth ' s . On one asteroid , the First Doctor , John and Gillian were able to jump high in the air . ( COMIC : " The Therovian Quest " ) Later , on the Moon , they reminded two astronaut s who had fallen down a crevasse that because of the low gravity they could escape by jumping . ( COMIC : " Moon Landing " ) On another visit to the Moon , the Second Doctor , Ben , Polly and Jamie amused themselves by jumping around in the low gravity until Jamie accidentally injured himself . ( TV : " The Moonbase " ) According to the Fifth Doctor , Mars had gravity which was " about a third " of the sorts of planets the human , Peri Brown , was used to . The Doctor warned Peri not to " just go jumping about " inside the tomb of Izdaal , as she was " liable " of hitting her head on the structure ' s ceiling . ( AUDIO : " Red Dawn " ) Manipulating gravity . The Gravitron was installed in the moonbase in the year 2050 . By using it to alter the Earth ' s tides , people were able to control the Earth ' s weather . In 2070 , the Cybermen attempted to take over the Gravitron as part of their invasion of Earth . ( TV : " The Moonbase " ) When a Morestran probe ship tried to leave Zeta Minor with anti - matter mineral s onboard , it found that the gravity pull of the planet increased . This as due to the influence of the anti - matter creature , unwilling to let them leave with the material . After the Fourth Doctor fulfilled his promise to return the anti - matter , the ship was able to leave Zeta Minor . ( TV : " Planet of Evil " ) The Tractator s could control gravity with their minds . This power could be amplified by tunnel systems built in a precise way . On Frontios , the Tractators used an excavation machine to create a series of tunnels with which to create a gravity motor . ( TV : " Frontios " ) The " Byzantium " had artificial gravity . On Alfava Metraxis in the 51st century , the Eleventh Doctor shot a gravity globe floating above him and ordered his companion s to jump . This caused them to land on the " Byzantium " above them . ( TV : " The Time of Angels " / " Flesh and Stone " ) The failure of this gravity caused the Weeping Angel s pursuing the Doctor , Amy Pond and River Song to fall into a crack in the universe . ( TV : " Flesh and Stone " ) Professor Alice Dubrovnik worked on the graviton inverter , which was used on the " Pollyanna " on its mission to circumnavigate the Sun . It could flip gravitational force and turn it back on itself . Without it , the " Pollyanna " would have been " squished " by the Sun ' s gravitational force . ( COMIC : " The Eye of Torment " )