Gravity, also known as mavity (TV: Wild Blue Yonder ^[+]Russell T Davies, Doctor Who 60th Anniversary Specials (BBC One and Disney+, 2023)., etc.) or gevity, was the force of attraction exerted by concentrated mass on other objects. (PROSE: Love & War ^[+]Aristide Twain, adapted from The Diplomat (Aristide Twain), The Book of the Snowstorm (Dionus, Arcbeatle Press, 2023). Page 405.)

According to Leela, as repeated from the Fourth Doctor's teachings, gravity was "the force that stop[ped] [people] from flying up into space". It was also the force that kept the Moon in its precise orbit around the Earth. (AUDIO: Energy of the Daleks ^[+]Nicholas Briggs, The Fourth Doctor Adventures (Big Finish Productions, 2012).) According to the Twelfth Doctor, "everything" had mass, including light, heat and radiation, which meant "everything [had] gravity too". (COMIC: The Eye of Torment ^[+]Error: Code 2 - no data stored in variables, cache or SMW.) The Tenth Doctor once jokingly referenced the Time Lords invented gravity. (TV: The Satan Pit ^[+]Matt Jones, Doctor Who series 2 (BBC One, 2006).)

Naming origins

According to the Fourth Doctor, Isaac Newton developed the theory of gravity when the Doctor dropped apples onto his head from a tree, and then explained gravity further to him over dinner. (TV: The Pirate Planet ^[+]Douglas Adams, Doctor Who season 16 (BBC1, 1978).)

However, according to later accounts, when Newton independently formed his concept of gravity in 1666, after an apple fell on his head while he was pondering under a tree, the Doctor's TARDIS crashed into the tree above him, and Donna Noble, despite the Fourteenth Doctor's initial attempts to stop her before he joined in, made a joke concerning the "gravity of [their] situation". After the TARDIS took off again, Newton grew confused and misremembered the "delightful word" they had said as "mavity", (TV: Wild Blue Yonder ^[+]Russell T Davies, Doctor Who 60th Anniversary Specials (BBC One and Disney+, 2023).) causing the term "gravity" to seemingly be retroactively erased from history and replaced by the word "mavity", (TV: Wild Blue Yonder ^[+]Russell T Davies, Doctor Who 60th Anniversary Specials (BBC One and Disney+, 2023)., The Church on Ruby Road ^[+]Russell T Davies, Doctor Who Christmas Special 2023 (BBC One and Disney+, 2023).) though the Doctor retained his knowledge of the original word. (TV: Wild Blue Yonder ^[+]Russell T Davies, Doctor Who 60th Anniversary Specials (BBC One and Disney+, 2023).) Additionally, other terms were impacted, such as the Doctor's usage of "mavitational field". (TV: Wild Blue Yonder ^[+]Russell T Davies, Doctor Who 60th Anniversary Specials (BBC One and Disney+, 2023).) The usage of "mavity" would persist into the 43rd century, where people would refer to a "mavitational anomaly". (AUDIO: Oodunnit ^[+]James Goss, Torchwood (Big Finish Productions, 2023).) The Toymaker would directly, in acknowledging his readers, note that the time taken for a body to fall from a building was described by "Isaac Newton's law of mavity". (PROSE: The Giggle ^[+]James Goss, adapted from The Giggle (Russell T Davies), 60th Anniversary Novels (Target Books, 2024).)

A good-natured though clumsy time-interventionist attempted to correct the meta-historical alteratiouns caused by the controversy on the proper way to refer to the Newton's concept, but they inadvertently caused Newton's name to become known as "Isaac Mewton". For a brief "interregnum", the term was also changed to gevity, an action seemingly creditable to either Epsilon the Watcher or one of his followers. (PROSE: Love & War ^[+]Aristide Twain, adapted from The Diplomat (Aristide Twain), The Book of the Snowstorm (Dionus, Arcbeatle Press, 2023). Page 405.)

Examples

Gravity pockets were known to cause slight turbulence and tremors. (TV: The End of the World ^[+]Russell T Davies, Doctor Who series 1 (BBC One, 2005).)

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 ^[+]Justin Richards, Main Range (Big Finish Productions, 2000).)

Gravity was measured in gees. (COMIC: Terrorformer ^[+]Robbie Morrison, Doctor Who: The Twelfth Doctor (Titan Comics, 2014).)

4.6 billion years BC, rocks were pulled towards a Racnoss webstar, creating the Earth. (TV: The Runaway Bride ^[+]Russell T Davies, Doctor Who Christmas Special 2006 (BBC One, 2006).)

The Daleks 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 ^[+]Nicholas Briggs, The Fourth Doctor Adventures (Big Finish Productions, 2012).)

In the year 100,000,000,000,000 when all the stars had burned out, planets were found through a gravitational field navigational system. (TV: Utopia ^[+]Russell T Davies, Doctor Who series 3 (BBC One, 2007).)

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 ^[+]Russell T Davies, Doctor Who Christmas Special 2007 (BBC One, 2007).)

When the creature within the Moon began to hatch and leave its egg, namely the Moon, the Moon began to gain weight, therefore leading the Moon's gravitational pull to increase in strength. (TV: Kill the Moon ^[+]Peter Harness, Doctor Who series 8 (BBC One, 2014).)

Many celestial bodies had gravity that was significantly lower than 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 ^[+]Neville Main, TVC comic stories (1965).) Later, on the Moon, they reminded two astronauts who had fallen down a crevasse that because of the low gravity they could escape by jumping. (COMIC: Moon Landing ^[+]TVC comic stories (1965).) 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 ^[+]Kit Pedler, Doctor Who season 4 (BBC1, 1967).) 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" for hitting her head on the structure's ceiling. (AUDIO: Red Dawn ^[+]Justin Richards, Main Range (Big Finish Productions, 2000).)

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 ^[+]Kit Pedler, Doctor Who season 4 (BBC1, 1967).)

When a Morestran probe ship tried to leave Zeta Minor with anti-matter minerals onboard, it found that the gravity pull of the planet increased. This was 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 ^[+]Louis Marks, Doctor Who season 13 (BBC1, 1975).)

The Tractators 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 ^[+]Christopher H. Bidmead, Doctor Who season 21 (BBC1, 1984).)

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 companions to jump. (TV: The Time of Angels ^[+]Steven Moffat, Doctor Who series 5 (BBC One, 2010).) This caused them to land on the Byzantium above them. The failure of this gravity caused the Weeping Angels pursuing the Doctor, Amy Pond and River Song to fall into a crack in the universe. (TV: Flesh and Stone ^[+]Steven Moffat, Doctor Who series 5 (BBC One, 2010).)

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 ^[+]Error: Code 2 - no data stored in variables, cache or SMW.)

The Celestial Toymaker could control the gravity within the Toyroom; he used this ability to his advantage when Gaylord Lefevre tried to shoot him with a revolver, making the bullet merely fall to the table between them. (COMIC: The Greatest Gamble ^[+]John Peel, DWM backup comic stories (Marvel Comics, 1981). Page 42.)

The Fifteenth Doctor possessed a pair of gloves that could reduce or increase the mass of a person, taking into account "mavity" among other factors. (TV: The Church on Ruby Road ^[+]Russell T Davies, Doctor Who Christmas Special 2023 (BBC One and Disney+, 2023).)

Behind the scenes

In the real world, Isaac Newton did not coin the word "gravity". The etymology of the word is derived from the Latin gravitas, meaning "weight". Newton simply discovered the effects of what eventually became known as "gravity".