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Gravity

Updated: Nov 30, 2022

Writer: Bedirhan Atabay

Gravity is the force that matters have. This is the reason why some matters pull other matters. Gravity was first discovered in 1687 by Isaac Newton. Newton said, “Every particle of matter in the universe attracts every other particle with a force that is directly proportional to the product of the masses of the particles and inversely proportional to the square of the distance between them.” Even though there were theories about gravity before 1687, Newton was the one who saw the big picture and proved the existence of gravity. Later, in the 20th century, Einstein developed a revolutionary theory about gravity: he suggested that gravity is the warping between space and time.


Every single matter has its gravity. However, different objects have different gravity levels. For example, Earth has a larger gravity than the Moon; therefore, the Earth pulls the Moon, which instance is similar to the Earth has a superior gravity level than you; therefore, it pulls you into its barycenter and this is the reason why you have a weight. Weight depends on the gravity level; therefore, you would have different weights on different planets, if you are 735 Newton on the Earth, you would be 122 Newton on the Moon, or if you are 500 Newton on the Earth, you would be 1260 Newton on Jupiter.


We said that the Earth has a different gravity than other matters, however, did you know that gravity changes on the Earth’s surface too? For example, if one object weighs 100 N on the equator, then this means that it would weigh nearly 105 N on the poles. GRACE is a mission to record differences in gravity on Earth’s surface.


There are four natural forces: Gravity, Weak Force, Electromagnetic Force, Strong Nuclear, and Gravity Force. “The Weak Force” is the force that appears when bosons are exchanged. “Electromagnetic Force” is the force that appears when electrons and protons interact with each other. “The Strong Nuclear Force '' is the force that happens when two subatomic particles get extremely near to each other. “Gravity” is the weakest of those four forces. We are not sure if these four natural forces are sub-branches of one single force, or if these forces are all separated from each other.


As we mentioned before, every matter has its gravity. However, we did not mention how much gravity celestial bodies possess. Jupiter has the largest gravity alongside the planets in the Solar System. Jupiter’s gravity is around 2.5 g ( g: the gravity of Earth). The Sun possesses a gravity of around 28 G. This number can seem small to you, however, the great one hasn’t come yet: An ordinary black hole possesses 1.6 trillion g gravity. This is massive.


Gravitational waves, which are released when massive objects like neutron stars and black holes rotate around one another, have also recently been observed by scientists. This is another effect of Einstein's relativity. By spotting the incredibly low signal of such occurrences, the Laser Interferometer Gravitational-Wave Observatory (LIGO) has since 2017 unlocked a new door to the cosmos.


Einstein said that gravity is related to time, right? We call gravity’s effects on time “Gravitational Time Dilation”. Well, there are many examples of Gravitational Time Division. For instance, if you climb on a tree, then time will go on faster for you than you are on the Earth’s surface (as accepted the top of the tree is a higher place than the Earth’s Surface.

These attempts appear to be a long way from Newton and his apple, but they serve as a microcosm for science as a whole: sometimes the universe is far more interesting and complex than previously believed.

Further Reading:

  1. Rummel, R. (2020). Earth’s gravity from space. Rendiconti Lincei. Scienze Fisiche E Naturali, 31(S1), 3–13. https://doi.org/10.1007/s12210-020-00889-8

  2. Child, B. (2018, February 22). Gravity’s science exploded by top astrophysicist Neil DeGrasse Tyson. The Guardian. https://www.theguardian.com/film/2013/oct/08/gravity-science-astrophysicist

  3. Syed, H. S. (2020, May). Time and Gravity. https://www.researchgate.net/publication/341775924_Time_and_Gravity

  4. Jörges, B. (2017). Gravity as a Strong Prior: Implications for Perception and Action. Frontiers. https://www.frontiersin.org/articles/10.3389/fnhum.2017.00203/full

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