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Short answer

Gravity is the force by which a planet or other body pulls objects toward its center. It keeps the planets in orbit around the Sun and is why things fall when you drop them. [S1]

Key points

• All masses attract each other. The pull weakens with the square of the distance but never fully disappears. [S2]
• Einstein described gravity as a curve in space around a massive object. [S1]
• Kepler's laws and Newton's mechanics describe how planets move under gravity. [S2]

Claims

• id: C1 claim: Gravity draws objects toward a body's center. source: S1 evidence: "Gravity is the force by which a planet or other body draws objects toward its"
• id: C2 claim: Gravity keeps the planets in orbit around the Sun. source: S1 evidence: "The force of gravity keeps all of the planets in orbit around the sun."
• id: C3 claim: Gravitation is the mutual attraction of all masses. source: S2 evidence: "Gravitation is the mutual attraction of all masses in the universe."
• id: C4 claim: Gravity's effect falls with distance squared. source: S2 evidence: "its effect decreases in proportion to distance squared"

Sources

• [S1] What Is Gravity?. NASA. https://spaceplace.nasa.gov/what-is-gravity/en/ . License: US government work, public domain. Accessed 2026-11-04.
• [S2] Chapter 3: Gravity & Mechanics. NASA. https://science.nasa.gov/learn/basics-of-space-flight/chapter3-1/ . License: US government work, public domain. Accessed 2026-11-04.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).

@misc{iil_note_2e1tcvjt,
  author = {{iinventedlight}},
  title = {{What is gravity?}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-11-04},
  url = {https://iinventedlight.com/library/notes/what-is-gravity/},
  note = {Permanent ID iil:note:2e1tcvjt. License: CC-BY-4.0.},
}

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