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How does gravity work?

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Quick answer

Gravity is the attraction between any objects that have mass. The more mass an object has, the stronger it pulls; the farther apart two objects are, the weaker the pull. Near Earth, this pull accelerates falling objects downward at about 9.8 meters per second squared.

Gravity works because every object with mass attracts every other object. Einstein's deeper explanation: mass curves the fabric of spacetime, and other objects follow that curve — which we feel as the pull of gravity.

Step by step

  1. Every object with mass attracts every other object with mass, however weakly.
  2. The strength of that attraction grows with the amount of mass involved on both sides.
  3. The pull weakens quickly with distance, dropping with the square of the separation.
  4. Near Earth, the planet's mass dominates, so objects accelerate downward at about 9.8 m/s².
  5. In Einstein's picture, mass curves spacetime and objects follow the straightest available path.
  6. Orbiting bodies keep falling toward a mass but move sideways fast enough to keep missing it.

Key things to understand

  1. More mass means more pull; greater distance means weaker pull (it falls off with the square of distance).
  2. Newton modeled gravity as a force between masses; it predicts orbits and falling objects with great accuracy.
  3. Einstein showed mass and energy curve spacetime, and objects simply follow the straightest path through that curved space.
  4. Near Earth's surface, gravity accelerates everything downward at about 9.8 m/s², regardless of mass.

Labelled diagram

  1. Massive object

    A star or planet sits at the center and distorts the space around it.

  2. Curved grid

    Spacetime bends inward near the mass, like a heavy ball on a stretched sheet.

  3. Smaller object

    A moon or ball follows the curve rather than moving in a straight line.

  4. Orbital path

    Repeated falling along the curve produces a stable orbit around the mass.

  5. Observer

    We interpret the curved motion as a gravitational pull toward the mass.

How mass curves spacetime and guides motion

Real-world examples

  • An apple dropping from a tree falls toward Earth's center because Earth's mass pulls it downward.
  • The Moon orbits Earth instead of flying off because Earth's gravity continuously bends its path.
  • A bathroom scale reads your weight, which is the gravitational force Earth exerts on your body.
  • GPS satellites adjust their clocks because gravity slightly changes the rate of time near Earth.

Common mistake

✗ Myth: Astronauts float in space because there is no gravity up there.

✓ Fact: Gravity still acts strongly in orbit. Astronauts float because they and their spacecraft are falling around Earth together, so they never feel the ground push back.

People also ask

How does gravity work in space?
Gravity works the same way in space as on Earth: every mass attracts every other mass. Astronauts appear weightless because they are in continuous free fall around Earth, not because gravity disappears. The same attraction keeps the Moon orbiting Earth and the planets orbiting the Sun.
Why does gravity pull things down?
Gravity pulls things toward Earth's center because Earth's huge mass attracts smaller nearby objects. "Down" simply means the direction toward that center. On the opposite side of the planet, down points the other way, which is why people there do not fall off.
Who discovered gravity?
Isaac Newton did not invent gravity but described it mathematically in the 1600s, showing that the same force governs falling apples and orbiting planets. Albert Einstein later reframed gravity as the curvature of spacetime. Many earlier thinkers, including Galileo, had already studied how objects fall.
Why do objects fall at the same rate?
A heavier object feels more gravitational force but also resists acceleration more. The two effects cancel, so all objects fall equally fast in a vacuum.
Does gravity work in space?
Yes. Astronauts float because they're in continuous free fall around Earth (orbiting), not because gravity is absent.
How is gravity related to spacetime?
In general relativity, mass curves spacetime, and what we perceive as gravitational pull is objects following that curvature.

Part of the guide: Space & Astronomy →