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natural-science

How Gravity Works

Gravity is the attraction that makes masses move toward one another.

Picture a stretched sheet dipping under a heavy ball. A smaller rolling ball bends toward the dip—not because space is truly rubber, but because mass changes the paths things follow.

  1. A small mass and a large mass shown with weaker and stronger gravitational attraction.Less massMore massSmall rockMoonEarth

    Step 1

    Every mass has gravity

    Anything with mass attracts other mass. More mass creates a stronger gravitational effect.

  2. A person and falling ball with arrows pointing toward the center of Earth.fallsgravity pointsObjectGroundEarth's center

    Step 2

    Earth pulls you inward

    Earth's enormous mass pulls nearby objects toward its center. The ground stops you from continuing downward.

  3. A person and Earth pulling on each other with equal force arrows but very different motion.YouSmall massNoticeableaccelerationEarthHuge massTiny acceleration

    Step 3

    The pull works both ways

    Earth pulls you, and you pull Earth with an equal force. Earth's much larger mass makes its motion tiny.

  4. A satellite moving sideways while continuously curving downward around Earth.AgainMove sidewaysFall inwardMiss the groundKeep orbiting

    Step 4

    Sideways falling makes an orbit

    A fast-moving satellite keeps falling toward Earth while moving sideways enough to keep missing the surface.

  5. An astronaut and spacecraft falling together around Earth and appearing weightless inside.Elevator fallingtogether=Astronautsorbiting together

    Step 5

    Gravity still works in orbit

    Astronauts float because they and their spacecraft fall together, not because gravity disappeared.

  6. Newton's force model compared with Einstein's curved spacetime model of gravity.Newton's modelMasses attractExcellent for manycalculationsEinstein's modelSpacetime curvesExplains extremegravity

    Step 6

    Spacetime gives the deeper picture

    Newton describes gravity as a force. Einstein describes mass and energy curving spacetime, changing how objects move.

Common trap

There is no gravity in space.

Gravity reaches through space. Orbiting astronauts feel weightless because they and their spacecraft are falling together.

Quick check

Why does an orbiting satellite keep missing Earth?

  1. It moves sideways while falling
  2. Gravity turns off above the atmosphere
  3. Space pushes it away
Show the answer

Gravity bends the satellite's path inward while its sideways speed carries it past the curved surface.

Sources

  1. Newton's Law of Universal Gravitation and Einstein's TheoryOpenStax
  2. GravityEuropean Space Agency