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SCIENCE

The Claim

In a vacuum, heavier objects fall faster than lighter objects.

Verified by Lenz ·

The Short Version

The claim is contradicted by both basic physics and direct experiment. In a vacuum, heavier and lighter objects fall at the same rate because gravitational acceleration does not depend on an object's mass. NASA's Apollo 15 hammer-feather drop and precision tests of the equivalence principle confirm this.

Caveats

  • This confusion often comes from everyday observations in air, where drag can make lighter objects fall more slowly; that does not apply in a vacuum.
  • The claim reverses the established result of free-fall physics: mass affects gravitational force, but also inertia, and those effects cancel in the acceleration.
  • Low-authority video mirrors or summaries add no weight here because the core evidence already comes from primary scientific and institutional sources.

The Receipts

  1. The Apollo 15 Hammer-Feather Drop

    NASA Science

  2. Free Falling Object

    NASA Glenn Research Center

  3. Apollo 15 Hammer-Feather Drop

    NASA Goddard Space Flight Center (NSSDC)

  4. Falling Physics

    American Physical Society

  5. Do heavier objects fall faster than lighter objects?

    ScienceLine (UC Santa Barbara)

  6. Apollo 15 Hammer-Feather Drop

    NASA

  7. A most precise test for the fundamental law of gravity

    Nature

  8. Galileo's free-fall experiment confirmed

    Nature

  9. A critique of one of Galileo's mental experiments and an explanation ...

    arXiv

  10. Newtonian Equivalence Principles

    Philosophy of Science (via PubMed Central)

+ 13 more sources — see the full list on Lenz

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