SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/eng-radiation-no-medium

Which heat-transfer mode can cross a vacuum?

Thermal radiation can cross empty space.

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  1. Convection
  2. Thermal radiation ✔
  3. Conduction

Why: Thermal radiation travels as electromagnetic waves and needs no material medium. Conduction and convection require matter, so sunlight reaches Earth by radiation.

Huh, didn't know that: Every object above absolute zero emits thermal radiation.

The dad joke
Radiation crossed the vacuum because it needed no ride.
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References

Answer: Thermal radiation. Thermal radiation travels as electromagnetic waves and needs no material medium. Conduction and convection require matter, so sunlight reaches Earth by radiation.

  1. OpenStax Physics, Heat, Specific Heat, and Heat Transfer openstax.org/books/physics/pages/11-2-heat-specific-heat-and-heat-transfer
    Radiation is the only method of heat transfer where no medium is required
    Checked 2026-10-10.

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