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SESK: Stuff Everyone Should Know · sesk.info/aero-explorer1-van-allen-belts

What did America's first satellite, Explorer 1, help scientists discover?

Radiation belts around Earth, now called the Van Allen belts.

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  1. Radiation belts held around Earth ✔
  2. Ice on the Moon
  3. Earth's ozone layer

Why: Explorer 1 carried a cosmic ray detector. Its readings led Dr. James Van Allen to find belts of radiation trapped around Earth by its magnetic field.

Huh, didn't know that: Explorer 1 went to space on January 31, 1958, less than four months after Sputnik.

The dad joke
Why did Explorer 1 get good grades? It was a very bright satellite in its class orbit.
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References

Answer: Radiation belts held around Earth. Explorer 1 carried a cosmic ray detector. Its readings led Dr. James Van Allen to find belts of radiation trapped around Earth by its magnetic field.

  1. NASA JPL, Explorer 1 www.jpl.nasa.gov/missions/explorer-1
    Dr. James Van Allen's discovery of radiation belts around Earth held in place by the planet's magnetic field.
    Checked 2026-10-10.

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