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SESK: Stuff Everyone Should Know · sesk.info/aero-sun-fusion-hydrogen-helium

What powers the Sun deep in its core?

Nuclear fusion: hydrogen nuclei join to make helium.

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  1. Burning coal and gas like a giant fire
  2. Fusing hydrogen into helium ✔
  3. Splitting uranium atoms apart

Why: The Sun's core is so hot and squeezed that hydrogen nuclei smash together and fuse into helium. That fusion releases the huge energy that becomes sunlight. It is not burning like a campfire.

Huh, didn't know that: Core temperatures top about 15 million degrees Celsius (27 million degrees Fahrenheit).

The dad joke
Hydrogen and helium walk into the Sun's core. Things get pretty heated.
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References

Answer: Fusing hydrogen into helium. The Sun's core is so hot and squeezed that hydrogen nuclei smash together and fuse into helium. That fusion releases the huge energy that becomes sunlight. It is not burning like a campfire.

  1. NASA Science, Basics of Space Flight, Chapter 1 science.nasa.gov/learn/basics-of-space-flight/chapter1-1
    sustaining a thermonuclear reaction fusing hydrogen nuclei and producing helium nuclei
    Checked 2026-10-10.
  2. NASA Science, Sun Facts science.nasa.gov/sun/facts
    where temperatures top 27 million °F (15 million °C).
    Checked 2026-10-10.

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