🪐intro to astronomy review

Fission

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Fission is a nuclear reaction in which an atomic nucleus splits into two or more smaller nuclei, along with the release of energy. This process is fundamental to nuclear power and certain types of weaponry but is not the primary process fueling the Sun.

5 Must Know Facts For Your Next Test

  1. Fission releases a significant amount of energy due to the conversion of mass into energy, as described by Einstein's equation E=mc^2.
  2. In fission, heavy elements like uranium-235 and plutonium-239 are typically used as fuel.
  3. The Sun primarily uses fusion, not fission, to generate its immense energy.
  4. Fission can be initiated by bombarding a heavy nucleus with neutrons.
  5. The products of fission include smaller nuclei (fission fragments), free neutrons, and gamma photons.

Review Questions

Fission Definition - Intro to Astronomy Key Term | Fiveable