Fusion

Definition

Fusion is the process where two light atomic nuclei combine to form a heavier nucleus, releasing an enormous amount of energy. This process powers stars, including our Sun, and is fundamental to understanding stellar evolution and the universe's energy dynamics.

5 Must Know Facts For Your Next Test

1. Fusion in the Sun primarily involves hydrogen nuclei combining to form helium through the proton-proton chain reaction.
2. The energy produced by fusion in stars counteracts gravitational collapse, maintaining their stability.
3. Fusion reactions convert mass into energy according to Einstein's equation E=mc².
4. In massive stars, fusion progresses through a series of stages, producing heavier elements up to iron before ending in a supernova explosion.
5. Fusion has been a key driver since the Big Bang, influencing the formation and evolution of galaxies and stars.

Review Questions

• What role does fusion play in maintaining the stability of stars?
• Explain how fusion reactions convert mass into energy using Einstein's equation.
• Describe the stages of fusion in massive stars leading up to a supernova explosion.

Related terms

Nuclear Fusion:

A nuclear reaction where two atomic nuclei combine to form a heavier nucleus with the release of energy.

Proton-Proton Chain Reaction: A series of nuclear reactions that occur in the cores of stars like the Sun, converting hydrogen into helium.

Supernova:

A powerful explosion that occurs at the end of a massive star's life cycle following extensive fusion processes creating heavy elements.