SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/astro-heavy-elements-supernovae

During some supernovae, how can nuclei grow heavier than iron?

They rapidly capture neutrons, then some of those neutrons convert into protons.

Start playing free

  1. Ordinary core fusion releases energy
  2. They collect electrons from surrounding gas
  3. Nuclei capture neutrons that later become protons ✔

Why: Some supernovae create neutron-rich conditions. Nuclei can rapidly capture neutrons, then nuclear decay converts some neutrons into protons, building heavier elements. Neutron-star mergers are another confirmed site of this process.

Huh, didn't know that: NASA observations confirmed that a 2017 neutron-star merger could have created gold, platinum and other heavy elements.

The dad joke
Gold asked a neutron to stick around. The answer carried a lot of weight.
Like this card?
Play the game

References

Answer: Nuclei capture neutrons that later become protons. Some supernovae create neutron-rich conditions. Nuclei can rapidly capture neutrons, then nuclear decay converts some neutrons into protons, building heavier elements. Neutron-star mergers are another confirmed site of this process.

  1. Astronomy 2e, 23.2 Evolution of Massive Stars: An Explosive Finish openstax.org/books/astronomy-2e/pages/23-2-evolution-of-massive-stars-an-explosive-finish
    These neutrons can be absorbed by iron and other nuclei where they can turn into protons.
    Checked 2026-10-10.
  2. NASA Science, Where Does Gold Come From? science.nasa.gov/universe/stars/neutron-stars/magnetars/where-does-gold-come-from-nasa-data-has-clues
    they confirmed that this event could have created gold, platinum, and other heavy elements.
    Checked 2026-10-10.

Think this answer is wrong? Tap "Challenge this answer" on the card in the game and tell us why.

Test yourself in the game

Astronomy & SpaceWhere did elements heavier than primordial lithium mainly form?Astronomy & SpaceWhat explodes to make a Type Ia supernova, the standard candle for far galaxies?Astronomy & SpaceWhen a massive star's iron core collapses into a neutron star, about how big does it end up?

That's stuff everyone should know.