Which process is primarily responsible for the formation of heavy elements such as gold and uranium in the universe?

• A. Radioactive decay of lighter elements
• B. Chemical reactions in planetary atmospheres
• C. Neutron capture during supernova explosions
• D. Nuclear fusion in the cores of massive stars

Answer: (C)

Verified step by step guidance

1. Understand that the formation of heavy elements beyond iron in the universe cannot be explained by simple nuclear fusion in stars, as fusion of elements heavier than iron consumes energy rather than releasing it.
2. Recognize that radioactive decay of lighter elements and chemical reactions in planetary atmospheres do not create new heavy elements; they only transform existing atoms or molecules.
3. Learn that neutron capture is a process where atomic nuclei capture neutrons, which can then undergo beta decay to form heavier elements.
4. Identify that supernova explosions provide the extreme conditions (high neutron flux and energy) necessary for rapid neutron capture, known as the r-process, which is responsible for creating many heavy elements like gold and uranium.
5. Conclude that neutron capture during supernova explosions is the primary astrophysical process responsible for the formation of heavy elements in the universe.