What is believed to be the source of ultra-high-energy cosmic rays?

Question

Quizplus · Accepted Answer

While the exact source of ultra-high-energy cosmic rays is not yet fully understood, black holes are thought to be the most likely source due to their intense gravitational fields and ability to accelerate particles to extremely high energies. Other possible sources such as active supernovae, globular clusters, and quasars have not been observed to produce particles with the necessary energies to account for ultra-high-energy cosmic rays.

What Is Believed to Be the Source of Ultra-High-Energy Cosmic