The Highest-Energy Cosmic Rays That Reach Earth

question 31

Multiple Choice

The highest-energy cosmic rays that reach Earth

• A) could actually originate outside the Milky Way Galaxy.
• B) are produced in particle accelerators here on Earth.
• C) emerge from the supermassive black hole at the center of the Milky Way.
• D) are in fact X-ray and gamma-ray photons.
• E) are the best candidates for explaining dark matter.

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Definitions:

Economic Efficiency

A condition where resources are allocated in a way that maximizes the net benefit to society.

Runs Out

A situation where a supply or quantity of something is completely used up or exhausted.

Next Century

A future period of 100 years, used to forecast or plan long-term visions or developments.

Economic Viability

The ability of an entity or activity to sustain itself financially over the long term.