Astroparticle Basics — Name for High-Energy Particles from Space What do we call the high-energy subatomic particles that originate in outer space and constantly strike Earth’s atmosphere?

Introduction / Context:
Astroparticle physics and space science introduce the concept of energetic particles arriving at Earth from outside our planet. These particles, spanning a range of energies and compositions, are collectively called cosmic rays, a term that appears often in general science examinations.

Given Data / Assumptions:

• Particles come from outer space and hit Earth’s atmosphere.
• They possess high energies compared to typical terrestrial background particles.
• We need the umbrella term, not a specific particle species.

Concept / Approach:
Cosmic rays are primarily high-energy protons and heavier nuclei, with a smaller component of electrons and other particles. When they collide with atmospheric nuclei, they produce extensive air showers of secondary particles (muons, pions, etc.). Because the composition is mixed, the correct answer is the generic label “cosmic rays,” not a single species such as “protons” or “electrons.”

Step-by-Step Solution:

Verification / Alternative check:
Introductory physics texts define cosmic rays as high-energy particles from space; ground detectors and balloon experiments measure resulting secondary showers.

Why Other Options Are Wrong:

• Protons / electrons: Components of cosmic rays, but not the correct collective name.
• None of the above: Incorrect because “cosmic rays” is the established term.

Common Pitfalls:
Equating “cosmic rays” with “gamma rays.” Cosmic rays are charged particles; gamma rays are high-energy photons.

Final Answer:
cosmic rays