Cosmic rays

(Last edited: Saturday, 30 September 2023, 5:48 PM)

Short definition: Cosmic rays are high energy particles that travel through space at nearly the speed of light. Most cosmic rays are represented by atomic nuclei stripped of their atoms.

Detailed definition: Cosmic rays were discovered by Victor Hess in 1912. They originate from the Sun, from the Milky Way, and from distant galaxies. Most cosmic rays (89%) are protons of hydrogen, but some of them are nuclei of helium (around 10%) and other, heavier nuclei. Only about 1% of cosmic rays are lone electrons. Once a cosmic ray reaches the Earth’s atmosphere, it collides with other atoms there and bursts them into different particles, namely pions, muons and neutrinos.
The extremely high energy that cosmic rays have often causes electronics to malfunction: for example, corrupted data in memory devices or incorrect performance in CPUs. Cosmic rays used to be a problem mainly in spacecraft, satellites and high-altitude aircraft, but is becoming a concern in regular electronics too due to transistors becoming smaller in size.

Etymology: Cosmic comes from Ancient Greek κόσμος (kósmos, “order, proper order of the world”). The term ray likely arose because cosmic rays were initially believed to be electromagnetic radiation.

Sample sentence(s): Cosmic rays follow convoluted paths and arrive at the top of the Earth’s atmosphere from all directions.


French: Rayonnement cosmique

German: Kosmische Strahlung

Italian: Raggi cosmici

Polish: Promieniowanie kosmiczne, promienie kosmiczne

Swedish:  Kosmiska partiklar

Links to Videos/Articles:

Cosmic Rays - Introduction. (n.d.).

Friedlander, M. W. (2023, April 21). Cosmic ray | Definition, Types, Effects, & Facts. Encyclopedia Britannica.

Vox. (2019, August 30). The mysterious rays shooting at us from space [Video]. YouTube.

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