一いち次じ宇う宙ちゅう線せん

noun

primary cosmic rays

Technical term in astrophysics; refers to high-energy particles from space before they interact with the Earth's atmosphere.

• 一いち次じ宇う宙ちゅう線せんは主おもに陽よう子しからなる。

  Primary cosmic rays consist mainly of protons.