Discoveries using the telescopes on Mauna Kea

[TomK]

Cosmic ray shower captured by Subaru on Mauna Kea

Cosmic rays are actually high-energy particles that are formed by energetic events such as supernovae (exploding stars). They travel the Galaxy and universe at very high relativistic speeds and carry a lot of energy. Because they tend to be charged (most are protons with a positive charge) they are affected by magnetic fields so get deflected, so figuring out exactly where they come from is almost impossible.

When one of the particles hits the Earth's atmosphere, it collides with an atom or molecule and a massive reaction occurs. The cosmic ray particle exchanges its energy in the collision and several other smaller particles are formed (muons). They go on to collide with other particles and more muons are produced. These muons have a ridiculously short half-life, around 2 microseconds, but because they are moving at relativist speeds, that's more than enough time to collide with another particle in our atmosphere. You end up with a cascade of particles that are not harmful to us.

I don't recall this ever being imaged, but now it has.




This is from https://www.nature.com/articles/s41598-023-42164-4

https://subarutelescope.org/en/results/2.../3310.html