#173 | ast10 – Cosmic rays

Hi guys,

I’ve seen a psychologist today, I am not too surprised with the result. I have a second appointment, we will see what will happen next time though. Oh well boy.

A short post, I am feeling a bit tired from this hour of talking. This time, I will write about cosmic rays. The question I am asking to myself today is “what are cosmic rays and where did they come from?“. Let’s try to look for some answers together.

What are cosmic rays?

Cosmic rays are high-energized particles coming from deep-space. In fact, cosmic rays are the nuclei of elements (hydrogen, carbon, etc) which traveled at extremely high speed in space and which are mostly formed by protons. They are also rare to be detected on the surface of Earth due to magnetic shielding provided by our planet: ” the rate of their arrival at the top of the atmosphere is only about one per square kilometer per year, the equivalent to one cosmic ray hitting an area the size of a soccer field about once per century.“[1]
When the ray entered into our atmosphere, the particles are dispersed into a shower of protons, electrons and, muons (#note to myself). These showers are then interacting with others nuclei, splitting the showers into more showers of particles. Cosmic rays can be detected through this decomposition phenomenon. It is possible through a medium (like water) by tracking electromagnetic radiation left by these particles.

Where did they come from?

From this article [2], it seems that these nuclei are hypothetically from supernova explosions. These particles are charged in energy and accelerated in high-speed by the energy wave from the explosion. To be able to track the cosmic rays from the supernova, the scientists are tracking pions (sub-particle produced when a cosmic ray interact with another material, exactly like cosmic rays which enter into our atmosphere I suppose). These pions are then decaying into gamma ray that can be detected by special telescope. But it seems it is rather difficult to know exactly if these gamma rays (#note) are from cosmic rays with high energized proton nuclei or are from high energy electrons because of most the gamma rays interacting in the observations.
So the answer to my question is still in a hypothesis state, but I am rather satisfied with this answer even if I am still curious about the final result of the researches.


[1] Michigan Technological University. “Detecting cosmic rays from a galaxy far, far away.” ScienceDaily. ScienceDaily, 21 September 2017. <www.sciencedaily.com/releases/2017/09/170921141257.htm>.

[2]« Science: Evidence Shows That Cosmic Rays Come From Exploding Stars ». AAAS – The World’s Largest General Scientific Society, 13 février 2013. https://www.aaas.org/news/science-evidence-shows-cosmic-rays-come-exploding-stars.

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