A group of scientists have confirmed that the highest energy cosmic rays come from outside of our Galaxy.
The latest confirmation comes via a recently published paper in Science where a group of 400 scientists described how they managed to detect an anisotropy, an asymmetry in the cosmic particles’ distribution of arrival directions as they approach the Earth.
In the paper, Gregory Snow, University of Nebraska-Lincoln physics professor said, “There have been other pieces of evidence, but I would say this paper really confirms that most of the highest energy cosmic ray particles are not coming from the Milky Way galaxy.”
“By understanding the origins of these particles, we hope to understand more about the origin of the Universe, the Big Bang, how galaxies and black holes formed and things like that. These are some of the most important questions in astrophysics.”
If you are familiar with the history of ultrahigh cosmic rays, then you might already know that scientists are observing the rays for more than 50 years but due the rays’ charged nature, it’s extremely difficult to detect their origin. Due to the charged nature, the rays interact with magnetic fields throughout the universe meaning intergalactic energy fields deflect the cosmic ray particles by a small amount as they move.
Snow wrote, “The sun emits low-energy cosmic ray particles that are detected here on Earth, but they are nowhere near as high energy as the particles detected at the Auger Observatory. The particles we detect are so energetic they have to come from astrophysical phenomena that are extremely violent. Some galaxies have an explosive, massive black hole in their centers and there are theories that these very violent centers accelerate particles of very high energy that eventually reach Earth.”
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