A very powerful cosmic ray hit the Earth: Source unknown

Michelle Starr*

A cosmic ray crashing into Earth’s atmosphere has stunned astrophysicists.

The tiny particle carried energy of more than 240 exa-electron volts, or 2.4 x 1020 electron volts, second only to the famous, mind-boggling 320 exa-electron volt ‘Oh My God particle’ detected in 1991.

But there is still a conundrum here. Just like the ‘Oh My God’ particle, scientists were unable to trace the new particle to an open source.

John Matthews, a physicist at the University of Utah in the USA and a member of the Telescope Array collaboration team that made the discovery, said: “The particles have such a high energy that they should not be affected by galactic and extragalactic magnetic fields. “You have to be able to show where they came from in the sky,” he said. Matthews continued:

“On the other hand, in the case of the ‘Oh My God particle’ and this new particle, you trace its orbit back to its source and you can’t find anything with an energy high enough to create it. “That’s what makes it mysterious: What’s going on there?”

COSMIC RAYS ARE STILL A COSMIC PUZZLE

Cosmic rays are partly a cosmic puzzle. Even though we’ve been able to detect them for over a century, we don’t yet have a definitive idea of ​​all the different ways they can spread throughout the Universe.

Cosmic rays are not fundamentally radiation like light; They are particles that mostly have an atomic nucleus. In addition, they are subnuclear particles such as protons and electrons, which flow through the Universe more powerfully than they should, at close to the speed of light.

Scientists think they form under high-energy conditions such as supernovae and stellar collisions. Sources with less energy, such as stars, including the Sun, produce lower energy cosmic rays; but the stronger ones have also proven harder to detect.

Our atmosphere protects us from cosmic rays, which is truly a wonderful thing; After all, we have extremely useful methods of detecting them. When a cosmic ray hits our atmosphere, it collides with other particles within it, creating a shower of particles that rain down on Earth. We have observatories that can detect these particles and correlate them with the cosmic ray collision that produced them.

‘I THOUGHT THIS MUST BE A MISTAKE’

However, rain created by energetic cosmic rays falls over a relatively wide area. This shows that we need to cover an extremely large area if we are to reconstruct the particle phenomenon with any accuracy.

The Telescope Array, carried out in international cooperation, covers an effective detection area spanning 700 square kilometers. On May 27, 2021, the telescope array detected a signal. After performing various calculations and analyses, checking and re-checking them, the Telescope Array collaborating team concluded that they had detected a particle on the energy scale of the ‘Oh My God’ particle.

“When I first discovered this extremely high-energy cosmic ray, I thought it must be a mistake because it has exhibited an unprecedented energy level over the past 30 years,” said Toshihiro Fujii, a physicist at Osaka Metropolitan University who led the research.

The discovery, made in a different region of the sky using a different technique than the one that revealed the Oh My God particle, revealed that these observations, although rare, represent real astrophysical events. The detection of the Oh My God particle was not a coincidence or a mistake.

IT TAKES ITS NAME FROM THE JAPANESE GODDESS

The research team named the new particle ‘Amaterasu’, after the powerful Shinto sun goddess. Both particles are likely protons, the researchers said.

Confirmation of the existence of extremely high-energy cosmic rays means that we are now faced with a difficult situation. As can be seen, there is a significant cutoff in extremely high energy particles; This is an energy known as the ‘Greisen-Zatsepin-Kuzmin limit’, reaching 5 x 1019 electron volts.

Because cosmic rays lose energy as they travel through space, this is thought to be the highest energy level a particle can maintain over long distances, about 160 million light-years. Apparently there are things that can produce cosmic rays at such a distance from us. However, nothing powerful enough to produce the ‘Oh My God’ or ‘Amaterasu particle’ has been detected within 160 million light years of the Solar System.

‘WHAT FACES US IS A REAL MYSTERY’

“Even things that people think of as high energy, like supernovae, pale in comparison,” Matthews said. “As the particle accelerates, you need huge amounts of energy, really high magnetic fields, to confine it.”

Retracing Amaterasu’s path through space requires returning to a cosmic void, a region with relatively little space within the universal network where galaxies tend to cluster. This makes me think there is something being overlooked somehow. Or maybe magnetic fields are better at accelerating particles than we thought. Maybe there’s a source nearby that we can’t see. Or maybe the particles point to an astrophysical phenomenon we’ve never seen before.

Physicist John Belz from the University of Utah in the USA said, “Defects in the structure of the space-time fabric may be overlapping cosmic networks. Actually, I’m listing the crazy ideas that people come up with; because there is no ordinary explanation for this. “What we have before us is a real mystery,” he said.

The research paper was published in the journal Science.

*Journalist.

Original article Science Alert taken from the website. (Translated by: Tarkan Tufan)