Scientists discover highest-energy light coming from Sun


New York, Aug 7 (IANS) An international team of scientists has discovered the highest-energy light coming from the sun.

“The sun is more surprising than we knew,” said Mehr Un Nisa, a postdoctoral research associate at Michigan State University in the US.

“We thought we had this star figured out, but that’s not the case.”

The team also found that this type of light, known as gamma rays, is surprisingly bright.

Although the high-energy light doesn’t reach the Earth’s surface, these gamma rays create telltale signatures that were detected by the team working with High-Altitude Water Cherenkov Observatory, or HAWC.

The energy of the original gamma ray is liberated and redistributed amongst new fragments consisting of lower energy particles and light.

It’s these particles — and the new particles they create on their way down — that HAWC can “see”.

When the shower particles interact with water in HAWC’s tanks, they create what’s known as Cherenkov radiation that can be detected with the observatory’s instruments. The team began collecting data in 2015 and in 2021, had accrued enough data to start examining the sun’s gamma rays with sufficient scrutiny.

“After looking at six years’ worth of data, out popped this excess of gamma rays,” Nisa said.

“When we first saw it, we were like, ‘We definitely messed this up. The sun cannot be this bright at these energies’.”

The gamma rays that the team observed had about 1 trillion electron volts, or 1 tera electron volt, abbreviated 1 TeV. Not only was this energy level surprising, but so was the fact that they were seeing so much of it. For the first time, the team has shown that the energies of the sun’s rays extend into the TeV range, up to nearly 10 TeV, which does appear to be the maximum, Nisa said, in the new paper published in the journal Physical Review Letters.

Currently, the discovery creates more questions than answers.

Solar scientists will now scratch their heads over how exactly these gamma rays achieve such high energies and what role the sun’s magnetic fields play in this phenomenon, Nisa said.

When it comes to the cosmos, though, that’s part of the excitement. It tells us that there was something wrong, missing or perhaps both when it comes to how we understand our nearest and dearest star.



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