Sun’s Gamma Rays Baffle Scientists, Challenge Solar Models
The Sun is not only the source of life on Earth, but also a mystery that keeps surprising scientists. A new study has revealed that the Sun emits gamma rays, the highest-energy light in the universe, at energies that are one trillion times more intense than the visible light we see on Earth. This discovery challenges the current models of how the Sun works and what causes its high-energy emission.
The study, published in the journal Physical Review Letters, was conducted by an international team of researchers using the High Altitude Water Cherenkov (HAWC) observatory in Mexico. HAWC is a large array of water tanks that detect the secondary particles and photons produced by cosmic rays, which are high-energy particles from outer space that collide with the Earth’s atmosphere.
The researchers observed the Sun’s gamma rays for four years, from 2015 to 2019, and detected gamma rays with energies up to 100 tera-electron volts (TeV), which is equivalent to the energy of a flying mosquito. However, this is extremely high for photons, which are massless particles of light. For comparison, the visible light we see on Earth has energies of about 2 electron volts (eV).
“We didn’t expect that we would see anything above a few tens of GeV (giga-electron volts),” said Jordan Goodman, a professor of physics at the University of Maryland and U.S. lead investigator and spokesperson for HAWC.
The Sun’s gamma rays are produced by cosmic rays that hit the solar atmosphere and create a cascade of secondary particles and photons. The researchers found that the gamma-ray emission is highly variable and depends on the solar cycle, which is the 11-year period of changing magnetic activity on the Sun. The gamma rays are more abundant during the solar minimum, when the Sun’s magnetic field is weaker and less complex.
“These observations imply that either our understanding of cosmic ray acceleration near the Sun is incomplete or that some other process is producing these energetic photons,” said John Pretz, an associate professor of physics at Drexel University and a member of HAWC.
The current models of how the Sun works and what causes its high-energy emission cannot explain the observed gamma rays at such extreme energies. The researchers suggest that new probes are needed to solve this mystery and understand the role of the Sun’s magnetic field in producing these gamma rays.
“The Sun is a new source of gamma rays, but what is producing these gamma rays? We don’t know,” said Petra Huentemeyer, a professor of physics at Michigan Technological University and a founding member of HAWC.
The discovery of the Sun’s gamma rays has implications for astrophysics, particle physics, and space weather. It could help us learn more about the origin and acceleration of cosmic rays, the physics of particle interactions at very high energies, and the potential hazards of radiation exposure for astronauts and satellites.
“It’s really amazing that nature accelerates particles to these very high energies in such a variety of ways,” said Francis Halzen, a physicist at the University of Wisconsin-Madison who was not involved in the study.
“This is exciting because it shows us something new about how our star works,” said Brian Fields, an astrophysicist at the University of Illinois Urbana-Champaign who was not involved in the study.
Relevant articles:
- Baffled Scientists Detect Massive Unexplained Radiation From the Sun, Study Reports, Vice, August 7, 2023
- Scientists surprised after detecting ‘highest-energy light’ from the sun, Science News, August 5, 2023
- Surprise: Scientists Discover Unprecedented High-Energy Light From the Sun, SciTechDaily, August 4, 2023
- Strange Solar Gamma Rays Discovered at Even Higher Energies, Quanta Magazine, August 2, 2023
Originally published at https://trendydigests.com on August 8, 2023.
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