Researchers have found that the Sun produces light with higher energy than previously assumed. Gamma rays with energies of over 1 tera electron volt (TeV), which are at least five times more energetic than previously thought, were discovered by a novel type of telescope. The Sun emits light that ranges in energy from infrared to ultraviolet and everything in between. Gamma rays, the highest energy form of electromagnetic radiation, were thought to be produced by the Sun through interactions with cosmic rays from far-off sources, although they would hardly ever be detected on Earth.
Utilized different types of equipment
SciIn 2011, NASA’s Fermi Gamma-ray Space Telescope finally made the discovery of these gamma rays. Fermi discovered that the Sun was producing about seven times more gamma rays than was anticipated as additional observations were made over the years. The highest energy that Fermi can pick up was 200 giga electron volts (GeV), which is where their energies were found to be. Scientists, therefore, utilized different equipment for the new study that is sensitive beyond that limit.
The High-Altitude Water Cherenkov Observatory (HAWC) is the device in question, and it functions differently from a typical telescope. It consists of 300 large tanks, each holding 200 tonnes of water.
A cascade of lower energy particles
A cascade of lower energy particles is produced when gamma rays strike molecules in the Earth’s atmosphere; these particles can interact with the water molecules in those large tanks. Scientists can compute the energy of the original gamma ray by working backward after detecting these interactions with sensitive equipment.
The researchers found that the Sun was generating gamma rays with energy much above those that Fermi could detect using HAWC data collected between 2015 and 2021. With some spiking to about 10 TeV, they were achieving energy on the order of TeV.
“After looking at six years’ worth of data, out popped this excess of gamma rays,” said Mehr Un Nisa, the study’s corresponding author. We immediately thought, “We definitely messed this up,” upon seeing it. At these energies, the Sun cannot be as brilliant.
However, the volume of data collected during those six years made it clear that this was the case. The exact mechanism by which the Sun generates them is yet unknown, according to the team, but additional studies will look into how their energy soars and what function the Sun’s magnetic field may play.