The sun is the source of life on Earth, but it is also a mystery that scientists are still trying to unravel. One of the most intriguing aspects of the sun is its emission of gamma rays, which are the most energetic form of light in the universe. Gamma rays are usually produced by extreme cosmic events like supernovas or black holes, but the sun can also emit them, albeit at much lower energies. However, a recent discovery has challenged this assumption and revealed that the sun can blast gamma rays with an energy of about 1 trillion electron volts, which is seven times higher than the previous record. This finding raises new questions and challenges for solar physics, and shows that there is still much to learn about the sun and its mysteries.
How Did Scientists Detect These Gamma Rays?
Gamma rays are very hard to detect, because they are easily absorbed by the Earth’s atmosphere. Therefore, scientists need special observatories that can observe them from high altitudes or from space. One of these observatories is called HAWC, which stands for High Altitude Water Cherenkov. HAWC is located in Mexico, at an elevation of about 4,100 meters above sea level. HAWC consists of 300 large water tanks that are filled with purified water. When gamma rays hit the water molecules, they produce a faint blue light called Cherenkov radiation. By measuring the intensity and direction of this light, scientists can infer the energy and origin of the gamma rays.
HAWC has a unique advantage over other gamma-ray observatories: it can observe gamma rays during the day, unlike other telescopes that can only see them at night. This allows HAWC to study the sun’s gamma-ray emission, which is usually overshadowed by the bright sunlight. By using HAWC, scientists have detected gamma rays from the sun with an energy of about 1 trillion electron volts (TeV), which is seven times higher than the previous record of 140 gigaelectron volts (GeV) set by another observatory called Fermi-LAT in 2017.
How Can the Sun Produce Such High-Energy Gamma Rays?
The discovery of these high-energy gamma rays from the sun is surprising and challenging for solar physics, because it contradicts the current understanding of how the sun works. The sun is powered by nuclear fusion, which is a relatively low-energy process that converts hydrogen atoms into helium atoms and releases energy in the form of light and heat. Nuclear fusion can only produce gamma rays with an energy of up to a few MeV (million electron volts), which is much lower than the TeV gamma rays detected by HAWC.
So how can the sun produce such high-energy gamma rays? Scientists have proposed some possible explanations, but none of them are conclusive or satisfactory. One explanation is that these gamma rays are produced by the sun’s magnetic field, which can accelerate charged particles like electrons and protons to very high speeds and make them collide with each other or with solar material. These collisions can then produce gamma rays through a process called bremsstrahlung or inverse Compton scattering. However, this theory has some problems: it requires very strong magnetic fields and very high densities of particles, which are not observed on the sun; it also predicts a different spectrum and distribution of gamma rays than what HAWC has measured.
Another explanation is that these gamma rays are produced by cosmic rays, which are high-energy particles that come from outside the solar system and bombard the Earth and other planets. When cosmic rays hit the sun’s atmosphere or surface, they can produce gamma rays through a process called pion decay or proton-proton interaction. However, this theory also has some problems: it requires very high fluxes of cosmic rays, which are not observed near the sun; it also predicts a different time variation and polarization of gamma rays than what HAWC has observed.
What Are the Implications and Applications of This Discovery?
The discovery of these high-energy gamma rays from the sun has important implications and applications for solar physics and other fields of science. For solar physics, this discovery opens up new questions and challenges for understanding how the sun works and what processes are involved in its emission of gamma rays. It also provides a new way to probe the sun’s interior and exterior structure, as well as its magnetic field and activity. For example, by studying how these gamma rays vary with time and location on the sun, scientists can learn more about how the sun’s magnetic field changes over time and how it affects solar flares and coronal mass ejections, which are powerful eruptions that can affect space weather and Earth’s climate.
For other fields of science, this discovery offers a new opportunity to study fundamental physics and astrophysics using the sun as a natural laboratory. For example, by measuring the energy and spectrum of these gamma rays, scientists can test and constrain various theories and models of particle physics and cosmology, such as dark matter, axions, primordial black holes, and quantum gravity. By comparing the gamma rays from the sun with those from other sources, such as pulsars, blazars, and gamma-ray bursts, scientists can also learn more about the origin and nature of these cosmic phenomena and how they relate to each other.
Conclusion
The sun is the closest star to Earth, but it is also a mystery that scientists are still trying to unravel. One of the most intriguing aspects of the sun is its emission of gamma rays, which are the most energetic form of light in the universe. A recent discovery has revealed that the sun can blast gamma rays with an energy of about 1 trillion electron volts, which is seven times higher than the previous record. This finding raises new questions and challenges for solar physics, and shows that there is still much to learn about the sun and its mysteries. It also opens up new possibilities for studying fundamental physics and astrophysics using the sun as a natural laboratory. The sun is not only the source of life on Earth, but also a source of wonder and inspiration for science.
