In a surprising turn of events, NASA’s Fermi Gamma-ray Space Telescope has detected no high-energy gamma rays from a nearby supernova that occurred in 2023. This finding challenges the long-held assumption that supernovae are the primary sources of cosmic rays, which are particles accelerated to near light-speed.
Cosmic rays are a fundamental aspect of astrophysics, and their origins have been a subject of intense research for decades. The prevailing theory suggests that supernovae, the explosive deaths of massive stars, are responsible for accelerating these high-energy particles. However, the recent observation by Fermi raises questions about this assumption.
The Fermi Gamma-ray Space Telescope and Supernovae
The Fermi Gamma-ray Space Telescope, a partnership between NASA and international partners, is designed to detect gamma rays, the highest-energy form of light. Gamma rays are produced when cosmic rays interact with matter, making them a crucial tool for understanding the origins of these high-energy particles.
In the case of the nearby supernova, Fermi’s non-detection of gamma rays is unexpected. Supernovae are known to produce shock waves that can accelerate particles to extreme energies. These accelerated particles, in turn, should produce gamma rays that Fermi should be able to detect. However, the telescope has found no such emission.