### Scientists Detect Record-Breaking Cosmic Rays Near Earth

Researchers have recently detected the most energetic cosmic rays ever observed, emanating from unidentified sources relatively close to Earth. These rays, made up of electrons and positrons, were observed with energies reaching up to 40 teraelectronvolts (TeV), which is 40,000 times the energy of visible light. This significant discovery was made using the High Energy Stereoscopic System (HESS) observatory in Namibia.

The HESS observatory, equipped with an array of five 12-meter telescopes, detected these cosmic rays despite the significant energy loss they experience while traveling through space due to interactions with light and magnetic fields. This energy depletion suggests that the origin of these high-energy rays must be relatively close to our planet. Surprisingly, the exact sources remain a mystery. The groundbreaking findings were published on November 25 in the journal Physical Review Letters.

Kathrin Egberts, the head of experimental astroparticle physics at the University of Potsdam in Germany, noted the importance of the discovery. She explained that the cosmic ray electrons likely originate from a few sources within a few thousand light-years from our solar system, which is a small distance in astronomical terms, especially considering that the Milky Way is about 100,000 light-years across.

Cosmic rays, known to be high-energy particles, are produced by various phenomena such as the sun, supernovas, pulsars, and other yet-unknown sources. Upon entering Earth's upper atmosphere, these rays disintegrate into particle showers detectable on the planet's surface. However, reconstructing the original rays from these showers is an intricate and uncertain process.

The researchers, utilizing the HESS observatory over a decade, scanned the upper atmosphere for Cherenkov radiation. This faint blue glow is created when particles move through a medium faster than the speed of light, analogous to a sonic boom created by supersonic aircraft. By detecting this radiation and applying advanced algorithms to filter out noise, the scientists successfully mapped the energy spectrum of these cosmic rays with unprecedented detail.

Mathieu de Naurois, a researcher at the French National Centre for Scientific Research in Paris, emphasized that the very low fluxes at higher energy levels limit the potential of space-based detectors to capture these rays in significant numbers. He added that their findings not only provide crucial data in a previously unexplored energy range but also set a benchmark for future research in understanding cosmic rays and their sources.

In conclusion, the discovery of these highly energetic cosmic rays near Earth opens new avenues for understanding the cosmic neighborhood and poses exciting challenges for future space-based missions aiming to unravel these celestial mysteries.