Unveiling the Cosmic 'Knee': A Mystery Solved by China's Observatory
The enigma of the cosmic 'knee' has finally been unraveled, and it's a game-changer for astrophysics!
China's Large High Altitude Air Shower Observatory (LHAASO) has made groundbreaking discoveries, offering crucial insights into the role of black holes in the origin of cosmic rays. But here's where it gets controversial: the findings challenge long-held beliefs and present a new perspective on these enigmatic celestial bodies.
The 'knee' phenomenon, a sharp decrease in the cosmic ray energy spectrum above 3 peta-electronvolts (PeV), has puzzled scientists for nearly seven decades. Now, thanks to LHAASO's advanced research, we have a clearer picture.
Two studies published in prestigious journals reveal that micro-quasars, driven by black hole system accretion, are powerful particle accelerators in our Milky Way galaxy. These black holes, when pulling material from companion stars, create near light-speed jets, forming micro-quasars. LHAASO's observations detected ultra-high-energy gamma rays from these micro-quasars for the first time, suggesting primary cosmic rays with energies surpassing the 'knee' threshold.
This discovery addresses a long-standing issue: previously recognized cosmic ray sources, like supernova remnants, couldn't reach these energy levels. To understand this phenomenon better, precise measurements of cosmic ray energy spectra are vital. However, due to the rarity of cosmic rays in the 'knee' region and atmospheric interference, distinguishing protons from other nuclei was considered nearly impossible.
Enter LHAASO's multiparameter measurement techniques. The research team obtained a large sample of high-purity protons, revealing an unexpected new structure in the energy spectrum—a 'high-energy component.' This, combined with the low-energy and intermediate-energy components measured by space-borne experiments, shows multiple accelerator populations within the Milky Way, each with unique capabilities and energy ranges.
The 'knee' represents the acceleration limit of these sources, and these two discoveries paint a comprehensive scientific picture. It's a significant advancement in understanding the 'knee' origin and provides crucial evidence for black holes' role in cosmic ray generation.
LHAASO's hybrid detector array design allows for the detection of cosmic ray sources through ultra-high-energy gamma rays and precise measurement of cosmic ray particles near our solar system. For the first time, the 'knee' structure has been observationally linked to a specific astrophysical source—a black hole jet system. There are an estimated dozen or so of these sources in our galaxy.
This research not only deepens our understanding of the universe but also has practical applications. The working principles of artificial accelerators resemble cosmic ray accelerations, and understanding these mechanisms could revolutionize the next generation of particle accelerators.
LHAASO, designed and operated by Chinese scientists, is located at a high altitude in Sichuan Province, China. Its sensitivity in gamma-ray astronomy and cosmic ray precision measurement has led to a series of global impact discoveries, contributing to our knowledge of extreme physical processes in the universe.
So, what do you think? Does this new perspective on black holes and cosmic rays challenge your existing beliefs? Share your thoughts in the comments and let's spark a discussion!
