In a groundbreaking discovery, China’s Large High Altitude Air Shower Observatory (LHAASO) has unveiled a pivotal mechanism behind the formation of high-energy cosmic rays. The research, led by an international team of scientists, reveals that black holes, particularly those in binary systems, act as powerful particle accelerators, contributing significantly to the production of cosmic rays in the Milky Way. This finding not only addresses a long-standing mystery in astrophysics but also deepens our understanding of extreme physical processes in black hole systems. Cosmic rays, primarily composed of protons, are charged particles originating from outer space. Their origin has been a central question in modern astrophysics for decades. The LHAASO team focused on the ‘knee’ region of the cosmic ray energy spectrum, a critical turning point around 3 PeV (peta-electron volt), which has puzzled researchers for nearly 70 years. The study identified microquasars—black hole systems that accrete material from companion stars—as the likely sources of this phenomenon. These microquasars generate relativistic jets, which accelerate particles to ultra-high energies. For instance, the microquasar SS 433 was found to produce proton energies exceeding 1 PeV, equivalent to the energy released by 400 trillion hydrogen bombs per second. Similarly, gamma rays from the microquasar V4641 Sgr reached 0.8 PeV, suggesting parent particle energies surpassing 10 PeV. The findings, published in *National Science Review* and *Science Bulletin*, highlight the role of black holes as cosmic particle accelerators. Located in Sichuan Province at an elevation of 4,410 meters, LHAASO’s advanced equipment enabled precise measurements of cosmic ray energy spectra, revealing unexpected structures. This discovery not only resolves the ‘knee’ mystery but also provides crucial evidence for understanding the origins of cosmic rays. LHAASO, designed and operated by Chinese scientists, has positioned China at the forefront of high-energy cosmic ray research, contributing to global advancements in astrophysics.