Milestone results released by the Large High Altitude Air Shower Observatory (LHAASO) on November 16 have solved a decades-old mystery about the cosmic ray energy spectrum—which shows a sharp decrease in cosmic rays above 3 PeV, giving it an unusual knee-like shape.

At over 4,400 meters above sea level on the Qinghai-Xizang Plateau in Daocheng, southwest China's Sichuan Province, stands the world's most advanced cosmic-ray observatory – the Large High Altitude Air Shower Observatory (LHAASO). Since its completion in 2021, it remains the world's highest, largest and most sensitive observatory for detecting high-energy cosmic rays and gamma rays.

The Large High Altitude Air Shower Observatory (LHAASO), located at an altitude of 4,410 meters on Mount Haizi in Daocheng County, began regular operations in July 2021. It has since been recognized as a leading international facility with the world's highest sensitivity and accuracy for gamma-ray and cosmic-ray detection.