China has started the construction of one of the world's largest and most sensitive cosmic-ray facilities. Located about 4,410 meters above sea level in the mountainous areas in southwest China’s Sichuan Province, the 1.2 billion yuan ($180m) Large High Altitude Air Shower Observatory (LHAASO) will attempt to search for the origin of high energy cosmic rays, to study the evolution of the universe and high energy celestial bodies, as well as to push forward the frontier of new physics.

The project was approved by the National Development and Reform Commission, China's top economic planning body, on December 31, 2015. The construction of the LHAASO is set for completion in January 2021. The project will be a key frontier project for cosmic ray research internationally.

China's high altitude observatory will have four different arrays to detect γ- and cosmic rays. (IHEP)

Cosmic rays are particles that originate in outer space and are accelerated to energies higher than those that can be achieved in even the largest man-made particle accelerators. The origin of the cosmic rays, however, has remained a mystery since they were first spotted some 100 years ago. LHAASO will be mankind’s first attempt to hunt for the highest-energy Gamma ray, which is the bursts of radiation thought to be produced alongside cosmic rays in our Galaxy.

LHAASO is expected to offer a unique perspective on the origins of cosmic rays, high-energy particles that rain down on Earth. Scientist says that LHAASO could establish the maximum energies that cosmic events in the Milky Way can produce.