A laboratory in China reveals the secrets of the universe: They built it for ten years 700 meters underground

China is completing construction of its $300 million physics research facility located 700 meters underground in rural Guangdong province. The Jiangmen Underground Neutrino Observatory (JUNO) has been under construction for 10 years, and in a few months it will be shut down for the next 30 years while experiments and data are collected. JUNO aims to determine which types of neutrinos have the most mass. Neutrinos can pass through normal objects unhindered and undetected, making them incredibly difficult to investigate. JUNO deputy administrator Cao Jun says that understanding the neutrino mass hierarchy will solve a long-standing mystery in physics and is key to understanding the fundamental laws of nature. Much can be learned about the elusive particle, but JUNO principal scientist Wang Yifang is confident that China will be the first to solve the mystery of which type of neutrino has the most mass.