BEIJING, June 8: Chinese scientists have built the world's highest observatory in the northern hemisphere, 4,300 meters above sea level on the Tibet plateau at Yangbajan.The observatory will conduct research usually carried out by satellites and space stations, Xinhua news agency said.One of the observatory's main objectives is to study the Milky Way, Gamma sources and Gamma ray eruptions at the beginning of the 21st century.The Chinese Academy of Sciences (CAS), will cooperate with Japan and Italy in installing a solar-neutron monitor and solar-neutron telescopes at Yangbajan to study high-energy particles.