Photo taken on June 28, 2016 shows experimenters at the Jinping Underground Laboratory, which is 2,400 meters under a mountain in Sichuan Province. It has a store of xenon, one of the few materials that interact with dark matter, and the cosmic rays that commonly interfere with attempts to observe dark matter generally cannot penetrate to such a depth underground. China's Dark Matter Particle Explorer (DAMPE) has detected unexpected and mysterious signals in its measurement of high-energy cosmic rays, which might bring scientists a step closer to shedding light on invisible dark matter. The satellite, also called Wukong, or Monkey King, has measured more than 3.5 billion cosmic ray particles with the highest energy up to 100 tera-electron-volts (TeV for short, corresponding to 1 trillion times the energy of visible light), including 20 million electrons and positrons, with unprecedentedly high energy resolution. The initial detection results were published in the latest issue of the academic journal, Nature. (Xinhua/Xue Yubin)