The intrepid bearers of the celestial sword

A group of Chinese scientists have something on their mind, and it does not get any darker than this

This is a search unlike any other: It's going on in the darkness of outer space, and the hunters have no idea where their quarry is or when it will pop up. In fact they do not know what they are searching for looks like either. One of those hunters is Chang Jin, who says: "It must be there. But we don't know if we will be lucky enough to catch it, or even whether it's a bear or a rabbit."

Chang is chief scientist on China's Dark Matter Particle Explorer (Dampe) program, and he and others working on it seem to be a breed apart, as unusual as the enigmatic matter they are looking for. It is not unknown for Chang to be at home and, as though lost in space, to be mumbling numbers to himself; Another researcher, Fan Yizhong, 38, talks of insomnia and of dark-matter worries that have turned his hair white.