On the sidelines of 'serious' military research, optics Professor Liu Jiansheng accidentally created something he never expected to see in his laboratory: a snowfall.
Playing around with a laser beam at the Shanghai Institute of Optics and Fine Mechanics at the Chinese Academy of Sciences, Liu and his team triggered a tiny flurry in their lab's cloud chamber.
'We had not anticipated the event at all. It was beautiful,' Liu said.
For more than a decade, scientists have known a powerful laser beam can manipulate the nature of air, but all they could achieve was condensation barely visible to the naked eye.
As other researchers elsewhere have done, Liu's team fired a laser into the cloud chamber, a sealed environment containing vapour, in bursts one quadrillionth of a second apart.
When energy is released in such short bursts, it can tear apart molecules, charge particles and create plasma. Experiments conducted by teams overseas have focused on low-frequency blasts, while Liu fired his pulse at a higher one.
The higher frequency proved key - as the laser beam pierced the cloud chamber, it severed electrically charged nitrogen, oxygen and hydrogen atoms from air component molecules, such as carbon dioxide. These atoms provided the essential 'seeds' for condensation and then snow.