‘For example, we can put something such as sodium in the core, mixing with a transition metal and then coated with a protective outer layer. I don’t think you could make these by any other means.

"A liquid water layer or pocket in contact with the rock, which is deep below Enceladus' surface, will acquire sodium from the rock - essentially leaching the rock," he says.

The laser beam is tuned to a frequency that lights up sodium atoms, which are left by disintegrating meteorites in a thin layer of the atmosphere.