Jingszo !

Injecting far-flung ice-covered lunar oceans with earthly microbes to see how life is shaped may seem like the diabolical plot of a comic book supervillain.

But researchers say that given the likelihood of liquid oceans lying under the surfaces of places like Enceladus, Titan or Europa—all moons of Saturn or Jupiter—now is a good time to take the idea of inoculating a world with life seriously.

“Could this be humanity’s first biosphere genesis experiment?” says Charles Cockell, an astrobiologist at the University of Edinburgh in Scotland.

But life may be there already, which presents the first major ethical conundrum in any discussion of inoculating other worlds with life from Earth. Ideally, to conduct an inoculation experiment, you’d want a world that is uninhabited but habitable. If already inhabited, then any introduction we might make could really throw the alien ecosystem out of whack.

Our own planet is already full of inoculation experiments gone wrong.