The European Space Agency's (ESA) mission to the moons of Jupiter has started its 8 year journey.

Could there really be alien life on these moons?

byline:-
Jonathan Amos
Science correspondent, BBC News

For a long time, Mars has been considered by scientists to be the most likely candidate to host extra-terrestrial life, if not today then sometime in its distant past.
But, for astrobiologists - scientists who study the possibility of life elsewhere in the Universe - the ice-covered moons of Jupiter and also Saturn are really starting to pique their interest and could feature the kind of volcanic vent systems on ocean floors that some scientists think could have been the origin of life on Earth.
"If I were a betting man, I'd probably put my money on Europa having life that is alive, that exists today," says Prof Lewis Dartnell, an astrobiologist at the University of Westminster.
“The chances of that are much higher than finding extant (living) life on Mars today."

If the probe does find any form of life, imagine how the majority of the world's religions would falter!