‘It’s like finding needles in a haystack’: the mission to discover if Jupiter’s moons support life

The European Space Agency's Juice probe launches next month, flying closer to icy moons - including Ganymede, the solar system's largest - than ever before

For most of the past 200 years, were you to ask an astronomer where the most likely place in the solar system is to find life, the answer will have been Mars. The red planet and its potential inhabitants have captured our collective imagination for centuries, transforming from an imaginary canal-building civilisation in the 19th century to the much more scientifically plausible microbes of today. But now, the thinking is different.

In the past few decades, astronomers have been increasingly drawn to the deeper, darker realms of the solar system. Specifically, they have become fascinated by the icy moons of Jupiter and Saturn. Years of research have all but proved that some of these moons contain vast oceans of liquid water below their frozen surfaces.