On Earth, wherever we find liquid water, we find life, whether in bubbling hot springs, drops of brine inside ice, or films of water around minerals deep in the crust. ‘Life in the Solar System’ asks: which worlds might be habitable today? Many of the cold outer Solar System objects used to be dismissed as potential habitats. But perceptions have shifted. It's possible that there are subsurface ammonia-rich oceans on Saturn's moon Rhea and Uranus's largest moons Titania and Oberon. Given that so many objects in the Solar System are potential refuges for life, billions of similar possibilities surely exist throughout our galaxy.