On 28 August 1789, astronomer William Herschel discovered a moon encircling Saturn and called it Enceladus. Just under 225 years later, a joint venture between NASA’s Cassini spacecraft and the Deep Space Network (DSN) found that it housed a vast ocean underneath its surface.
Enceladus’ water reserve is thought to be 30-40 kilometres (19-25 miles) below the surface of the moon and is 10 kilometres (6 miles) deep. The presence of this ocean means that it could potentially harbour life.
Is the discovery of Enceladus one of the 50 greatest space discoveries of all time? Find out in our epic space feature in How It Works 63.