It's believed to have been formed about 4 billion years ago during a cosmic collision with another Neptunian moon called "Proteus". Hippocamp is one of the seven 'inner moons' - six of which were discovered 30 years ago during Voyager 2's fly-by. (Image: Mark R. Showalter, SETI Institute)They are probably younger than the planet itself - forming soon after the largest known as Triton. It enabled the researchers to see the inner moons despite the rapid speed at which they hurtle around Neptune. Dr Showalter said: "The discovery of tiny Hippocamp contributes to our understanding of the history of Neptune's inner system.

Source: Daily Mirror February 20, 2019 18:00 UTC