After many years of analysis, a team of scientists using NASA's Hubble Space Telescope has finally come up with an explanation for the mysterious moon around Neptune that they discovered with the Hubble in 2013.
So why does the tiny moon exist? Hippocamp is likely a chipped-off piece of the larger moon that resulted from a collision with a comet billions of years ago. The diminutive moon, only 20 miles (about 34 kilometres) across, is 1/1000th the mass of Proteus (which is 260 miles [about 418 kilometres] across).
Image Credits: NASA, ESA and J. Olmsted (STScI)