Mysterious Moon Around Neptune

After several years of analysis, a group of planetary scientists using NASA's Hubble Space Telescope has discovered the mysteries behind the moon around the Neptune. Astronomers called it "the moon that shouldn't be there."

The moon is  very tiny and it is called Hippocamp. It is close to a much larger neptunian moon called Proteus. Actually, a moon like Proteus should have gravitationally swept aside or swallowed the smaller moon while paving way for its orbital path.

The  Hippocamp is likely a cut-off piece of the larger moon that is caused by collision with a comet billions of years ago.

Mark Showalter of the SETI Institute in Mountain View, California said, "the first thing we realized was that you wouldn't expect to find such a tiny moon right next to Neptune's biggest moon. In the distance past, given slow migration outward of the larger moon, Proteus was once were Hippocamp is now."

"Based on estimates of comet populations, we we know that other moons in the outer solar system have been split by comets, smashed apart, and re-accreted multiple times," said Jack Lissauer of NASA's Ames research Center in California's Silicon Valley, a Coauthor on the new research. This pair of satellites provides a dramatic illustration that moons are often split apart by comets.