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By David Freeman
Say hello to Hippocamp, a heavenly pipsqueak that makes big waves at the edge of our solar system. Using NASA's Hubble Space Telescope, astronomers have confirmed the existence of this tiny moon in orbit around Neptune.
With a diameter of just 20 miles, the newly characterized Moon ̵
Hippocamp was first seen in Hubble 2013 photos. His presence – near a much larger moon known as Proteus – posed a mystery: why did not Hippocampus grow together or be discarded with Proteus, an irregularly shaped, 260-mile-wide moon that is about 1,000 times massive? been?
Some call themselves S / 2004 N1, as Hippocampus was originally called, "The Moon That Should Not Be There."
But after several years of slaughter – including a fresh look at photos of the Neptune system made by Hubble and the NASA satellite Voyager 2 – astronomers led by Mark Showalter of the SETI Institute – In Mountain View, California , it was discovered that Hippocampus is a piece of Proteus that had been sheared off before the big moon when a comet hit it billions of years ago.
There is no smoke weapon for such an old collision. But as Showalter and his colleagues say in an article published on Thursday in the journal Nature about their research, a large impact crater consistent with a comet shock can be seen in photos of Proteus taken in 1989 by the NASA spacecraft Voyager 2 were recorded. The origin scenario we discussed in the paper is in line with everything we know about the history of the Neptune system, "Showalter told E-mail NBC News MACH." It's the only workable scenario we've identified , On the other hand, if someone else in the astronomy community suggests an alternate explanation, we'd like to hear about it. "
It's a big backstory for such moonshine, but other astronomers agree that this is probably the right one. [SaraSeageraplanetaryscientistatMITinCambridgeMassachusettssaidinanemailthattheexplanationmadesensecallingit"afascinatinghypothesisfortheoriginofthetinymoon-withsolidsupportfortheHubbledatafromthe
Hundred's Monsters were found in our solar system, but the Pr oteus hippocamp pair "dramatically shows that moons are sometimes broken by comets," said Jack Lissauer, a scientist at NASA's Ames Research Center in Mountain View, California, and a co-author of the newspaper, a written statement said.
The discovery of Hippocampus brings the number of moons discovered in orbit around Neptune to 14. There are seven inner moons, including Hippocampus, as well as six outer moons and the largest moon of Neptune, Triton
Triton a bit strange, because it is the only moon in the solar system with a so-called retrograde orbit, that is, it moves in the opposite direction to the orbit of its planet.
Showalter said we learned almost everything we can about Hippocamp, at least for now. But he added that if NASA or the European Space Agency put a spacecraft into orbit around Neptune or its planetary neighbor Uranus, "we could learn more in a few days than the sum of all the things we've ever learned about any of the planets have gone far! "
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