About 8,000 light-years away, a giant planet circles an aging star, marching once around its sun in a single Earth-year. But that planet, called Kepler 1625b, might not be traveling completely alone. From a report: Scientists now suspect the planet's skies are filled by an orbiting mega-moon, a stunningly large world the size of Neptune that may be the first moon spotted outside our solar system. Early hints of its existence surfaced in July 2017, when scientists tentatively announced that they'd found some evidence of an orbital companion for Kepler 1625b. But it wasn't until the Hubble Space Telescope aimed its eye at the faraway star a year ago that scientists were able to gather enough data to build the case for the so-called exomoon's presence. Now, the two scientists behind the discovery are hoping for independent confirmation of their finding to really shore up the extraordinary claim. "I'm confident that we've done a thorough job vetting this thing, but I also anticipate there 查看全文>>