The first plausible moon beyond our solar system may be circling a brown dwarf

More than 6,000 planets have been found beyond our solar system, but never a confirmed moon. A team led by Kevin Hoy, based in Chile, used the European Southern Observatory's Very Large Telescope to watch a brown dwarf — an object bigger than a planet but not quite a star — in the system CD-35 2722, and spotted a subtle wobble in its motion. That wobble points to a companion at least as heavy as Jupiter circling the brown dwarf itself. The researchers, whose study appears in Nature, call it the first plausible detection of an exosatellite — a moon beyond our solar system. It still needs confirming, and bigger future telescopes should help settle it.