So far, humanity has yet to find its first "exomoon"—a moon orbiting a planet outside of the solar system. But that hasn't been for lack of trying. According to a new paper by Thomas Winterhalder of the European Southern Observatory and his co-authors, which is available on the arXiv preprint server, the reason isn't because those moons don't exist, but simply because we lack the technology to detect them. They propose a new "kilometric baseline interferometer" that can detect moons as small as Earth up to 200 parsecs (652 light years) away.
