Could a vagabond giant from the outermost regions of interstellar space be poised on the cusp of sweeping by our cosmic doorstep? Astronomers say yes and they have the data to support it. Using the Pan-STARRS survey telescope on Hawaii and the European Southern Observatory’s Very Large Telescope (VLT) in Chile, researchers have found a giant rogue planet, possibly as massive as Jupiter, speeding toward the solar system. It is a transient discovery made possible by the combination of wide-sky monitoring and the capability of high-resolution spectroscopy. Pan-STARRS first notified astronomers to the object with weak, creeping light signals near...