NASA recently spotted two massive space objects hurtling towards Earth. While the American space agency has pinpointed one as a comet, the other has left it slightly more baffled. The comet is set to fly close to Earth this week, but the mystery object isn't expected to make an appearance until February. The object, dubbed "2016 WF9", was detected by NASA's asteroid- and comet-hunting NEOWISE project on 27 November 2016. It is roughly 0.3 to 0.6 miles (0.5 to 1 kilometres) across and is in an orbit that takes it on a scenic tour of our solar system. At its...