There is a sentence that has stuck with Mark Matney for almost four decades: “And the star which they had seen rising passed before them to the place where the child was; there it stood still.” As a college student in the late 1980s, Matney had worked at a planetarium in Texas. Every year in the Christmas show, this sentence from the Gospel according to Matthew about the journey of the wise men from the East to the newborn baby Jesus was read out. “It was said at the time that there were no astronomical phenomena that fit that description,” Matney remembers. Cometsmeteors, novae or supernova explosions, even special planetary constellations – none of these celestial events suddenly stop in the firmament. As seen from Earth, they all move due to Earth’s rotation. “The statement took me aback, and I thought back then: Hmm, I can think of something that would fit the description.”