More than a year ago, the asteroid 2015 BZ509 made headlines among astronomers, because it is circling our Sun as a wrong-way driver – its direction of motion is opposite that of all the planets and most other objects. To make this work, this asteroid selected an especially clever orbit, a trisectrix, which is apparently stable over the long term. Even a year ago, the following was being still said: “Nobody knows exactly where 2015 BZ509 comes from. It might be a former comet that, however, is no longer active.” That wasn’t enough for two astronomers. The researchers simulated the…