The first of the new large near-Earth asteroid discoveries is named 2013 UQ4, and it is perhaps the most unusual. This approximately 19-kilometer (12-mile) wide object was spotted by the Catalina Sky Survey on Oct. 23 when the asteroid was 435 million kilometers (270 million miles) away from Earth. Not only is this object unusually large, it follows a very unusual highly inclined, retrograde orbit about the Sun, which means it travels around the Sun in the opposite direction of all the planets and the vast majority of asteroids. The only objects usually found in retrograde orbits are comets, which...