Astronomers may have detected a previously undiscovered "mini-moon" in the solar system: a rocky object orbiting a small asteroid near Jupiter. If the rocky satellite, which is just a little wider than the width of Manhattan, is confirmed to be a proper moon, it would be one of the smallest moons ever spotted. The tiny satellite was discovered by scientists working on NASA's Lucy mission, which is sending a space probe to study some of the Trojan asteroids, two massive groups of space rocks that are located on each side of Jupiter on its orbit around the sun. The Lucy...