New Moon Outside Our Solar System Discovered

For a long time, the only moon human beings knew of was our own. In the early-17th century, the invention of the telescope extended our vision into the cosmos and allowed Galileo to discover four new moons, in orbit around Jupiter. Five moons around Saturn were found in that century, and two more in the next. By the 19th century, astronomers had detected moons around Mars, Neptune, and Uranus. Today, we know the solar system is flush with them. There are nearly 200 known moons, dutifully circling their planets and dwarf planets.