Galileo's Pendulum

Earth’s Moon is the fifth largest satellite in the Solar System, making it one of the larger objects, period: only Io, Callisto, Ganymede, Titan, and the eight planets are larger. None of the dwarf planets designated by the International Astronomical Union (IAU)—Ceres, Eris, Haumea, Makemake, or Pluto—are bigger, and the Moon is significantly more massive…