Mercury is the closest planet to the Sun in our solar system, only slightly larger than Earth's Moon. It belongs to the terrestrial planets. Its orbital speed around the Sun is higher than any other planet. The planet is named after the ancient Roman god of commerce.
Mercury is the smallest planet. Mercury's radius is smaller than that of Ganymede and Titan, the two largest moons in the solar system.
Mercury's surface resembles the Moon's surface, with many craters from meteorites and comets. Craters on Mercury are named after famous deceased artists, musicians, or authors.