The seven largest natural satellites in the solar system (over 2,500 km in diameter) are the four Jovian Galilean moons - Ganymede, Callisto, Io, and Europa - Saturn's moon Titan, Earth's own Moon, and the satellite captured natural of Neptune Triton.
They move around a larger body. They revolve around these bodies because of their gravitational pull. The orbits that they describe when turning on these bodies can be regular or irregular.
