Messier 57, also known as the Ring Nebula, is a planetary nebula located in the constellation Lyra. It is approximately 2,300 light-years away from Earth and is one of the most studied nebulae due to its distinct ring shape and bright central star. The nebula was formed when a dying star expelled its outer layers, creating a glowing shell of gas. The central star of Messier 57 is a white dwarf, which is the remnant of the original star that created the nebula. The nebula spans about 1 light-year across and is best observed through telescopes, appearing as a small, round object with a greenish hue.