In a 2000 NASA image, the Hubble Space Telescope took this photograph of the Eskimo Nebula that displays gas clouds so complex they are not fully understood. In 1787, astronomer William Herschel discovered the Eskimo Nebula, which from the ground resembles a person's head surrounded by a parka hood. The Eskimo Nebula is a planetary nebula, a glowing shell of gas and plasma formed by certain types of stars at the end of their lives. The outer disk contains unusual light-year long orange filaments. (UPI Photo/Andrew Fruchter/NASA)