A comet is a celestial body of ice, dust, and rock that orbits the Sun, often called a "dirty snowball," which develops a glowing head (coma) and a tail of gas and dust as it gets close to the Sun, pushed away by solar wind and radiation. These ancient remnants from the solar system's formation, originating from the outer reaches like the Kuiper Belt and Oort Cloud, can provide clues about the early solar system and potentially delivered water and organic materials to Earth.