ocr: ASTRONOMICAL PLUTO SYMBOL Cratered PLUTO, THE NINTH planet from the surface is a cold, dark world in which Sun, the Sun appears as only a bright star in the sky. Pluto is smaller than the Earth's Moon, and consists of rock andices. It has a thin atmosphere that forms when the planet is close to the Sun but freezes as it moves away. Pluto's orbit is tilted farther from the ecliptic than that of any other planet, and is also very elongated. One orbit lasts 248.5 years and, for about 20 of those years, Pluto is closer to the Sun than Neptune is. These unusual features lead some astronomers to pro ...
