Pluto is believed to contain a layer of water ice underneath another thin layer of frozen nitrogen. In addition, there is speculation that Pluto may contain a water ocean. More »

The surface of Pluto is extremely cold and completely lifeless. The minimum surface temperature of Pluto is minus 387 degrees Fahrenheit. The maximum surface temperature is minus 369 degrees Fahrenheit. More »

Pluto is a dwarf planet in the area of the Kuiper belt, which is an area with many dwarf planets, according to the National Aeronautics and Space Administration (NASA). The dwarf planet is after Neptune in the planetary ... More »

Neptune has no identifiable surface layer, and the icy, gaseous atmosphere eventually transitions to a slushy water and liquid ammonia ocean with a rocky, iron core at the center. As the depth increases, the intense pres... More »

www.reference.com Science Astronomy Planets

Neptune has no definite surface, only a layer of gas above a layer of ice and water. While the planet has a core of rock and metal, Neptune's mantle consists of an ocean that contains more than 10 times the mass of Earth... More »

www.reference.com Science Astronomy Planets

Saturn's atmosphere is made up of about 75 percent hydrogen and 25 percent helium, along with trace amounts of water ice and other gases. Like the other planets in the outer solar system, Saturn is a gas giant that lacks... More »

Although no one knows exactly what Pluto is made of, most scientists agree that it is between 50 and 70 percent rock, with the remainder being composed of various ices. Pluto’s core is composed of dense rock, while the i... More »