Uranus Mass = 15 Earths Axis of rotation is turned over so that the planet rotates “on its side”. Has dark rings of dust and ice. Atmosphere is mostly H and He with water, ammonia and methane ice. Methane gives planet a blue- green color.
Pluto’s very elongate and inclined orbit: occasional passage inside Neptune’s orbit.
Pluto and Charon orbit about a common center of mass located above Pluto’s surface. Charon and Pluto are so similar in size, they are referred to as a double dwarf planet.
In 2006, Pluto was officially classified as a dwarf planet by the International Astronomical Union.
Before the 1850s, the Solar System consisted of more than 8 planets until some of the bodies were classified as asteroids.
The Dwarf Planets Dwarf planets – A new class of planets: –Celestial bodies that orbit the Sun. –Have sufficient gravity to maintain a rounded shape. –Are not satellites to more massive bodies. –Unlike planets, they lack the gravity to have cleared away other bodies around their orbits (orbital dominance).
The Dwarf Planets PlutoErisCeres Beyond Pluto’s orbit. Larger than Pluto. Located in the Kuiper Belt. Located in the Asteroid Belt.
The Dwarf Planets Most recent Kuiper Belt objects to be given dwarf planet status by the IAU. Haumea Makemake
Beyond Pluto Hundreds of icy bodies similar to Pluto are located beyond the orbit of Neptune in the Kuiper Belt. –Disk-shaped region past the orbit of Neptune extending from 30 to 50 AU from the Sun. –Also contains numerous comets.