Titan The largest of Saturn’s moons: larger than Mercury. Has a thick nitrogen atmosphere with traces of organic compounds such as hydrocarbons. Surface temperature: minus178°C
Titan’s surface is composed mostly of dirty water ice and hydrocarbon ice. Rounded pebbles of water ice in hydrocarbon soil.
Lakes of liquid methane and ethane detected by radar. Surface apparently shaped by erosion with drainage channels and shoreline-like features
Enceladus The brightest body in the Solar System. Has an icy surface consisting of both young and old geologic terrains. Tectonic deformation of surface = fissures and ridges.
Cryovolcanism: eruptions produced by partial melting of ice rather than silicate rocks.
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.
Uranus’ Moons 27 known moons. Mostly composed of water ice and rock. The strangest moon, Miranda consists of a “jigsaw puzzle” of different geologic terrains.
Miranda’s Bizarre Surface – probably tectonic in origin.
Ariel’s Fault-Bound Valleys
Neptune Mass = 17 Earths Similar composition to Uranus. Has a dynamic atmosphere with winds as great as 1,500 mi/hr. Has a ring system.
“Great Dark Spot” “Small Dark Spot”
Neptune’s Moons Has 13 known moons. The 6 smaller moons orbit in opposite directions of the 2 largest moons.
Triton Largest moon with a retrograde orbit in Solar System. Nearly the size of Earth’s moon. Coldest surface temperature measured in solar system: minus 235°C Has a thin nitrogen atmosphere.
Triton Surface composed of frozen methane, nitrogen, and water-ice. Surface shaped by cryovolcanism. Volcanoes may erupt a mixture of nitrogen gas, water-ice, ammonia, methane, and dust.
Pluto Mass = Earths. Surface temperature: -235°C to -210°C. Is composed of a mixture of ice and rock – surface covered with frozen nitrogen. 5 moons discovered so far.
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.
Comets Comet: small solar system bodies that are loose masses of ice, dust, and rocky material. Leftover debris from the formation of the Solar System.
Image of Comet 67P/C-G taken by the Rosetta spacecraft (ESA) in August, 2014
Close up views of the surface taken on November, 2014.
Comet Ison in November, 2013
Comet McNaught (January, 2007)
Nucleus of Halley’s Comet imaged by the Giotto space probe in Every 76 years, the comet returns to the inner Solar System.
Comet Hale-Bopp (April, 1997) will make a return appearance in the year, 4385.
The Asteroid Belt Asteroids: minor bodies of rocky and metallic material (compositions like those of terrestrial planets). –More than 600,000 discovered so far. Meteoroids: smaller fragments.
The Asteroid Belt Leftover debris from the nebula that formed the Solar System.
Asteroid Eros imaged by the NEAR-Shoemaker probe.
Image of Vesta taken by the Dawn spacecraft in the summer of 2011.
At 940 km in diameter, the dwarf planet, Ceres is the largest member of the asteroid belt.