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The Solar System Part 2 – Saturn through the Oort Cloud. It suddenly struck me that that tiny pea, pretty and blue, was the Earth. I put up my thumb and shut one eye, and my thumb blotted out the planet Earth. I didn't feel like a giant. I felt very, very small . -Neil Armstrong.
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The Solar System Part 2 – Saturn through the Oort Cloud It suddenly struck me that that tiny pea, pretty and blue, was the Earth. I put up my thumb and shut one eye, and my thumb blotted out the planet Earth. I didn't feel like a giant. I felt very, very small. -Neil Armstrong
As most people know our Solar System, for a long time, was considered the home of nine planets.
Saturn Second largest planet. 1/8th the density of Earth, but 95 times its mass. Core is iron and nickel surrounded by metallic and liquid hydrogen and liquid helium. Ammonia crystals give the atmosphere a yellow color. Magnetic field is slightly weaker than Earth’s. Ring system has 9 rings and 3 arcs, composed of ice and rock. Has many moons with Titan being the 2nd largest in the Solar system. Photo is from the Cassini probe taken in March of 2004.
Saturn Characteristics Takes 29.45 years to orbit the Sun. It takes 10 ½ hours for Saturn to rotate once on its axis. It is the only planet that is less dense than water. (0.69 g/cm3). Together Jupiter and Saturn hold 92% of the Solar systems mass. Core is very hot 11, 7000 C. The planet radiates 2.5 times more energy than it receives from the Sun. The clouds are composed of Hydrogen (96.3%) and Helium (3.25%). Ammonia, acetylene, ethane and methane make up the rest of the atmosphere. The winds are second fastest in the Solar system (1800 km/h) The photo shows a great storm which encircled the planet in 2011.
Rings The rings extend from 6,630 km to 120,700 km above the equator. 93% water ice 7% amorphous carbon. Particles range in size from dust to rocks 10 m in diameter. Rings may have formed from a destroyed moon or they may be left over from the original material that made the planet. Some material seems to come from the moon Enceladus’s ice volcanoes. Some of Saturn’s moons act as shepherd moons. Their gravity helping to keep the rings in place.
Ring Diagram The rings have gaps caused, in part by Saturn’s many moons. Some gaps are cleared out areas by moonlets like Pan. Some gaps are maintained by the gravitational effects of shepherd moons. Mimas maintains the Cassini division. The rings possess their own Oxygen atmosphere. It seems that some of the ice comes from the ice volcanoes of Enceladus.
Moons There are at least 62 moons. The largest is Titan. Many of the moons are very small and some are not named. Some play a strong role in the ring system of this planet. This photo is a montage of pictures taken by the Voyager 1 spacecraft in November 1980. This view shows Dione in the forefront, Saturn rising behind, Tethys and Mimas fading in the distance to the right, Enceladus and Rhea off Saturn's rings to the left, and Titan in its distant orbit at the top.
Rhea Its low density means it is mostly made up water ice. It has a very thin atmosphere of oxygen and carbon dioxide. There may be a small ring system orbiting this moon. This picture, taken by the Cassini probe in 2008, shows the ice cliffs and carters common on this moon.
Enceladus 6th largest moon of Saturn. Cryovolcanoes at the south pole shoot large jets of water ice particles into space. Some of this water falls back onto the moon as snow, some adds to Saturn’s rings and some reaches the planet itself. This water near the surface may allow Enceladus to support life. This Cassini picture from 2005 shows the cryovolcanoes in the southern hemisphere.
Titan This is the largest moon of Saturn and the 2nd largest moon in the Solar System. It is the only one with a dense atmosphere. It is the only other object, other than the Earth, with stable bodies of surface liquid. Titan is primarily composed of water ice and rocks. The surface liquid was discovered to by hydrocarbons. The atmosphere is primarily composed of nitrogen with methane, ethane and organic smog. It has wind, rain, and surface features like rivers, lakes, dunes and seas.
Cassini-Huygens The Cassini probe arrived at Saturn in 2004. The huygens part of this space probe detached from Cassini and soft-landed on the moon Titan in 2005. This was the first probe to land on a body outside of the inner solar system. Because of the heat loss from the probe it is suspected that Huygens landed in mud. This picture is part of a panorama that shows the surface of Titan as huygens was descending through the clouds. The lake is most likely composed of hydrocarbons. (gasoline)
Many of the “Rocks” in this picture are water ice. There is a mineral/organic dirt or mud that the Huygens landed on. The atmosphere is colored with a hydrocarbon like smog.
Mimas Surface area a bit less than Spain. Density = 1.15 g/cm3, so moslty water ice. Giant impact crater Herschel (81 miles in diameter) nearly split Mimas in two. The central peak in Mimas rises nearly 4 miles about the floor of the crater.
Uranus Uranus has the 4th largest mass in the Solar System. Uranus and Neptune are considered ice giants. It has the coldest atmosphere in the Solar System (-2240 C) Uranus has a ring system, a magnetosphere and numerous moons. Its axial tilt is 970, so its poles are in line with the plane of the Solar Syste Orbital period is 84 years and a day is 17 hours. It’s rotation is clockwise (retrograde). Wind speeds can reach 560 mph. This diagram shows the position of two new moons discovered by Hubble and the Ring structure.
A 1998 false-colour near-infrared image of Uranus showing cloud bands, rings, and moons obtained by the Hubble Space Telescope's NICMOS camera.
Uranus with cloud bands Uranus in 2005. Rings, southern collar and a bright cloud in the northern hemisphere are visible. (HST ACS image).
Uranus’ magnetic field. It does not originate from the center.It does not line up well with the geographic north and south poles.
Miranda These photos are from Voyager 2, 1986 Miranda is the most geologically active moon. It is 288 miles in diameter. The surface is mostly water ice with some silicate rock in the interior. It is suspected that its unusual terrain was the result of gravitational interactions with another moon umbriel. It is the closest large moon to Uranus.
Titania Titania is the largest of the moons of Uranus and the eighth largest moon in the Solar System at a diameter of 981mi. It consists of equal amounts of rock and ice. Infrared spectroscopy conducted from 2001 to 2005 revealed the presence of water ice as well as frozen carbon dioxide on the surface of Titania. This is a Voyager 2 image of Titania's southern hemisphere taken on January 24, 1986. The Voyager 2 flyby is the only time the Uranian system has been photographed.
Neptune 8th and farthest planet from the Sun. 4th largest by diameter and 3rd largest by mass. The only pictures come from Voyager 2 in 1989. Orbital period is 165 years. Rotates once about every 18 hours. 13 known moons. Very active, stormy atmosphere with the Great Dark Spot. Winds speed up to 1,300 mph. Has a faint fragmented ring system.
5 principal rings.First imaged by Voyager 2 in 1989.System is similar to Uranus’ ring system.
Triton 1,688 miles in diameter. 7th largest moon. Retrograde orbit and icy composition cause people to believe it is a captured Kuiper Belt object. Surface is frozen nitrogen and water ice. It has a rocky core. This picture is from Voyager 2 1989. Triton has the coldest surface known anywhere in the Solar System, -3910F. Most of Triton's nitrogen is condensed as frost, making it the only satellite in the Solar System known to have a surface made mainly of nitrogen ice
Pluto 2nd most massive dwarf planet after Eris. One of several comet-like bodies in the Kuiper Belt. Pluto is composed primarily of rock and ice. It is approximately one-sixth the mass of the Earth's Moon and one-third its volume. Pluto has five known moons, the largest being Charon, discovered in 1978. In 2015 the New Horizons will give us the first close look at Pluto and its moons. 246 years to orbit the Sun. It rotates once every 6.39 days. It is half ice and half rock. The picture is a Hubble view of Pluto and its rotation.
Charon Discovered in 1978. Diameter is 750 miles. Seems to be mostly nitrogen and methane ice. This is a Hubble view of Pluto and Charon taken in 1990. Some feel that Charon formed from an impact.
Kuiper Belt Similar to the Asteroid belt only much larger. (30 to 50 AU). Consists mainly of small icy bodies. It is home to at least three dwarf planets: Pluto, Haumea and Makemake. It is felt that some of the outer planets moons (Triton, phoebe) are captured Kuiper bodies. First discovered in 1990, now over 1,000 KBO,s over 62 miles in diameter are known. Not the source of periodic comets as was originally thought. In the diagram objects in the belt are green, scattered are orange and are called centaurs.
Quaoar Quaoar ("Kwawar") is a rocky trans-Neptunian object in the Kuiper belt with one known moon. Has a diameter of 731 miles. Orbits the Sun every 286 years. The picture is an artist’s impression of the dwarf planet and its moon Weywot.
Eris Most massive dwarf planet. 2,326 km (1,454 mi.) in diameter. Discovered 2005 Three times farther away than Pluto. Eris was discovered in January 2005 by a Palomar Observatory-based team. It is a trans-Neptunian object (TNO). It is a member of a high-eccentricity population known as the scattered disc. It has one known moon, Dysnomia.
Scattered Disk The scattered disk contains far distant (30 to 100 AU) objects with extremely elliptical orbits. These objects have been affected by the gravity of Neptune and their orbits have been changed. It is felt that most periodic comets and some of the moons of Neptune, Uranus and Saturn came from these bodies. This is a Hubble photo of Eris and its moon Dysnomia.
Haumea Discovered in 2004 at Palomar. Egg shape is caused by rapid rotation. Haumea is a plutoid, a dwarf planet beyond Neptune. It orbits the Sun every 283 Earth years. It is about 720 miles long. The surface is most likely composed of water ice. The two moons are named Rudolph and Blitzen