Copyright 2010 Pearson Education, Inc. Lecture Outline Chapter 7 The Jovian Planets Copyright 2010 Pearson Education, Inc. Chapter 7 The Jovian Planets Copyright 2010 Pearson Education, Inc. Observations of Jupiter and Saturn The Discoveries of Uranus and Neptune Bulk Properties of the Jovian Planets Jupiters Atmosphere The Atmospheres of the Outer Jovian Worlds Jovian Interiors Summary of Chapter 7 Units of Chapter 7 Copyright 2010 Pearson Education, Inc. Jupiter can be imaged well from Earth, even with a small telescope. Here: Jupiter with its Galilean moons 7.1 Observations of Jupiter and Saturn Copyright 2010 Pearson Education, Inc. True-color image of Jupiter 7.1 Observations of Jupiter and Saturn Copyright 2010 Pearson Education, Inc. Natural-color image of Saturn 7.1 Observations of Jupiter and Saturn Copyright 2010 Pearson Education, Inc. Cassini image of Jupiter, true color 7.1 Observations of Jupiter and Saturn Copyright 2010 Pearson Education, Inc. Uranus, in natural color. Note the absence of features. 7.2 The Discoveries of Uranus and Neptune Copyright 2010 Pearson Education, Inc. Neptune in natural color 7.2 The Discoveries of Uranus and Neptune Copyright 2010 Pearson Education, Inc. The Jovian planets are large and much less dense than the terrestrial planets; Saturn is less dense than water! 7.3 Bulk Properties of the Jovian Planets Copyright 2010 Pearson Education, Inc. Jovian planets, compared to Earth 7.3 Bulk Properties of the Jovian Planets Copyright 2010 Pearson Education, Inc. Peculiarity of Uranus: Axis of rotation lies almost in the plane of its orbit. Seasonal variations are extreme. 7.3 Bulk Properties of the Jovian Planets Copyright 2010 Pearson Education, Inc. Atmosphere has bright zones and dark belts. Zones are cooler, and are higher than belts. Stable flow underlies zones and bands, called zonal flow. Simplified model: 7.4 Jupiters Atmosphere Copyright 2010 Pearson Education, Inc. No solid surface; take top of troposphere to be 0 km. Lowest cloud layer cannot be seen by optical telescopes. Measurements by Galileo probe show high wind speeds even at great depth probably due to heating from planet, not from Sun. 7.4 Jupiters Atmosphere Copyright 2010 Pearson Education, Inc. The Galileo probe descended into Jupiters atmosphere and returned valuable data. The arrow indicates its entry point. 7.4 Jupiters Atmosphere Copyright 2010 Pearson Education, Inc. Major visible features: Bands of clouds; Great Red Spot 7.4 Jupiters Atmosphere Copyright 2010 Pearson Education, Inc. Two examples of smaller storms merging, first into a smaller red spot, second into existing Great Red Spot 7.4 Jupiters Atmosphere Copyright 2010 Pearson Education, Inc. The atmosphere of Saturn is similar to that of Jupiter, except that Saturn is somewhat colder and its atmosphere is thicker. 7.5 The Atmospheres of the Outer Jovian Worlds Copyright 2010 Pearson Education, Inc. Saturns atmosphere is similar to Jupiters, except pressure is lower. It has three cloud layers. Cloud layers are thicker than Jupiters; see only top layer. 7.5 The Atmospheres of the Outer Jovian Worlds Copyright 2010 Pearson Education, Inc. Saturn also has large storms, and bands. 7.5 The Atmospheres of the Outer Jovian Worlds Copyright 2010 Pearson Education, Inc. Storms near Saturns equator 7.5 The Atmospheres of the Outer Jovian Worlds Copyright 2010 Pearson Education, Inc. Enormous thunderstorm on Saturn 7.5 The Atmospheres of the Outer Jovian Worlds Copyright 2010 Pearson Education, Inc. Rotation of Uranus can be measured by watching storms. 7.5 The Atmospheres of the Outer Jovian Worlds Copyright 2010 Pearson Education, Inc. Neptune has storm systems similar to those on Jupiter, but fewer. The large storm system at top has disappeared in recent years. 7.5 The Atmospheres of the Outer Jovian Worlds Copyright 2010 Pearson Education, Inc. No direct information is available about Jupiters interior, but its main components, hydrogen and helium, are quite well understood. The central portion is thought to be a rocky core. 7.6 Jovian Interiors Copyright 2010 Pearson Education, Inc. Magnetic fields of Uranus and Neptune must not be produced by dynamos, as the other planets fields are. Interior structure of Uranus and Neptune, compared to that of Jupiter and Saturn: 7.6 Jovian Interiors Copyright 2010 Pearson Education, Inc. Jupiters magnetosphere: Intrinsic field strength is 20,000 times that of Earth. Magnetosphere can extend beyond the orbit of Saturn. 7.6 Jovian Interiors Copyright 2010 Pearson Education, Inc. Aurorae are seen on Jupiter, and have the same cause as those on Earth the interaction of solar wind particles with the magnetosphere. 7.6 Jovian Interiors Copyright 2010 Pearson Education, Inc. Uranus and Neptune both have substantial magnetic fields, but at a large angle to their rotation axes. The rectangle within each planet shows a bar magnet that would produce a similar field. Note that both Uranuss and Neptunes are significantly off center. 7.6 Jovian Interiors Copyright 2010 Pearson Education, Inc. Summary of Chapter 7 Jupiter and Saturn were known to the ancients; Uranus was discovered by chance, and Neptune was predicted from anomalies in the orbit of Uranus. Jovian planets are large but not dense; they are fluid and display differential rotation. Cloud layers have light zones and dark bands; wind pattern, called zonal flow, is stable. Copyright 2010 Pearson Education, Inc. Summary of Chapter 7, cont. Storms appear with regularity; the Great Red Spot of Jupiter has lasted for hundreds of years (that we know of). Due to conductive interiors and rapid rotation, Jovian planets have large magnetic fields. Jupiter, Saturn, and Neptune radiate more energy than they receive from the Sun.