The Jovian PlanetsTopicsJovian planets (Jupiter-like)SizeDistance from the SunPowerPoint PresentationCompositionJupiterIoEuropaGanymeadeCallistoSaturnTitanUranusNeptuneTritonExtrasolar planetsHow do we know?The Jovian PlanetsChapter 7Topics•Jupter, Saturn, Uranus, Neptune•How do we know?•Why do we care?•What is common about the outer planets?•What is peculiar to each of these planets?Jovian planets (Jupiter-like)Sizeradius is about 1/10 of the radius of the SunDistance from the SunTerrestrialJovianTerrestrial Jovian small--1/100 radius of the Sunlarge --1/10 radius of the Sunorbit at 0.4 to 1.5 AUorbit at 5 to 30 AUfew many (# growing)none all have ringsSizeLocationMoonsRingsCompositionrocks and metals gasses and iceComposition0.71 to 1.67 g/cm3So what are they made of?mostly gasses (hydrogen, helium) and iceJupiter•largest planet•Great Red Spot•studied by Pioneer, Voyager 1 & 2, Galileo spacecraft•liquid interior (very high pressure and temperature)•16 moons (4 largest are the Galilean moons)Io•Active volcanoesEuropa•subsurface ocean•cracked iceGanymeade•lots of faults•strong magnetic fieldCallisto•old surface (meaning that it’s not undergoing lots of change except for impact craters)Saturn•Large, thin rings •Rings are held together by the gravitational attraction of “shepharding” satellites •Major Gaps: The Cassini and Enke divisionsTitan•larger than Mercury•has an atmosphere•probably has oceans of methaneUranus•discovered in 1781•shows no cloud banding•axis of rotation is only tilted 8 degrees from the ecliptic•84 year orbital period•rings originally discovered during occultation of a star•young rings (what’s the source of dust?)Neptune•noted by Galileo•the exact path of Uranus could not be explained by the gravitational pulls of the Sun, and the other planets. What does this mean?•discovered in 1846•164 year orbital period•strong magnetic fieldTriton•density 2.1 g/cm3•atmosphere (nitrogen)•impact craters due to comets•ice made of water•active ice volcanoes•retrograde orbit (it’s going the wrong way)•probably captured by NeptuneExtrasolar planets•How many planets have we discovered besides those in our solar system?•I’m starting to lose count, but it’s now over 100.•Planets are even found in binary star systems.•We analyze the wobble in a star by studying the Doppler shift in its spectrum and determine the approximate masses and distances of the orbiting planets.How do we know?•How do we know that the outer planets are mostly gas and mostly made up of hydrogen and helium?•How do we know that the atmosphere of a planet has methane?•How do we know the period of rotation of the outer planets? (Note: we use a different technique of measuring rotational period of the terrestrial planets.)•How do we know that a moon’s surface is ice?•How do we know the size of matter within the rings?•How do we know that a moon has an “old” surface and that the moon has little geologic