Rings, Moons, and Pluto High Energy Physics atWayne State環(huán)衛(wèi)星和冥王星在韋恩高能物理學(xué)

1、chapter 11: moons,rings and plutoring and satellite systemsgeneral properties.jupiters moons52 known satellites (as of about 2 years ago)large galilean moonsioeuropaganymedecallisto callisto, ganymede, europa, io first seen by galileo (the astronomer) studied by the galileo space probe hubble space

2、telescope observations combined data has found important similarities to the terrestrial planets differences between moons mostly due to distance from jupitercallisto: crater packeduoutermost of the galilean satellites.u2 million km from jupiter.unoontime surface temperature: 130 k (140craters on ca

3、llistoganymede: largest, most variedulargest satelliteucratered, but less so than callistou of the surface seem to have formed “recently”ganymedeold dark terrain new bright terrain unew due to fewer craters ubright due to fracturing of the icy surfacecraters varying degradationgeologically active.wh

4、y is ganymede different from callisto?usmall difference in europa: ice-covered oceanreal colorenhanced colorueuropas surface is covered with a layer of ice uunder the ice is io uio is the most volcanically active world in the solar system uio has an elliptical orbit, so the tidal forces on it vary w

5、ith time uthese changing forces squeeze and flex io producing heat uthe hot interior produces massive volcanism uthe interior heat has also produced a differentiated interior io has an iron core surrounded by a molten, rocky mantle iojupitervolcanism on iouio has no impact craters they have been era

6、dicated by lava uvolcanoes produce plumes of material that extend up to 280 km above the surface uthe colors on io come from sulfur (yellow, black, red) and from sulfur dioxide (so2, white) uvolcanoes can be very long lived some have been observed for 20 yearsloki volcano eruptspele volcanoios plasm

7、a torusuios volcanoes put lots of ions into its orbit ions are atoms that have lost an electron giving them a net electrical charge uthe ions are effected by jupiters magnetic field producing a plasma torus uas jupiter rotates its changing magnetic field produces an electrical current through the to

8、rus and interiorsaturns moons and ringsu30 known satellites (before cassini)dense atmosphere: pressure 1.5 times earths mostly nitrogen plus 6% argon and a few percent methane. trace amounts of organic compounds (i.e. ethane, hydrogen cyanide, carbon dioxide) and water water is formed when methane i

9、n titans upper atmosphere is exposed to sunlight.chemical activity despite low surface temperature, 94 k (-290 f). like the smog found over large cities, but much thicker. conditions like earth early in its history when life was first getting started. may have the necessary building blocks for life!

10、titan: cloud worldhuygens probe lands on titanuranus systemuring and satellite tilted at 98neptune systemu8 known satellitestriton: ice worldorbit is retrograde: didnt form with neptune! perhaps a captured kuiper belt object capture may have shattered another neptunian mooncapture scenario accounts

11、for:tritons orbit unusual orbit of nereid provides energy to melt and differentiate tritons interior historical connection to pluto?similar bulk properties pluto has eccentric neptune-crossing orbitis triton a captured comet? what about pluto?triton: ice world plume rising 8 km above the surface and

12、 extending 140 km downwind triton: eruptions of volatile gases like nitrogen or methane driven by seasonal heating from the sun. earth, venus, mars: rocky magma driven by internal heat. io: sulfur compounds driven by tidal interactions with jupiter.plumetritons atmospheretenuous cloudssummary: six l

13、arge moonsplutoudiscovered through systematic search.hst pictureplutocharonpluto basicsunot visited by spacecraft,quaoar new planet?uorbit more circular than plutosucloser to the ecliptic 7.9 degree inclination compared to plutos 17 degrees.udiameter 1280 km vs. plutos 2240 kmupossibly pluto and qua

14、oar are both kuiper belt objectsplutos orbit11.3.4 the nature of plutoupluto is not like the terrestrial or jovian planets. upluto, quaoar, xena, charon, and possibly triton, are examples of kuiper belt objects.ringsuall four giant planets have ringsueach ring is a system of billions of small partic

15、les (moonlets).ueach ring displays complicated structure related to the interaction between the rings and satellites.uthe four ring systems are quite different.ring basicsusaturnwhat causes rings?uring = collection of vast numbers of particlesring causes continuedugravitation of the planetrings of s

16、aturnumany rings and sub-rings: a, b, cub-ring : brightest, most closely packed particlesua/c-rings : translucent.utotal mass of b that of icy satellite 250 km in a diameter.ua & b separated by a wide gap called cassini division.urings are broad and very thin.umain ring 70000 km, thickness 20 m.

17、ucomposed of water ice.uparticles range from grains the size of sand up to house-sized bouldersua handful of narrow rings 100 km, in addition to the main rings. unarrow and blackualmost invisible from earthunine rings discovered (1977) during observation of a star occultationufirst seen by voyager (

18、1986)uoutermost and most massive called epsilonrings of uranus and neptunesatellite-ring interactionsurings have intricate structure as discovered by voyager.ustructures due to mainly gravitational effects of satellites. innermost and smallest of the five major satellites, just 480 kilometers (about 300 miles) in diameter. two