Transcript powerpoint
Jupiter Vital Statistics • • • • • • • • • R = 71,492 km M = 1.90 x 1027 kg Rorbit = 778.4 x 106 km T = 124° K Eccentricity = 0.048 axial tilt = 3.08° “day” = 9.84 hours “year” = 11.86 years orbital inclination = 1.31° • 11.21 RÅ • 317.8 MÅ • 5.2 A.U. A bit of background • • • • Known since prehistoric times One of Galileo’s 4 big discoveries 63(?) moons to date moons are named for figures in the life of Zeus (mostly his lovers) • faint rings • gradually slowing down • Io, Europa, and Ganymede are locked in a 1:2:4 orbital resonance (in a few million years, Callisto will be locked as well, with an orbit 8 times that of Io) Claims to fame • Largest planet in the solar system – so large that even causes a wobble in the sun’s motion that would be detectable from other stars • Boasts the most geologically active moon in solar system • Great Red Spot • visible bands (even visible from Earth with backyard telescopes) The Great Red Spot • Origin is unknown • A storm about 2 times Earth’s diameter • Has been raging for at least 300 years (Discovered by either Cassini or Robert Hooke in the mid-17th century) • gas flow around the spot is counterclockwise, with a period of about 6 days at speeds up to 2770 mph • center is tranquil (like the eye of a hurricane) • gas north of the spot flows westward, whereas gas south of the spot flows east Series of pictures taken by HST between 1992 and 1999 Movie interlude • • • • http://www.nineplanets.org/pxjup.html look at Jupiter “Day” Rotating Jupiter Red spot Visits • • • • • Pioneer 10 in 1973 (1st visit) Pioneer 11 Voyager 1 Voyager 2 Ulysses (was really just using Jupiter for a gravity boost) • Galileo Pioneers • 10 was 1st to Jupiter - just a flyby • Pioneers were designed to test the ability of spacecraft to survive passage through the asteroid belt and Jupiter’s magnetosphere • 11’s power supply is dead, but 10 is still functioning • will be 1st craft to reach interstellar space – bear plaques trying to convince aliens we’re intelligent Voyagers Voyagers • Voyager 1 launched Sept 5, 1977 and flew past Jupiter March 5, 1979 • Voyager 2 launched Aug. 20, 1977 (before V1) and flew by Jupiter August 7, 1979 • Most of what we know about the gas giants comes from Voyagers 1 and 2 • Discovered – that Jupiter has complicated atmospheric dynamics, lightning, and aurorae – 3 new satellites – ring system – Io has active sulfurous volcanoes Galileo Galileo • • • • Launched Oct 18, 1989, arrived 1995 1 slingshot around Venus, 2 around Earth Tested instruments while at Venus High-gain antenna didn’t open as planned, so they reprogrammed the computer to use the smaller antenna (and we got most of the data it sent) • Discovered a “moon” orbiting the asteroid Ida Galileo • In 1994, could see Shoemaker-Levy 9 crash into Jupiter • Spacecraft (orbiter) and probe • Probe descended 95 miles, collected 58 minutes of data on weather • appeared that atmosphere is dryer than we thought (but later we realized the probe had entered a hot spot) • near end of 58 minutes, probe measured winds of 450 mph (melted and vaporized shortly after that) Structure and Atmosphere • Atmosphere: 86.1% H2, 13.8% He – also: ammonia, methane, water vapor • Presence of lots of H2 and He is a result of strong gravity • Bright “zones” (other gas planets have them, but they’re most pronounced on Jupiter) and dark “belts” Atmosphere • Upwelling in zones, sinking in belts • high pressure in zones (low in belts) Atmosphere - Zonal flow • Underlying the bands is a stable pattern of eastward and westward wind flow, known as “zonal flow” • note: belts and zones are related to zonal flow pattern • Note - equatorial regions of atmosphere rotate faster than the planet - average flow speed of about 85 mph (similar to Earth’s jet stream) Atmosphere - structure • None of the gases listed earlier can account for coloration • We believe cloud colors are the result of complex chemical processes • A model based on available data and some math • Galileo probe made it to the bottom of this diagram Internal structure • This diagram is based on Voyager data and theoretical modeling Auroras Rings Galileo image - clearly shows radial structure that had only been hinted in Voyager images Moons • Ganymede, Callisto, Europa, Io • Metis, Adrastea, Amalthea, Thebe • Leda, Himalia, Lysithea, Elara, Ananke, Carme, Pasiphae, and Sinope • At least 47 others, some of which have been named Ganymede • Largest moon in Solar System • Weird grooves 27 Callisto • Oldest, most cratered surface of any body in Solar System • uniform interior of ice and rock mixture 29 30 Io • Very close to Jupiter • Active volcanos 31 Europa • Only other body in Solar System with liquid water • VERY smooth 32 Europa interior