Jupiter

1. Jupiter Jupiter - named after the Roman God of rain and lord of the sky who overthrew his father Saturn to become King of the gods Known for seductions of Io, Europa and Callisto (left) as well as the abduction of Ganymede One of the brightest objects in the night time sky

2. Jupiter • Fifth planet from the Sun • Largest planet in our Solar System • Contains most of the SS material not included in the Sun (99.87% vs 0.13%) • “Cool star” • 67 known satellites • Four Galilean satellites • Many smaller yet unnamed • Thin ring system

3. Jupiter Statistics • Orbit = 5.2 AU from the Sun • Year = 11.87yrs • Day = 9.91hrs • Axis tilt = 3.1 degrees • Diameter = 142,984km (12,756) • 11 X the Earth’s • Surface gravity = 22.88m/sec2 (9.78m/sec2) • 80lbs on Earth = 203lbs on Jupiter • Atmosphere • By mass • 75% H • 25%He • By # molecules • 90% H • 10% He • Traces of methane, water, ammonia and “rock” • Close to primordial solar nebula comp

4. Jupiter (cont’d) • Albedo = .52 (.37) • Mean cloud temperature = -121C (-185F) • Two orders of magnitude below temps needed to initialize fusion at core • Thick gaseous material in latitudinal zones of diff comp and velocities • Only planet that we’ve witnessed and imaged a large celestial impact event • Gravitational pull between Sun and Jupiter could be responsible for failure of 10th planet to form (asteroid belt)

5. Pinball Wizards • 1960’s Jim Long @ JPL realized in 15yrs J,S,U,N would be aligned perfectly • Wouldn’t occur again for 176 yrs • How to achieve velocities to get through outer system < decade? • Gary Flandro – gravity assists for a Grand Tour of the outer SS • Utilize and update Pioneer probes into Voyagers

6. Voyager 1 & 2 • Voyager 1’s trajectory was changed to send it out of the ecliptic & past Titan • Atmosphere was of interest because of make-up • Voyager 2 continued outward along the ecliptic plane past Uranus & Neptune (Pluto was in a position along its orbit such that it was impossible to visited by the probe) • Both are believed to currently be within the heliopause boundary

7. Jupiter’s Interior • The outer layer is primarily composed of molecular H • At > depths the H begins to resembe a liquid • 10,000kms deep, H reaches pressure of 1,000,000 bars with a temperature of 6,000° K (10,341°F) • H changes into liquid metallic H phase • H atoms break down yielding ionized protons and electrons similar to the Sun's interior • Below this is a layer dominated by ice • "ice" denotes a soupy liquid mixture of water, methane, and ammonia under high temps and press • At the center is a rocky or rocky-ice core of up to 10 Earth masses

8. Jupiter’s Magnetosphere • Bubble of charged particles trapped within the magnetic environment of the planet • In this image, a magnetic field is lined over the image for perspective • Lines extend in the horizontal plane to a width 30 X the radius of Jupiter • Shown for scale and location are the disk of Jupiter (black circle) • Approximate position (yellow circles) of the doughnut-shaped torus created from material spewed out by volcanoes on Io, inner-most of Jupiter's large moons

9. Atmospheric Banding • 2 types • Light = Zones • Dark = Belts • Latitudinal Distribution • Little solar energy - internal heat may supply distribution along with quick rotation • Chemical and temperature differences create varied colored banding • Shear turbulence along boundaries • Winds in bands blow in opposite direction to adjacent bands • Shear winds may reach 400mph • Shear winds may reach to great depths in atmosphere

10. Jupiter’s Great Red Spot • Great Red Spot • Visible for > 300yrs • 2X diam Earth • Anti-cyclonic (high pressure) storm • Rotation is CCW, with a period of about 6 days • (A hurricane in Earth's Southern hemisphere rotates clockwise because it is a low pressure system) • Clouds of the Spot appear to be about 8 km above neighboring cloud tops • Color of cloud = height • Blue or black areas are deep clouds • Pink areas are high, thin hazes • White areas are high, thick clouds

11. Two New Red Spots • 2006 & 2008 new Red Spot storms appear • 2006 was consolidation of 3 smaller white spots from the 30’s • Red color comes after material is exposed to UV sunlight • Climate change?

12. Curtains of light caused by hi-energy electrons racing along planet's magnetic field into upper atmosphere • Electrons excite atmospheric gases, causing them to glow • Main oval of the aurora, centered on the magnetic N pole, & more diffuse emissions inside the polar cap • Resembles the same phenomenon in Earth's polar regions • Hubble image shows unique emissions from the magnetic "footprints" of three of Jupiter's largest moons • These points are reached by following Jupiter's magnetic field from each satellite down to the planet • From Io (along the left hand limb), Ganymede (near the center), and Europa (just below and to the right of Ganymede's auroral footprint) Jupiter’s Aurora

13. Jupiter’s Ring System • First discovered by Voyager 1 in 1979 • Three main sections • The innermost, cloud-like ring is called the Halo Ring • Next is the Main Ring, quite narrow and thin • Beyond the Main Ring is the wispy, nearly transparent Gossamer Ring • The Gossamer Ring has two parts: the Amalthea Gossamer Ring (closer to Jupiter) and the Thebe Gossamer Ring • Jupiter's rings are different from Staurn’s: • Very dark and difficult to see • Made up of small bits of dust • Meteors striking the surface of Jupiter's small, inner moons kick up dust which then goes into orbit around Jupiter, forming the rings

14. Jupiter’s Ring System

15. Jupiter’s Rings and associated moons • Movie clip taken by NASA's Cassini spacecraft as it approached Jupiter • Shows motions, over a 16 hour-period, of two satellites embedded in Jupiter's ring • Adrastea is the fainter of the two • Metis is the brighter

16. Galilean Satellites

17. Galilean Satellite Interiors • Except for Callisto, all the satellites are believed to have metallic (Fe, Ni) cores • Except Callisto, all the cores are surrounded by rock (silicate) shells • Io's rock shell extends to the surface • Rock layers of Ganymede and Europa are in turn surrounded by shells of water in ice or liquid form • Callisto is shown as a relatively uniform mixture of comparable amounts of ice and rock that extends up to a possible salty ocean beneath a thick icy crust • Surface layers of Ganymede and Callisto (shown as white) indicate they may differ from the underlying ice/rock layers in a variety of ways including, for example, the % of rock they contain • Europa could have a similar surface, although it could also suggest an ice layer overlying a liquid water ocean • It is not certain if there is a liquid water ocean on Europa at present

18. Orbital Resonance • Over time, orbital periods of satellites can stabilize into predictable patterns • 1 orbit for Ganymede • 2 orbits for Europa • 4 orbits for Io • Callisto hasn’t had time to become locked

19. Io and Europa Voyager 1 image of Jupiter and two of its satellites (Io, left, and Europa) Io is about 350,000 kms above Jupiter's Great Red Spot; Europa is about 600,000 kms above Jupiter's clouds Both satellites have about the same albedo, however, Io's color is very different from Europa's

20. Io • Diameter 3,630km • ~ size and mass of our Moon • Orbital & rotational period • Same ~1.7 days • Core (1792km) • Fe & Fe-sulfide • Most volcanically active object in SS • No Impact Craters • <1 million year old surface • Magnetic Field? • Hole in Jupiter’s MF suggests possibility • Torus • Na gas and S ions stream along Io’s orbital path • Observed from Earth • Generated by volcanic material that reaches escape velocity • Ionosphere • Ionized O, S and S02 at 888kms above Io • Pumped into that region by Io's relentless volcanism

21. IO • Image mosaic of the eruption of Pele on Jupiter's moon Io as imaged by Voyager 2 • The volcanic plume rises 300 km above the surface in an umbrella-like shape • The plume fallout covers an area the size of Alaska

22. Io Volcanic Eruption Sequences • These images show a new eruption, 398km in diam (~ size of Arizona) surrounding a volcanic center named Pillan Patera • Galileo imaged a 120km high plume erupting from this location during its ninth orbit • Pele, the larger plume deposit, also appears different, perhaps due to interaction between the two large eruptions • Prometheus (upper right) volcanic center shifts over 17yr period betwn Voyager and Galileo

23. IORifting • At low resolution, many of the dark features, called pateras, appear to be calderas • Higher resolution images suggest a different origin • At Hi-iaka, the northern and southern margins of the pateras have very similar shapes which appear to fit together • May indicate crustal extension has created a depression that has subsequently been covered or filled in by darker lava flows • The two mountains bordering Hi-iaka Patera also appear to fit together

24. Europa • Very tenuous atmosphere • Mostly Oxygen • Galileo discovers hydrogen peroxide on surface as well • Either destroyed by ultraviolet light or changed by contact with other chemicals • Life span on Europa is only a few weeks or months • Hydrogen peroxide becomes another reactive chemical called hydroxyl, and can ultimately produce oxygen and hydrogen gas

25. EuropaRidge Complex • One of the youngest features in this area is the double ridge cutting across this image • ~2.6 kms wide and 300 m high • Note small craters in the smooth deposits along the south margin of the prominent ridge • The complexly ridged terrain shows parts of the icy crust have been modified by intense faulting and disruption • Structure and deposits are driven by energy from the planet's interior

26. EuropaLenticulae • The spots and pits in this region are each ~10km across • The dark spots are called "lenticulae," Latin for freckles • Their similar sizes and spacing suggest that Europa's icy shell may be churning with small thermal convection cells • Other evidence has shown that Europa likely has a deep melted ocean under its icy shell • Reddish ice erupting onto the surface in/near these lenticulae may hold clues to the composition of the ocean and to whether it could support life

27. EuropaThera and Thrace • Thera (left) is about 69 by 85 km and appears to lie slightly below the level of the surrounding plains • Bright icy plates inside appear to be dislodged from the edges of the chaos region • Curved fractures along its boundaries suggest that collapse may have been involved in Thera's formation • Thrace (right) is longer, shows a hummocky texture, and appears to stand at or slightly above the older surrounding bright plains • One model is that warm ice welled up from below and caused partial melting and disruption of the surface

28. EuropaChaos Terrain • Mosaic of the Conamara Chaos region • Clearly indicates relatively recent resurfacing • Irregularly shaped blocks of water ice formed by the break up and movement of existing crust • Blocks were shifted, rotated, and even tipped and partially submerged within a mobile material that was either liquid water, warm mobile ice, or an ice and water slush • Young fractures cutting through this region indicate the surface re-froze

29. Ganymede • Global view of Ganymede's trailing side (colors enhanced to emphasize differences) • Frosty polar caps can be seen along with two predominant terrains on Ganymede • Bright, grooved terrain • Older, dark furrowed areas • Violet hues at poles may be the result of small particles of frost (scatter more light at < wavelengths) • Ganymede's magnetic field, may be partly responsible for the appearance of the polar terrain • Compared to Earth's polar caps, Ganymede's polar terrain is relatively vast • Frost on Ganymede reaches latitudes as low as 40 degrees on average and 25 degrees at some locations • For comparison with Earth, Miami, Florida lies at 26 degrees north latitude, and Berlin, Germany is located at 52 degrees north

30. Ganymede Grooved Terrain • Magnetic Field • 1st satellite to exhibit magnetic field • Very thin oxygen atmosphere (thickest near poles) • Bombardment of surface could release free oxygen gas • Comparable to Earth’s atmosphere near orbit of Space Station • New terrain overlays older terrain, which overlays still older surface

31. GanymedeGrooved Terrain • Arbela Sulcus • Parallel ridges stacked “domino-like” • Note traces of modified craters (why not “squashed” outline? • Wide-graben like structure suggests • Crustal extension • Normal faulting • Warmer upwelling material

32. Callisto • Most heavily cratered object in SS • “line of fire” • Little resurfacing • Very ancient surface

33. CallistoValhalla Multi-ringed Basin • Four-frame Voyager mosaic shows the ancient impact structure Valhalla Basin • ~3800 km across • Little topo relief indicating upwelling from beneath surface as a result of deep impact • A bright central zone is surrounded by discontinuous rings • The rings are tectonic features with scarps near the central zone and troughs at the outer margin • Younger large impacts have smashed into Callisto after its formation

34. CallistoEroding Spires? • Galileo has detected a thin CO2 atmosphere • Also confirmed existence of CO2 on surface • Spire-like "knobs" 80 to 100m high • Possibly material thrown outward from major impact billions of years ago • Mostly ice, but also contain some darker dust • Dark material seems sliding down knobs collecting in low-lying areas • Represents continuing erosion • Could eventually disappear • Some ice sublimates leaving behind dust that was bound in ice • Accumulating dark material could absorb enough Solar heat to warm the surrounding ice and keep the process going

35. CallistoCrater Chain • A portion of a chain of impact craters is seen in this image taken by Galileo spacecraft on November 4, 1996 • Crater chain is believed to result from the impact of a split object • Perhaps similar to the fragments of Comet Shoemaker-Levy 9 • Smallest visible crater is about 120m across

36. Galileo • Probe indicates much less He than expected • Carbon – staggeringly abundant • Gravity sink for comets like the Shoemaker-Levy • Lightning up to 1,000 X Earth’s power • Magnetic data shows evidence that Ganymede and Callisto have liquid water oceans beneath their crusts as well • I, E and G all have metallic cores • All have “surface-bound exospheres” • Ionized gases loosely bound to surface • G has own magnetic field, only moon known to have one

37. Comet Shoemaker-Levy 9 • Hi-res image of Comet Shoemaker-Levy • mosaic of images taken by the Hubble on January 24-27, 1994 • Twenty nuclei are visible (one slightly outside of the FOV) • Each nucleus has its own coma and tail • The fourth nucleus from the left (the first bright one) is apparently starting to separate into at least two pieces

38. Comet Shoemaker-Levy 9 Impacts • Eight impact sites are visible in this Hubble image • From left to right are the E/F complex (barely visible on the edge of the planet), the star-shaped H site, on the far right limb the D/G complex • D/G complex also shows extended haze • Features rapidly evolved on timescales of days • The smallest features in this image are less than 200 kilometers across

39. Possible asteroid impact • AMATEUR ASTRONOMER DISCOVERY • Scars last several months but less than Comet Shoemaker • Diff in composition of impactors?

40. Ida and Dactyl Ida ~11km wide Dactyl ~.6km Galileo probe on its way to Jupiter took image during close encounter Color image made from the Galileo spacecraft about 14 minutes before its closest approach to asteroid 243 Ida on August 28, 1993 First known asteroid w/moon Many are now known including Trans-Neptunian objects