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176 Cards in this Set
- Front
- Back
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Meteorites |
-solid samples of bodies of inner solar system that have impacted Earth, which consequently grows by accretion; -much of what arrives at outer limit of Earth’s atmosphere either vaporized or burned up, due to frictional heat and never reaches surface -Asteroid - Bolide passing by Earth outside of its Atmosphere -Meteoroid - Bolide passing through Earth’s atmosphere -Meteor - Lighting of the bolide in response to friction caused by Earth’s atmosphere. - Meteorite - passage of the bolide through the atmosphere to land -entry velocities range from 16-42 km/s (58,000-150,000 km/h) -impact may have significant effects on biosphere -most believed to originate from asteroid belt between orbits of Mars and Jupiter, with a few dislodged from Mars (54 as of 3/11) or the Moon (65 as of 3/11) by grazing (low angle) meteorite impacts of those bodies -falls - recovered meteorites whose passage was observed -fins - discovered some time after their fall. |
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Stony Meteorites |
-dominated by Fe + Mg silicates that are chemically unstable and rapidly weathered -may not survive exposure very long, and if they do, might not be identified as meteorites as such, but rather terrestrial mafic igneous rocks in absence of detailed analysis. |
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Chondrites |
-contain small (~1 mm diameter) spherules, or chondrules, of silicate minerals in finer matrix/groundmass -carbonaceous chondrites right in C-bearing compounds and other volatiles and include amino acids, some chemically equivalent to biotic ones, some unique to these chondrites. - Their elemental composition, except for extreme volatiles such as C, H and He, matches solar abundance data -undifferentiated bodies that have not undergone melting or fractionation -representative of primitive planetesimal chemistry, whose ages may thus yield the age of formation of solar system -ordinary chondrites contain less volatiles, due to secondary metamorphic heating |
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Achondrites |
-lack chondrules -exhibit chemistry and textures of mafic igneous rocks, mostly basalts -represent product of melting to form differentiated crust on parent planetesimals (perhaps diameters of 10s to 100s of km required for sufficient heat to drive this process.) -included in this group are Martian SNC meteorites -some are brecciated |
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Stony-iron Meteorites (most rare) |
-also called pallasites or mesosiderites (“middle iron”) -characterized by intimate association of silicates and Fe + Ni metal, exhibiting liquid immiscibility textures; they are rare -formed at/near mantle/core boundary; silicates are primarily olivine, to be expected based on the high olivine content of Earth’s ultramafic mantle -a planetesimal underwent differentiation, was impacted, and then reassembly occurred to produce this mixed body, with liquid immiscibility textures; (this idea has been superseded) |
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Iron Meteorites |
-collector’s prize; these have Fe and Ni metal, ± Fe-sulphide, are durable and frequently recovered -recognized by intergrowth of Fe and Ni alloys called Widmanstätten structure or pattern, revealed by polishing and acid etching - distinguishes them from iron-bearing artifacts such as slag -also understood to be products of differentiation and core formation of reasonably large bodies, (20-300 km), to allow slow enough cooling for Widmanstätten structure to form |
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Origin of Meteorites |
-An undifferentiated planetesimal would yield carbonaceous chondrites as fragments if impacted; if volatiles had been released due to early heating, regular chondrites i.e. non-carbonaceous, would result -oldest non-carbonaceous chondrites converge on dates slightly younger than Allende CAI; eucrites (like basaltic crust) at 4.540 G.a., Ador at 4.551 G.a., and Ibitra at 4.556 G.a., are oldest non-carbonaceous ones, it suggests that depletion of C as a volatile has occurred early in history of planetesimals -impact and fragmentation of differentiated planetesimals would yield iron, stony-iron, and achondrites upon impact -orbits of meteorites that were tracked coincide with a particular group of asteroids, Apollo (Earth-crossing asteroids) |
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Asteroids |
-Ceres is a dwarf planet, because it orbits the Sun as its primary, has sufficient mass to pull itself into nearly spherical shape, has not cleared neighborhood around its orbit; accounts for approximately 1/3 of total mass of Asteroid Belt -Main Belt asteroids: Orbiting between Mars and Jupiter, do not cross Earth’s orbit. -Apollo asteroids: strong elliptical orbits that cross Earth’s, 700 that exceed 1 km diameter -Amor asteroids: orbits cross that of Mars (responsible for SNC meteorites) -spectroscopy of asteroids indicates a range of compositions similar to meteorites; in general terms, achondrites have high albedo (reflectance; bright), carbonaceous chondrites have low albedo (dark) -Ceres (largest asteroid) now classified as dwarf planet, matches carbonaceous chondrites -we observe compositional zonation to asteroids as a group, such that those with outermost orbits are chondritic (chondrules cannot be detected, but are volatile-rich, probably representing undifferentiated bodies), inner belt asteroids match volatile-poor chondrites, or achondrites & metals representing what are interpreted as differentiated bodies -appear to have originated by one of two means: fragmented planetesimals, or never did accrete as planets (more favoured) -latter case would be rapid formation of gas giant Jupiter, whose gravitational field swept much material out of a proto-asteroid belt, promoted fragmentation vs accretion -asteroid 4 Vesta lacks solar weathering, production & condensation of nanophase (few nanometers) Fe particles produced by vaporization of magic silicates target rocks; account in part for darkening of older ejecta on Moon -explanations advanced to account for this; 1. remanent magnetic field may shield 4 Vesta from solarwinds. 2. lesser mass=weaker gravitational field (incoming bolides travel @ ~5 km/sec, rather than 15 km/sec for Moon); → less kinetic energy→ less melting (agglutinates) and vaporization (nanophase Fe) on airless body; 4 Vesta’s weathering is “cosmic gardening” -Dawn entered orbit around Ceres 3/06/15, adding to what was learned from the Herschel IR and Hubble telescopes -cratered body with subdued relief and some fracturing; Herschel confirmed presence of water vapour above Ceres’ surface, likely by sublimation rather than cryovolcanism; may constitute tenuous atmosphere -numerous bright spots thought to represent water ice, but are magnesium sulphate hexahydrite salts (formed in subsurface water ocean) -what happened: impact cratering removed “dust” cover to expose this material, and water ice has sublimated, leaving bright salts (similar to Epsom salts) -Dawn detected ammonia, not as ammonia (would sublimate due to Ceres close prox. to Sun, ~2.7 AU); bound up in crystal structure of clay minerals -such an ammonia inventory unlikely within the “snow line/frost line”, around 2.7 AU, suggests Ceres originated farther out, and has been nudged into present non-ecliptic orbit (inclined 10.6 degrees), closer to Sun. |
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Which of the following planets/bodies has the least number of impact craters on its surface? A. Earth B. Mars C. Mercury D. Moon |
A. Earth |
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An event that drastically modified Earth’s geological history approximately 3.8-3.5 G.a. was the A. advent of life B. beginning of a period of intense impact C. outgassing of an atmosphere D. all the above |
A. Advent of Life |
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The fact that the Moon and Earth plot on the same oxygen isotope trend primarily argues for which model of the Moon’s Origin? A. binary accretion B. capture C. collision D. fission from Earth |
C. Collision |
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Which of the following types of meteorites would not be from a differentiated body? A. achondrites B. chondrites C. iron D. stony-iron |
B. Chondrites |
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A bolide that has encountered the Earth’s system but has yet to light up is called a(n)? A. asteroid - body orbiting through space B. meteor — lights up in Earth’s atmosphere C. meteorite — If it strikes Earth’s surface D. meteoroid — enters Earth’s atmosphere |
D. Meteoroid |
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K/T Meteorite Impact Hypothesis |
-Walter Alvarez studied K/T boundary section in marine limestones exposed near Gubbio, Italy; suggested that sedimentation rate could be calculated from iridium (Ir) concentration in clay layer at boundary -analysis revealed exceptionally high concentrations of Ir (up to 9 ppb) compared to background levels (<0.01 ppb) associated with Earth’s crustal abundances, which are very low -most plausible explanation was introduction of significant quantity of Ir from extraterrestrial source, very short time span; most probable bolide (impactor), a meteorite representing undifferentiated body, with Ir concentrations in 1-20 ppb range -Earth has same total or bulk concentration of Ir as these meteorites; but Ir is siderophile → is concentrated in core, & depleted in crust due to affinity to Fe - A meteorite 10 km diameter would have carried enough Ir for anomaly, and would have produced an impact crater approximately 100-200 km in diameter, tektites, and shocked minerals |
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K/T Meteorite Impact Hypothesis |
-Walter Alvarez studied K/T boundary section in marine limestones exposed near Gubbio, Italy; suggested that sedimentation rate could be calculated from iridium (Ir) concentration in clay layer at boundary -analysis revealed exceptionally high concentrations of Ir (up to 9 ppb) compared to background levels (<0.01 ppb) associated with Earth’s crustal abundances, which are very low -most plausible explanation was introduction of significant quantity of Ir from extraterrestrial source, very short time span; most probable bolide (impactor), a meteorite representing undifferentiated body, with Ir concentrations in 1-20 ppb range -Earth has same total or bulk concentration of Ir as these meteorites; but Ir is siderophile → is concentrated in core, & depleted in crust due to affinity to Fe - A meteorite 10 km diameter would have carried enough Ir for anomaly, and would have produced an impact crater approximately 100-200 km in diameter, tektites, and shocked minerals |
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Iridium Anomalies |
-within a few years of discovery of anomaly at Gubbio, a similar Ir anomaly found in scores of marine K/T sections, in clay layer right above highest/last Cretaceous fossils -objection was raised that some marine diagenetic (post-depositional) process has concentrated Ir, and anomaly was artificial (significant thickness of calcium carbonate was dissolved, thus concentrating Ir into compact area) -subsequent search for Ir anomaly in terrestrial sections first revealed Ir anomaly near Raton, NM, in freshwater coal swamp deposits; anomaly is known worldwide at over 75 sites, in both marine and terrestrial sediments, is thus legitimate, and of sufficient scale and coverage to represent globally significant impact |
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Shocked Quartz |
-shocked quartz (SiO2) exhibits 2 sets of deformation lamellae that intersect at ~120∞ -produced by rapid application if extreme pressures (>30 GPa), as produced at… a) Meteorite impact sites b) Nuclear test sites c) Laboratories -only impacts are natural, and shocked quartz is associated with bolide impact craters. -these shocked quartz grains are found in all North American K/T sections, less common to rare in Europe and Pacific; indicates proximity to actual impact site (note quartz is found in felsic rocks, not mafic rocks) |
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Microtektites |
-small glass spherules. have chemistry but not crystalline structure of minerals. found near known meteorite impact sites, produced by quenching (rapid cooling) of droplets of molten rock splashed out of impact site -very abundant at certain K/T sites, especially near Beloc, Haiti, has 30 cm-thick layer dominated by microtektites (most common near impact); many North American K/T sections also have these suggesting proximity to impact site |
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Impact Crater |
-the search for a K/T impact site centred on the Caribbean (concentration of shocked quartz grains and microtektites) -candidate site for crater was published by Hildebrand et al., 1991 - Chicxulub Puerto on Yucatán Peninsula of Mexico, exhibits nearly coincident geophysical anomalies → show concentric circle configuration, similar to known impact sites -legitimacy of this negative feature is established by petroleum exploration drilling; 180 km in diameter, in shallow marine platform sequence of carbonates (CaCO3) and anhydrite (CaSO4) 3-6 km thick -depth of excavation is uncertain, but ~ minimum of 1 km -melt rock within structure dated at 64.98 m.y.a., ±0.05; Haitian tektites date at 65.01 m.y.a., ±0.08. -supposed/calculated that a bolide of this size would have produced impact measuring 13 on Richter Scale (a quake of magnitude 9 induces “total destruction”), ≅1014 tons TNT |
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Other Evidence |
- in many terrestrial K/T boundary sections, there is a layer of finely disseminated carbon, at concentrations >104 present levels, inferred to represent soot (ash) accumulation from global wildfires -fern spike just above boundary clay shows severe decline in angiosperm (flowering plant) pollen, increase in proportion of fern spores, a hardier plant life, generally with one of a few species predominant - within ~15 cm, basal Tertiary sediments, proportions of pollen & spores return to values comparable to those of latest Cretaceous; comparable to succession seen after mass kill (e.g. forest fire) today - some North American sites have microdiamonds (high pressure C) within boundary sediments, neither above nor below; could have been deposited directly from bolide (some meteorites have them), or produced from C in CaCO3 target rocks 4. Postulated Effects of Bolide Impact - some of these independent of target site -postulated that incoming bolide could compress atmosphere & induce heating by friction, to as much as 2000 K, inducing burning of N2 to produce NOx & HNO3, nitric acid, for extreme acid rain (pH almost 0) - a large bolide would have tremendous kinetic energy, which would be converted to other forms, including heat, with impact of hot bolide fragments, could trigger global wildfires - volume of sulphate target rocks excavated would have introduced up to 2X1011 tons of SO2 into atmosphere, triggering acid rain & cooling by aerosol effect (scattering incident sunlight) of suspended SO2 - impacting the carbonates would have introduced sufficient CO2 into atmosphere to cause a 10-fold increase, & have led to greenhouse warming of as much as 10 degrees C for 104 – 105 years, before a return to “normal” conditions. - particulates (dust) would have been ejected into atmosphere, resulting in drastically reducing incident sunlight for a period as long as a few years to cause cooling, as well as curtail photosynthesis. net result would have been effective shut-down of marine & terrestrial photosynthesis for a period of several months to a few years. would affect high-end heterotrophs (consumers), but not groups with dormancy mechanisms, or feeding strategies aimed at deposit feeding; this may explain both extinctions & survivors - other postulated effects include shock-wave induced earthquakes & tsunamis 5. Eocene Extinction - Late Eocene (35 m.y.a.) extinction also related to bolide impact, in fact a series of extinctions, spread over almost 10 m.y., best explained as result of rapid climate deterioration triggered by separation of Australia from Antarctica (altered oceanographic circulation patterns) |
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Jupiter & its Satellites |
-Voyager 1 & 2 launched in 1977, arrived at Jupiter 1979, & Voyager 1 near or beyond edge of solar system (3/13; some controversy) -Galileo launched in 1989, arrived at Jupiter 1995; probe sent into Jupiter’s atmosphere, & ultimately craft was sent into Jupiter’s atmosphere to be burned up, to eliminate possibility of bacterial contamination of Galilean satellites -think of Jupiter as being centre of its own planetary system, having 63 known satellites -mass = 2.5 times sum of other planets, it plus Saturn contain over 90% of mass of Solar System, apart from Sun; calculations suggest if it had been 100 times more massive, there would have been two “suns” in solar system |
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Jupiter - Statistics |
-fifth planet from Sun, first of Jovian planets -rotates on axis (Jupiter day) every ~10 hours, & revolves around Sun (Jupiter year) in 11.9 Earth years - diameter is 144,000 km, mass is 318 times that of Earth, & its gravitational field strength is 2.4 times Earth’s -density is 1.3 g/cm3 (vs. 5.52 g/cm3 for Earth), & must have radically different composition -Jupiter has “atmosphere” dominated by H2 & lesser He (H2:He is ~10:1), as a gas-rich planet, the term atmosphere doesn’t carry same significance as it does for terrestrial planets -observed planet surface consists of clouds, primarily ammonia ice (NH3), some NH4SH, C2H6, C2H4, CO, & PH3 -well organized atmospheric system of light zones & dark belts that have opposed wind directions which creates wind shearing at interfaces, & vortices that may be stable or trapped; most famous is the Great Red Spot, a feature known for over 300 years, equivalent of a hurricane, but larger (26,000 km diameter) than Earth; it towers 30 km above the clouds -temperature at the cloud tops is 125 K (~-150° C) -magnetic field = 20,000 times the intensity of Earth’s |
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Internal Structure |
-internal structure is quite simple; with a thick (~20,000km) layer of molecular hydrogen below atmosphere -below this, a layer 30-40,000 km thick, of liquid metallic hydrogen, whose highly charged state, coupled with rapid rotation of the planet, produces the huge magnetic field. -small silicate rock & ice core is postulated, as a nucleus for accumulation of H (reasonable in view of the fact that some of Jupiter’s satellites have some silicate materials, & so such materials were present in this region of Solar System) -lack of a solid surface as such means there are no conventional geological features, no crust, & no impact craters, just a transition from gas to liquid. |
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Jupiters Galilean Satellites - Io |
- most noteworthy for spectacular volcanic activity; apparently most thermally active planetary body, erupts 100 times more lava than Earth does -very young surface (< 1 m.y.a) seen in absence of craters; this points to active resurfacing, & an erosive process (speculative; no H2O.) -images reveal eruptions take form of umbrella-shaped plumes that extend as much as 300km high by 1000km diameter; Voyager 1 detected 9 active volcanoes, but number has been revised upward to 80 based on data from Galileo mission’s spacecraft -thought to cover surface in volcanic ash, sulphur, & So2 frost that accumulate as a ring around calderas -measurements from Galileo expedition reveal volcanic temperatures from fissure eruptions in range of 1700-2000 K (1425-1725° C), over 400° higher than basalt temperatures, too high for molten sulphur; ash & lava plains result -lacks surface ices of other moons of Jupiter, based on density (3.57 g/cm3), probably dominated by silicates -volatiles such as N2, H2O & CO2 have been lost to space upon eruption, S-compounds condense from plumes & fissure eruptions as S snow. -heat for planetary melting, in addition to more conventional sources, derived from tidal friction, pull of Jupiter & Europa in particular, and other moons flexing lo; facilitated by Io’s eccentric orbit around Jupiter (closer to Jupiter’s cloud tops than Moon is to Earth) -sweeping of Jupiter’s magnetic field across rapidly rotating moon could generate heat -Io apparently has its own magnetic field, rather than being bathed in Jupiter’s; Io would be a largely solid planet, with currently active, internal, dynamo field |
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Jupiters Galilean Satellites - Io |
- most noteworthy for spectacular volcanic activity; apparently most thermally active planetary body, erupts 100 times more lava than Earth does -very young surface ( -images reveal eruptions take form of umbrella-shaped plumes that extend as much as 300km high by 1000km diameter; Voyager 1 detected 9 active volcanoes, but number has been revised upward to 80 based on data from Galileo mission’s spacecraft -thought to cover surface in volcanic ash, sulphur, & So2 frost that accumulate as a ring around calderas -measurements from Galileo expedition reveal volcanic temperatures from fissure eruptions in range of 1700-2000 K (1425-1725° C), over 400° higher than basalt temperatures, too high for molten sulphur; ash & lava plains result -lacks surface ices of other moons of Jupiter, based on density (3.57 g/cm3), probably dominated by silicates -volatiles such as N2, H2O & CO2 have been lost to space upon eruption, S-compounds condense from plumes & fissure eruptions as S snow. -heat for planetary melting, in addition to more conventional sources, derived from tidal friction, pull of Jupiter & Europa in particular, and other moons flexing lo; facilitated by Io’s eccentric orbit around Jupiter (closer to Jupiter’s cloud tops than Moon is to Earth) -sweeping of Jupiter’s magnetic field across rapidly rotating moon could generate heat -Io apparently has its own magnetic field, rather than being bathed in Jupiter’s; Io would be a largely solid planet, with currently active, internal, dynamo field |
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Europa |
- surface covered by H2O ice, of speculative thickness; rather than glaciated, “lithosphere” may be a cryosphere. -icy surface heavily fractured, indicating movement of ice, with injection of “slush dikes” into fractures -larger blocks that look like ice rafts/ice jams, with previously healed fractures within blocks -surface also characterized by low relief, especially compared to other moons of Jupiter, fresh, very few craters; is this due to resurfacing by eruptions of water, or simply caused by plastic flow of ice smoothing out features, in response to gravity? -Galileo mission led us to believe there had been/still was, a water ocean underneath icy crust; extreme view suggests crust as thin as 2 km, with deep/thick liquid water ocean beneath for ~ 160 km; tidal heating also significant -internal structure largely speculative, density of 2.97 g/cm3 suggests silicates (inferred) & H2O (observed) -presence of a small magnetic field means small iron core is possible, but not demonstrable; possibly induced by interaction between Jupiter’s magnetic field and salty, subsurface ocean. -observations from Keck II Telescope & OSIRIS spectrometer on Hawaii support notion of saline ocean -spectral signature of magnesium sulphate salts (epsomite equivalent) detected at surface of Europa, on trailing face, most heavily influenced by particle radiation from magnetic fields & plasma in Jupiter system -source of sulphur is lo’s volcanic activity, Mg derived from Europa’s subsurface ocean, being no surface source; the ocean is likely to comprise chlorides of Mg (plus Na, K; inferred) i.e. is a saline environment that may be amenable to life. -Mg-chlorides evidently reach surface through breaches in ice layer; there is thus exchange between surface & subsurface environments -couple of large irregularities in icy surface layer, called “chaos terrain”, may be equivalent of Earth’s dynamic ice shelves, perhaps a means of transferring materials (including nutrients?) to the ocean below -Hubble telescope detected water vapour (2013), in plumes perhaps 200 km high, erupted from fissures that open when Europa is farthest from Jupiter (orbital period is 3.5 days) -perhaps best place to look for extant life in the solar system outside of Earth |
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Ganymede |
-largest satellite in solar system, ~1.5X size of Earth’s Moon, Io, or Europa, (all have comparable radius) -progressing outward from Jupiter, continued decline in bulk density, to 1.94 g/cm3; suggests lesser refractory elements, & a great boost in H2O & other volatile constituents (half the bulk?) -H2O ice surface, showing two basic types of terrain: i. Cratered Terrain -heavily cratered, concentration of cratering being consistent with earliest bombardment in Solar System, 4.0 G.a. or older; appears to be darkened by accumulation of debris ii. Bright & Grooved Terrain - exhibits odd patterns of fractures interrupting fractures, some evident cratering consistent with age of approximately 3.5 G.a.; tectonism of some sort -younger craters have bright ejecta rays -has thicker ice layer than Europa, consisting of a mantle ~700 km thick; formerly thought to have silicate core, but Galileo mission has changed that, by detecting a magnetic field associated with Ganymede -core is ~1500 km in radius, likely an Fe+S sphere (to account for magnetic field) encased in silicates; on basis of size, the core of Ganymede should have turned solid within ~1 b.y., but orbital resonance of Jupiter & its moons produces significant tidal heating. -phenomenon developed in more detail & applied to Galilean satellites as a group: lo orbits Jupiter 4 times in same time as Europa orbits twice, & Ganymede once; thus volcanism on lo, subsurface liquid water ocean on Europa, & magnetic field on Ganymede all allowed by same basic heating mechanism. -ozone (O3) is detected in Ganymede’s cryosphere, rather than atmosphere, & is produced abiotically; thus we cannot rely on detection of O3 as indicator of life on other planets/bodies. |
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Jupiters Galilean Satellites - Io |
- most noteworthy for spectacular volcanic activity; apparently most thermally active planetary body, erupts 100 times more lava than Earth does -very young surface ( -images reveal eruptions take form of umbrella-shaped plumes that extend as much as 300km high by 1000km diameter; Voyager 1 detected 9 active volcanoes, but number has been revised upward to 80 based on data from Galileo mission’s spacecraft -thought to cover surface in volcanic ash, sulphur, & So2 frost that accumulate as a ring around calderas -measurements from Galileo expedition reveal volcanic temperatures from fissure eruptions in range of 1700-2000 K (1425-1725° C), over 400° higher than basalt temperatures, too high for molten sulphur; ash & lava plains result -lacks surface ices of other moons of Jupiter, based on density (3.57 g/cm3), probably dominated by silicates -volatiles such as N2, H2O & CO2 have been lost to space upon eruption, S-compounds condense from plumes & fissure eruptions as S snow. -heat for planetary melting, in addition to more conventional sources, derived from tidal friction, pull of Jupiter & Europa in particular, and other moons flexing lo; facilitated by Io’s eccentric orbit around Jupiter (closer to Jupiter’s cloud tops than Moon is to Earth) -sweeping of Jupiter’s magnetic field across rapidly rotating moon could generate heat -Io apparently has its own magnetic field, rather than being bathed in Jupiter’s; Io would be a largely solid planet, with currently active, internal, dynamo field |
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Europa |
- surface covered by H2O ice, of speculative thickness; rather than glaciated, “lithosphere” may be a cryosphere. -icy surface heavily fractured, indicating movement of ice, with injection of “slush dikes” into fractures -larger blocks that look like ice rafts/ice jams, with previously healed fractures within blocks -surface also characterized by low relief, especially compared to other moons of Jupiter, fresh, very few craters; is this due to resurfacing by eruptions of water, or simply caused by plastic flow of ice smoothing out features, in response to gravity? -Galileo mission led us to believe there had been/still was, a water ocean underneath icy crust; extreme view suggests crust as thin as 2 km, with deep/thick liquid water ocean beneath for ~ 160 km; tidal heating also significant -internal structure largely speculative, density of 2.97 g/cm3 suggests silicates (inferred) & H2O (observed) -presence of a small magnetic field means small iron core is possible, but not demonstrable; possibly induced by interaction between Jupiter’s magnetic field and salty, subsurface ocean. -observations from Keck II Telescope & OSIRIS spectrometer on Hawaii support notion of saline ocean -spectral signature of magnesium sulphate salts (epsomite equivalent) detected at surface of Europa, on trailing face, most heavily influenced by particle radiation from magnetic fields & plasma in Jupiter system -source of sulphur is lo’s volcanic activity, Mg derived from Europa’s subsurface ocean, being no surface source; the ocean is likely to comprise chlorides of Mg (plus Na, K; inferred) i.e. is a saline environment that may be amenable to life. -Mg-chlorides evidently reach surface through breaches in ice layer; there is thus exchange between surface & subsurface environments -couple of large irregularities in icy surface layer, called “chaos terrain”, may be equivalent of Earth’s dynamic ice shelves, perhaps a means of transferring materials (including nutrients?) to the ocean below -Hubble telescope detected water vapour (2013), in plumes perhaps 200 km high, erupted from fissures that open when Europa is farthest from Jupiter (orbital period is 3.5 days) -perhaps best place to look for extant life in the solar system outside of Earth |
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Ganymede |
-largest satellite in solar system, ~1.5X size of Earth’s Moon, Io, or Europa, (all have comparable radius) -progressing outward from Jupiter, continued decline in bulk density, to 1.94 g/cm3; suggests lesser refractory elements, & a great boost in H2O & other volatile constituents (half the bulk?) -H2O ice surface, showing two basic types of terrain: i. Cratered Terrain -heavily cratered, concentration of cratering being consistent with earliest bombardment in Solar System, 4.0 G.a. or older; appears to be darkened by accumulation of debris ii. Bright & Grooved Terrain - exhibits odd patterns of fractures interrupting fractures, some evident cratering consistent with age of approximately 3.5 G.a.; tectonism of some sort -younger craters have bright ejecta rays -has thicker ice layer than Europa, consisting of a mantle ~700 km thick; formerly thought to have silicate core, but Galileo mission has changed that, by detecting a magnetic field associated with Ganymede -core is ~1500 km in radius, likely an Fe+S sphere (to account for magnetic field) encased in silicates; on basis of size, the core of Ganymede should have turned solid within ~1 b.y., but orbital resonance of Jupiter & its moons produces significant tidal heating. -phenomenon developed in more detail & applied to Galilean satellites as a group: lo orbits Jupiter 4 times in same time as Europa orbits twice, & Ganymede once; thus volcanism on lo, subsurface liquid water ocean on Europa, & magnetic field on Ganymede all allowed by same basic heating mechanism. -ozone (O3) is detected in Ganymede’s cryosphere, rather than atmosphere, & is produced abiotically; thus we cannot rely on detection of O3 as indicator of life on other planets/bodies. |
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Callisto |
-outermost Galileo satellite, lower density still (1.86 g/cm3), therefore even more water ice-rich, shows no signs of recent activity; apparently undifferentiated. -heavily cratered ice ball, surface is likely >4 G.a. -large multiring basins have evenly spaced rings with peculiar ghost/relict structures called palimpsests, wherein liquid water apparently flooded basin at the time -signs of activity less recent than for Ganymede, because Callisto would have less radiogenic heat & more rapid heat loss. -perturbs Jovian magnetic field, only viable explanation seems to be presence, subsurface, of a layer of salt water few tens of km thick; heat must be sufficient to permit this, yet low enough not to allow differentiation |
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Jupiters Galilean Satellites - Io |
- most noteworthy for spectacular volcanic activity; apparently most thermally active planetary body, erupts 100 times more lava than Earth does -very young surface ( -images reveal eruptions take form of umbrella-shaped plumes that extend as much as 300km high by 1000km diameter; Voyager 1 detected 9 active volcanoes, but number has been revised upward to 80 based on data from Galileo mission’s spacecraft -thought to cover surface in volcanic ash, sulphur, & So2 frost that accumulate as a ring around calderas -measurements from Galileo expedition reveal volcanic temperatures from fissure eruptions in range of 1700-2000 K (1425-1725° C), over 400° higher than basalt temperatures, too high for molten sulphur; ash & lava plains result -lacks surface ices of other moons of Jupiter, based on density (3.57 g/cm3), probably dominated by silicates -volatiles such as N2, H2O & CO2 have been lost to space upon eruption, S-compounds condense from plumes & fissure eruptions as S snow. -heat for planetary melting, in addition to more conventional sources, derived from tidal friction, pull of Jupiter & Europa in particular, and other moons flexing lo; facilitated by Io’s eccentric orbit around Jupiter (closer to Jupiter’s cloud tops than Moon is to Earth) -sweeping of Jupiter’s magnetic field across rapidly rotating moon could generate heat -Io apparently has its own magnetic field, rather than being bathed in Jupiter’s; Io would be a largely solid planet, with currently active, internal, dynamo field |
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Europa |
- surface covered by H2O ice, of speculative thickness; rather than glaciated, “lithosphere” may be a cryosphere. -icy surface heavily fractured, indicating movement of ice, with injection of “slush dikes” into fractures -larger blocks that look like ice rafts/ice jams, with previously healed fractures within blocks -surface also characterized by low relief, especially compared to other moons of Jupiter, fresh, very few craters; is this due to resurfacing by eruptions of water, or simply caused by plastic flow of ice smoothing out features, in response to gravity? -Galileo mission led us to believe there had been/still was, a water ocean underneath icy crust; extreme view suggests crust as thin as 2 km, with deep/thick liquid water ocean beneath for ~ 160 km; tidal heating also significant -internal structure largely speculative, density of 2.97 g/cm3 suggests silicates (inferred) & H2O (observed) -presence of a small magnetic field means small iron core is possible, but not demonstrable; possibly induced by interaction between Jupiter’s magnetic field and salty, subsurface ocean. -observations from Keck II Telescope & OSIRIS spectrometer on Hawaii support notion of saline ocean -spectral signature of magnesium sulphate salts (epsomite equivalent) detected at surface of Europa, on trailing face, most heavily influenced by particle radiation from magnetic fields & plasma in Jupiter system -source of sulphur is lo’s volcanic activity, Mg derived from Europa’s subsurface ocean, being no surface source; the ocean is likely to comprise chlorides of Mg (plus Na, K; inferred) i.e. is a saline environment that may be amenable to life. -Mg-chlorides evidently reach surface through breaches in ice layer; there is thus exchange between surface & subsurface environments -couple of large irregularities in icy surface layer, called “chaos terrain”, may be equivalent of Earth’s dynamic ice shelves, perhaps a means of transferring materials (including nutrients?) to the ocean below -Hubble telescope detected water vapour (2013), in plumes perhaps 200 km high, erupted from fissures that open when Europa is farthest from Jupiter (orbital period is 3.5 days) -perhaps best place to look for extant life in the solar system outside of Earth |
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Ganymede |
-largest satellite in solar system, ~1.5X size of Earth’s Moon, Io, or Europa, (all have comparable radius) -progressing outward from Jupiter, continued decline in bulk density, to 1.94 g/cm3; suggests lesser refractory elements, & a great boost in H2O & other volatile constituents (half the bulk?) -H2O ice surface, showing two basic types of terrain: i. Cratered Terrain -heavily cratered, concentration of cratering being consistent with earliest bombardment in Solar System, 4.0 G.a. or older; appears to be darkened by accumulation of debris ii. Bright & Grooved Terrain - exhibits odd patterns of fractures interrupting fractures, some evident cratering consistent with age of approximately 3.5 G.a.; tectonism of some sort -younger craters have bright ejecta rays -has thicker ice layer than Europa, consisting of a mantle ~700 km thick; formerly thought to have silicate core, but Galileo mission has changed that, by detecting a magnetic field associated with Ganymede -core is ~1500 km in radius, likely an Fe+S sphere (to account for magnetic field) encased in silicates; on basis of size, the core of Ganymede should have turned solid within ~1 b.y., but orbital resonance of Jupiter & its moons produces significant tidal heating. -phenomenon developed in more detail & applied to Galilean satellites as a group: lo orbits Jupiter 4 times in same time as Europa orbits twice, & Ganymede once; thus volcanism on lo, subsurface liquid water ocean on Europa, & magnetic field on Ganymede all allowed by same basic heating mechanism. -ozone (O3) is detected in Ganymede’s cryosphere, rather than atmosphere, & is produced abiotically; thus we cannot rely on detection of O3 as indicator of life on other planets/bodies. |
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Callisto |
-outermost Galileo satellite, lower density still (1.86 g/cm3), therefore even more water ice-rich, shows no signs of recent activity; apparently undifferentiated. -heavily cratered ice ball, surface is likely >4 G.a. -large multiring basins have evenly spaced rings with peculiar ghost/relict structures called palimpsests, wherein liquid water apparently flooded basin at the time -signs of activity less recent than for Ganymede, because Callisto would have less radiogenic heat & more rapid heat loss. -perturbs Jovian magnetic field, only viable explanation seems to be presence, subsurface, of a layer of salt water few tens of km thick; heat must be sufficient to permit this, yet low enough not to allow differentiation |
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Jupiter - Summery |
-strong evidence for early temperature gradient centered on Jupiter; for Galilean satellites, densities decrease & volatile inventories increase moving out from Jupiter, just as planets do for the sun. -there apparent surface ages of Galilean satellites increase moving outward from Jupiter, reflecting a decrease in tidal flexing with distance from Jupiter |
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Jupiters Galilean Satellites - Io |
- most noteworthy for spectacular volcanic activity; apparently most thermally active planetary body, erupts 100 times more lava than Earth does -very young surface ( -images reveal eruptions take form of umbrella-shaped plumes that extend as much as 300km high by 1000km diameter; Voyager 1 detected 9 active volcanoes, but number has been revised upward to 80 based on data from Galileo mission’s spacecraft -thought to cover surface in volcanic ash, sulphur, & So2 frost that accumulate as a ring around calderas -measurements from Galileo expedition reveal volcanic temperatures from fissure eruptions in range of 1700-2000 K (1425-1725° C), over 400° higher than basalt temperatures, too high for molten sulphur; ash & lava plains result -lacks surface ices of other moons of Jupiter, based on density (3.57 g/cm3), probably dominated by silicates -volatiles such as N2, H2O & CO2 have been lost to space upon eruption, S-compounds condense from plumes & fissure eruptions as S snow. -heat for planetary melting, in addition to more conventional sources, derived from tidal friction, pull of Jupiter & Europa in particular, and other moons flexing lo; facilitated by Io’s eccentric orbit around Jupiter (closer to Jupiter’s cloud tops than Moon is to Earth) -sweeping of Jupiter’s magnetic field across rapidly rotating moon could generate heat -Io apparently has its own magnetic field, rather than being bathed in Jupiter’s; Io would be a largely solid planet, with currently active, internal, dynamo field |
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Europa |
- surface covered by H2O ice, of speculative thickness; rather than glaciated, “lithosphere” may be a cryosphere. -icy surface heavily fractured, indicating movement of ice, with injection of “slush dikes” into fractures -larger blocks that look like ice rafts/ice jams, with previously healed fractures within blocks -surface also characterized by low relief, especially compared to other moons of Jupiter, fresh, very few craters; is this due to resurfacing by eruptions of water, or simply caused by plastic flow of ice smoothing out features, in response to gravity? -Galileo mission led us to believe there had been/still was, a water ocean underneath icy crust; extreme view suggests crust as thin as 2 km, with deep/thick liquid water ocean beneath for ~ 160 km; tidal heating also significant -internal structure largely speculative, density of 2.97 g/cm3 suggests silicates (inferred) & H2O (observed) -presence of a small magnetic field means small iron core is possible, but not demonstrable; possibly induced by interaction between Jupiter’s magnetic field and salty, subsurface ocean. -observations from Keck II Telescope & OSIRIS spectrometer on Hawaii support notion of saline ocean -spectral signature of magnesium sulphate salts (epsomite equivalent) detected at surface of Europa, on trailing face, most heavily influenced by particle radiation from magnetic fields & plasma in Jupiter system -source of sulphur is lo’s volcanic activity, Mg derived from Europa’s subsurface ocean, being no surface source; the ocean is likely to comprise chlorides of Mg (plus Na, K; inferred) i.e. is a saline environment that may be amenable to life. -Mg-chlorides evidently reach surface through breaches in ice layer; there is thus exchange between surface & subsurface environments -couple of large irregularities in icy surface layer, called “chaos terrain”, may be equivalent of Earth’s dynamic ice shelves, perhaps a means of transferring materials (including nutrients?) to the ocean below -Hubble telescope detected water vapour (2013), in plumes perhaps 200 km high, erupted from fissures that open when Europa is farthest from Jupiter (orbital period is 3.5 days) -perhaps best place to look for extant life in the solar system outside of Earth |
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Ganymede |
-largest satellite in solar system, ~1.5X size of Earth’s Moon, Io, or Europa, (all have comparable radius) -progressing outward from Jupiter, continued decline in bulk density, to 1.94 g/cm3; suggests lesser refractory elements, & a great boost in H2O & other volatile constituents (half the bulk?) -H2O ice surface, showing two basic types of terrain: i. Cratered Terrain -heavily cratered, concentration of cratering being consistent with earliest bombardment in Solar System, 4.0 G.a. or older; appears to be darkened by accumulation of debris ii. Bright & Grooved Terrain - exhibits odd patterns of fractures interrupting fractures, some evident cratering consistent with age of approximately 3.5 G.a.; tectonism of some sort -younger craters have bright ejecta rays -has thicker ice layer than Europa, consisting of a mantle ~700 km thick; formerly thought to have silicate core, but Galileo mission has changed that, by detecting a magnetic field associated with Ganymede -core is ~1500 km in radius, likely an Fe+S sphere (to account for magnetic field) encased in silicates; on basis of size, the core of Ganymede should have turned solid within ~1 b.y., but orbital resonance of Jupiter & its moons produces significant tidal heating. -phenomenon developed in more detail & applied to Galilean satellites as a group: lo orbits Jupiter 4 times in same time as Europa orbits twice, & Ganymede once; thus volcanism on lo, subsurface liquid water ocean on Europa, & magnetic field on Ganymede all allowed by same basic heating mechanism. -ozone (O3) is detected in Ganymede’s cryosphere, rather than atmosphere, & is produced abiotically; thus we cannot rely on detection of O3 as indicator of life on other planets/bodies. |
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Callisto |
-outermost Galileo satellite, lower density still (1.86 g/cm3), therefore even more water ice-rich, shows no signs of recent activity; apparently undifferentiated. -heavily cratered ice ball, surface is likely >4 G.a. -large multiring basins have evenly spaced rings with peculiar ghost/relict structures called palimpsests, wherein liquid water apparently flooded basin at the time -signs of activity less recent than for Ganymede, because Callisto would have less radiogenic heat & more rapid heat loss. -perturbs Jovian magnetic field, only viable explanation seems to be presence, subsurface, of a layer of salt water few tens of km thick; heat must be sufficient to permit this, yet low enough not to allow differentiation |
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Jupiter - Summery |
-strong evidence for early temperature gradient centered on Jupiter; for Galilean satellites, densities decrease & volatile inventories increase moving out from Jupiter, just as planets do for the sun. -there apparent surface ages of Galilean satellites increase moving outward from Jupiter, reflecting a decrease in tidal flexing with distance from Jupiter |
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The Saturn System |
-a gas bag with a bunch of satellites (23 orbiting moons, text says at least 17) & some rings - added to what was discovered by Voyager, we have the results of the Cassini-Huygens mission, consisting of a Saturn orbiter & a Titan (moon of Saturn) probe, launched Oct. 15, 1997 -mission arrived at Saturn July 1, 2004, & in a four year tour made 74 orbits of Saturn & 44 flybys of Titan (& other moons); June 11, 2004 Cassini flew by Phoebe, on July 1 it crossed the ring plane -December 25 Huygens probe separated, January 14, 2005 Huygens probe descended to Titan’s surface, it lasted for 1 hour & 10 minutes; encountered Titan’s atmosphere at altitude of 1270 km, & exited haze/clouds at 30 km altitude -plutonium-powered Cassini craft projected to run out of power in 2017; to be steered into Saturn’s atmosphere for incineration, to avoid contamination of its satellites |
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Jupiters Galilean Satellites - Io |
- most noteworthy for spectacular volcanic activity; apparently most thermally active planetary body, erupts 100 times more lava than Earth does -very young surface ( -images reveal eruptions take form of umbrella-shaped plumes that extend as much as 300km high by 1000km diameter; Voyager 1 detected 9 active volcanoes, but number has been revised upward to 80 based on data from Galileo mission’s spacecraft -thought to cover surface in volcanic ash, sulphur, & So2 frost that accumulate as a ring around calderas -measurements from Galileo expedition reveal volcanic temperatures from fissure eruptions in range of 1700-2000 K (1425-1725° C), over 400° higher than basalt temperatures, too high for molten sulphur; ash & lava plains result -lacks surface ices of other moons of Jupiter, based on density (3.57 g/cm3), probably dominated by silicates -volatiles such as N2, H2O & CO2 have been lost to space upon eruption, S-compounds condense from plumes & fissure eruptions as S snow. -heat for planetary melting, in addition to more conventional sources, derived from tidal friction, pull of Jupiter & Europa in particular, and other moons flexing lo; facilitated by Io’s eccentric orbit around Jupiter (closer to Jupiter’s cloud tops than Moon is to Earth) -sweeping of Jupiter’s magnetic field across rapidly rotating moon could generate heat -Io apparently has its own magnetic field, rather than being bathed in Jupiter’s; Io would be a largely solid planet, with currently active, internal, dynamo field |
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Europa |
- surface covered by H2O ice, of speculative thickness; rather than glaciated, “lithosphere” may be a cryosphere. -icy surface heavily fractured, indicating movement of ice, with injection of “slush dikes” into fractures -larger blocks that look like ice rafts/ice jams, with previously healed fractures within blocks -surface also characterized by low relief, especially compared to other moons of Jupiter, fresh, very few craters; is this due to resurfacing by eruptions of water, or simply caused by plastic flow of ice smoothing out features, in response to gravity? -Galileo mission led us to believe there had been/still was, a water ocean underneath icy crust; extreme view suggests crust as thin as 2 km, with deep/thick liquid water ocean beneath for ~ 160 km; tidal heating also significant -internal structure largely speculative, density of 2.97 g/cm3 suggests silicates (inferred) & H2O (observed) -presence of a small magnetic field means small iron core is possible, but not demonstrable; possibly induced by interaction between Jupiter’s magnetic field and salty, subsurface ocean. -observations from Keck II Telescope & OSIRIS spectrometer on Hawaii support notion of saline ocean -spectral signature of magnesium sulphate salts (epsomite equivalent) detected at surface of Europa, on trailing face, most heavily influenced by particle radiation from magnetic fields & plasma in Jupiter system -source of sulphur is lo’s volcanic activity, Mg derived from Europa’s subsurface ocean, being no surface source; the ocean is likely to comprise chlorides of Mg (plus Na, K; inferred) i.e. is a saline environment that may be amenable to life. -Mg-chlorides evidently reach surface through breaches in ice layer; there is thus exchange between surface & subsurface environments -couple of large irregularities in icy surface layer, called “chaos terrain”, may be equivalent of Earth’s dynamic ice shelves, perhaps a means of transferring materials (including nutrients?) to the ocean below -Hubble telescope detected water vapour (2013), in plumes perhaps 200 km high, erupted from fissures that open when Europa is farthest from Jupiter (orbital period is 3.5 days) -perhaps best place to look for extant life in the solar system outside of Earth |
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Ganymede |
-largest satellite in solar system, ~1.5X size of Earth’s Moon, Io, or Europa, (all have comparable radius) -progressing outward from Jupiter, continued decline in bulk density, to 1.94 g/cm3; suggests lesser refractory elements, & a great boost in H2O & other volatile constituents (half the bulk?) -H2O ice surface, showing two basic types of terrain: i. Cratered Terrain -heavily cratered, concentration of cratering being consistent with earliest bombardment in Solar System, 4.0 G.a. or older; appears to be darkened by accumulation of debris ii. Bright & Grooved Terrain - exhibits odd patterns of fractures interrupting fractures, some evident cratering consistent with age of approximately 3.5 G.a.; tectonism of some sort -younger craters have bright ejecta rays -has thicker ice layer than Europa, consisting of a mantle ~700 km thick; formerly thought to have silicate core, but Galileo mission has changed that, by detecting a magnetic field associated with Ganymede -core is ~1500 km in radius, likely an Fe+S sphere (to account for magnetic field) encased in silicates; on basis of size, the core of Ganymede should have turned solid within ~1 b.y., but orbital resonance of Jupiter & its moons produces significant tidal heating. -phenomenon developed in more detail & applied to Galilean satellites as a group: lo orbits Jupiter 4 times in same time as Europa orbits twice, & Ganymede once; thus volcanism on lo, subsurface liquid water ocean on Europa, & magnetic field on Ganymede all allowed by same basic heating mechanism. -ozone (O3) is detected in Ganymede’s cryosphere, rather than atmosphere, & is produced abiotically; thus we cannot rely on detection of O3 as indicator of life on other planets/bodies. |
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Callisto |
-outermost Galileo satellite, lower density still (1.86 g/cm3), therefore even more water ice-rich, shows no signs of recent activity; apparently undifferentiated. -heavily cratered ice ball, surface is likely >4 G.a. -large multiring basins have evenly spaced rings with peculiar ghost/relict structures called palimpsests, wherein liquid water apparently flooded basin at the time -signs of activity less recent than for Ganymede, because Callisto would have less radiogenic heat & more rapid heat loss. -perturbs Jovian magnetic field, only viable explanation seems to be presence, subsurface, of a layer of salt water few tens of km thick; heat must be sufficient to permit this, yet low enough not to allow differentiation |
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Jupiter - Summery |
-strong evidence for early temperature gradient centered on Jupiter; for Galilean satellites, densities decrease & volatile inventories increase moving out from Jupiter, just as planets do for the sun. -there apparent surface ages of Galilean satellites increase moving outward from Jupiter, reflecting a decrease in tidal flexing with distance from Jupiter |
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The Saturn System |
-a gas bag with a bunch of satellites (23 orbiting moons, text says at least 17) & some rings - added to what was discovered by Voyager, we have the results of the Cassini-Huygens mission, consisting of a Saturn orbiter & a Titan (moon of Saturn) probe, launched Oct. 15, 1997 -mission arrived at Saturn July 1, 2004, & in a four year tour made 74 orbits of Saturn & 44 flybys of Titan (& other moons); June 11, 2004 Cassini flew by Phoebe, on July 1 it crossed the ring plane -December 25 Huygens probe separated, January 14, 2005 Huygens probe descended to Titan’s surface, it lasted for 1 hour & 10 minutes; encountered Titan’s atmosphere at altitude of 1270 km, & exited haze/clouds at 30 km altitude -plutonium-powered Cassini craft projected to run out of power in 2017; to be steered into Saturn’s atmosphere for incineration, to avoid contamination of its satellites |
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Saturn - Statistics |
-rotates on axis every 10.2 hours, revolves around Sun every 29.5 years -diameter is 120,660 km (huge), density is 0.69 g/cm3 -temperature at cloud tops is 90 K; atmosphere of H & He with abundant NH3 clouds that produce haze that obscures belts & zones, unlike Jupiter -heat from planet drives system, with eddies, cyclones, & jet streams, winds up to 1500 km/hr |
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Saturn - Internal Structure |
-H constitutes 80% of Saturn, He 18%, & remaining 2% consists mostly of O, Fe, Ne, N, & Si -at ~30,000 km depth, transition from H2 to liquid metallic H+; this zone is proportionately smaller than for Jupiter, hence Saturn has a weaker magnetic field (0.4E vs. Jupiter’s at 20,000E) that is aligned with rotational axis -core of ices & silicates, 17 times as massive as Earth, representing only small portion of Saturn |
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Saturn - Internal Structure |
-H constitutes 80% of Saturn, He 18%, & remaining 2% consists mostly of O, Fe, Ne, N, & Si -at ~30,000 km depth, transition from H2 to liquid metallic H+; this zone is proportionately smaller than for Jupiter, hence Saturn has a weaker magnetic field (0.4E vs. Jupiter’s at 20,000E) that is aligned with rotational axis -core of ices & silicates, 17 times as massive as Earth, representing only small portion of Saturn |
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Saturn's Ring System |
-ring system begins 7000 km beyond outer limit of Saturn’s atmosphere, & extends to 74,000 km beyond -conventionally split into a number of divisions labeled alphabetically in order of discovery; each division has own characteristics, & discontinuity from its neighbour -some rings constrained gravitationally by so-called shepherd moons -density is ~1.0 g/cm3, with spectral properties indicating water ice plus some “rocky” dust; total mass of ring material is equivalent to relatively small icy body -thickness limit for rings is 150-200 m, but true thickness is a few to 10’s of m, with particles averaging 3-5 m, some as fine as 10 μm |
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Saturn - Internal Structure |
-H constitutes 80% of Saturn, He 18%, & remaining 2% consists mostly of O, Fe, Ne, N, & Si -at ~30,000 km depth, transition from H2 to liquid metallic H+; this zone is proportionately smaller than for Jupiter, hence Saturn has a weaker magnetic field (0.4E vs. Jupiter’s at 20,000E) that is aligned with rotational axis -core of ices & silicates, 17 times as massive as Earth, representing only small portion of Saturn |
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Saturn's Ring System |
-ring system begins 7000 km beyond outer limit of Saturn’s atmosphere, & extends to 74,000 km beyond -conventionally split into a number of divisions labeled alphabetically in order of discovery; each division has own characteristics, & discontinuity from its neighbour -some rings constrained gravitationally by so-called shepherd moons -density is ~1.0 g/cm3, with spectral properties indicating water ice plus some “rocky” dust; total mass of ring material is equivalent to relatively small icy body -thickness limit for rings is 150-200 m, but true thickness is a few to 10’s of m, with particles averaging 3-5 m, some as fine as 10 μm |
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Saturn - Ring formation Model 1. Gravitational Disruption of a Satellite |
- a body passing close enough to Saturn supposed to have been disrupted by pull of Saturn (note comet Shoemaker-Levy 9 torn into 20+ pieces when it got close enough to Jupiter in 1992; impacts of 21 of those fragments were observed in 1994) -a liquid satellite would be disrupted if it got within Roche Limit, ~2.5 planet radii, which is outer limit for Saturn’s rings; solid bodies would be torn apart within 1.5 radii -1848, the Roche Limit is the closest orbit at which a satellite can withstand the planet’s or primary’s tidal forces -these numbers apply to a satellite of comparable density to primary; given a satellite of Titan’s density, the Roche Limit is reduced to 71%, & if the satellite has density of 4.0 g/cm3, it’s reduced to 56% of stated values; all considerations of Roche Limit & its implications depend on nature of the body we’re considering |
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Saturn - Internal Structure |
-H constitutes 80% of Saturn, He 18%, & remaining 2% consists mostly of O, Fe, Ne, N, & Si -at ~30,000 km depth, transition from H2 to liquid metallic H+; this zone is proportionately smaller than for Jupiter, hence Saturn has a weaker magnetic field (0.4E vs. Jupiter’s at 20,000E) that is aligned with rotational axis -core of ices & silicates, 17 times as massive as Earth, representing only small portion of Saturn |
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Saturn's Ring System |
-ring system begins 7000 km beyond outer limit of Saturn’s atmosphere, & extends to 74,000 km beyond -conventionally split into a number of divisions labeled alphabetically in order of discovery; each division has own characteristics, & discontinuity from its neighbour -some rings constrained gravitationally by so-called shepherd moons -density is ~1.0 g/cm3, with spectral properties indicating water ice plus some “rocky” dust; total mass of ring material is equivalent to relatively small icy body -thickness limit for rings is 150-200 m, but true thickness is a few to 10’s of m, with particles averaging 3-5 m, some as fine as 10 μm |
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Saturn - Ring formation Model 1. Gravitational Disruption of a Satellite |
- a body passing close enough to Saturn supposed to have been disrupted by pull of Saturn (note comet Shoemaker-Levy 9 torn into 20+ pieces when it got close enough to Jupiter in 1992; impacts of 21 of those fragments were observed in 1994) -a liquid satellite would be disrupted if it got within Roche Limit, ~2.5 planet radii, which is outer limit for Saturn’s rings; solid bodies would be torn apart within 1.5 radii -1848, the Roche Limit is the closest orbit at which a satellite can withstand the planet’s or primary’s tidal forces -these numbers apply to a satellite of comparable density to primary; given a satellite of Titan’s density, the Roche Limit is reduced to 71%, & if the satellite has density of 4.0 g/cm3, it’s reduced to 56% of stated values; all considerations of Roche Limit & its implications depend on nature of the body we’re considering |
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Saturn - Ring Formation Model 2. Fragmentation of Moons |
- model demonstrated in Voyager video -bolides impacted a moon or moons, debris orbiting Saturn in a flattened ring; continual collisions & fragmentation -appeal of this model is it is dynamic, & causes replenishment of rings; particles from rings are known to spiral into Saturn, & so the present rings may be as young as 10-100 m.y., nowhere near 4.6 G.a. (the rings could not persist that long, given that material spirals in to Saturn) -problem with this model is moons may never have been able to accrete within the Roche Limit, for subsequent impact & fragmentation -almost all satellites of Saturn orbit within limits of ring system, & Jupiter’s faint rings appear to be formed from debris derived from its inner satellites, which are within Roche Limit |
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Saturn Ring Formation Model 3. Accretionary Remnant |
-planetary nebula accreted to form satellites, but gravitational effects prevented this within Roche Limit -rings are old/primordial; resolution of (ii) vs. (iii) depends on longevity of rings -analysis of data from Cassini mission reveals a complexity and variety that argues for possibility of multiple origins for rings |
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Saturn Ring Formation Model 3. Accretionary Remnant |
-planetary nebula accreted to form satellites, but gravitational effects prevented this within Roche Limit -rings are old/primordial; resolution of (ii) vs. (iii) depends on longevity of rings -analysis of data from Cassini mission reveals a complexity and variety that argues for possibility of multiple origins for rings |
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The Strength of Jupiter’s magnetic field is what multiple of Earth’s: A. 200 B. 2,000 C. 20,000 D. 200,000 |
C. 20,000 |
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Saturn Ring Formation Model 3. Accretionary Remnant |
-planetary nebula accreted to form satellites, but gravitational effects prevented this within Roche Limit -rings are old/primordial; resolution of (ii) vs. (iii) depends on longevity of rings -analysis of data from Cassini mission reveals a complexity and variety that argues for possibility of multiple origins for rings |
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The Strength of Jupiter’s magnetic field is what multiple of Earth’s: A. 200 B. 2,000 C. 20,000 D. 200,000 |
C. 20,000 |
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Sinuous rilles on the Moon are produced by A. Compressional tectonics B. Extensional tectonics C. Flow of lava D. Flow of water |
C. Flow of Lava |
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Saturn Ring Formation Model 3. Accretionary Remnant |
-planetary nebula accreted to form satellites, but gravitational effects prevented this within Roche Limit -rings are old/primordial; resolution of (ii) vs. (iii) depends on longevity of rings -analysis of data from Cassini mission reveals a complexity and variety that argues for possibility of multiple origins for rings |
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The Strength of Jupiter’s magnetic field is what multiple of Earth’s: A. 200 B. 2,000 C. 20,000 D. 200,000 |
C. 20,000 |
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Sinuous rilles on the Moon are produced by A. Compressional tectonics B. Extensional tectonics C. Flow of lava D. Flow of water |
C. Flow of Lava |
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SNC meteorites represent A. Mars B. Mercury C. Moon D. Venus |
A. Mars |
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Iridium anomaly that marks the Cretaceous/ Tertiary boundary was first detected A. Haiti B. Italy C. Mexico D. New Mexico |
B. Italy |
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Iridium anomaly that marks the Cretaceous/ Tertiary boundary was first detected A. Haiti B. Italy C. Mexico D. New Mexico |
B. Italy |
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Which of the following satellites of Jupiter is least dense? A. Callisto B. Europa C. Ganymede D. Io |
A. Callisto |
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Saturn's Satellites - Titan |
-5150 km diameter, bulk density of 1.9 g/cm3; silicate core covered by ices dominated by H2O, CH4, and NH3 -appreciable subsurface liquid (water?) implied by Titan’s response to tidal flexing; 10 m solid tides exceed the 1 m that was expected for rocky solid body -only moon/satellite in solar system with an atmosphere, that is composed of N2 (>80%), with lesser CH4, than other hydrocarbons (produced by dissociation of NH3 to yield N + H, which combined with CH4, for example); atmospheric pressure is 1.5X that of Earth -Methane & Ethane rain out of the atmosphere in a hydrocarbon cycle; HCs exist in all three stats at the surface, given the combination of P&T -confirmed by Cassini - July 2006, toward poles are lakes (comparable in size to Lake Superior) & stream beds (Cassini discovered a channel exceeding 400 km length, feeding Ligeia Mare in north polar region) occupied by liquid methane & ethane -variation in radio reflectivity of lake surfaces suggests presence of blocks of ice (methane ice bergs); solid methane is more dense than liquid form -incorporation of as little as 5% “air” (N2-dominated atmosphere) would make the ice float at T<90 K, the freezing point of methane; a rise in temperature would alter balance of incorporation of gases, & ice should then sink; Cassini monitoring to see what happens in spring -strong W to E winds produce dunes in equatorial region, & dry stream beds also observed -methane recombines to form more complex organic molecules, which “rain” onto surface as “sandy” particles that litter surface & subdue crater expression |
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Saturn's Satellites - Titan |
-5150 km diameter, bulk density of 1.9 g/cm3; silicate core covered by ices dominated by H2O, CH4, and NH3 -appreciable subsurface liquid (water?) implied by Titan’s response to tidal flexing; 10 m solid tides exceed the 1 m that was expected for rocky solid body -only moon/satellite in solar system with an atmosphere, that is composed of N2 (>80%), with lesser CH4, than other hydrocarbons (produced by dissociation of NH3 to yield N + H, which combined with CH4, for example); atmospheric pressure is 1.5X that of Earth -Methane & Ethane rain out of the atmosphere in a hydrocarbon cycle; HCs exist in all three stats at the surface, given the combination of P&T -confirmed by Cassini - July 2006, toward poles are lakes (comparable in size to Lake Superior) & stream beds (Cassini discovered a channel exceeding 400 km length, feeding Ligeia Mare in north polar region) occupied by liquid methane & ethane -variation in radio reflectivity of lake surfaces suggests presence of blocks of ice (methane ice bergs); solid methane is more dense than liquid form -incorporation of as little as 5% “air” (N2-dominated atmosphere) would make the ice float at T<90 K, the freezing point of methane; a rise in temperature would alter balance of incorporation of gases, & ice should then sink; Cassini monitoring to see what happens in spring -strong W to E winds produce dunes in equatorial region, & dry stream beds also observed -methane recombines to form more complex organic molecules, which “rain” onto surface as “sandy” particles that litter surface & subdue crater expression |
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Phoebe |
-retrograde orbit (opposite direction to others) inclined at 150∞ -outermost known satellite, ~220 km diameter & spherical; usually at this size, bodies have insufficient gravity to pull themselves into that shape -dark & of very low albedo/reflectance, presumed to be rocky/silicate, rather than icy -likely a captured asteroid that formed elsewhere |
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Saturn's Satellites - Titan |
-5150 km diameter, bulk density of 1.9 g/cm3; silicate core covered by ices dominated by H2O, CH4, and NH3 -appreciable subsurface liquid (water?) implied by Titan’s response to tidal flexing; 10 m solid tides exceed the 1 m that was expected for rocky solid body -only moon/satellite in solar system with an atmosphere, that is composed of N2 (>80%), with lesser CH4, than other hydrocarbons (produced by dissociation of NH3 to yield N + H, which combined with CH4, for example); atmospheric pressure is 1.5X that of Earth -Methane & Ethane rain out of the atmosphere in a hydrocarbon cycle; HCs exist in all three stats at the surface, given the combination of P&T -confirmed by Cassini - July 2006, toward poles are lakes (comparable in size to Lake Superior) & stream beds (Cassini discovered a channel exceeding 400 km length, feeding Ligeia Mare in north polar region) occupied by liquid methane & ethane -variation in radio reflectivity of lake surfaces suggests presence of blocks of ice (methane ice bergs); solid methane is more dense than liquid form -incorporation of as little as 5% “air” (N2-dominated atmosphere) would make the ice float at T<90 K, the freezing point of methane; a rise in temperature would alter balance of incorporation of gases, & ice should then sink; Cassini monitoring to see what happens in spring -strong W to E winds produce dunes in equatorial region, & dry stream beds also observed -methane recombines to form more complex organic molecules, which “rain” onto surface as “sandy” particles that litter surface & subdue crater expression |
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Phoebe |
-retrograde orbit (opposite direction to others) inclined at 150∞ -outermost known satellite, ~220 km diameter & spherical; usually at this size, bodies have insufficient gravity to pull themselves into that shape -dark & of very low albedo/reflectance, presumed to be rocky/silicate, rather than icy -likely a captured asteroid that formed elsewhere |
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Enceladus |
-~500 km in diameter, bulk density - 1.61 g/cm3, an ice ball that is most geologically active satellite of Saturn -much crater-free terrain, implying resurfacing within last 100 m.y.; apparently accomplished by fissure eruption of slush/ice -influence of Enceladus on Cassini indicates mass deficiency in southern hemisphere, coincident with more obviously resurfaced terrain; interpretation is of liquid water ocean, 10 km thick, below the 40 km-thick ice crust, confined to southern hemisphere -Cassini documented active eruption, of H2O vapour plus ice particles, NaCl crystals & other materials, probably sourced by pressurized subsurface liquid h2o chambers (“magma chambers”) erupting in “cold geyser” model; principal source of Saturn’s E ring -thermal source almost surely tidal flexing related to Dione, which orbits Saturn once for every 2 orbits of Enceladus -melting point likely lowered by small amount of ammonia, possibly by as much as 100 k |
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Saturn's Satellites - Titan |
-5150 km diameter, bulk density of 1.9 g/cm3; silicate core covered by ices dominated by H2O, CH4, and NH3 -appreciable subsurface liquid (water?) implied by Titan’s response to tidal flexing; 10 m solid tides exceed the 1 m that was expected for rocky solid body -only moon/satellite in solar system with an atmosphere, that is composed of N2 (>80%), with lesser CH4, than other hydrocarbons (produced by dissociation of NH3 to yield N + H, which combined with CH4, for example); atmospheric pressure is 1.5X that of Earth -Methane & Ethane rain out of the atmosphere in a hydrocarbon cycle; HCs exist in all three stats at the surface, given the combination of P&T -confirmed by Cassini - July 2006, toward poles are lakes (comparable in size to Lake Superior) & stream beds (Cassini discovered a channel exceeding 400 km length, feeding Ligeia Mare in north polar region) occupied by liquid methane & ethane -variation in radio reflectivity of lake surfaces suggests presence of blocks of ice (methane ice bergs); solid methane is more dense than liquid form -incorporation of as little as 5% “air” (N2-dominated atmosphere) would make the ice float at T<90 K, the freezing point of methane; a rise in temperature would alter balance of incorporation of gases, & ice should then sink; Cassini monitoring to see what happens in spring -strong W to E winds produce dunes in equatorial region, & dry stream beds also observed -methane recombines to form more complex organic molecules, which “rain” onto surface as “sandy” particles that litter surface & subdue crater expression |
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Phoebe |
-retrograde orbit (opposite direction to others) inclined at 150∞ -outermost known satellite, ~220 km diameter & spherical; usually at this size, bodies have insufficient gravity to pull themselves into that shape -dark & of very low albedo/reflectance, presumed to be rocky/silicate, rather than icy -likely a captured asteroid that formed elsewhere |
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Enceladus |
-~500 km in diameter, bulk density - 1.61 g/cm3, an ice ball that is most geologically active satellite of Saturn -much crater-free terrain, implying resurfacing within last 100 m.y.; apparently accomplished by fissure eruption of slush/ice -influence of Enceladus on Cassini indicates mass deficiency in southern hemisphere, coincident with more obviously resurfaced terrain; interpretation is of liquid water ocean, 10 km thick, below the 40 km-thick ice crust, confined to southern hemisphere -Cassini documented active eruption, of H2O vapour plus ice particles, NaCl crystals & other materials, probably sourced by pressurized subsurface liquid h2o chambers (“magma chambers”) erupting in “cold geyser” model; principal source of Saturn’s E ring -thermal source almost surely tidal flexing related to Dione, which orbits Saturn once for every 2 orbits of Enceladus -melting point likely lowered by small amount of ammonia, possibly by as much as 100 k |
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Dione |
-1120 km diameter, about twice as large as Enceladus, bulk density of 1.43 vs. 1.20 g/cm3, implying higher silicate content, comprising ⅓ satellite’s mass -cratered terrain, as well as smoother terrain - implies significant resurfacing -wispy streaks that suggest major eruptions of water ice/frost along large scale fractures, after early cratering -thermal activity believed to be significantly augmented by radiogenic heat (remember its higher rocky content) |
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Saturn's Satellites - Titan |
-5150 km diameter, bulk density of 1.9 g/cm3; silicate core covered by ices dominated by H2O, CH4, and NH3 -appreciable subsurface liquid (water?) implied by Titan’s response to tidal flexing; 10 m solid tides exceed the 1 m that was expected for rocky solid body -only moon/satellite in solar system with an atmosphere, that is composed of N2 (>80%), with lesser CH4, than other hydrocarbons (produced by dissociation of NH3 to yield N + H, which combined with CH4, for example); atmospheric pressure is 1.5X that of Earth -Methane & Ethane rain out of the atmosphere in a hydrocarbon cycle; HCs exist in all three stats at the surface, given the combination of P&T -confirmed by Cassini - July 2006, toward poles are lakes (comparable in size to Lake Superior) & stream beds (Cassini discovered a channel exceeding 400 km length, feeding Ligeia Mare in north polar region) occupied by liquid methane & ethane -variation in radio reflectivity of lake surfaces suggests presence of blocks of ice (methane ice bergs); solid methane is more dense than liquid form -incorporation of as little as 5% “air” (N2-dominated atmosphere) would make the ice float at T<90 K, the freezing point of methane; a rise in temperature would alter balance of incorporation of gases, & ice should then sink; Cassini monitoring to see what happens in spring -strong W to E winds produce dunes in equatorial region, & dry stream beds also observed -methane recombines to form more complex organic molecules, which “rain” onto surface as “sandy” particles that litter surface & subdue crater expression |
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Phoebe |
-retrograde orbit (opposite direction to others) inclined at 150∞ -outermost known satellite, ~220 km diameter & spherical; usually at this size, bodies have insufficient gravity to pull themselves into that shape -dark & of very low albedo/reflectance, presumed to be rocky/silicate, rather than icy -likely a captured asteroid that formed elsewhere |
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Enceladus |
-~500 km in diameter, bulk density - 1.61 g/cm3, an ice ball that is most geologically active satellite of Saturn -much crater-free terrain, implying resurfacing within last 100 m.y.; apparently accomplished by fissure eruption of slush/ice -influence of Enceladus on Cassini indicates mass deficiency in southern hemisphere, coincident with more obviously resurfaced terrain; interpretation is of liquid water ocean, 10 km thick, below the 40 km-thick ice crust, confined to southern hemisphere -Cassini documented active eruption, of H2O vapour plus ice particles, NaCl crystals & other materials, probably sourced by pressurized subsurface liquid h2o chambers (“magma chambers”) erupting in “cold geyser” model; principal source of Saturn’s E ring -thermal source almost surely tidal flexing related to Dione, which orbits Saturn once for every 2 orbits of Enceladus -melting point likely lowered by small amount of ammonia, possibly by as much as 100 k |
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Dione |
-1120 km diameter, about twice as large as Enceladus, bulk density of 1.43 vs. 1.20 g/cm3, implying higher silicate content, comprising ⅓ satellite’s mass -cratered terrain, as well as smoother terrain - implies significant resurfacing -wispy streaks that suggest major eruptions of water ice/frost along large scale fractures, after early cratering -thermal activity believed to be significantly augmented by radiogenic heat (remember its higher rocky content) |
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Uranus - Stastics |
-rotates on axis every 17.24 hours, & revolves around Sun every 84 years -mass is 14.4 X Earth, density is 1.28 g/cm3 (comparable to that of Jupiter, & much greater than that of Saturn) -temperature at surface is 80 K, with some ices likely -rotational axis inclined 98° to “expected” relationship of normal to ecliptic i.e. is nearly parallel to ecliptic plane, Uranus does not so much spin like a top as roll like a ball -one explanation for this is that it was hit by a large object (Earth-sized) early in history, before satellites & rings became established; these latter objects orbit Uranus at an angle to ecliptic -magnetic field that is unusual - tilt is 60 degrees to rotational axis, not diametric i.e. does not pass through center -magnetic field may be in process of polarity reversal; observed field of strength has varied between 0.25E & 2.75E |
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Saturn's Satellites - Titan |
-5150 km diameter, bulk density of 1.9 g/cm3; silicate core covered by ices dominated by H2O, CH4, and NH3 -appreciable subsurface liquid (water?) implied by Titan’s response to tidal flexing; 10 m solid tides exceed the 1 m that was expected for rocky solid body -only moon/satellite in solar system with an atmosphere, that is composed of N2 (>80%), with lesser CH4, than other hydrocarbons (produced by dissociation of NH3 to yield N + H, which combined with CH4, for example); atmospheric pressure is 1.5X that of Earth -Methane & Ethane rain out of the atmosphere in a hydrocarbon cycle; HCs exist in all three stats at the surface, given the combination of P&T -confirmed by Cassini - July 2006, toward poles are lakes (comparable in size to Lake Superior) & stream beds (Cassini discovered a channel exceeding 400 km length, feeding Ligeia Mare in north polar region) occupied by liquid methane & ethane -variation in radio reflectivity of lake surfaces suggests presence of blocks of ice (methane ice bergs); solid methane is more dense than liquid form -incorporation of as little as 5% “air” (N2-dominated atmosphere) would make the ice float at T<90 K, the freezing point of methane; a rise in temperature would alter balance of incorporation of gases, & ice should then sink; Cassini monitoring to see what happens in spring -strong W to E winds produce dunes in equatorial region, & dry stream beds also observed -methane recombines to form more complex organic molecules, which “rain” onto surface as “sandy” particles that litter surface & subdue crater expression |
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Phoebe |
-retrograde orbit (opposite direction to others) inclined at 150∞ -outermost known satellite, ~220 km diameter & spherical; usually at this size, bodies have insufficient gravity to pull themselves into that shape -dark & of very low albedo/reflectance, presumed to be rocky/silicate, rather than icy -likely a captured asteroid that formed elsewhere |
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Enceladus |
-~500 km in diameter, bulk density - 1.61 g/cm3, an ice ball that is most geologically active satellite of Saturn -much crater-free terrain, implying resurfacing within last 100 m.y.; apparently accomplished by fissure eruption of slush/ice -influence of Enceladus on Cassini indicates mass deficiency in southern hemisphere, coincident with more obviously resurfaced terrain; interpretation is of liquid water ocean, 10 km thick, below the 40 km-thick ice crust, confined to southern hemisphere -Cassini documented active eruption, of H2O vapour plus ice particles, NaCl crystals & other materials, probably sourced by pressurized subsurface liquid h2o chambers (“magma chambers”) erupting in “cold geyser” model; principal source of Saturn’s E ring -thermal source almost surely tidal flexing related to Dione, which orbits Saturn once for every 2 orbits of Enceladus -melting point likely lowered by small amount of ammonia, possibly by as much as 100 k |
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Dione |
-1120 km diameter, about twice as large as Enceladus, bulk density of 1.43 vs. 1.20 g/cm3, implying higher silicate content, comprising ⅓ satellite’s mass -cratered terrain, as well as smoother terrain - implies significant resurfacing -wispy streaks that suggest major eruptions of water ice/frost along large scale fractures, after early cratering -thermal activity believed to be significantly augmented by radiogenic heat (remember its higher rocky content) |
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Uranus - Stastics |
-rotates on axis every 17.24 hours, & revolves around Sun every 84 years -mass is 14.4 X Earth, density is 1.28 g/cm3 (comparable to that of Jupiter, & much greater than that of Saturn) -temperature at surface is 80 K, with some ices likely -rotational axis inclined 98° to “expected” relationship of normal to ecliptic i.e. is nearly parallel to ecliptic plane, Uranus does not so much spin like a top as roll like a ball -one explanation for this is that it was hit by a large object (Earth-sized) early in history, before satellites & rings became established; these latter objects orbit Uranus at an angle to ecliptic -magnetic field that is unusual - tilt is 60 degrees to rotational axis, not diametric i.e. does not pass through center -magnetic field may be in process of polarity reversal; observed field of strength has varied between 0.25E & 2.75E |
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Uranus - Internal Structure |
-core, probably of mafic silicates, surrounded by thick mantle of ice &/or rock/ice mixture, with ices probably comprising H2O, CH4, & NH3 -outer layer molecular H2 & He, no metallic zone developed due to insufficient pressure -atmosphere made of methane, which accounts for blue-green colour with ammonia as well |
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Uranus' Satellites |
-of 15 known moons, five of some significance -appears to be an age significance to size of craters, not just their density/concentration -older surfaces characterized by common craters ranging from 50-100 km diameter, whereas younger, resurfaced terrains have craters <60 km diameter -histories of these moons determined by which generation of craters appears to have affect surface as well as superposition of smooth/resurfaces areas, & crosscutting by fractures related to extension -volcanism/resurfacing evidently produced by eruption of ice/slush/liquid water -do not see orbital resonance as we did for Io (Jupiter) & Enceladus (Saturn), bodies evidently too small to have retained heat -cannot overlook the role of ammonia in lowering melting point, by as much as 100 k -Miranda exhibited complex history of shattering & re-accretion, now understood that geometrically complex terrains were formed by a combination of extensional fractures & fissure eruptions of ices, subsequent to impact history of older surfaces |
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Uranus' Satellites |
-of 15 known moons, five of some significance -appears to be an age significance to size of craters, not just their density/concentration -older surfaces characterized by common craters ranging from 50-100 km diameter, whereas younger, resurfaced terrains have craters <60 km diameter -histories of these moons determined by which generation of craters appears to have affect surface as well as superposition of smooth/resurfaces areas, & crosscutting by fractures related to extension -volcanism/resurfacing evidently produced by eruption of ice/slush/liquid water -do not see orbital resonance as we did for Io (Jupiter) & Enceladus (Saturn), bodies evidently too small to have retained heat -cannot overlook the role of ammonia in lowering melting point, by as much as 100 k -Miranda exhibited complex history of shattering & re-accretion, now understood that geometrically complex terrains were formed by a combination of extensional fractures & fissure eruptions of ices, subsequent to impact history of older surfaces |
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The least dense planet it: A. Jupiter B. Saturn C. Neptune D. Uranus |
B. Saturn |
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Which of the follow statements about Venus is true? A. The atmospheric gases create a large ghg effect B. The diameter of Venus is almost the same as that of Titan C. It is the only planet without a natural satellite D. Venus lacks significant landforms |
A. The atmospheric gases create a large ghg effect |
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Saturn’s satellites are dominated by what kind of ice? A. Ammonia B. Methane C. Water D. They don’t have ice |
C. Water |
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Which one of the following moons/satellites is least likely to have/have had life? A. Enceladus B. Europa C. Io D. Titan |
C. Io |
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Which of the following satellites of Jupiter doesn’t exhibit resonance with the others? A. Callisto B. Europa C. Ganymede D. Io |
B. Europa |
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Which of the following satellites of Jupiter doesn’t exhibit resonance with the others? A. Callisto B. Europa C. Ganymede D. Io |
B. Europa |
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Neptune - Statistics |
- rotates on axis every 16 hours, revolves around Sun every 165 years -diameter is 49,500 km, density is 1.64 g/cm3, most dense of the Jovian planets -magnetic field with ¼ the strength of Earth’s; field axis not aligned with rotational axis, but is at 50 degrees to it, strongly offset from diameter as well. -unlikely that the two planets are experiencing magnetic polarity reversal at same time; a different mechanism for generating the magnetic field and accounting for its orientation may be required -text suggests there is convection in near surface, water-rich, conductive layer; (Earth’s magnetic field approximates a dipole i.e. is complex in detail, but net effect is same as if there was a dipole through centre) -atmosphere is banded, with spots/cyclones, consists primarily of H2, He, and CH4, hence blue colour for Neptune |
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Neptune - Structure |
-planet’s structure is by now familiar for Jovian planets -fairly large core of rock and ice; rocky materials account for slightly less than half the mass of Neptune (i.e. proportionately slightly more than for Uranus) -There seems to be a bit higher carbon content for Uranus and Neptune than there is for Jupiter and Saturn, and much CO |
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Triton (Neptune) |
-inner moon of Neptune, one of 8 satellites; diameter is ~0.8 that of our Moon -retrograde revolution or orbit about Neptune that should bring it within Roche Limit in ~10 billion years, but the Sun should have burned out by then -although orbit is now circular, it would have originally been elliptical (by either a capture model or deflected moon model), almost certainly much tidal heating until circular orbit was established -no evidence of water ice, but we detect CH4 and NH3 ices at its surface, temperature is 37 K; tenuous atmosphere of N2 and CH4 -polar ice cap is on south pole, which faces Sun; as a result, it should soon vapourize, these volatiles should condense on north pole, seasonal cycle caused by inclined rotational axis. -two basic terrains i) fractured plains (cantaloupe terrain), criss-crossing fractures that suggest ages <3 G.a. (based on cratering concentration), coupled with viscous eruptions, and ii) flooded volcanic plains (frozen lakes of the video) -active volcanism exhibited by the plumes; these rise ~8 km, then are swept northeastward by winds -developed only within ice cap, interpreted as nitrogen rising within cap, then boiling rapidly and erupting, carrying some methane as well (dark “foofoo dust”) -thereby joins Earth, Io, Europa and Enceladus in limited but growing list of planets and satellites with documented active volcanism |
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Triton (Neptune) |
-inner moon of Neptune, one of 8 satellites; diameter is ~0.8 that of our Moon -retrograde revolution or orbit about Neptune that should bring it within Roche Limit in ~10 billion years, but the Sun should have burned out by then -although orbit is now circular, it would have originally been elliptical (by either a capture model or deflected moon model), almost certainly much tidal heating until circular orbit was established -no evidence of water ice, but we detect CH4 and NH3 ices at its surface, temperature is 37 K; tenuous atmosphere of N2 and CH4 -polar ice cap is on south pole, which faces Sun; as a result, it should soon vapourize, these volatiles should condense on north pole, seasonal cycle caused by inclined rotational axis. -two basic terrains i) fractured plains (cantaloupe terrain), criss-crossing fractures that suggest ages <3 G.a. (based on cratering concentration), coupled with viscous eruptions, and ii) flooded volcanic plains (frozen lakes of the video) -active volcanism exhibited by the plumes; these rise ~8 km, then are swept northeastward by winds -developed only within ice cap, interpreted as nitrogen rising within cap, then boiling rapidly and erupting, carrying some methane as well (dark “foofoo dust”) -thereby joins Earth, Io, Europa and Enceladus in limited but growing list of planets and satellites with documented active volcanism |
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Pluto |
-discovered in 1930, largest and innermost satellite Charon only discovered/resolved in 1978; 4 more moons have been resolved; Nix and Hydra (both 2005), Kerberos (2011), and Styx (2012) -New Horizons mission launched 1/19/06, closest approach 7/14/15, Pluto encounter ended 1/16, data return expected to last through much of 2016 i.e. story is developing -is Pluto a planet? -2006 decision of the International Astronomical Union (IAU) downgraded Pluto from “planet” to “dwarf planet” status; now a Kuiper Belt Object (KBO; later re:comets) -eight planets of Solar System: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune |
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Triton (Neptune) |
-inner moon of Neptune, one of 8 satellites; diameter is ~0.8 that of our Moon -retrograde revolution or orbit about Neptune that should bring it within Roche Limit in ~10 billion years, but the Sun should have burned out by then -although orbit is now circular, it would have originally been elliptical (by either a capture model or deflected moon model), almost certainly much tidal heating until circular orbit was established -no evidence of water ice, but we detect CH4 and NH3 ices at its surface, temperature is 37 K; tenuous atmosphere of N2 and CH4 -polar ice cap is on south pole, which faces Sun; as a result, it should soon vapourize, these volatiles should condense on north pole, seasonal cycle caused by inclined rotational axis. -two basic terrains i) fractured plains (cantaloupe terrain), criss-crossing fractures that suggest ages <3 G.a. (based on cratering concentration), coupled with viscous eruptions, and ii) flooded volcanic plains (frozen lakes of the video) -active volcanism exhibited by the plumes; these rise ~8 km, then are swept northeastward by winds -developed only within ice cap, interpreted as nitrogen rising within cap, then boiling rapidly and erupting, carrying some methane as well (dark “foofoo dust”) -thereby joins Earth, Io, Europa and Enceladus in limited but growing list of planets and satellites with documented active volcanism |
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Pluto |
-discovered in 1930, largest and innermost satellite Charon only discovered/resolved in 1978; 4 more moons have been resolved; Nix and Hydra (both 2005), Kerberos (2011), and Styx (2012) -New Horizons mission launched 1/19/06, closest approach 7/14/15, Pluto encounter ended 1/16, data return expected to last through much of 2016 i.e. story is developing -is Pluto a planet? -2006 decision of the International Astronomical Union (IAU) downgraded Pluto from “planet” to “dwarf planet” status; now a Kuiper Belt Object (KBO; later re:comets) -eight planets of Solar System: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune |
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Pluto - Statistics |
-rotates on axis every 6.4 days, revolves around Sun every 248 years; axis of rotation is highly inclined to “expected” orientation normal to ecliptic, varying between 88 and 122 i.e. nearly parallel to ecliptic. -Charon rotates on its axis and revolves around Pluto with a 6.4 day period, the system is locked; not only does Pluto see same face of Charon all the time (as Earth does its Moon), but Charon sees same face of pluto as well -the barycenter (center of mass of two or more bodies that orbit each other) lies outside either body, some suggested these constitute a binary system or binary dwarf planet (no such official category yet, 3/16) -other satellites orbit Pluto in same plane as Charon, there are orbital resonances to their circular orbits -diameter: 2,372 km, density: 1.86 g/cm3, surface temperature: 37 K; -diameter of Charon: 1,208 km, bulk density: 1.70 g/cm3 (great similarity to Pluto’s density suggests that collision origin is inappropriate) -Pluto’s orbit highly elliptical (varies between 4.5 and 7.4X109 km from Sun; 30-49 AU) and inclined 20 degrees to ecliptic; sometimes closer to Sun than Neptune is, but has 2:3 orbital resonance with Neptune so they are never on collision course i.e. two orbits of Pluto for every three orbits of Neptune about Sun |
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Surface Features - Pluto |
-bulk density implies rocky core ~1,700 km diameter; may be liquid water at mantle/core boundary, with sufficient radioactivity of core component, producing a layer perhaps 100-200 km thick -surface: nitrogen ice (>98%), traces of methane and CO ice; tenuous atmosphere has these compounds in vapour phase, surface pressure of 1 Pa/10μbar (Earth’s atmospheric pressure is ~100 kPa) -much cycling between atmosphere and surface ices, with atmospheric pressure varying considerably on seasonal basis, as well as due to highly elliptical orbit -surface regions; one notes a large region shaped like and sometimes referred to as the “Heart” (Trombaugh Regio): this bright area opposite Charon includes the essentially craterless Sputnik Planum, whose surface age is inferred to be <10 Ma -Sputnik Planum: distinctive polygonal pattern that represents convection cell boundaries in nitrogen ice, occasional sublimation pits, irregular chunks of what is water ice rafted into this region on nitrogen glaciers; surrounding uplands are composed of water ice (older areas) |
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Surface Features - Charon |
-bulk density suggests smaller rocky core compared to pluto -surface is dominated by water ice; north polar region, dubbed “Mordor”, is reddish in colour; suggested mechanism is condensation of N2, CO, and CH4 in winter, coupled with reaction with UV solar radiation to produce tholins; sublimation in summer leaves these behind as an increasingly thick cap to obscure underlying icy crust -significant hemispherical difference, with smoother southern hemisphere dubbed Vulcan Planum, possibly resurfaced by cryovolcanism; rift valley over 1600 km long and several km deep separates two hemispheres |
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Surface Features - Charon |
-bulk density suggests smaller rocky core compared to pluto -surface is dominated by water ice; north polar region, dubbed “Mordor”, is reddish in colour; suggested mechanism is condensation of N2, CO, and CH4 in winter, coupled with reaction with UV solar radiation to produce tholins; sublimation in summer leaves these behind as an increasingly thick cap to obscure underlying icy crust -significant hemispherical difference, with smoother southern hemisphere dubbed Vulcan Planum, possibly resurfaced by cryovolcanism; rift valley over 1600 km long and several km deep separates two hemispheres |
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Pluto -Origin |
-highly speculative -first suggested it was ejected from Neptune’s satellite system, perhaps by an incoming Triton which would account for Triton’s orbit of Neptune being retrograde, and Pluto’s failure to conform to expected ecliptic orbit; perhaps Charon was the result of fragmentation of Pluto in impact: -unlikely due to need to have established Neptune-Pluto orbital resonance before collision would have occurred; -Pluto and Charon should have re-accreted rather than remain as distinct bodies -second suggests: both Pluto and Triton accreted beyond Neptune, as large comets rather than distant gassy planets/bodies -Triton then captured by Neptune (accounting for Triton’s retrograde orbit) then Pluto got locked into its 2:3 orbital resonance -perhaps Charon was then blasted away from Pluto by collision → disrupted Pluto’s rotational axis (out of favour due to very similar densities of both bodies:) -perhaps collision of two remarkably similar large comets/KBOs has occurred |
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Surface Features - Charon |
-bulk density suggests smaller rocky core compared to pluto -surface is dominated by water ice; north polar region, dubbed “Mordor”, is reddish in colour; suggested mechanism is condensation of N2, CO, and CH4 in winter, coupled with reaction with UV solar radiation to produce tholins; sublimation in summer leaves these behind as an increasingly thick cap to obscure underlying icy crust -significant hemispherical difference, with smoother southern hemisphere dubbed Vulcan Planum, possibly resurfaced by cryovolcanism; rift valley over 1600 km long and several km deep separates two hemispheres |
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Pluto -Origin |
-highly speculative -first suggested it was ejected from Neptune’s satellite system, perhaps by an incoming Triton which would account for Triton’s orbit of Neptune being retrograde, and Pluto’s failure to conform to expected ecliptic orbit; perhaps Charon was the result of fragmentation of Pluto in impact: -unlikely due to need to have established Neptune-Pluto orbital resonance before collision would have occurred; -Pluto and Charon should have re-accreted rather than remain as distinct bodies -second suggests: both Pluto and Triton accreted beyond Neptune, as large comets rather than distant gassy planets/bodies -Triton then captured by Neptune (accounting for Triton’s retrograde orbit) then Pluto got locked into its 2:3 orbital resonance -perhaps Charon was then blasted away from Pluto by collision → disrupted Pluto’s rotational axis (out of favour due to very similar densities of both bodies:) -perhaps collision of two remarkably similar large comets/KBOs has occurred |
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Comets and Kuiper Belt Objects |
-analogous to asteroids, represent “unaccreted” materials of Jovian, rather than terrestrial, portion of Solar System. -volatile rich bodies dominated by ices, with some silicate rock materials as well -centre is called the nucleus, typically 1-10 km in diameter, perhaps reaching 100 km, comprising the solids (silicate dust plus ices/snow) -once they get near the Sun (~3 AU), sublimation of water ice occurs to produce the coma, a diffuse region that might be 105-106 km across; some material exits comet through openings in its solid exterior as jets -most spectacular features are the tails, stretching for several X107 km+; directed away from the Sun, as seen in Hale-Bopp, Spring 1997 -the tails:one comprises dust and has yellowish color due to reflected light, the other comprises plasma (ions and electrons) and fluoresces blue due to CO+; two tails are offset slightly, with plasma tail lagging behind dust tail opposite to direction of travel of comet -comets believed to characterize one of two regions of space |
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Surface Features - Charon |
-bulk density suggests smaller rocky core compared to pluto -surface is dominated by water ice; north polar region, dubbed “Mordor”, is reddish in colour; suggested mechanism is condensation of N2, CO, and CH4 in winter, coupled with reaction with UV solar radiation to produce tholins; sublimation in summer leaves these behind as an increasingly thick cap to obscure underlying icy crust -significant hemispherical difference, with smoother southern hemisphere dubbed Vulcan Planum, possibly resurfaced by cryovolcanism; rift valley over 1600 km long and several km deep separates two hemispheres |
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Pluto -Origin |
-highly speculative -first suggested it was ejected from Neptune’s satellite system, perhaps by an incoming Triton which would account for Triton’s orbit of Neptune being retrograde, and Pluto’s failure to conform to expected ecliptic orbit; perhaps Charon was the result of fragmentation of Pluto in impact: -unlikely due to need to have established Neptune-Pluto orbital resonance before collision would have occurred; -Pluto and Charon should have re-accreted rather than remain as distinct bodies -second suggests: both Pluto and Triton accreted beyond Neptune, as large comets rather than distant gassy planets/bodies -Triton then captured by Neptune (accounting for Triton’s retrograde orbit) then Pluto got locked into its 2:3 orbital resonance -perhaps Charon was then blasted away from Pluto by collision → disrupted Pluto’s rotational axis (out of favour due to very similar densities of both bodies:) -perhaps collision of two remarkably similar large comets/KBOs has occurred |
|
|
Comets and Kuiper Belt Objects |
-analogous to asteroids, represent “unaccreted” materials of Jovian, rather than terrestrial, portion of Solar System. -volatile rich bodies dominated by ices, with some silicate rock materials as well -centre is called the nucleus, typically 1-10 km in diameter, perhaps reaching 100 km, comprising the solids (silicate dust plus ices/snow) -once they get near the Sun (~3 AU), sublimation of water ice occurs to produce the coma, a diffuse region that might be 105-106 km across; some material exits comet through openings in its solid exterior as jets -most spectacular features are the tails, stretching for several X107 km+; directed away from the Sun, as seen in Hale-Bopp, Spring 1997 -the tails:one comprises dust and has yellowish color due to reflected light, the other comprises plasma (ions and electrons) and fluoresces blue due to CO+; two tails are offset slightly, with plasma tail lagging behind dust tail opposite to direction of travel of comet -comets believed to characterize one of two regions of space |
|
|
Oort Cloud |
-very distant, up to 50,000 AU (Pluto averages 39.5 AU) -orbital periods extraordinarily long (at least 200 years - as long as 30X106 years) orbits geometrically odd, possibly perturbed; these may impact Earth |
|
|
Surface Features - Charon |
-bulk density suggests smaller rocky core compared to pluto -surface is dominated by water ice; north polar region, dubbed “Mordor”, is reddish in colour; suggested mechanism is condensation of N2, CO, and CH4 in winter, coupled with reaction with UV solar radiation to produce tholins; sublimation in summer leaves these behind as an increasingly thick cap to obscure underlying icy crust -significant hemispherical difference, with smoother southern hemisphere dubbed Vulcan Planum, possibly resurfaced by cryovolcanism; rift valley over 1600 km long and several km deep separates two hemispheres |
|
|
Pluto -Origin |
-highly speculative -first suggested it was ejected from Neptune’s satellite system, perhaps by an incoming Triton which would account for Triton’s orbit of Neptune being retrograde, and Pluto’s failure to conform to expected ecliptic orbit; perhaps Charon was the result of fragmentation of Pluto in impact: -unlikely due to need to have established Neptune-Pluto orbital resonance before collision would have occurred; -Pluto and Charon should have re-accreted rather than remain as distinct bodies -second suggests: both Pluto and Triton accreted beyond Neptune, as large comets rather than distant gassy planets/bodies -Triton then captured by Neptune (accounting for Triton’s retrograde orbit) then Pluto got locked into its 2:3 orbital resonance -perhaps Charon was then blasted away from Pluto by collision → disrupted Pluto’s rotational axis (out of favour due to very similar densities of both bodies:) -perhaps collision of two remarkably similar large comets/KBOs has occurred |
|
|
Comets and Kuiper Belt Objects |
-analogous to asteroids, represent “unaccreted” materials of Jovian, rather than terrestrial, portion of Solar System. -volatile rich bodies dominated by ices, with some silicate rock materials as well -centre is called the nucleus, typically 1-10 km in diameter, perhaps reaching 100 km, comprising the solids (silicate dust plus ices/snow) -once they get near the Sun (~3 AU), sublimation of water ice occurs to produce the coma, a diffuse region that might be 105-106 km across; some material exits comet through openings in its solid exterior as jets -most spectacular features are the tails, stretching for several X107 km+; directed away from the Sun, as seen in Hale-Bopp, Spring 1997 -the tails:one comprises dust and has yellowish color due to reflected light, the other comprises plasma (ions and electrons) and fluoresces blue due to CO+; two tails are offset slightly, with plasma tail lagging behind dust tail opposite to direction of travel of comet -comets believed to characterize one of two regions of space |
|
|
Oort Cloud |
-very distant, up to 50,000 AU (Pluto averages 39.5 AU) -orbital periods extraordinarily long (at least 200 years - as long as 30X106 years) orbits geometrically odd, possibly perturbed; these may impact Earth |
|
|
Kuiper Belt |
-shorter orbital periods (~ 20 years,& < 200 years), orbit within ecliptic, and may be remnants of outer solar system accretion that failed to achieve planetary size (if there even is such a thing): may be highly informative -Kuiper Belt Objects (KBO); currently 12 such objects that exceed 900 km diameter; perhaps 200 million objects at least 10-20 km diameter -Eris (originally named 2003 UB 313); 2,400 km diameter, orbit that varies between 38 and 97 AU, has a satellite -Sedna, 2004, maximum diameter of 1,500 km, elliptical orbit that varied between 76 and 990 AU; lies well beyond conventional outer limit of Kuiper Belt, but well within accepted inner limit of Oort Cloud; some regard it as “detached” KBO -New Horizon mission was launched in 1/19/06, arrived at Pluto 7/2015, should perform flybys of various KBOs in 2016-2020; resurrected Pluto Kuiper Express mission that was due to launch in 2004, but was cancelled for budgetary reasons |
|
|
Surface Features - Charon |
-bulk density suggests smaller rocky core compared to pluto -surface is dominated by water ice; north polar region, dubbed “Mordor”, is reddish in colour; suggested mechanism is condensation of N2, CO, and CH4 in winter, coupled with reaction with UV solar radiation to produce tholins; sublimation in summer leaves these behind as an increasingly thick cap to obscure underlying icy crust -significant hemispherical difference, with smoother southern hemisphere dubbed Vulcan Planum, possibly resurfaced by cryovolcanism; rift valley over 1600 km long and several km deep separates two hemispheres |
|
|
Pluto -Origin |
-highly speculative -first suggested it was ejected from Neptune’s satellite system, perhaps by an incoming Triton which would account for Triton’s orbit of Neptune being retrograde, and Pluto’s failure to conform to expected ecliptic orbit; perhaps Charon was the result of fragmentation of Pluto in impact: -unlikely due to need to have established Neptune-Pluto orbital resonance before collision would have occurred; -Pluto and Charon should have re-accreted rather than remain as distinct bodies -second suggests: both Pluto and Triton accreted beyond Neptune, as large comets rather than distant gassy planets/bodies -Triton then captured by Neptune (accounting for Triton’s retrograde orbit) then Pluto got locked into its 2:3 orbital resonance -perhaps Charon was then blasted away from Pluto by collision → disrupted Pluto’s rotational axis (out of favour due to very similar densities of both bodies:) -perhaps collision of two remarkably similar large comets/KBOs has occurred |
|
|
Comets and Kuiper Belt Objects |
-analogous to asteroids, represent “unaccreted” materials of Jovian, rather than terrestrial, portion of Solar System. -volatile rich bodies dominated by ices, with some silicate rock materials as well -centre is called the nucleus, typically 1-10 km in diameter, perhaps reaching 100 km, comprising the solids (silicate dust plus ices/snow) -once they get near the Sun (~3 AU), sublimation of water ice occurs to produce the coma, a diffuse region that might be 105-106 km across; some material exits comet through openings in its solid exterior as jets -most spectacular features are the tails, stretching for several X107 km+; directed away from the Sun, as seen in Hale-Bopp, Spring 1997 -the tails:one comprises dust and has yellowish color due to reflected light, the other comprises plasma (ions and electrons) and fluoresces blue due to CO+; two tails are offset slightly, with plasma tail lagging behind dust tail opposite to direction of travel of comet -comets believed to characterize one of two regions of space |
|
|
Oort Cloud |
-very distant, up to 50,000 AU (Pluto averages 39.5 AU) -orbital periods extraordinarily long (at least 200 years - as long as 30X106 years) orbits geometrically odd, possibly perturbed; these may impact Earth |
|
|
Kuiper Belt |
-shorter orbital periods (~ 20 years,& < 200 years), orbit within ecliptic, and may be remnants of outer solar system accretion that failed to achieve planetary size (if there even is such a thing): may be highly informative -Kuiper Belt Objects (KBO); currently 12 such objects that exceed 900 km diameter; perhaps 200 million objects at least 10-20 km diameter -Eris (originally named 2003 UB 313); 2,400 km diameter, orbit that varies between 38 and 97 AU, has a satellite -Sedna, 2004, maximum diameter of 1,500 km, elliptical orbit that varied between 76 and 990 AU; lies well beyond conventional outer limit of Kuiper Belt, but well within accepted inner limit of Oort Cloud; some regard it as “detached” KBO -New Horizon mission was launched in 1/19/06, arrived at Pluto 7/2015, should perform flybys of various KBOs in 2016-2020; resurrected Pluto Kuiper Express mission that was due to launch in 2004, but was cancelled for budgetary reasons |
|
|
1. The comet that was visible in the northern sky during the Spring of 1997 is known as: A. Hale-Bopp B. Halle -Berry C. Halley D. Bill Haley and the Comets |
A. Hale-Bopp |
|
|
Surface Features - Charon |
-bulk density suggests smaller rocky core compared to pluto -surface is dominated by water ice; north polar region, dubbed “Mordor”, is reddish in colour; suggested mechanism is condensation of N2, CO, and CH4 in winter, coupled with reaction with UV solar radiation to produce tholins; sublimation in summer leaves these behind as an increasingly thick cap to obscure underlying icy crust -significant hemispherical difference, with smoother southern hemisphere dubbed Vulcan Planum, possibly resurfaced by cryovolcanism; rift valley over 1600 km long and several km deep separates two hemispheres |
|
|
Pluto -Origin |
-highly speculative -first suggested it was ejected from Neptune’s satellite system, perhaps by an incoming Triton which would account for Triton’s orbit of Neptune being retrograde, and Pluto’s failure to conform to expected ecliptic orbit; perhaps Charon was the result of fragmentation of Pluto in impact: -unlikely due to need to have established Neptune-Pluto orbital resonance before collision would have occurred; -Pluto and Charon should have re-accreted rather than remain as distinct bodies -second suggests: both Pluto and Triton accreted beyond Neptune, as large comets rather than distant gassy planets/bodies -Triton then captured by Neptune (accounting for Triton’s retrograde orbit) then Pluto got locked into its 2:3 orbital resonance -perhaps Charon was then blasted away from Pluto by collision → disrupted Pluto’s rotational axis (out of favour due to very similar densities of both bodies:) -perhaps collision of two remarkably similar large comets/KBOs has occurred |
|
|
Comets and Kuiper Belt Objects |
-analogous to asteroids, represent “unaccreted” materials of Jovian, rather than terrestrial, portion of Solar System. -volatile rich bodies dominated by ices, with some silicate rock materials as well -centre is called the nucleus, typically 1-10 km in diameter, perhaps reaching 100 km, comprising the solids (silicate dust plus ices/snow) -once they get near the Sun (~3 AU), sublimation of water ice occurs to produce the coma, a diffuse region that might be 105-106 km across; some material exits comet through openings in its solid exterior as jets -most spectacular features are the tails, stretching for several X107 km+; directed away from the Sun, as seen in Hale-Bopp, Spring 1997 -the tails:one comprises dust and has yellowish color due to reflected light, the other comprises plasma (ions and electrons) and fluoresces blue due to CO+; two tails are offset slightly, with plasma tail lagging behind dust tail opposite to direction of travel of comet -comets believed to characterize one of two regions of space |
|
|
Oort Cloud |
-very distant, up to 50,000 AU (Pluto averages 39.5 AU) -orbital periods extraordinarily long (at least 200 years - as long as 30X106 years) orbits geometrically odd, possibly perturbed; these may impact Earth |
|
|
Kuiper Belt |
-shorter orbital periods (~ 20 years,& < 200 years), orbit within ecliptic, and may be remnants of outer solar system accretion that failed to achieve planetary size (if there even is such a thing): may be highly informative -Kuiper Belt Objects (KBO); currently 12 such objects that exceed 900 km diameter; perhaps 200 million objects at least 10-20 km diameter -Eris (originally named 2003 UB 313); 2,400 km diameter, orbit that varies between 38 and 97 AU, has a satellite -Sedna, 2004, maximum diameter of 1,500 km, elliptical orbit that varied between 76 and 990 AU; lies well beyond conventional outer limit of Kuiper Belt, but well within accepted inner limit of Oort Cloud; some regard it as “detached” KBO -New Horizon mission was launched in 1/19/06, arrived at Pluto 7/2015, should perform flybys of various KBOs in 2016-2020; resurrected Pluto Kuiper Express mission that was due to launch in 2004, but was cancelled for budgetary reasons |
|
|
1. The comet that was visible in the northern sky during the Spring of 1997 is known as: A. Hale-Bopp B. Halle -Berry C. Halley D. Bill Haley and the Comets |
A. Hale-Bopp |
|
|
Normally, the most distant object in the Solar system are: |
A: Comets |
|
|
Surface Features - Charon |
-bulk density suggests smaller rocky core compared to pluto -surface is dominated by water ice; north polar region, dubbed “Mordor”, is reddish in colour; suggested mechanism is condensation of N2, CO, and CH4 in winter, coupled with reaction with UV solar radiation to produce tholins; sublimation in summer leaves these behind as an increasingly thick cap to obscure underlying icy crust -significant hemispherical difference, with smoother southern hemisphere dubbed Vulcan Planum, possibly resurfaced by cryovolcanism; rift valley over 1600 km long and several km deep separates two hemispheres |
|
|
Pluto -Origin |
-highly speculative -first suggested it was ejected from Neptune’s satellite system, perhaps by an incoming Triton which would account for Triton’s orbit of Neptune being retrograde, and Pluto’s failure to conform to expected ecliptic orbit; perhaps Charon was the result of fragmentation of Pluto in impact: -unlikely due to need to have established Neptune-Pluto orbital resonance before collision would have occurred; -Pluto and Charon should have re-accreted rather than remain as distinct bodies -second suggests: both Pluto and Triton accreted beyond Neptune, as large comets rather than distant gassy planets/bodies -Triton then captured by Neptune (accounting for Triton’s retrograde orbit) then Pluto got locked into its 2:3 orbital resonance -perhaps Charon was then blasted away from Pluto by collision → disrupted Pluto’s rotational axis (out of favour due to very similar densities of both bodies:) -perhaps collision of two remarkably similar large comets/KBOs has occurred |
|
|
Comets and Kuiper Belt Objects |
-analogous to asteroids, represent “unaccreted” materials of Jovian, rather than terrestrial, portion of Solar System. -volatile rich bodies dominated by ices, with some silicate rock materials as well -centre is called the nucleus, typically 1-10 km in diameter, perhaps reaching 100 km, comprising the solids (silicate dust plus ices/snow) -once they get near the Sun (~3 AU), sublimation of water ice occurs to produce the coma, a diffuse region that might be 105-106 km across; some material exits comet through openings in its solid exterior as jets -most spectacular features are the tails, stretching for several X107 km+; directed away from the Sun, as seen in Hale-Bopp, Spring 1997 -the tails:one comprises dust and has yellowish color due to reflected light, the other comprises plasma (ions and electrons) and fluoresces blue due to CO+; two tails are offset slightly, with plasma tail lagging behind dust tail opposite to direction of travel of comet -comets believed to characterize one of two regions of space |
|
|
Oort Cloud |
-very distant, up to 50,000 AU (Pluto averages 39.5 AU) -orbital periods extraordinarily long (at least 200 years - as long as 30X106 years) orbits geometrically odd, possibly perturbed; these may impact Earth |
|
|
Kuiper Belt |
-shorter orbital periods (~ 20 years,& < 200 years), orbit within ecliptic, and may be remnants of outer solar system accretion that failed to achieve planetary size (if there even is such a thing): may be highly informative -Kuiper Belt Objects (KBO); currently 12 such objects that exceed 900 km diameter; perhaps 200 million objects at least 10-20 km diameter -Eris (originally named 2003 UB 313); 2,400 km diameter, orbit that varies between 38 and 97 AU, has a satellite -Sedna, 2004, maximum diameter of 1,500 km, elliptical orbit that varied between 76 and 990 AU; lies well beyond conventional outer limit of Kuiper Belt, but well within accepted inner limit of Oort Cloud; some regard it as “detached” KBO -New Horizon mission was launched in 1/19/06, arrived at Pluto 7/2015, should perform flybys of various KBOs in 2016-2020; resurrected Pluto Kuiper Express mission that was due to launch in 2004, but was cancelled for budgetary reasons |
|
|
1. The comet that was visible in the northern sky during the Spring of 1997 is known as: A. Hale-Bopp B. Halle -Berry C. Halley D. Bill Haley and the Comets |
A. Hale-Bopp |
|
|
Normally, the most distant object in the Solar system are: |
A: Comets |
|
|
3. Which of the following moons/Satellites possess an atmosphere? A. Callisto B. Io C. Titan D. Triton |
C. Titan D. Triton |
|
|
Surface Features - Charon |
-bulk density suggests smaller rocky core compared to pluto -surface is dominated by water ice; north polar region, dubbed “Mordor”, is reddish in colour; suggested mechanism is condensation of N2, CO, and CH4 in winter, coupled with reaction with UV solar radiation to produce tholins; sublimation in summer leaves these behind as an increasingly thick cap to obscure underlying icy crust -significant hemispherical difference, with smoother southern hemisphere dubbed Vulcan Planum, possibly resurfaced by cryovolcanism; rift valley over 1600 km long and several km deep separates two hemispheres |
|
|
Pluto -Origin |
-highly speculative -first suggested it was ejected from Neptune’s satellite system, perhaps by an incoming Triton which would account for Triton’s orbit of Neptune being retrograde, and Pluto’s failure to conform to expected ecliptic orbit; perhaps Charon was the result of fragmentation of Pluto in impact: -unlikely due to need to have established Neptune-Pluto orbital resonance before collision would have occurred; -Pluto and Charon should have re-accreted rather than remain as distinct bodies -second suggests: both Pluto and Triton accreted beyond Neptune, as large comets rather than distant gassy planets/bodies -Triton then captured by Neptune (accounting for Triton’s retrograde orbit) then Pluto got locked into its 2:3 orbital resonance -perhaps Charon was then blasted away from Pluto by collision → disrupted Pluto’s rotational axis (out of favour due to very similar densities of both bodies:) -perhaps collision of two remarkably similar large comets/KBOs has occurred |
|
|
Comets and Kuiper Belt Objects |
-analogous to asteroids, represent “unaccreted” materials of Jovian, rather than terrestrial, portion of Solar System. -volatile rich bodies dominated by ices, with some silicate rock materials as well -centre is called the nucleus, typically 1-10 km in diameter, perhaps reaching 100 km, comprising the solids (silicate dust plus ices/snow) -once they get near the Sun (~3 AU), sublimation of water ice occurs to produce the coma, a diffuse region that might be 105-106 km across; some material exits comet through openings in its solid exterior as jets -most spectacular features are the tails, stretching for several X107 km+; directed away from the Sun, as seen in Hale-Bopp, Spring 1997 -the tails:one comprises dust and has yellowish color due to reflected light, the other comprises plasma (ions and electrons) and fluoresces blue due to CO+; two tails are offset slightly, with plasma tail lagging behind dust tail opposite to direction of travel of comet -comets believed to characterize one of two regions of space |
|
|
Oort Cloud |
-very distant, up to 50,000 AU (Pluto averages 39.5 AU) -orbital periods extraordinarily long (at least 200 years - as long as 30X106 years) orbits geometrically odd, possibly perturbed; these may impact Earth |
|
|
Kuiper Belt |
-shorter orbital periods (~ 20 years,& < 200 years), orbit within ecliptic, and may be remnants of outer solar system accretion that failed to achieve planetary size (if there even is such a thing): may be highly informative -Kuiper Belt Objects (KBO); currently 12 such objects that exceed 900 km diameter; perhaps 200 million objects at least 10-20 km diameter -Eris (originally named 2003 UB 313); 2,400 km diameter, orbit that varies between 38 and 97 AU, has a satellite -Sedna, 2004, maximum diameter of 1,500 km, elliptical orbit that varied between 76 and 990 AU; lies well beyond conventional outer limit of Kuiper Belt, but well within accepted inner limit of Oort Cloud; some regard it as “detached” KBO -New Horizon mission was launched in 1/19/06, arrived at Pluto 7/2015, should perform flybys of various KBOs in 2016-2020; resurrected Pluto Kuiper Express mission that was due to launch in 2004, but was cancelled for budgetary reasons |
|
|
1. The comet that was visible in the northern sky during the Spring of 1997 is known as: A. Hale-Bopp B. Halle -Berry C. Halley D. Bill Haley and the Comets |
A. Hale-Bopp |
|
|
Normally, the most distant object in the Solar system are: |
A: Comets |
|
|
3. Which of the following moons/Satellites possess an atmosphere? A. Callisto B. Io C. Titan D. Triton |
C. Titan D. Triton |
|
|
Which of the following bodies is most likely to presently have life? A. Callisto B. Europa - Liquid Water here C. Titan - Liquid Methane D. Only Earth has life |
B. Europa - Liquid Water C. Titan - Liquid Methane |
|
|
Surface Features - Charon |
-bulk density suggests smaller rocky core compared to pluto -surface is dominated by water ice; north polar region, dubbed “Mordor”, is reddish in colour; suggested mechanism is condensation of N2, CO, and CH4 in winter, coupled with reaction with UV solar radiation to produce tholins; sublimation in summer leaves these behind as an increasingly thick cap to obscure underlying icy crust -significant hemispherical difference, with smoother southern hemisphere dubbed Vulcan Planum, possibly resurfaced by cryovolcanism; rift valley over 1600 km long and several km deep separates two hemispheres |
|
|
Pluto -Origin |
-highly speculative -first suggested it was ejected from Neptune’s satellite system, perhaps by an incoming Triton which would account for Triton’s orbit of Neptune being retrograde, and Pluto’s failure to conform to expected ecliptic orbit; perhaps Charon was the result of fragmentation of Pluto in impact: -unlikely due to need to have established Neptune-Pluto orbital resonance before collision would have occurred; -Pluto and Charon should have re-accreted rather than remain as distinct bodies -second suggests: both Pluto and Triton accreted beyond Neptune, as large comets rather than distant gassy planets/bodies -Triton then captured by Neptune (accounting for Triton’s retrograde orbit) then Pluto got locked into its 2:3 orbital resonance -perhaps Charon was then blasted away from Pluto by collision → disrupted Pluto’s rotational axis (out of favour due to very similar densities of both bodies:) -perhaps collision of two remarkably similar large comets/KBOs has occurred |
|
|
Comets and Kuiper Belt Objects |
-analogous to asteroids, represent “unaccreted” materials of Jovian, rather than terrestrial, portion of Solar System. -volatile rich bodies dominated by ices, with some silicate rock materials as well -centre is called the nucleus, typically 1-10 km in diameter, perhaps reaching 100 km, comprising the solids (silicate dust plus ices/snow) -once they get near the Sun (~3 AU), sublimation of water ice occurs to produce the coma, a diffuse region that might be 105-106 km across; some material exits comet through openings in its solid exterior as jets -most spectacular features are the tails, stretching for several X107 km+; directed away from the Sun, as seen in Hale-Bopp, Spring 1997 -the tails:one comprises dust and has yellowish color due to reflected light, the other comprises plasma (ions and electrons) and fluoresces blue due to CO+; two tails are offset slightly, with plasma tail lagging behind dust tail opposite to direction of travel of comet -comets believed to characterize one of two regions of space |
|
|
Oort Cloud |
-very distant, up to 50,000 AU (Pluto averages 39.5 AU) -orbital periods extraordinarily long (at least 200 years - as long as 30X106 years) orbits geometrically odd, possibly perturbed; these may impact Earth |
|
|
Kuiper Belt |
-shorter orbital periods (~ 20 years,& < 200 years), orbit within ecliptic, and may be remnants of outer solar system accretion that failed to achieve planetary size (if there even is such a thing): may be highly informative -Kuiper Belt Objects (KBO); currently 12 such objects that exceed 900 km diameter; perhaps 200 million objects at least 10-20 km diameter -Eris (originally named 2003 UB 313); 2,400 km diameter, orbit that varies between 38 and 97 AU, has a satellite -Sedna, 2004, maximum diameter of 1,500 km, elliptical orbit that varied between 76 and 990 AU; lies well beyond conventional outer limit of Kuiper Belt, but well within accepted inner limit of Oort Cloud; some regard it as “detached” KBO -New Horizon mission was launched in 1/19/06, arrived at Pluto 7/2015, should perform flybys of various KBOs in 2016-2020; resurrected Pluto Kuiper Express mission that was due to launch in 2004, but was cancelled for budgetary reasons |
|
|
1. The comet that was visible in the northern sky during the Spring of 1997 is known as: A. Hale-Bopp B. Halle -Berry C. Halley D. Bill Haley and the Comets |
A. Hale-Bopp |
|
|
Normally, the most distant object in the Solar system are: |
A: Comets |
|
|
3. Which of the following moons/Satellites possess an atmosphere? A. Callisto B. Io C. Titan D. Triton |
C. Titan D. Triton |
|
|
Which of the following bodies is most likely to presently have life? A. Callisto B. Europa - Liquid Water here C. Titan - Liquid Methane D. Only Earth has life |
B. Europa - Liquid Water C. Titan - Liquid Methane |
|
|
Exoplanets |
-Give insight into our Solar System by seeing star/planetary systems at different stages in their development -Looking for planets in the habitable zone, or Goldilocks zone (“just right”) |
|
|
Surface Features - Charon |
-bulk density suggests smaller rocky core compared to pluto -surface is dominated by water ice; north polar region, dubbed “Mordor”, is reddish in colour; suggested mechanism is condensation of N2, CO, and CH4 in winter, coupled with reaction with UV solar radiation to produce tholins; sublimation in summer leaves these behind as an increasingly thick cap to obscure underlying icy crust -significant hemispherical difference, with smoother southern hemisphere dubbed Vulcan Planum, possibly resurfaced by cryovolcanism; rift valley over 1600 km long and several km deep separates two hemispheres |
|
|
What is your opinion of the Solar Nebula Hypothesis? A. It’s a brilliant model that explain everything elegantly B. It has a few hitches, but we can explain all of them satisfactorily C. It’s so full of hole, it’s like swiss cheese. It should be scrapped D. What’s the Solar Nebula Hypothesis |
A strong possibility that we eventually need to revise the Solar Nebula Hypothesis |
|
|
Pluto -Origin |
-highly speculative -first suggested it was ejected from Neptune’s satellite system, perhaps by an incoming Triton which would account for Triton’s orbit of Neptune being retrograde, and Pluto’s failure to conform to expected ecliptic orbit; perhaps Charon was the result of fragmentation of Pluto in impact: -unlikely due to need to have established Neptune-Pluto orbital resonance before collision would have occurred; -Pluto and Charon should have re-accreted rather than remain as distinct bodies -second suggests: both Pluto and Triton accreted beyond Neptune, as large comets rather than distant gassy planets/bodies -Triton then captured by Neptune (accounting for Triton’s retrograde orbit) then Pluto got locked into its 2:3 orbital resonance -perhaps Charon was then blasted away from Pluto by collision → disrupted Pluto’s rotational axis (out of favour due to very similar densities of both bodies:) -perhaps collision of two remarkably similar large comets/KBOs has occurred |
|
|
Comets and Kuiper Belt Objects |
-analogous to asteroids, represent “unaccreted” materials of Jovian, rather than terrestrial, portion of Solar System. -volatile rich bodies dominated by ices, with some silicate rock materials as well -centre is called the nucleus, typically 1-10 km in diameter, perhaps reaching 100 km, comprising the solids (silicate dust plus ices/snow) -once they get near the Sun (~3 AU), sublimation of water ice occurs to produce the coma, a diffuse region that might be 105-106 km across; some material exits comet through openings in its solid exterior as jets -most spectacular features are the tails, stretching for several X107 km+; directed away from the Sun, as seen in Hale-Bopp, Spring 1997 -the tails:one comprises dust and has yellowish color due to reflected light, the other comprises plasma (ions and electrons) and fluoresces blue due to CO+; two tails are offset slightly, with plasma tail lagging behind dust tail opposite to direction of travel of comet -comets believed to characterize one of two regions of space |
|
|
Oort Cloud |
-very distant, up to 50,000 AU (Pluto averages 39.5 AU) -orbital periods extraordinarily long (at least 200 years - as long as 30X106 years) orbits geometrically odd, possibly perturbed; these may impact Earth |
|
|
Kuiper Belt |
-shorter orbital periods (~ 20 years,& < 200 years), orbit within ecliptic, and may be remnants of outer solar system accretion that failed to achieve planetary size (if there even is such a thing): may be highly informative -Kuiper Belt Objects (KBO); currently 12 such objects that exceed 900 km diameter; perhaps 200 million objects at least 10-20 km diameter -Eris (originally named 2003 UB 313); 2,400 km diameter, orbit that varies between 38 and 97 AU, has a satellite -Sedna, 2004, maximum diameter of 1,500 km, elliptical orbit that varied between 76 and 990 AU; lies well beyond conventional outer limit of Kuiper Belt, but well within accepted inner limit of Oort Cloud; some regard it as “detached” KBO -New Horizon mission was launched in 1/19/06, arrived at Pluto 7/2015, should perform flybys of various KBOs in 2016-2020; resurrected Pluto Kuiper Express mission that was due to launch in 2004, but was cancelled for budgetary reasons |
|
|
1. The comet that was visible in the northern sky during the Spring of 1997 is known as: A. Hale-Bopp B. Halle -Berry C. Halley D. Bill Haley and the Comets |
A. Hale-Bopp |
|
|
Normally, the most distant object in the Solar system are: |
A: Comets |
|
|
3. Which of the following moons/Satellites possess an atmosphere? A. Callisto B. Io C. Titan D. Triton |
C. Titan D. Triton |
|
|
Which of the following bodies is most likely to presently have life? A. Callisto B. Europa - Liquid Water here C. Titan - Liquid Methane D. Only Earth has life |
B. Europa - Liquid Water C. Titan - Liquid Methane |
|
|
Exoplanets |
-Give insight into our Solar System by seeing star/planetary systems at different stages in their development -Looking for planets in the habitable zone, or Goldilocks zone (“just right”) |
