GEO Test 3
Here are the answers to your questions based on the provided document:
What layers make up Ganymede’s internal structure? Ganymede's internal structure is fully differentiated: iron core → rock layer → ice layer.
What evidence suggests Ganymede is fully differentiated? Low moment of inertia is evidence for Ganymede's differentiation.
How deep is Ganymede's potential subsurface ocean? Ganymede may have a possible salt-water ocean ~200 km beneath the surface.
What two factors contribute to Ganymede's internal heating? Faster accretion trapped heat inside, and greater tidal heating due to gravitational interactions contribute to Ganymede's internal heating.
What material is likely responsible for Ganymede's induced magnetic field? Electrically conductive material, likely saltwater, is likely responsible for Ganymede's induced magnetic fields.
Why is ice alone not sufficient to conduct electricity in Ganymede? Ice alone is a poor conductor; saltwater conducts electricity well.
What is the 4:2:1 resonance among Io, Europa, and Ganymede? In the 4:2:1 resonance among Io, Europa, and Ganymede, Io orbits four times, Europa twice, and Ganymede once.
How does orbital resonance increase tidal heating? Resonance increases orbital eccentricity, which yields greater tidal and frictional heating.
Why doesn’t Callisto experience significant tidal heating? Callisto is not part of the resonance system, so its orbit has little eccentricity and subsequent tidal heating.
What is the composition of Europa’s surface? Europa has a thin icy crust over a potential subsurface ocean.
What surface features are observed on Europa? Cracks, ridges, and grooves across Europa's surface suggest tectonic and/or cryovolcanic activity.
What does the low number of impact craters on Europa suggest? The low number of impact craters on Europa suggests a young surface.
What is Europa's approximate density? Europa's density is ~2.99 g/cm³.
What are the two proposed internal models for Europa? Two proposed internal models for Europa are a thick hard icy shell (~few to 30 km) overlying a liquid water ocean, or a warm interior with soft convecting ice.
What feature on Europa resembles icebergs? The Conamara Chaos region on Europa resembles icebergs frozen in ice.
What terrestrial feature does Conamara Chaos resemble? The Conamara Chaos region resembles Earth's ice shelves.
Why is Europa considered a candidate for life? Europa is considered a candidate for life because potential deep-sea hydrothermal vents could provide habitats for life.
What mission is scheduled to launch to Europa in 2024? The Europa Clipper mission is scheduled to launch in 2024.
When is the Europa Clipper mission expected to arrive at Europa? The Europa Clipper mission is expected to arrive in 2030.
What is the ESA JUICE mission? The ESA JUICE Mission studies Europa, Ganymede, and Callisto.
When was the ESA JUICE mission launched? The ESA JUICE Mission was launched in 2023.
When is the ESA JUICE mission expected to reach Jupiter? The ESA JUICE Mission is expected to reach Jupiter in 2031.
What makes Io’s surface unique in the solar system? Io's surface is the most volcanically active body in the Solar System.
Why are there no impact craters on Io? There are no impact craters on Io due to constant resurfacing from volcanic activity.
What is Io’s approximate density? Io's density is ~3.53 g/cm³.
What type of atmosphere does Io have? Io has a thin sulfur dioxide atmosphere.
What volcanic features are observed on Io? Huge plumes extending hundreds of kilometers are observed on Io.
How were Io’s volcanic activities predicted? Io's volcanism was predicted due to intense tidal heating.
What is the composition of Io’s interior? Io's interior is composed of an iron core and silicate mantle.
How much of Io’s mantle might be molten? Io's mantle may be 10-20% molten.
What are Saturn’s rings primarily made of? Saturn's rings are primarily made of water ice (~93%) and minor carbonaceous material.
What is the typical particle size in Saturn’s rings? The typical particle size in Saturn's rings is from 1 meter to less than 1 micrometer.
How far do Saturn’s rings extend above the equator? Saturn's rings extend from 7,000 to 80,000 km above Saturn's equator.
How thick are Saturn’s rings? Saturn's rings are very thin, ~10 meters thick.
Name one theory about the formation of Saturn’s rings. One theory about the formation of Saturn's rings is the destruction of a moon/planet within the Roche limit.
What evidence suggests Saturn’s rings might be young? Brightness and "cleanliness" suggest Saturn's rings might be younger than 4.5 billion years.
What is the Roche limit? The Roche limit is a distance within which any body inside it can be torn apart.
How close to Saturn does the Roche limit extend? The Roche limit extends within ~90,000 km from Saturn.
How large is Titan compared to other moons? Titan is the second-largest moon.
What is Titan's approximate diameter? Titan's diameter is 5,150 km.
What is Titan’s density? Titan's density is ~1.89 g/cm³.
What is Titan’s atmosphere primarily composed of? Titan's atmosphere is primarily composed of dense atmosphere (~95% nitrogen, ~5% methane).
What causes the organic haze in Titan’s atmosphere? UV processing of methane and nitrogen causes the organic haze in Titan's atmosphere.
What probe landed on Titan in 2004? The Huygens probe landed on Titan in 2004.
What surface features did the Huygens probe observe on Titan? The Huygens probe observed dry riverbeds, lakebeds, and rounded ice rocks on Titan.
What did Cassini’s radar detect on Titan? Cassini's radar detected lakes of liquid methane, ethane, and propane on Titan.
Why is the presence of methane in Titan’s atmosphere surprising? The presence of methane in Titan's atmosphere is surprising because methane should be destroyed by sunlight, implying active replenishment.
What does Titan serve as a natural laboratory for? Titan serves as a natural lab for early-Earth-like chemistry.
What is the Dragonfly mission? The Dragonfly Mission is a drone exploration of Titan's surface and chemistry.
When is the Dragonfly mission scheduled to launch? The Dragonfly Mission is scheduled to launch in 2034.
What evidence suggests Titan has a subsurface ocean? Likely liquid water ocean beneath frozen crust suggests Titan has a subsurface ocean.
Where are geysers observed on Enceladus? Water-ice geysers are observed near the south pole of Enceladus.
What provides the heat source for Enceladus’s activity? Resonance with Dione provides heat for Enceladus's activity.
How does resonance with Dione affect Enceladus? Resonance with Dione provides heat for Enceladus.
What phenomenon causes localized heating on Enceladus? Observed heat exceeding expected suggests localized heating via "shear localization" on Enceladus.
What has been detected in the plumes of Enceladus? Salt and organic molecules have been detected in the plumes of Enceladus.
What does the presence of salt in Enceladus’s plumes suggest? The presence of salt in Enceladus's plumes suggests a liquid saltwater ocean.
What organic molecules have been found in Enceladus's plumes? Methane, propane, acetylene, and formaldehyde have been found in Enceladus's plumes.
Why is Enceladus considered a good candidate for astrobiology? Enceladus is considered a good candidate for astrobiology because its subsurface ocean is possibly in contact with a rocky core, which is important for life-supporting chemistry.
Who began the search for Planet X? Percival Lowell began the search for Planet X in 1906.
When was Pluto discovered? Pluto was discovered in 1930.
Who discovered Pluto? Clyde Tombaugh discovered Pluto.
What assumption led to Pluto's discovery? The discovery of Pluto was based on incorrect assumptions about Uranus' orbit.
What is Pluto classified as today? Pluto is classified as a "dwarf planet" today.
How does Pluto’s radius compare to Triton’s? Pluto's radius is 1153 km, similar to Triton's at 1353 km.
What is Pluto’s approximate density? Pluto's density is ~2.0 g/cm³.
What is Pluto primarily composed of? Pluto is primarily composed of a mix of rock (~50-70%) and ice.
What moon of Pluto was discovered in 1978? Charon, a moon of Pluto, was discovered in 1978.
What two additional moons of Pluto were discovered in 2005? Nix and Hydra, two additional moons of Pluto, were discovered in 2005 by the Hubble Space Telescope.
What surface variations were observed on Pluto before New Horizons? Brightness and color variations were observed on Pluto before New Horizons.
What causes Pluto’s reddish surface color? Organic molecules formed from methane and ammonia ice exposed to UV cause Pluto's reddish surface color.
What are the three layers in Pluto’s internal structure? The three layers in Pluto's internal structure are Layer 1: Frozen nitrogen, Layer 2: Water ice, and Layer 3: Rock and iron core.
What provides internal heat to Pluto? Radioactive decay (potassium, uranium, thorium) in rocky material could melt internal water, providing internal heat to Pluto.
What surface feature would Pluto have if no subsurface ocean ever existed? If no subsurface ocean ever formed, Pluto would have an equatorial bulge from early rotation and mostly extensional tectonic features.
What surface feature would indicate the presence of a subsurface ocean on Pluto? Mostly compressional surface features (e.g., wrinkle ridges) or a mixture of compressional/extensional features if the ocean refroze would indicate the presence or past presence of a subsurface ocean on Pluto.
When was the New Horizons spacecraft launched? The New Horizons spacecraft was launched in 2006.
When did New Horizons fly by Pluto? New Horizons flew by Pluto in July 2015.
What shape is Pluto’s overall structure? Pluto is almost perfectly spherical.
What does Pluto’s shape suggest about its interior? Pluto's almost perfectly spherical shape suggests a subsurface ocean may have existed or still exists.
What is Sputnik Planum? Sputnik Planum is a vast frozen nitrogen sea on Pluto.
What is Sputnik Planum composed of? Sputnik Planum is composed of frozen nitrogen.
What atmospheric component dominates Pluto’s atmosphere? Pluto's atmosphere is primarily nitrogen.
How was Pluto’s atmospheric thickness measured? Pluto's atmospheric thickness was measured by light refraction during the flyby.
What surface processes are believed to occur in Sputnik Planum? Surface features indicate convection within soft nitrogen ice in Sputnik Planum.
What are the surface features of Charon? Charon's surface features include large canyon systems and grabens, and hemispheric differences (southern hemisphere smoother, northern hemisphere rugged).
What do Charon’s canyon systems suggest about its crust? Charon's large canyon systems and grabens suggest crustal extension.
What hemispheric differences are seen on Charon? Hemispheric differences seen on Charon are that the southern hemisphere is smoother, while the northern hemisphere is rugged.
What evidence on Charon supports a past subsurface ocean? Possible past subsurface ocean, similar to Pluto, is evidence on Charon that supports a past subsurface ocean.
Why was Pluto reclassified as a dwarf planet? Pluto was reclassified as a "dwarf planet" due to the discovery of many similar-sized Kuiper Belt objects (e.g., Eris).
What Kuiper Belt object is similar in size to Pluto? Eris is a Kuiper Belt object similar in size to Pluto.
What is the Planet Nine hypothesis? The Planet Nine hypothesis suggests a strange clustering of distant Kuiper Belt orbits indicates a massive unseen planet (>10 Earth masses) at ~700 AU.
What clues suggest the existence of Planet Nine? Strange clustering, or non-random orientations in the argument of perihelion of several very distant Kuiper Belt objects, suggests the existence of Planet Nine.
How massive is the hypothetical Planet Nine thought to be? The hypothetical Planet Nine is thought to be >10 Earth masses.
How far from the Sun might Planet Nine be located? Planet Nine might be located at ~700 AU from the Sun.
How does volcanic activity affect planetary habitability? Volcanism can contribute to the habitability of a planet because an atmosphere that keeps stable surface temperatures is required for planetary habitability, and a decline in volcanic and plate tectonic activity can lead to a decrease in CO2 released into the atmosphere.
What role does Mars’s cooling play in its atmospheric loss? A decline in volcanic and plate tectonic activity led to a decrease in CO2 released, and as a result of decreased plate tectonics, the magnetic field strength decreased, allowing solar wind to erode the atmosphere. Silicate weathering also contributed to the decline of CO2 in the atmosphere. The decreased strength of the atmosphere removed its blanketing effect, and as a result, Mars began cooling.
What determines the rotation rate of gas giants like Jupiter? We can measure the rate of rotation of gas giants like Jupiter by measuring the rate of spin of their magnetic field axes.
What makes Saturn’s magnetic field unusual? Saturn's magnetic field behavior is more complex than expected, and there is no exact rate of rotation we can pinpoint from it.
What two observations support the idea of an ocean beneath Europa? The lightly-cratered surface suggests it may have been reworked by cryovolcanism or plate tectonics, and the tidal heating the moon experiences due to orbital eccentricity may yield enough heat to sustain liquid water underneath the icy surface.
Why are hydrogen and helium absent from terrestrial planet atmospheres? Hydrogen and helium have low mass and move quickly, so they were able to escape the terrestrial planets’ atmospheres.