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110 Cards in this Set
- Front
- Back
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What objects are brighter in the night sky than Jupiter?
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the Moon and Venus
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What are the most visible features of Jupiter?
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the latitudinal atmospheric bands and the Great Red Spot
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What is Jupiter's mass, in kg and Earth masses?
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1.9*10^27 kg, 318 Earth masses
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How does Jupiter's mass compare to the other planets and to the Sun?
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It has more than twice the mass of the rest of the planets combined, but only .1% of the Sun's mass
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What is Jupiter's radius, in km and Earth radii?
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71500 km or 11.2 Earth radii
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How is Jupiter's mass determined?
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from the Galilean moons
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How is Jupiter's radius determined?
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from its angular size and distance
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How is Jupiter's density determined?
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from its mass and radius
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What is Jupiter's density?
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1300 kg/m^3
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What is Jupiter primarily made of?
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hydrogen and helium
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If Jupiter is made of hydrogen and helium, how is it so dense?
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Its enormous gravitational field compresses these gases to the high density.
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What makes Jupiter's rotation rate hard to measure?
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It has no solid surface, so it exhibits differential rotation.
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What is differential rotation?
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rotation in fluid bodies like Jupiter that is different at different locations
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What are the rotation periods of Jupiter's atmosphere at the equator and poles?
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9 hours, 50 minutes and 9 hours, 55 minutes
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How does Jupiter's magnetic field indicate its rotation rate?
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Charged particles accelerating in the magnetic field emit in the radio frequencies, indicating that the core rotates with a period of 9 hours, 55 minutes
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What is the result of Jupiter's rotation on its shape?
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It is flattened, with an equatorial radius of 71500 km and polar radius of 66900 km.
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What is one way Jupiter's interior structure has been determined?
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Its shape isn't flat enough; we need there to be a dense core at the center with a mass of 5 to 10 Earths.
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What are the colors of some of Jupiter's clouds?
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pale yellow, light blue, deep brown, drab tan, and vivid red
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How big is the Great Red Spot and how long has it been spinning?
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twice the size of Earth, 25000 km by 15000 km, and hundreds of years old
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What percentages of Jupiter's atmosphere are hydrogen and helium?
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86.1% and 13.8%
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What gases are present in Jupiter's atmosphere in small concentrations?
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methane, ammonia, water vapor
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Why is there so much hydrogen and helium in Jupiter's atmosphere?
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Its enormous gravitational field can retain these light gases, unlike the gravitational fields of the terrestrial planets.
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What are the names of the bright and dark stripes in Jupiter's atmosphere?
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The light ones are called zones, and the dark ones called belts.
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What is happening in Jupiter's atmosphere's zones and belts?
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Zones have upwelling atmosphere, while belts have downwelling atmosphere.
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What causes the color difference between the zones and belts in Jupiter's atmosphere?
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Zones are higher in the atmosphere, and therefore cooler, so they have different chemical reactions.
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Why are zones and belts long and narrow?
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The rapid rotation rate stretches these high- and low-pressure systems around the globe.
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What is Jupiter's zonal flow?
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the stable pattern of eastward and westward flow of the atmosphere, beyond or countering the regular rotation
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How are the zones and belts related to zonal flow?
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The belts move eastward and the zones move westward, but this picture is a bit over-simplified.
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What happens to zonal flow as one moves away from the equator of Jupiter?
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Flow rates oscillate and generally diminish in magnitude.
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Why doesn't Jupiter have seasons?
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It has a low eccentricity orbit and a rotation axis almost parallel to its axis of revolution about the sun.
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How is elevation in Jupiter defined?
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There is no solid surface, so the top of the troposphere is given a altitude of 0 and most of the atmosphere is at negative altitudes.
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What occurs above Jupiter's troposphere?
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Photochemical reactions take place at 110 K.
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What are Jupiter's three cloud layers?
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ammonia ice, ammonium bisulfide ice, and water ice
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What is the color, temperature and depth of the ammonia ice clouds on Jupiter?
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white, 125-150 K, -40 km
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What is the color, temperature and depth of the ammonium bisulfide ice clouds on Jupiter?
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tawny, 200 K, -60 km
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What is the color, temperature and depth of the water ice clouds on Jupiter?
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white, 270 K, -80 km
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What elements are thought to be essential in the coloring of Jupiter's clouds?
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sulfur and possibly phosphorus
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What makes Jupiter's cloud chemistry hard to decipher?
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The atmosphere is always moving, and each color is sensitive to numerous conditions.
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What measurements were used to discover most of Jupiter's atmosphere?
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Voyager
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What surprising feature did the probe Galileo discover when it was crashed into Jupiter?
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Winds persist to -150 km, where the probe was crushed by atmospheric pressure.
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What molecules did the probe Galileo discover and not discover when it was crashed into Jupiter?
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ethane and phosphine, but no complex organic molecules or bacteria
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Why was the probe Galileo unable to make any measurements on Jupiter's clouds?
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It happened to fall into an uncommon hole in Jupiter's atmosphere.
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When and by whom was the Great Red Spot first found?
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in the mid-17th century by Robert Hooke
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What is thought to stabilize the Great Red Spot?
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Zonal flow around it could stabilize it, as it flows counterclockwise around the spot.
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What are the two examples of storms of a smaller scale than the Great Red Spot?
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white ovals and brown ovals
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Describe white ovals.
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They are smaller than the Great Red Spot, they rotate counterclockwise, have high cloud tops, and are at least 40 years old.
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Which direction does the Great Red Spot rotate?
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counterclockwise
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Describe brown ovals.
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They are holes in the clouds that only exist around 20°N and are smaller and shorter-lived than the Great Red Spot.
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What were the theoretical and experimental values for the temperature at the top of Jupiter's clouds?
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105 K and 125 K
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Why does the temperature at Jupiter's cloud tops matter?
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It indicates the emission rate; it means that Jupiter emits about twice as much energy as it receives from the sun, so it has its own heat source.
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What is Jupiter's heat source?
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gravitational energy released when it formed
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What effect does Jupiter's extra radiative loss have on temperature?
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a very small one, around a millionth of a Kelvin per year
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Where does much of our knowledge of Jupiter's interior come from?
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theoretical modeling and the collision of a comet in 1994
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Why are we fairly confident about our theoretical models of Jupiter?
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It mainly consists of two gases we know well, hydrogen and helium.
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What are the layers of Jupiter's interior from outside to inside?
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liquid molecular hydrogen, metallic hydrogen, and a rocky (chemically) core
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What is the depth, temperature, and pressure of the outside of the liquid molecular hydrogen layer in Jupiter's atmosphere?
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100 km, 300 K, 10 atm
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What is the depth, temperature, and pressure at the molecular hydrogen/metallic hydrogen boundary of Jupiter's interior?
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20k km, 11k K, 3M atm
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What is the depth, temperature, and pressure on the outside of Jupiter's rocky core?
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60k km, 25k K, 12M atm
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What is the depth, temperature, and pressure in Jupiter's center?
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70k km, 40k K, 50M atm
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Why is the metallic hydrogen layer in Jupiter's interior important?
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It is an excellent conductor of electricity, making Jupiter's magnetic field.
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What on Earth is analogous to Jupiter's magnetosphere?
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the Van Allen belts
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Why is Jupiter's magnetosphere so dangerous?
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It has charged particles accelerated to relativistic speeds that can damage sensitive electrical equipment.
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How far across is Jupiter's magnetosphere?
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30 million km, bigger than the Sun
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How far behind the planet (from the Sun) does Jupiter's magnetosphere extend?
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over 4 AU, through Saturn's orbit
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How close to the planet is Jupiter's magnetosphere?
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3 million km, close enough to generate huge aurorae at Jupiter's poles
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What is the structure of Jupiter's outer magnetosphere?
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unstable, expanding and contracting with gusts in the solar wind
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What is the structure of Jupiter's inner magnetosphere?
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a flat current sheet lying on the magnetic equator
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What angle is Jupiter's magnetic axis inclined to its rotation axis?
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10°
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Which way do magnetic field lines point around Jupiter?
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from north to south, opposite Earth
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How many times stronger is Jupiter's magnetic field than Earth's?
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20k times
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As of 2007, how many satellites does Jupiter have?
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63
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From interior to exterior, name Jupiter's four Galilean moons.
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Io, Europa, Ganymede, Callisto
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What shape do the orbits of the Galilean moons have?
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all are nearly circular
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What spacecraft have flown by and taken pictures of the Galilean moons?
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Voyager I in 1979 and Galileo in the late 1990s
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How many moons of Jupiter lie within Io's orbit?
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four
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How were the Amalthean moons discovered?
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E. E. Barnard found Amalthea in 1892, and the other three were seen by Voyager I.
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Describe Amalthea.
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irregularly shaped, less than 300 km across, orbits with synchronous rotation, very close to Jupiter's cloud tops
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What are the biggest moons lying outside the Galileans that were discovered before the Voyager missions?
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There are eight of them: four that rotate regularly around 11 million km from Jupiter and four that rotate in retrograde fashion around 22 million km from Jupiter.
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What is the most likely origin of the extra-Galilean moons of Jupiter?
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They probably are fragments of two large asteroids or comets that were captured by Jupiter.
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How are the Galilean moons similar to the inner solar system?
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They rotate directly, in roughly circular orbits, close to Jupiter's equatorial plane, decrease in density from Io to Callisto, and have some similar layering
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How are the Galilean moons different from the inner solar system?
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They are all locked synchonous rotation, and have a 1:2:4:~8 period ratio, indicating resonance
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What is Io's claim to fame?
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It is the most geologically active object in the entire solar system.
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What properties of Io are similar to Earth's moon?
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mass and radius, so density, but that's it
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What colors are found on Io?
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red, yellow, and blackish browns
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How many active volcanoes have been identified on Io?
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more than 80
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What temperatures are Io's lava found to be at?
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Most are 650-900 K, but some are as high as 2000 K.
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Why are no dents or cracks found in Io's surface?
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The constant volcanic eruptions produce lava that fills it in, making for a smooth surface.
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Why is Io orange?
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sulfur compounds in lava
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Which moon of Jupiter influences its magnetosphere the most?
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Io
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What is Io's atmosphere made of, and why?
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sulfur dioxide, likely from the volcanic eruptions
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What role does Io have in Jupiter's magnetosphere?
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It produces many heavy ions to the inner magnetosphere, the Io plasma torus.
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Why is the Io plasma torus important?
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It is a hazard to spacecraft with lethal radiation levels.
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What powers Io's volcanism?
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Jupiter produces strong tidal forces on Io that lock it into synchronous orbit, but Europa constantly tugs it, producing wobbles that heat Io's interior, generating 100 terrawatts.
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What does Europa's surface indicate?
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It has relatively few craters, indicating geologic youth.
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What is the surface of Europa made of?
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It has been theorized, and verified so far, that a vast ocean with a frozen ice layer on top covers Europa.
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What evidence supports the existence of Europa's ice and water surface?
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Liquid water would cover up craters in the ice, and Europa's weak magnetic field, caused by Jupiter's acting in the saltwater, is consistent with this interpretation.
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What is Europa's claim to fame?
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It's the only other place in the solar system with liquid water; it could have life...
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How far are the Galilean moons from Jupiter?
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Io 420k km, 5.9 Jupiter radii
Europa 670k, 9.4 Ganymede 1.1M, 15 Callisto 1.9M, 26 |
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What is Ganymede's claim to fame?
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It is the biggest moon in the solar system and even bigger than Mercury!
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What is analogous between Ganymede and our own moon?
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Dark regions like Galileo Regio are like highlands, lighter-colored parts are like maria, with liquid water corresponding to lava.
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What is not analogous between Ganymede and our own moon?
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Ganymede has faultlines like Earth's, has a very faint magnetosphere, and might have some slushy water on its surface.
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What did Galileo's measurements indicate about Ganymede that contradicted past theories?
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The "younger" sections might be so heavily cratered that they appear smooth, which would make Ganymede much older.
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How is Callisto different from Ganymede?
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Callisto has more craters and fewer fault lines.
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What is the most obvious feature of Callisto?
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Valhalla, a basin with concentric ridges on either side, and a similar basin opposite Valhalla and Jupiter
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How did Valhalla likely form?
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an asteroid or comet impact
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What indicates that Callisto was never molten?
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It is not differentiated, and no faults or grooves appear in its surface.
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What challenges scientists' assumptions about Ganymede?
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It is structured and has a magnetic field, indicating melting at some point recently, after crater impacts and radioactivity could have heated it.
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What is one theory postulated about Ganymede's late melting?
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If Ganymede shifted into the 1:2:4 resonance system around a billion years ago, it might have released enough energy to melt the interior of the moon.
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Which spacecraft discovered Jupiter's ring?
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Voyager 1
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How far does Jupiter's ring extend from the planet's clouds?
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50000 km
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