The Solar System Assignment#5 Name _______________________
I.D.# _______________________
·
Circle the
correct multiple choice answer.
·
Use back
of page for numerical calculations if necessary … but
·
Write final
numerical answer on underline provided with question.
· Use space provided to answer non-numerical questions.
Chapter 12 Jupiter
1. An argument that Jupiter and the Sun
have a common origin is _______.
(a) Jupiter has a great red spot and the Sun has sunspots.
(b) Jupiter rotates very rapidly, like the Sun.
(c) Jupiter has belts and zones in its atmosphere, like the Sun.
(d) Jupiter is composed mostly of hydrogen and helium, like the Sun.
(e) Nuclear fusion in its core generates Jupiter’s excess heat that it radiates into space.
2. Jupiter is a huge planet that contains an enormous amount of hydrogen and helium that gathered together by gravitational collapse during the formation of the planet. As the hydrogen and helium collapsed together, the loss of gravitational energy of this material was converted into random kinetic energy of motion (the hydrogen and helium molecules picked up speed). This random energy of motion is called thermal energy and much of this heat is still retained by the planet. It is called “original heat of formation.” However, all objects warmer than their surroundings eventually cool by radiating infrared light (heat). This heat slowly escapes and ________.
(a)
is the source of the thermal radiation that it
radiates into space in excess of that which it continually receives from the
Sun
(b)
when
it’s gone, Jupiter will completely disappear as a black hole
(c)
will
eventually heat Mars up enough that it will become a possibly habitable planet
(d)
will
cause the atmosphere of Jupiter to heat up and slowly leak away into space
(e)
in the
future, could be used by a more technologically advanced civilization on Earth
as a virtually unlimited source of energy
(a) winds … gravitational
(b) van Allen belts … centrifugal
(c) magnetic fields … electromagnetic
(d) gasses … frictional
(e) convection cells … Coriolis
4. Liquid metallic hydrogen is hydrogen under such tremendous pressure that it becomes liquid. It is metallic because the hydrogen atom has one outer electron, just like metals do, and in the liquid or solid state, hydrogen can be tremendously conductive due to the freedom of this outer electron to easily move from one nearby atom to another. In Jupiter’s case, because this conductive hydrogen lies inside a rapidly rotating planet, it _________.
(a) cannot be detected by any known means
(b) will eventually get flung outward from Jupiter’s axis of rotation and blow the planet apart
(c) will generate strong electric currents that would electrocute any astronaut foolish enough to land on its surface
(d) acts like an electric dynamo that generates its enormously strong magnetic field
(e) periodically causes surface eruptions that spew large amounts of liquid hydrogen onto Io, its nearby Moon, which constantly erodes its craters
5. If Jupiter emitted exactly as much
energy (as infrared radiation) as it receives from the Sun (as most planets
do), the average temperature of the planet’s cloud tops would be about 107
K. Given that Jupiter actually emits
twice as much energy as it receives from the Sun, find what this average
temperature must actually be (hint:
see text, p.101, Chapt 5).
6. Use orbital data for the Jovian
satellite, Elara (see Appendix 3)
and calculate the mass of Jupiter. _______________________________________
Saturn
7. During the planning stages for the Pioneer 11 mission, when relatively
little was known about Saturn’s rings, it was proposed to have the spacecraft
fly through the Cassini division. … Good
or bad idea? … and why?
(a)
Bad … Pioneer 11 would be torn apart by Saturn’s tremendous tidal forces if
it got that close to Saturn. That’s why there’s nothing in the Cassini
division.
(b)
Bad … the Cassini division provides the only safe route through Saturn’s
rings but the spacecraft would pass too close to Saturn and fall in.
(c)
Good… Voyager 1 easily made it
through the Cassini division, so the likelihood is great that Pioneer 11 would make it through also.
(d)
Good … if you’re going to get close enough to the ring system to examine it in
detail, it’s the only possible way to do it.
(e)
Bad …
the Cassini division is not empty. It is
filled with many small particles that could damage a spacecraft that attempted
a fly through.
8.
Small objects are bound together primarily by chemical bonds
which are based on electromagnetic forces --- not gravity. Chemical bonds have a short range due to the
overall electrical neutrality of matter.
In other words, atoms interact with their nearest neighbors only and not
those far away. Thus, structures held
together primarily by chemical bonds can take on irregular shapes, like you and
me. On the other hand, gravity acts on neutral matter and is a long range
force. An atom anywhere on Earth
interacts gravitationally with every other atom on Earth (and, indeed, with
every other atom in the universe). You can always tell when gravity is the
dominant force holding together any structure.
The structure must be large and when large enough that gravity dominates
other types of forces because of the multiplicity of small interactions, it
will naturally assume a spherical shape.
The Roche limit only applies to objects held together primarily by
gravitational forces. Small structures
held together primarily by chemical bonds are too strongly bound to be ripped
apart by differential gravitational (tidal forces) except under the extreme
gravitational conditions that occur near a neutron star or black hole. This description of chemical bonds and
gravitational forces explains why _______.
(a)
artificial
satellites can orbit the Earth at distances on the order of 150 miles above its
surface.
(b)
the Moon
can orbit the Earth at distances on the order of 239,000 miles above its
surface.
(c)
even
dense objects like neutron stars can get swallowed up by black holes if they get
near enough to them.
(d)
the
Roche limit isn’t really a “good” limit.
(e)
gravity
is the strongest of the four known fundamental forces in nature.
9. Shown in the accompanying figure are two satellites orbiting Saturn. Their orbits are represented by the dashed lines. A hypothetical ring particle orbits in the region between them. Its orbit is represented by the solid line. The speed and direction of the motion of these objects when they are lined up together is indicated by the arrows. A long arrow means that the object is moving fast … a shorter arrow means that the object is moving more slowly.
The outer satellite moves more slowly than does the ring particle, which moves more slowly than the inner satellite. If the ring particle migrates outward towards the outer satellite, it will eventually pass it by and when it does so, the outer satellite will pull back on the passing particle causing it to lose energy and start to spiral inward. The reverse happens when the ring particle migrates too far inward. The inner satellite eventually passes it and pulls it forward, giving it some energy, which causes it to spiral outward. Thus, the satellites act to confine, or focus, ring particles to a narrow region within the orbital radii of the two satellites. ________.
(a)
The two satellites will eventually collide and
the resulting fragments will add to the ring changing it from a narrow one to a
wide one.
(b)
The two satellites eventually focus the ring
particles into such a narrow space that the collide, lose energy, fall into
Saturn, leaving a gap in the ring system.
(c)
Saturn’s F-ring is the result of the behavior of
the two shepherd satellites, Prometheus and Pandora, like the ones described
above.
(d)
The Cassini division is the result of the
behavior of two satellites, Achilles and
(e)
The two satellites will eventually be positioned
180 degrees on either side of Saturn and the ring will disperse.
10. All Galilean satellites orbit Jupiter in the same direction (CCW) in the same plane. They are so close to Jupiter that they are tidally locked to it, i.e., their orbital period and rotational periods are identical --- like our Moon’s. Their densities decrease with increasing distance. The outer two satellites, Ganymede and Callisto, have densities that are quite a bit lower than those of the inner two satellites, Io and Europa. Their composition is dominated by ices. This is analogous to the change in composition that occurs between the terrestrial and Jovian planets. The inner two satellites are geologically active. Io is the most geologically active member of the solar system. Indeed, many volcanoes are erupting on it at any given time! Europa shows evidence of plate tectonics probably because it is heated internally and its crust rests on liquid water. Io exhibits no craters and Europa’s surface is very smooth except for thin cracks, due to its plate tectonics. Ganymede also shows evidence of tectonic fractures but its surface is also heavily cratered indicating that it is no longer geologically active. Callisto is far enough away from Jupiter that it froze up long ago in the past. It is not geologically active now and hasn’t been for quite some time as evidenced by its large number of craters. The Galilean moons are therefore “sequenced” relative to Jupiter, much like the planets are “sequenced” relative to the Sun, except ______________.
(a) they don’t have any life on, or in, them.
(b) they formed much later than the rest of the solar system, as evidenced by the fact that Io and Europa have no craters
(c) the largest Galilean satellite is not a Jovian
(d) they condensed and formed mostly from rock and ice as opposed to metal and rock and ice
(e) their orbital plane is not in, or closely aligned with, the plane of the ecliptic.
11. What is the source of energy that powers
Io’s volcanoes?
(a) radioactive decay
(b) original heat of formation
(c) heat released when Io differentiated
(d) plate tectonics
(e) tidal flexing
12. What is the evidence for liquid water, possibly
as extensive as a global ocean, beneath Europa’s icy surface?
(a) A thin atmosphere was discovered around Europa that contained water vapor.
(b) The cameras on board the Galileo orbiter showed fish-like creatures swimming below the thin icy crust.
(c) It is completely covered with thin cracks showing fresh ice. The surface is remarkably smooth indicating an active geology, which implies that it still has a lot of internal heating. It also has “ice rafts,” much like Antarctic ice, that were formed by folding and breakup as happens with tectonic action.
(d) Probes to Europa’s surface from the Galileo orbiter drilled holes thru its thin crust and inserted thermometers which measured a temperature of 285 K, warm enough for water to be liquid.
(e) none of the above is good evidence for the presence of liquid water there.
13. What was the reason(s) that scientists
were surprised when they discovered that Ganymede has a magnetic field?
(a) Ganymede is tidally locked to Jupiter; therefore, it does not rotate.
(b) Ganymede could not possibly have an iron core; its density is too low.
(c) Its icy surface is electrically conductive, so any internally generated magnetic field could not escape the surface.
(d) Even though Ganymede is a large moon, it is small enough that it has lost its original heat of formation. Also, it couldn’t have enough radioactive elements in its core to generate much heat. Furthermore, it is far enough away from Jupiter that it cannot be heated much by tidal forces. Absent much internal heat it was not expected that any electrically conducting material could be in motion inside Ganymede that could generate much of a magnetic field.
(e) Ganymede’s orbit is synchronous with that of Europa and Io, in 1:2:4 ratios. Such synchronicity always destroys magnetic fields.
14. Why are numerous impact craters found on
Ganymede and Callisto but not on Io or Europa?
(a)
Io and Europa are geologically active so that
old surface features do not last long.
Ganymede and Callisto are geologically dead so that its surface features
are not continually modified.
(b)
Ganymede and Callisto are the outer Galilean
moons and they were impacted by all of the meteors in the nearby vicinity
during the period of heavy bombardment.
None were left that could impact the inner Galilean moons, Io and Europa.
(c)
Ganymede and Callisto are the two largest
Galilean moons and therefore were struck by meteors much more frequently than
Io and Europa.
(d)
Ganymede and Callisto are large enough to
support active volcanoes, which create the craters; Io and Europa are too
small.
(e)
There
are lots of craters on Io and Europa; we just haven’t sent any probes near
enough to see them.
15. The ______ is a doughnut-shaped plasma ring of electrons, sulfur ions and oxygen ions knocked out of Io’s volcanic plumes by rapidly moving charged particles in Jupiter’s magnetosphere.
(a)
Ionic
pentameter
(b)
Io torus
(c)
Io
Winchell store
(d)
Io
magnetic field
(e)
Io
electric dynamo
16. How long does it take for Ganymede to
enter or leave Jupiter’s shadow? Assume
that the shadow has a sharp edge.
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Saturn’s Satellites
17. Titan is a large enough and cold enough satellite to retain an atmosphere rich in nitrogen (90%), methane (CH4), and other ________ like ethane (C2H6), acetylene (C2H2), ethylene (C2H4) and propane (C3 H8). The Nitrogen comes from the breakup of _______ by exposure to the Sun’s ultraviolet rays. The hydrogen then escapes into space.
(a)
atoms …
hydrogen cyanide (HCN)
(b)
compounds
… fertilizer
(c)
hydrocarbons
… ammonia (NH3)
(d)
pollutants
… ozone
(e)
oxidized
gasses … nitrous oxides
18. Life began on Earth when a relatively simple polymer (a long chain hydrocarbon molecule made up of linked array of simpler chemical building blocks called monomers) began to increase in number by a rudimentary self-replication process. A self-replicating molecule would quickly become the dominant constituent of its environment and would represent the most primitive form of life. The initial stochastic assembly of a self-replicating molecule requires basic chemical building blocks, like simple hydrocarbon monomers, free to move around in a liquid environment and a source of energy to link them together. About 4 billion years ago on Earth, life likely began near volcanic vents, covered by oceans of liquid water. Hot magma, escaping from these vents, heated the surrounding water and provided the energy needed to assemble the first elementary organic polymers necessary for life. After 4 billion years of evolution, the assembly process has become more sophisticated. It is no longer a stochastic process; it is directed. For example, proteins, the workhorses in our bodies, are polymers formed by the linking together of individual monomers called amino acids. This process is carried out in the medium of liquid water in the cells of our bodies according to the manufacturing instructions coded in DNA. Some of the simple monomers that are necessary for life are known to exist on Titan! Could Titan have ________ covering volcanic vents where heat could escape its interior and power the assembly of more complex organic polymers… much like happened on early Earth? If so, is it possible that an active organic chemistry is taking place below Titan’s surface that could be the precursor of life?
(a) oceans of water
(b) large bodies of liquid methane
(c) a viscous, convective silicate mantle
(d) fractured, movable crustal plates
(e) subduction zone mountain ranges
19. The pressure on the surface of any planet
or moon must be large enough to support the weight of “column mass” of
atmosphere above, it. According to
where
m is the mass of the column of
atmosphere above an area A on the
surface. P is the surface
pressure. “Column mass” is usually
defined to be the mass of the column per unit area, or 
Now, the air
pressure, P, on Titan’s surface is
about 1.6 atm, yet Titan’s surface gravity, g,
is smaller than Earth’s, about 7.3 times smaller in fact. Thus, the column mass of Titan’s atmosphere
(or actual mass of atmospheric material that lies above any square meter on
Titan’s surface) must be much greater than Earth’s in order to generate such a
large surface air pressure. How much
more column mass is there in Titan’s atmosphere compared to Earth’s?
Hint: 
therefore, 
so calculate the ratio 
where the subscripts
should have obvious meaning. This will
be the ratio of the column masses of the 2 atmospheres.
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20. The methane gas in Titan’s atmosphere is
continually broken down by photodissociation and the freed-up hydrogen atoms
then escape the satellite into space. Thus, its atmospheric methane would
completely disappear in a time frame of about 10 7 years if it was
not being continually replenished somehow.
Is there a global ocean of liquid methane that covers Titan’s surface
that is responsible for the continual replenishment of the methane in its
atmosphere… or are there pockets of subsurface frozen or liquid methane? Are there lakes of liquid methane on a mostly
solid, frozen surface? Go to the web and
do a search to find out the latest results from the Cassini - Huygens mission
to Saturn and find the likely answer to this question.
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