Physics 9 The Solar System Prof. D. Tytler

Final December 5 2000

Please use your code number, NOT NAME. Please write an A after your code number.

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  1. What is the largest body in the Solar System?
  1. Zodiac
  2. Orion constellation
  3. Sun
  4. Earth
  5. Jupiter
  1. Which planet orbits most slowly around the Sun?
  1. Pluto
  2. Jupiter
  3. Mercury
  4. Venus
  5. Saturn
  1. Which planet has the shortest year?
  1. Venus
  2. Earth
  3. Mars
  4. Neptune
  5. Mercury
  1. What causes a planet to have seasons?
  1. Size and shape of its orbit
  2. Speed of rotation about its axis
  3. Solar weather patterns
  4. Orientation of rotation axis
  5. Composition of planet
  1. Jupiter possesses a gigantic magnetosphere. If it were visible from Earth, it would dwarf the apparent size of the Moon. Imagine that you knew the diameter of the magnetosphere in km, and its apparent angular size in the sky. Which formula would tell you haw far away Jupiter is?
  1. F = GMm/r2
  2. P2 = A3
  3. F = ma
  4. q = R / D
  5. v = D / T
  1. Why can you sometimes see the dark regions of a crescent moon?
  1. you cannot
  2. Moon reflects ambient starlight
  3. Interaction of Earth's radiation belts with Lunar Magnetic Field
  4. Light reflects off of sun facing side of Earth
  5. Reflection of city lights
  1. From the Earth, you observe a moon of Saturn is in approximately full phase. Approximately what phase does a person see from Saturn?
  1. New
  2. First Quarter
  3. Third Quarter
  4. Full
  5. any of the above – Saturn is so far away from the Sun and Earth that what an Earth based observer sees is almost what an observer "standing" on the Sun would see, and this is always full phase no matter where the moon is in relation to Saturn.
  1. How did we determine the surface composition of Pluto?
  1. Analysis of the light it reflects
  2. From the total density of the planet
  3. Measurements of surface samples in the laboratory
  4. From the shape of the craters.
  5. From its temperature.
  1. A large gas giant planet forms out of a cloud of gas and dust. During the formation process, two moons form, one close to the planet, the other farther away. All else equal, which moon most likely becomes tidally locked with its parent planet first?
  1. Inner Moon – tides, which changes of gravity, are highly sensitive to distance; roughly speaking, if the outer moon is twice as far away, it experiences one-eighth the effect, so clearly the strength of the effect drops off rapidly with distance
  2. Outer Moon
  3. Nearly the same time.
  4. Insufficient information.
  5. ---
  1. A JPL team constructs a satellite. Which of the following would give its mass?
  1. apply a known force, measure its acceleration
  2. drop it from a height of 1 meter above the surface of the earth
  3. measure deflections in its trajectory as it nears a planet
  4. place it in orbit at a given altitude and measure its period of revolution
  5. find its weight on a asteroid of unknown mass.
  1. What can you deduce from the mass and composition of an object?
  1. it's approximate size – composition (gas, ice, rock, metal) determines density; from mass and density you can compute volume; volume is proportional to size
  2. how far away it is
  3. how fast it is moving
  4. spin period
  5. it’s orbit around the Sun
  1. An astronomer a single still image of an object in which no motion is apparent. The Astronomer uses a telescope that has a given angular resolution of some number of degrees. Angular resolution means any object that appears smaller than that number of degrees cannot be magnified and looks like a point. What can the Astronomer determine about the distance to the object?
  1. Nothing, the Astronomer can't see it and so can't determine anything
  2. the minimum distance to the object – you know q = R / D ; you know the object must have some size, or radius, R ; thus, if the object appears smaller than the angle of the telescope’s angular resolution, you know it must be far enough away that R / D is less than qangular resolution. But if its twice that, thrice that, or a million times that far away, its impossible to know with just the information that’s provided.
  3. The distance to the object must be increasing
  4. The distance to the object must be decreasing
  5. –
  1. A comet has a 32 year period. Is it always farther from the sun than the earth?
  1. Yes, from Kepler's Law
  2. It depends on the shape of the orbit – the class example of Temple-Tuttle, which creates the Leonid meteor showers every November, has a period roughly 30 years long. Clearly, tho, the Earth’s orbit and the meteor’s orbit must intersect – otherwise we wouldn’t see the meteor showers ‘cause we wouldn’t run into the meteor debris trail
  3. It is always closer to the Sun than the Earth
  4. It depends whether the comets orbit lies in the plane of the ecliptic
  5. Depends on the spin of the comet
  1. If you observe a lunar eclipse today, when is the soonest you might observe the next solar eclipse?
  1. 1 day
  2. 1 week
  3. 1 fortnight (2 weeks)
  4. 1 month
  5. 1 year
  1. Comets get brighter as they move closer to the Sun. So why isn't it always easier to observe comets when they are 1/10 AU from the Sun versus when they are 2 AU away?
  1. It is always easier to observe comets that are 1/10 AU versus 2 AU from the Sun
  2. Comets 1/10 AU from the Sun are obscured by the bright Earth Sky – think of Mercury or Venus, which are always so close to the Sun that they’re overhead during the day when they’re obscured by the bright blue sky and are thus invisible
  3. Comets 2 AU from the Sun are usually directly behind the Sun
  4. Most comets burn out by the time they reach 1/10 AU
  1. Which is the most common element in the universe?
  1. Uranium
  2. Californium
  3. Berkelium
  4. Einsteinium
  5. Hydrogen
  1. We observe that the sun's rays are essentially parallel when they reach the Earth. What does this imply?
  1. The sun is very small
  2. The side of the Sun that faces the Earth is nearly flat
  3. Compared to its size, the Sun is very far away (that is, the ratio Diameter:Distance is small) – it’s not just distance that matters, but relative distances. If you look at a small object up close, or a big object far away, they both look about the same size. That size determines how parallel the rays are when the hit the Earth.
  4. Earth's atmosphere focuses the Sun's rays
  5. Earth's gravity bends the light rays
  1. What was profound about Galileo's observations of Jupiter?
  1. Strongly supported Copernicus's Geocentric Model of the Universe
  2. Proved that a rock and a cannon ball fall at the same rate
  3. Provided convincing evidence of extraterrestrial center of motion – Jupiter and its moons clearly demonstrated that Earth (terra) was not the center of all motions in the universe.
  4. Explained retrograde motion
  5. First evidence of planetary ring systems
  1. The four Galilean moons of Jupiter, ranked in order of increasing distance from Jupiter, are Io, Europa, Ganymede and Callisto. Which revolves most rapidly about the planet?
  1. Io
  2. Europa
  3. Ganymede
  4. Callisto
  5. They all orbit at nearly the same velocity
  1. Which of the following observations of Venus is (are) not explained in the Geocentric model?
  1. The angular size variation
  2. Cycle of Phases
  3. Retrograde motion
  4. Orbital period
  5. Both a) and b) – check out lecture notes or Chapter 1 of text
  1. Which of the following quantities would be most valuable for estimating the size of the craters produced by asteroids?
  1. Kinetic Energy (energy of motion) of asteroid
  2. Volume of asteroid
  3. Density of asteroid
  4. Shape of asteroid
  5. Composition of asteroid
  1. The inner most moon of Jupiter is Io. During the course of a single orbit about the planet -- 41 hours -- Io interacts with Jupiter and the other 3 Galilean moons. As a result of these interactions, parts of Io's surface rise and fall more than 300 feet. This is an example of:
  1. Moonquakes
  2. Solar Heating
  3. Tides – called ground swells; there’s also ground swells on the Earth amounting to roughly 10 cm (4 inches)
  4. Centrifugal forces
  5. Rock expanding as it cools
  1. Which of the following sets of quantities would allow you to determine the total amount of energy Jupiter receives from the Sun. Assume you also know the Sun's luminosity, but nothing else about Jupiter.
  1. The size of Jupiter
  2. The length of the Jovian day
  3. The length of the Jovian year
  4. both a & b
  5. both a & c – size determines how much area the planet has that can absorb energy; length of the Jovian year is related, via P2 = A3 , to how far it is from the Sun
  1. Which of the following is most important in determining the surface temperature of a planet?
  1. Mass
  2. Density
  3. Distance from the Sun
  4. Spin Period (length of its day)
  5. Number of Moons
  1. A giant planet is discovered that orbits a distant star. Its density is determined to be 0.9. Which of the following bodies would you expect to be most similar in terms of composition?
  1. Sun
  2. Earth
  3. Pluto
  4. Mars
  5. A meteoroid
  1. Why are Aurora most easily seen near the North and South poles on the Earth?
  1. The air is coldest near the poles.
  2. The atmosphere is thinnest above the poles.
  3. The magnetic field lines are directed towards the Earth's surface in those areas.
  4. The sky is darkest above the poles.
  5. There is no magnetic field near the poles.
  1. What can be determined from the precise shape of Pluto's orbit?
  1. The location and mass of an undiscovered outer planet – unexplained changes of the orbit would indicate this
  2. The mass of the Sun – this is a lot like the JPL satellite question above; as we learned about Gravity, the gravitational attraction of any object always causes all other objects to accelerate towards it at the same rate; thus, if Pluto were half, twice, or 10 times its mass, the Sun would cause it to move the same way, and thus its impossible to know about the planet’s mass
  3. The number of comets in the Kuiper belt
  4. The distance to the nearest star
  5. Pluto's mass (pretend that Pluto does not have a moon)
  1. Three percent of stars that are similar to the sun (in mass, luminosity and surface temperature) have giant planets with about Jupiter's mass, and orbital periods of a few days. Why was this discovery a surprise?
  1. We had thought that Jupiter mass planets can form only far from a star where it is cool enough for ice to solidify.
  2. We expected nearly all stars to have such planets
  3. Such orbits are not permitted by Newton's Law of Gravity
  4. Other types of stars do not have such planets
  5. Planets with such high masses should be rare in all stellar systems
  1. The four gas giant planets are all warmer than would be expected if they were heated by the sun alone. For the case of Saturn, it is believed that Helium differentiates from the Hydrogen to produce the extra heat energy. What is the analogous process for terrestrial planets?
  1. Iron and nickel sinking through rock material
  2. Unstable atoms decaying
  3. Subduction, where one tectonic plate slides under another and sinks into the mantle
  4. Earthquakes produced when unstable rock layers slide past each other
  5. Magma rising through vents in crust
  1. Green House Effect: The atmospheres of planets can act as thermal blankets because they ________ the high-energy light of the Sun and __________ the low energy light radiated by the planet.
  1. pass : pass
  2. pass : absorb – comes in, gets trapped, can’t go anywhere
  3. absorb : pass
  4. absorb : absorb