Astronomy Ch. 6 – The Solar System Answers – Flashcards
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The largest asteroid, and probably the only one to be a spherical "world" is
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Ceres.
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Which planet by itself contains the majority of mass of all the planets?
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Jupiter
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Our understanding of the solar system has come in a way that can best be described as:
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explosive, with us learning more in the past few decades than in all previous history.
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What is the goal of comparative planetology?
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to determine the origin and evolution of the solar system
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What is true about solar system densities?
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The denser planets lie closer to the Sun.
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The planet's orbital period is:
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the time it takes to return to the same location in the sky, relative to the Sun.
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Masses of the planets are easiest to determine if:
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they have natural satellites whose motions can be precisely measured.
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The average density of each planet in the solar system is determined by taking its mass and dividing that by its
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volume
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Which of these bodies has the lowest density?
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Saturn
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In order to determine the mass of a planet by applying Newton's laws of motion and gravity, the planet must have
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moons.
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The plane in which almost all planets orbit the sun is called the:
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ecliptic.
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The rotation periods of Venus, Jupiter, Saturn, Uranus and Neptune are difficult to determine because
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their surface features are obscured by their atmospheres.
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Which statement about the motion of the planets is incorrect?
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Most planets move in the Earth's equatorial plane.
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Mercury's most unusual orbital feature, as compared to the other planets, is
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the shape of its orbit.
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What aspects of the planets orbits are nearly the same for most planets?
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shape and tilt from the ecliptic
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Planetary orbits
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are almost circular, with low eccentricities.
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How do the densities of the jovian and terrestrial planets compare?
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All terrestrials are more dense than any of the jovians.
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Which of the following are the Jovian planets?
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Jupiter, Saturn, Uranus, and Neptune only
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In composition and mass and density, Jupiter is most like:
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the Sun.
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Which characteristic listed below describes the jovian planets?
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low density
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Which of the characteristics below describes the terrestrial planets?
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possessing weak magnetic fields
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The jovian planets
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all have rings around their equators.
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Most asteroids are found:
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between the orbits of Mars and Jupiter.
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The Kuiper Belt is found where in the solar system?
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beyond the orbit of Neptune
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In composition and density, the asteroids most resemble:
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pieces of terrestrial planets.
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In composition, asteroids and meteoroids are most like
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terrestrial planets.
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The difference between a meteoroid and an asteroid is the object's
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size.
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The smallest sort of interplanetary matter is called
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interplanetary dust.
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Which of the following is not icy in composition?
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asteroids
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The most detailed look we've had of an asteroid comes from
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spacecraft sent to an asteroid.
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The Kuiper Belt is an "outer asteroid belt" consisting of what types of solar system bodies?
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icy cometlike bodies
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Which of the following have an icy composition?
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comets
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A meteorite is
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a chunk of space debris that has struck the ground.
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Objects in the Kuiper belt
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lie beyond the orbit of Neptune, and close to the ecliptic.
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Which of the following is considered "interplanetary matter"?
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Comet Hale-Bopp
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The tail of a comet always points
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away from the Sun and becomes longest and brightest at perihelion.
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A gravitational "sling-shot":
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changes the speed and direction of a spacecraft nearing a massive planet.
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Which of these spacecraft went into orbit about Saturn in July 2004?
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Cassini
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Which spacecraft gave us our best information about Mercury, until Messenger arrives in 2009?
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Mariner 10
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The best present maps of the surface of Venus come from the:
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Magellan.
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The only spacecraft to be intentionally crashed into Jupiter was:
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Galileo.
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The "Grand Tour" of all four jovians was conducted by:
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Voyager 2.
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Our best close-up views of the jovian moons came from the many passes by:
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Galileo.
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The Mariner 10 spacecraft visited which bodies in the solar system?
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Mercury and Venus
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While Cassini was launched toward Saturn in 2004, its Huygens probe in 2005 went to:
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Titan.
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Which objects in the solar system have been least modified since the formation of the solar system?
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Kuiper Belt objects
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Which of these was the first to cross the asteroid belt and head to Jupiter?
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Pioneer 10
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Which statement about Mercury is not correct?
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Mariner 10 is now dead, but still in orbit about Mercury.
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Which of these landed on Venus?
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Venera 7
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As the solar nebula contracts due to gravitation, the cloud
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spins faster.
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What is the name of the theory that is currently used to describe the formation of the solar system?
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Nebular theory
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The Kuiper Belt is found where in the solar system?
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beyond the orbit of Neptune
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What is the role of irregularities in the solar system in terms of theories of its origin?
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They introduce a need for flexibility in theories of the solar system's origin.
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Which of these is not a characteristic of the solar nebula theory?
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Larger planets should form closer to their star, where there is more debris.
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What might have made the original solar nebula begin to contract?
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the shock wave from a nearby exploding star
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The meteorites that strike Earth are
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the oldest rocks known.
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A successful theory of the formation of the solar system must explain
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all observed properties of the solar system.
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Planetary orbits
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are almost circular, with low eccentricities.
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What is true about solar system densities?
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The denser planets lie closer to the Sun.
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The jovian planets
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all have rings around their equators.
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What phase of planet formation caused the jovian planets to form?
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core-accretion
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What happens when a solar nebula contracts?
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It heats up, It flattens out, It spins faster; all of the above
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In light of modern solar system theory, why do the orbits of the planets all lie in the same plane?
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The early solar nebula flattened into a disk.
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What is the process of accretion?
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growth of an object by the accumulation of matter
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Conservation of angular momentum means that a spinning body tends to
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keep spinning.
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Dust is an important part of the nebular theory of solar system formation because dust is needed to explain
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how the inner planets came to be rocky bodies.
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What factor caused different planets to form out of different types of material?
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The variation in temperature throughout the solar nebula; the higher the temperature, the lower the percentage of light elements in the forming planet.
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What was the primary role of dust in the formation of the solar system?
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Dust acted as condensation nuclei; platforms to which other particles could attach and form larger particles of matter.
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As the solar nebula contracts it
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spins faster due to conservation of angular momentum.
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As a rotating gas cloud contracts, it spins
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faster due to conservation of angular momentum.
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(SA) What are the chemical and physical properties of the solar system that any theory of its origin must explain?
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The inner planets have high densities, moderate atmospheres, and a mostly rocky composition. The outer planets have low densities, thick atmospheres, and a composition of mostly hydrogen and helium. The asteroids are composed of primitive, unevolved material unlike planets and the comets are icy objects that have also remained unchanged since the formation of the solar system.
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(SA) What do Pioneer 10 and 11 and Voyager 1 and 2 all have in common?
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All four of them flew past Jupiter, and all but Pioneer 10 past Saturn as well. All are now moving so fast from the gravity assists that they are far beyond Pluto, and escaping the Sun's gravity entirely, to become eventually lost in interstellar space.
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(SA) Explain the stage in which the solar system formed pretty much in a plane.
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The flat shape of the solar system is explained by the contraction of a slowly spinning cloud in the solar nebula theory.
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(SA) For what reasons do we consider the planets of the solar system to be of two fundamentally different types?
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There are multiple reasons we consider the planets of the solar system to be of two fundamentally different types. The two types of planets we divide our solar system into are: terrestrial planets and jovian planets. The terrestrial planets have low magnetic fields, small number of moons (if any), and are composed of heavier elements like iron. The jovian planets have very strong magnetic fields, a fairly large number of moons, and are composed of lighter elements like hydrogen and helium. These are the basic reasons as to why we categorize our planets into two different types of planets.
