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AST CH. 7 – Space

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Which of the following is not an exception to the general patterns of motion in the solar system?
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C) the rings of Saturn
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2- Why did the solar nebula heat up as it collapsed?
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B) As the cloud shrank, its gravitational potential energy was converted to thermal energy.
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3- Why did the solar nebula flatten into a disk?
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D) It flattened as a natural consequence of collisions between particles in the nebula, changing random motions into more orderly ones.
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4- According to our theory of solar system formation, why do all the planets orbit the Sun in the same direction and in nearly the same plane?
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C) The laws of conservation of energy and conservation of angular momentum ensure that any rotating, collapsing cloud will end up as a spinning disk.
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5- Which of the following is the origin of almost all the large moons around the jovian planets?
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D) They were formed by condensation and accretion in a disk of gas around the planet.
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6- Which of the following has not been detected around other stars in the Galaxy?
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D) terrestrial planets
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7- According to our theory of solar system formation, why do we find some exceptions to the general rules and patterns of the planets?
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B) Most of the exceptions are the result of giant impacts or close gravitational encounters.
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8- Based on our current theory of Earth’s formation, the water we drink comes from
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E) comets that impacted Earth.
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9- The nebular theory of the formation of the solar system successfully predicts all but one of the following. Which one does the theory not predict?
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C) the equal number of terrestrial and jovian planets (with the exception of Pluto)
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10- The age of the solar system can be established by radioactive dating of
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C) the oldest meteorites
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11- What do meteorites reveal about the solar system?
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D) They reveal that the age of the solar system is approximately 4.6 billion years.
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12- Which of the following methods has led to the most discoveries of massive planets orbiting near their parent stars?
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C) detecting the gravitational effect of an orbiting planet by looking for the Doppler shifts in the star’s spectrum
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13- Planets detected via the Doppler technique have been mostly
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C) Jupiter-mass, in very close orbits.
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14- What is astrometry?
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C) measuring the positions of stars on the sky
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15- The astrometric technique of planet detection works best for
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B) massive planets around nearby stars.
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16- The transit method of planet detection works best for
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A) big planets in edge-on orbits around small stars.
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17- Most of the planets discovered around other stars
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B) are more massive than Earth and orbit very close to the star.
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18- How do we think the “hot Jupiters” around other stars were formed?
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C) They formed as gas giants beyond the frost line and then migrated inwards.
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19- Which of the following is a consequence of the discovery of hot Jupiters for the nebular theory of solar system formation?
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C) It has been modified to allow for planets to migrate inwards or outwards due to gravitational interactions.
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20- How do scientists estimate how old the solar system is?
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C) They measure the abundances of radioactive elements in meteorites, and use their half-lives to calculate the age.
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21- Hot Jupiters were a surprise to astronomers. What is the current explanation for their existence?
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B) Jupiters are supposed to form far away from their host star, then they migrate closer through gravitational interactions with the protoplanetary disk.
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22- Which of the following statements best explains why the planets orbit in nearly a single plane and in the same direction around the Sun?
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A) The planets formed from a disk of rotating gas.
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23- Which of the following hypothetical discovery would force us to modify or discard our most current nebular theory?
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A) A star with 5 planets, orbiting in different directions
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24- As the solar nebula shrank in size three processes altered its density, temperature and shape, changing from a large diffuse cloud to a much smaller spinning disk. Which of the following is not one of this processes:
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D- Convection
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25- Which of the following is not true:
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C- The four inner planets formed through the collisions of Moon-sized bodies, at the same time that the Sun was formed.
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26- As an interstellar cloud of hydrogen gas shrinks in size, its rate of rotation
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A) increases, because its angular momentum is conserved.
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27- As an interstellar cloud of hydrogen gas shrinks in size, its temperature increases,
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A) because gravitational potential energy is converted to thermal energy.
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28- The jovian planets in our solar system are ________.
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A) Jupiter, Saturn, Uranus, and Neptune.
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29- The first planets around other Sun-like stars were discovered
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D) in 1995
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30- What are the two main differences between extrasolar planetary systems discovered to date and our Solar System?
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C) Extrasolar planet orbits tend to be closer and more eccentric than in our Solar System.
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31- Why are many of the newly detected extrasolar planets called “hot Jupiters”?
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C) Their masses are similar to Jupiter but they are very close to the central star and therefore hot.
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32- Where did the elements that formed planets come from?
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C) They were produced inside stars.
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33- How do we know that extrasolar planets are orbiting other stars?
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D) Both a and b above.
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34- What are the general characteristics of the extrasolar planets discovered so far?
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C) They have high mass and orbit close to their stars.
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35- How is the solar nebula theory supported by the motion of Solar System bodies?
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D) All of the above.
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36- Which of the following is NOT a property associated with terrestrial planets?
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D) They have low density.
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37- Where are most of the asteroids located?
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D) Between the orbits of Mars and Jupiter.
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38- Radiometric dating of rock samples indicates that the Solar System formed about 4.56 billion years ago. Which rock samples have this age?
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C) Meteorites.
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39- The following is the way that solar nebula theory accounts for the drastic differences between terrestrial and Jovian planets, except ______.
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E) All terrestrial planes emigrate after giant impacts
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40- How does the solar nebula theory explain the formation of an asteroid belt between Mars and Jupiter, rather than a planet at this location?
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D) Jupiter formed early, and its gravitational influence altered the orbits of nearby accreting planetesimals such that their collisions became destructive rather than constructive.
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41- How do scientists estimate how old the solar system is?
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C) They measure the abundances of radioactive elements in meteorites, and use their half-lives to calculate the age.
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42- Which of the following statements about our Sun is not true?
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A) The Sun’s diameter is about 5 times that of Earth.
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43- The terrestrial planets in our solar system are ________.
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A) Mercury, Venus, Earth, and Mars
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44- In essence, the nebular theory holds that ________.
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A) our solar system formed from the collapse of an interstellar cloud of gas and dust
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45- According to our theory of solar system formation, what three major changes occurred in the solar nebula as it shrank in size?
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A) It got hotter, its rate of rotation increased, and it flattened into a disk.
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46- What do we mean by the frost line when we discuss the formation of planets in the solar nebula?
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A) It is a circle at a particular distance from the Sun, beyond which the temperature was low enough for ices to condense.
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47- What do we mean by accretion in the context of planet formation?
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A) The growth of planetesimals from smaller solid particles that collided and stuck together
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48- According to our theory of solar system formation, what are asteroids and comets?
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A) Leftover planetesimals that never accreted into planets
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49- Which of the following discoveries would cause us to re-evaluate the nebular theory for forming planets?
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A) A star’s 5 terrestrial planets orbit in the opposite direction of its 3 jovian planets.
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50- Which of the following lists the planets of our solar system in the correct order from closest to farthest from the Sun?
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A) Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune