AST CH. 7

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