QUIZ: Formation of the Solar System
Mark your answers on the scantron provided
1. In essence, the nebular theory holds that:
a. Our solar system formed from the collapse of an interstellar cloud of gas and
dust
b. It is a discarded idea that imagined planets forming as a result of a nearcollision between our Sun and another star.
c. Nebulae are clouds of gas and dust in space.
d. The planets each formed from the collapse of their own separate nebulae.
2. Strong evidence for the existence of planetary systems in the process of formation
around other stars comes from
a. Photographs and infrared observation of disks of gas and dust.
b. Direct photography of star and planet forming areas
c. Detection of very regular pulses of radio energy from some stars.
d. Spectroscopic evidence of large quantities of molecules such as ammonia
and methane, which can only exist in planetary atmospheres.
3. According to most studies, what was the approximate chemical composition of the
solar nebula?
a. 50 % hydrogen and helium, 50 % everything else.
b. 98 % hydrogen and helium, 2 % everything else.
c. 98 % hydrogen, 2 % helium.
d. Roughly equal proportion of hydrogen, helium, water and methane.
4. According to modern studies of star (and planetary system) formation, which of the
following best explains why the vast majority of the mass of our solar system
consists of hydrogen and helium gas?
a. Hydrogen and helium are the most common elements throughout the
universe, because they were the only elements present when the universe
was young
b. Hydrogen and helium are produced in stars by nuclear fusion
c. All the other elements escaped from the solar nebula before the Sun and
planets formed.
d. All the other elements were swept out of the solar system by the solar wind.
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QUIZ: Formation of the Solar System
5. The terrestrial planets are made almost entirely of elements heavier than hydrogen
and helium. According to current theory, where did these elements come from?
a. They were made by chemical reactions in the interstellar gas.
b. They have been present in the universe since its birth.
c. They were produced by stars that lived and died before our solar system was
born.
d. They were produced by gravity in the solar nebula as it collapsed.
6. According to our current theory of solar system formation, which of the following
lists the major ingredients of the solar nebula in order from the most abundant to
the least abundant?
a. Hydrogen and helium gas; hydrogen compounds; rock; metal
b. Hydrogen compounds; hydrogen and helium; metal; rock
c. Hydrogen and helium gas; rock; metal; hydrogen compounds
d. Hydrogen; water; methane; and helium
7. The initial attraction of particles in the solar nebula was due to which force?
a. Electromagnetic (static electrical forces)
b. Strong Nuclear (strong force between the subatomic particles in the nucleus)
c. Gravitational
d. Centrifugal
8. According to our theory of solar system formation, what three major changes
occurred in the solar nebula as it shrank in size?
a. Its gas clumped up to form the terrestrial planets, nuclear fusion produced
heavy element to make the Jovian planets, and center temperatures rose to
more than a trillion Kelvin.
b. It gained energy, it gained angular momentum, and it flattened into a disk.
c. Its mass, temperature, and density all decreased
d. It got hotter, its rate of rotation increased, and it flattened into a disk.
9. Which characteristic, more than any other, most probably controlled the early
evolution of the planetary system and dictated the characteristics of the planets that
eventually formed?
a. The density of hydrogen gas in the nebula
b. The mix of chemical constituents
c. The overall rotation of the nebula
d. The temperature distribution within the nebula
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QUIZ: Formation of the Solar System
10. Why did the solar nebula heat up as it collapsed?
a. Nuclear fusion occurring in the core of the protosun produced energy that
heated the nebula
b. As the cloud shrank, its gravitational potential energy was converted to
kinetic energy and then into thermal energy
c. The shock wave from a nearby supernova heated the gas
d. Collisions among planetesimals generated friction and heat
11. 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
b. The formation of moons around planets.
c. The solidification of ices, rocks, and metal from the gas of the solar nebula.
d. The growth of the Sun as the density of gas increased in the center of the
solar nebula.
12. The most probable time sequence for the formation of the solar system was that
a. The planets formed first out of a cold nebula of gas and dust, followed by the
Sun, which formed when the gas had become much hotter.
b. The sun formed initially, and the planets and major moons were captured
much later as the drifted by then sun
c. The sun contracted first as a gas ball, and the planets and moons formed
shortly afterwards by accretion and condensation
d. The sun formed first, the planets were spun off from the Sun, and the moons
in turn were spun off from the planets.
13. Suppose that you were to go back in time and explore the early solar nebula (during
the formation of the solar system). If you were to travel outward from the protosun, the FIRST solid material you would encounter would be
a. Dust-sized grains of rocky material
b. Snowflakes made of frozen water, methane, ammonia and carbon dioxide
c. Snowflakes of frozen hydrogen and helium
d. Dust-sized grains of frozen hydrogen, water ice and rocky minerals.
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QUIZ: Formation of the Solar System
14. What kind of material in the solar nebula could remain solid at temperatures as high
as 1,500 K, such as existed in the inner most regions of the nebula?
a. Rocks
b. Metals
c. Silicon-based compounds
d. Hydrogen compounds
15. The formation of terrestrial-type of planets around a star is most likely to have
occurred by what process?
a. Accretion, or slow accumulation, of smaller particles by mutual gravitational
attraction.
b. Condensation of gas from the original star nebula.
c. Break-up of a large disk of matter which formed around the star
d. Capture of objects traversing the depths of space by the star.
16. What do we mean by the frost line (also known as ice or snow 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.
b. It is another way of stating the temperature at which water freezes into ice.
c. It marks the special distance from the Sun at which hydrogen compounds
become abundant; closer to the sun , there are not hydrogen compounds
d. It is the altitude in a planet’s atmosphere at which snow and ice can form.
17. According to our present theory of solar system formation, why were solid
planetesimals able to grow larger in the outer solar system than in the inner solar
system?
a. Because only metal and rock could condense in the inner solar system, while
ice also condensed in the outer solar system
b. Because gravity was stronger in the outer solar system, allowing more solid
material to collect
c. Because gas in the outer solar system contained a larger proportion of rock,
metal and hydrogen compound than the gas in the inner solar system
d. Because only the outer planets captured hydrogen and helium gas from the
solar nebula.
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QUIZ: Formation of the Solar System
18. Why are the inner planets made of denser materials than the outer planets?
a. The Sun’s gravity pulled denser materials toward the inner part of the solar
nebula, while lighter gases escaped more easily.
b. Denser materials were heavier and sank to the center of the nebula
c. In the inner part of the nebula only metals and rocks were able to condense
because of the high temperatures, whereas hydrogen compounds, although
more abundant, were only able to condense in the cooler outer regions.
d. When the solar nebula formed a disk, materials naturally segregated into
bands, and in our particular solar system the dense materials settled nearer
the Sun while lighter materials are found in the outer part.
19. The steps in which the large, outer planet formed were
a. Accretion of planetesimals to form a core, followed by gravitational capture
of hydrogen and helium gas.
b. Accretion of cold planetesimals containing large quantities of hydrogen and
helium
c. Gravitation condensation of hydrogen, helium, and dust in eddies or vortices
in the outer solar nebula.
d. Gravitation condensation of hydrogen and helium gas, followed by capture of
planetesimals.
20. According to the condensation theory, the most significant difference between the
formation of the terrestrial and the Jovian planets is that
a. The terrestrial planets formed by accretion of planetesimals, whereas the
outer planets formed by direct condensation of gas from the solar nebula
b. Both formed by accretion of rocky and icy planetesimals, but the terrestrial
planets were close enough to the Sun that almost all of the ices escaped back
to space after the planets formed.
c. Both formed by accretion of planetesimals but the outer planets became
massive enough to also pull gas onto them directly from the solar nebula
d. The terrestrial planets formed close to the Sun where there was a n
abundance of rock but no ice, whereas the outer planets formed far from the
Sun where there was an abundance of hydrogen and ice but no rocky
material.
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QUIZ: Formation of the Solar System
21. The timescale over which material in the solar nebula accreted to form planets was
about
a. 100 million years
b. 4.6 million years
c. 100 thousand years
d. 4.6 billion years
22. Which of the following are relatively unchanged fragments from the early period of
planet building in the solar system?
a. Meteorites
b. Asteroids
c. Kuiper belt comets
d. All of the above
23. According to our theory of solar system formation, why do we find some exceptions
to the general rules and patterns of the planets?
a. Our theory is not quite correct because it cannot explain these exceptions.
b. Most of the exceptions are the result of giant impacts.
c. The exceptions probably represent objects that formed recently, rather than
early in the history of the solar system.
d. The exceptions probably represent objects that were captured by our solar
system from interstellar space.
24. Based on our current theory of the earth’s formation, the water we drink comes
from
a. Ice that condensed in the solar nebula in the region where the earth formed
b. Chemical reaction that occurred in the earth’s crust after the earth formed
c. Comets that impacted the earth and volcanic outgassing
d. Material left behind during the giant impact that formed the Moon.
25. The age of our solar system is approximately
a. 10,000 years
b. 4.6 million years
c. 4.6 billion years
d. 13.7 billion years
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QUIZ: Formation of the Solar System
26. The age of the solar system can be established by radioactive dating of
a. The oldest rocks on earth
b. The oldest rocks on the moon
c. The oldest meteorites
d. The atmosphere of Mars.
27. What do meteorites reveal about the solar system?
a. They reveal that meteorites are much older than comets and planets
b. Nothing, because they come from other star systems
c. That the solar system once contained 9 planets
d. That the age of the solar system is approximately 4.6 billion years.
28. Which pair of planets listed originally formed at a location that had a temperature
above the boiling point of water?
a. Mars and Jupiter
b. Saturn and Jupiter
c. Mercury and Saturn
d. Earth and Mars
29. Which of the following properties of the planets does not tell us something about
the way in which our solar system must have evolved?
a. The planets all orbit in about the same plane.
b. The planets farther from the Sun take longer to complete their orbits.
c. The Sun spins in the same sense as the planets orbit.
d. The planets’ orbits are all nearly circular.
30. What important event occurred while the sun was in its T Tauri phase
a. Comets were pushed out of the solar system
b. The planets formed
c. Gas and dust remaining in the solar system were blown away
d. The sun shrank to its present size.
31. Most of the planets orbit the Sun on or close to
a. The plane of the Milky Way Galaxy
b. The equatorial plane
c. The ecliptic plane
d. The plane that contains the Prime Meridian
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QUIZ: Formation of the Solar System
32. According to our theory of solar system formation, which law best explains why the
central regions of the solar nebula got hotter and sun faster as the nebula shrank in
size
a. The law of conservation of energy
b. The law of universal gravitation
c. The law of conservation of angular momentum
d. Einstein’s Law that E = mc2
33. Angular momentum of a rotating object such as a planet depends on the
a. Mass, radius and volume
b. Mass, radius and velocity
c. Mass, weight and velocity
d. Linear momentum and speed
34. By the time planetesimals had formed, the accretion process was accelerated by the
effect of
a. Static electricity
b. Gravity
c. Centripetal motion
d. Angular momentum
35. High – speed collisions between planetesimals often led to ____________________
rather than accretion.
a. Condensation
b. Fragmentation
c. Out gassing
d. Solidification
36. Which of the following did not play an important role in determining many of the
irregularities in the solar system?
a. Collisions
b. Mergers
c. Interactions
d. Solar wind
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QUIZ: Formation of the Solar System
37. The reason the planetesimals of the asteroid belt did not form a larger object was
probably because
a. There was not enough material to form a planet at that distance from the
sun
b. The gravitational influence of Jupiter perturbed the accreted material in that
location
c. The planetesimals did not have enough mutual gravitational attraction to
accrete.
d. The planetesimals had too much angular momentum to accrete
True or False (mark A for true and B for false)
Questions 38 - 49 present properties of the solar system that any model of solar system
formation must explain. Which are correctly stated and which are not?
38. Each planet is relatively isolated in space.
39. The orbits of the planets are not circular but significantly elliptical.
40. The orbits of the planets all lay near the ecliptic plane.
41. The direction of planetary revolution is in the same direction as the Sun's rotation.
42. Planetary rotation is always in the same direction as the Sun's rotation.
43. Moons do not usually revolve in the same direction as their parent planet rotates.
44. The planetary system is highly differentiated.
45. Water could not have condensed out any closer than 3 or 4 A.U. from the Sun.
46. The accretion process occurred faster in the inner part of the solar system than it did
in the outer regions.
47. The condensation theory does not offer an explanation of the highly tilted rotation
axis of Uranus.
48. Random collisions, inherently a part of the condensation theory, can explain many of
the odd properties found among some solar system objects.
49. Which diagram represents retrograde rotation
a.
b.
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QUIZ: Formation of the Solar System
Answer the following questions on this paper.
Consider a planetary system in which a single planet is orbiting a star. If the planet were to
experience an impact by an asteroid sized object that changed the location of its orbit to half
the distance it was prior to the collision. Based on the law of conservation of angular
momentum, what would happen to its speed? (2 points)
Use the diagram below to draw and label the orbit of the Earth and label the Frost line for our
solar system. (2 points)
.3 AU
5 AU
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