Name: 
 

Summer Astronomy 19 & 20


Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 
Why would a decrease in the density of the ozone layer create a public health concern?
a.
The greenhouse effect would not be as efficient and the temperature of Earth would decrease.
b.
Plant life would no longer have the ozone it needs for photosynthesis to create chlorophyll.
c.
Infrared radiation from the sun would bombard Earth and cause an increase in skin cancers.
d.
The greenhouse effect would be more efficient and the temperature of Earth would increase.
e.
none of the above
 

 2. 
The oldest rocks found on Earth are about ____ years old.
a.
10 billion
b.
3.9 billion
c.
6.2 million
d.
5.3 billion
e.
4.6 billion
 

 3. 
Once a terrestrial planet had formed from a large number of planetesimals, heat from ____ could have melted it and allowed it to differentiate into a dense metallic core and a lower density crust.
a.
radioactive decay
b.
tidal forces
c.
volcanic eruptions
d.
impacts of small meteorites
e.
the sun
 

 4. 
The ozone layer is
a.
transparent to ultraviolet radiation.
b.
opaque to visible light.
c.
opaque to ultraviolet radiation.
d.
opaque to infrared radiation.
e.
responsible for producing most of the oxygen that animal life needs.
 

 5. 
The current atmosphere of Earth is believed to be
a.
the result of the melting and vaporizing of the glaciers from the last ice age.
b.
the remnants of the original gas from the solar nebula attracted by the protoplanet.
c.
the result of a collision between the sun and another star.
d.
composed of gases that were baked from the rocks sometime after the planet formed.
e.
composed primarily of hydrogen and helium.
 

 6. 
The terrestrial planets are all made of
a.
Helium only.
b.
hydrogen only.
c.
Hydrogen, Helium only.
d.
mostly rock, metal.
e.
all of the above
 

 7. 
Protoplanets of the Jovian planets could have grown very hot from
a.
the infall of material at high velocity.
b.
tidal forces due to the sun.
c.
radioactivity of light elements such as hydrogen and helium.
d.
collisions with large planetesimals.
e.
heat from the sun.
 

 8. 
If Earth's average surface temperature were to increase by several degrees,
a.
sea level would rise and flood coastal areas.
b.
the ozone layer would be destroyed.
c.
plant life in all areas of Earth would grow more efficiently and be more lush.
d.
the carbon dioxide in Earth's atmosphere would be destroyed.
e.
none of the above
 

 9. 
Condensation in the solar nebula probably led to the formation of
a.
metallic grains near the present orbit of Mercury.
b.
icy grains beyond the present orbit of Jupiter.
c.
silicate grains near the present orbit of Earth.
d.
all of the above
e.
none of the above
 

 10. 
A(n) ____ is a solar system object that enters Earth's atmosphere and becomes very hot due to friction between the object and Earth's atmosphere.
a.
meteoroid
b.
comet
c.
meteor
d.
planetesimal
e.
asteroid
 

 11. 
The nebular theory of the origin of the solar system was proposed by
a.
Laplace.
b.
Buffon.
c.
neither of these
 

 12. 
The discovery that Jovian-like planets are common around other stars and that gas and dust is swept out of the solar neighborhood fairly early in the formation of a star suggests that
a.
the Terrestrial planets must form earlier than the Jovian planets.
b.
all comets had to have formed as moons around one of the Jovian planets.
c.
the Terrestrial planets formed as moon around one of the Jovian planets.
d.
all asteroids had to have formed as moons around one of the Jovian planets.
e.
the Jovians may have formed directly, without the core accretion phase.
 

 13. 
The oxygen in Earth's atmosphere
a.
was manufactured inside stars.
b.
has grown more abundant since the origin of Earth.
c.
was added to the atmosphere by plant life.
d.
all of these
e.
none of these
 

 14. 
Which of the following is not produced by plate tectonics?
a.
rift valleys
b.
the Appalachian Mountains
c.
midocean rifts
d.
Earth's magnetic field
e.
the ring of fire
 

 15. 
Earth's magnetic field is generated by the dynamo effect in the
a.
aurora.
b.
solid central core.
c.
plastic mantle.
d.
the crust.
e.
molten metallic core.
 
 
Exhibit 20-1

nar001-1.jpg
 

 16. 
Refer to Exhibit 20-1. The diagram shows a schematic of Earth. If an earthquake occurs at point X on Earth's surface, at which of the locations indicated by numbers would observers receive P waves from this earthquake?
a.
1, 2, & 3
b.
1 & 2
c.
all of them
d.
only 4
e.
3 & 4
 

 17. 
Refer to Exhibit 20-1. The diagram shows a schematic of Earth. If an earthquake occurs at point X on Earth's surface, at which of the locations indicated by numbers would observers receive S waves from this earthquake?
a.
1, 2, & 3
b.
all of them
c.
3 & 4
d.
only 4
e.
1 & 2
 

 18. 
Which statement supports the solar nebula theory of the origin of the solar system?
a.
Disks are common around young stars.
b.
Planets are round.
c.
Disks are rare around young stars.
d.
The sun is the least massive object in the solar system.
 

 19. 
Which of the following is not a characteristic of the terrestrial planets?
a.
orbits inside the asteroids
b.
small diameters
c.
very few satellites
d.
low average density
e.
craters in old surfaces
 

 20. 
Slow surface evolution is caused by
a.
wind erosion.
b.
plate tectonics.
c.
cratering.
d.
all of the above
e.
a and b
 

 21. 
The youngest parts of Earth's crust are
a.
the Appalachian Mountains.
b.
the continental margins.
c.
the midocean rifts.
d.
the bottom layer found in the walls of the Grand Canyon.
e.
the continents.
 

 22. 
Why do astronomers believe that the angular momentum problem is no longer an objection to the solar nebula problem?
a.
The solar nebula theory has been proven false, so the angular momentum problem doesn't apply.
b.
The sun's magnetic field interacted with gas leaving the nebula and slowed the sun's rotation.
c.
Most of the angular momentum has been found to be contained in the planet's orbits.
d.
The current theory assumes that the solar nebula originally rotated slower than previously thought.
e.
The extra angular momentum is accounted for by the orbits of the comets.
 

 23. 
The terrestrial planets are
a.
Mercury, Venus, Earth and Moon, Mars.
b.
Jupiter, Saturn, Uranus, Neptune.
c.
Earth and Moon, Mercury, Jupiter, Saturn.
 

 24. 
The large planetesimals would have grown faster than the smaller planetesimals because
a.
their stronger gravity would pull in more material.
b.
there was more material located near them that could be accreted.
c.
they were moving faster in their orbits than the smaller planetesimals.
d.
the smaller planetesimals were covered by a layer of material that was lost during collisions.
e.
all of the above
 

 25. 
A future news release might report that a new planet has been found around a star very similar to our sun. This newly discovered planet is claimed to have a mass 40 times that of Earth and is located nearly 25 AU from the star it orbits. Which of the following would be a reasonable prediction about this planet?

I.The planet will probably have a mean density of around 5 g/cm3.
II.The planet will probably have a radius of around five to ten times greater than Earth's.
III.The planet will probably have several satellites.
IV.The planet will probably have a composition that is mostly hydrogen and helium.
a.
II, III, & IV
b.
I, II, & IV
c.
I, II, & III
d.
I and IV
e.
I, II, III, & IV
 

 26. 
The Van Allen belts are
a.
a series of large midocean rifts stretching across the ring of fire.
b.
the tropical zone of Earth's atmosphere where the predominant wind direction is from east to west.
c.
two large convection currents in Earth's liquid core that produce Earth's magnetic field.
d.
a series of midocean rifts stretching from the north polar region to the Antarctic.
e.
composed of high energy particles from the solar wind that are trapped in Earth's magnetosphere.
 

 27. 
The parts of a terrestrial planet from the center out are
a.
core, mantle, crust.
b.
crust, mantle, core.
c.
mantle, core, crust.
 

 28. 
The plates of Earth's lithosphere move at speeds of
a.
a few meters per day.
b.
a few centimeters per year.
c.
a few millimeters per year.
d.
a few centimeters per day.
e.
a few millimeters per century.
 

 29. 
The age of the solar system is believed to be approximately 4.6 billions years old based on the data from
a.
samples of meteorites.
b.
samples of earth rocks.
c.
samples of lunar rocks.
d.
all of the above
e.
none of the above
 

 30. 
Most planets thus far discovered around other stars were found by
a.
seeing the planet next to the star.
b.
varying Doppler shifts of the stars.
c.
traveling to the star.
d.
The planet blotting out the light of the star.
 

 31. 
In observations, ____ has a heavy element core, and a deep atmosphere made mostly of hydrogen.
a.
Mars
b.
an asteroid
c.
Venus
d.
Uranus
e.
a meteor
 

 32. 
Accretion among the grains in the solar nebula would have been aided by
a.
static electricity.
b.
high-velocity collisions.
c.
gravity.
d.
all of the above
e.
none of the above
 

 33. 
The graph below shows the temperature of material inside a hypothetical planet as a function of depth. Also plotted is the melting point temperature of the material at that depth. Which of the following statements is true for this planet?

mc033-1.jpg
a.
The core is part liquid and part solid.
b.
The core is completely solid.
c.
The mantle is a liquid.
d.
The planet surface is solid and liquid.
e.
both a and d
 

 34. 
Saying that Earth's mantle is plastic means that
a.
it has the properties of a solid but is capable of flowing under pressure.
b.
only S waves can travel through it.
c.
it has the properties of a liquid but because of the high pressure it transmits both P and S waves.
d.
only P waves can travel through it.
e.
Earth's mantle is made of common plastics.
 

 35. 
Which one of the following objects is most like the planetesimals that formed in the solar nebular?
a.
the sun
b.
Venus
c.
Earth
d.
Saturn
e.
asteroids
 

 36. 
If the terrestrial planets formed by homogeneous accretion, then
a.
the solar nebula changed during their fragmentation.
b.
the terrestrial planets should now have the same composition as the Jovian planets.
c.
they formed an iron core first and a silicate crust later.
d.
Earth's original atmosphere was rich in hydrogen.
e.
the terrestrials should have had several satellites each.
 

 37. 
Earth possesses few visible craters while the moon possesses many. This is because
a.
Earth formed later than the moon and, therefore, hasn't encountered as many meteorites.
b.
the moon doesn't have an atmosphere that could burn up many of the meteorites before impacting.
c.
erosion and plate tectonics have slowly removed evidence of past cratering on earth.
d.
all of the above
e.
only b and c
 

 38. 
Nearly all extra-solar planets actually found thus far are
a.
equal to earth's mass.
b.
much more massive than earth.
c.
less massive than earth.
 

 39. 
The passing star mechanism of the origin of the solar system was proposed by
a.
Descartes.
b.
Laplace.
c.
Buffon.
d.
none of the above
 

 40. 
Planets are thought to be forming today in ____ around stars.
a.
spherical clouds
b.
hot disks
c.
cold disks
d.
none of the above
 

 41. 
Which of the following observations would support the solar nebula theory over the passing star hypothesis?
a.
finding a planet located beyond the orbit of Pluto
b.
proving that none of the stars near the sun has planets orbiting them
c.
finding a meteorite whose age proved to be greater than 4.6 billion years
d.
proving that most of the solar like stars near the sun also have planets orbiting them.
e.
proving that Mercury has the same uncompressed density as Earth
 

 42. 
All terrestrial planets have ____.
a.
thick atmospheres
b.
craters
c.
strong magnetic fields
d.
liquid water oceans
 

 43. 
Which of the following is not one of the four stages in the development of a terrestrial planet?
a.
slow surface evolution
b.
differentiation
c.
cratering
d.
flooding
e.
accretion
 

 44. 
If a star is found with five planets orbiting it, which of the planets would be expected to have the greatest uncompressed density if the system was formed by a process like that described in the solar nebula theory?
a.
the one closest to the star
b.
the one with the greatest mass
c.
the one with the greatest radius
d.
the one that has liquid water on its surface
e.
the one farthest from the star
 

 45. 
The most important effect in clearing the solar nebula of gas and dust was
a.
the asteroid belt.
b.
the sun's magnetic field.
c.
the solar wind.
d.
impacts by planetesimals.
e.
radiation pressure.
 

 46. 
The ____ show(s) an emission spectrum and is(are) caused by large electrical currents that flow into Earth's atmosphere near the north and south poles.
a.
ozone layer
b.
Van Allen belts
c.
solar wind
d.
lithosphere
e.
aurora
 

 47. 
The condensation sequence suggests that ____ should condense closest to the sun.
a.
silicates
b.
low density materials
c.
metals and metal oxides
d.
ices of water, methane, and ammonia
e.
Jovian planets
 

 48. 
The energy that moves the plates of Earth's crust comes from
a.
friction between wind and the land surface.
b.
Earth's magnetic field.
c.
the solar wind.
d.
tides in the oceans.
e.
convection from the hot interior.
 

 49. 
That Earth ____ is evidence that Earth differentiated.
a.
rotates slowly
b.
has a magnetic field
c.
has an average density that is lower than the density of the crust
d.
has a surface that is 75% water
e.
all of these
 

 50. 
Which of the following provide evidence that Earth's core is at least partially molten?
a.
P waves do not penetrate Earth's core.
b.
Neither S nor P waves are refracted by Earth's core.
c.
P waves are reflected by Earth's core.
d.
S waves do not penetrate Earth's core.
e.
S waves are reflected by Earth's core.
 



 
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