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WorksheetsAstronomy Exam 4 Study
Total questions: 124
Worksheet time: 1hrs 14mins
a stony or metallic object orbiting the Sun that is smaller than a major planet but that shows no evidence of an atmosphere or of other types of activity associated with comets
(a)
a small body of icy and dusty matter that revolves about the Sun; when a comet comes near the Sun, some of its material vaporizes, forming a large head of tenuous gas and often a tail
(a)
gravitational separation of materials of different density into layers in the interior of a planet or moon
(a)
any of the planets Jupiter, Saturn, Uranus, and Neptune in our solar system, or planets of roughly that mass and composition in other planetary systems
(a)
time required for half of the radioactive atoms in a sample to disintegrate
(a)
a small piece of solid matter that enters Earth’s atmosphere and burns up, popularly called a shooting star because it is seen as a small flash of light
(a)
a portion of a meteor that survives passage through an atmosphere and strikes the ground
(a)
objects, from tens to hundreds of kilometers in diameter, that formed in the solar nebula as an intermediate step between tiny grains and the larger planetary objects we see today; the comets and some asteroids may be leftover planetesimals
(a)
process by which certain kinds of atomic nuclei decay naturally, with the spontaneous emission of subatomic particles and gamma rays
(a)
the cloud of gas and dust from which the solar system formed
(a)
any of the planets Mercury, Venus, Earth, or Mars; sometimes the Moon is included in the list
(a)
the process by which the greenhouse effect, rather than remaining stable or being lessened through intervention, continues to grow at an increasing rate
(a)
geological features that result from stresses and pressures in the crust of a planet; tectonic forces can lead to earthquakes and motion of the crust
(a)
chemical changes caused by electromagnetic radiation
(a)
the radiation emitted by charged particles being accelerated in magnetic fields and moving at speeds near that of light
(a)
an orbital condition in which one object is subject to periodic gravitational perturbations by another, most commonly arising when two objects orbiting a third have periods of revolution that are simple multiples or fractions of each other
(a)
the heating of a planet or moon’s interior by variable tidal forces caused by changing gravitational pull from a nearby planet or moon
(a)
the region of the solar system between the orbits of Mars and Jupiter in which most asteroids are located; the main belt, where the orbits are generally the most stable, extends from 2.2 to 3.3 AU from the Sun
(a)
a region of space beyond Neptune that is dynamically stable (like the asteroid belt); the source region for most short-period comets
(a)
an Earth-approaching asteroid, one whose orbit could bring it on a collision course with our planet (NEA)
(a)
a comet or asteroid whose path intersects the orbit of Earth (NEO)
(a)
the solid chunk of ice and dust in the head of a comet
(a)
the large spherical region around the Sun from which most “new” comets come; a reservoir of objects with aphelia at about 50,000 AU
(a)
(of a comet) a tail consisting of two parts: the dust tail is made of dust loosened by the sublimation of ice in a comet that is then pushed by photons from the Sun into a curved stream; the ion tail is a stream of ionized particles evaporated from a comet and then swept away from the Sun by the solar wind
(a)
The planet closest to the Sun in the solar system is:
Mercury
Pluto
Venus
Neptune
In the far future, a visiting tourist from another planetary system asks to see the most massive object in our solar system. Where would you take him/her/it?
the Sun
Jupiter
the asteroid belt
Comet Halley
Neptune
The first trans-Neptunian object astronomers found (in 1930) is called
Uranus
Pluto
Eris
Ceres
Bayonne
Which of the following is NOT a terrestrial planet?
Mars
Earth
Jupiter
Venus
Mercury
Which of the following characteristics do all four terrestrial planets have in common?
the all have one or more moons
all have liquid water on their surfaces
they all rotate in 24 hours or less
they all have thick atmospheres
they all have solid surfaces with signs of geological activity on them
Generally, planets and moons in our solar system are named after
great writers and poets from the past
gods and goddesses from mythology
the political leaders of Ancient Greece and Rome
leading scientists from long ago
The smaller objects in the solar system composed mainly of ices (frozen gases) that usually orbit far from the Sun are called:
snowroids
comets
asteroids
satellites
Jovians
If you were to take a large sample of the four giant planets, the most common element you would find in them is:
iron
hydrogen
oxygen
silicon
Today, the chemistry of the terrestrial planets does not include a lot of free hydrogen. Chemists call the chemistry in places like the Earth:
reduced
expanded
silicate
oxidized
comet-like
During the process of differentiation,
satellites separate from the parent planets and go into their own orbits
the faster planets move further out from the Sun
heavier materials sink to the centers of molten planets
the atmosphere of a planet changes from oxidized to reduced
the surface of a planet changes to resemble Bayonne, New Jersey
Which of the following places is most likely NOT to be differentiated?
a small asteroid
Earth
Jupiter
Venus, because it is so hot
Ganymede, the largest satellite in the solar system
In general, the further planets are from the Sun, the cooler they are. What other factor can have a significant influence on a planet's surface temperature?
its atmosphere (whether it has one and how thick it is)
the number of large moons that are close to the planet
how fast the planet is spinning (the length of its day)
whether its core has a lot of iron in it
What is one way that astronomers have actually gotten an idea of the age of the surfaces of terrestrial planets other than the Earth?
looking at the colors different surfaces show
bringing back samples and run radioactive dating tests
counting craters
measuring the thickness of the atmosphere above each surface
looking in the instruction manual that comes with each planet
The rate at which a collection of the same radioactive atoms will decay depends on:
the amount of radio waves falling on the material
the amount of light falling on the material
the temperature of the material
the size of the planet or moon on which the material is located
only on internal processes within the atoms; nothing external matters
In radioactive dating, the measure scientists use to note how long (on average) a particular radioactive nucleus will take to decay is called its
radioactive ratio
parent-daughter criterion
half-life
geological activity
Tinder activity
Radioactive dating techniques have revealed that our Earth and Moon are approximately how old?
about 6,000 years
about 2 million years
about 100 million years
about 4.5 billion years
The material that would eventually make all the major bodies in our solar system first gathered together as smaller pieces which astronomers call:
planetesimals
nubuloids
satellites
differentiated objects
Jovians
The inner planets are made mostly of rock and metal because:
lighter materials cannot orbit the Sun; they would fall in immediately
the Sun is made mostly of rock and metal and the inner planets are closest to the Sun
it was so hot where the inner planets formed that the lighter materials evaporated
Jupiter's large gravity immediately attracted all the lighter materials, and so there were few light atoms left by the time the inner planets were ready to form
What planet can come closest to the Earth in its orbit and look brightest in our skies?
Venus
Mars
Mercury
Jupiter
The planet that most resembles the Earth in size and internal composition is
Mars
Venus
Mercury
Jupiter
Why is it so much easier to determine the length of the day on Mars than on Venus?
Mars' atmosphere is generally pretty clear (so the surface is visible) while Venus is always cloudy
Mars rotates really slowly, so it's easy to follow; Venus rotates so fast, it's hard to track
Mars is much larger in diameter than Venus is, so it's easier to see
Mars is always much closer to the Earth than Venus
Mars is always visible in our nighttime sky, while Venus is only visible in the daytime sky
Which of the following is NOT a correct statement about the rotation of Venus?
Venus rotates in roughly the same time period as Earth
Venus rotates in a retrograde way (east to west)
the two definitions of a day (how long it takes for a star to return to the same position in the sky and how long it takes the Sun to return to the same position) do not agree on Venus
the rotation rate of Venus had to be determined from radar measurements
Venus has the longest rotation period of any planet in the solar system
The spacecraft that sent back the most detailed radar images of Venus and showed us features as small as a football field is:
Viking
Pioneer
Venera
Magellan
Mariner
The largest continental (highland) area on Venus is called:
Stein
Sapas Mons
Venera
Danu
Aphrodite
The spacecraft that soft-landed successfully on the surface of Venus (and briefly sent back pictures while sitting in that destructive environment) were called
Magellan
Venera
Pioneer
Voyager
Bayonne
Why are there no smaller craters on the surface of Venus, only bigger ones?
Because Venus is so close to the Sun, the Sun's gravity pulls all smaller chunks of material into the Sun before they can reach Venus
The seas and lakes of Venus erode away all the smaller craters when they flood
In Venus' thick atmosphere all smaller chunks of material burn up before they can reach the surface
Venus is so hot that smaller craters generally melt in the heat, becoming smooth surface
Which of the following is evidence for volcanic activity on Venus?
the fact that the lava plains are only 500 million or so years old
the existence of large volcanic mountains such as Sif Mons
the discovery of thousands of small volcanic cones of the surface of Venus
the pancake domes of Venus
all of the above
Which of the following statements about the planet Venus is true?
its thick nitrogen-oxygen atmosphere acts like a greenhouse, keeping it hot
it rotates on its axis in the same direction as the Earth does
it has a thick layer of clouds containing sulfuric acid droplets
the atmospheric pressure near the surface is about the same as Earth's
A very rich and eccentric tourist in the future hires you to fly him to a region of Venus' atmosphere where the temperatures and pressures are the most Earth-like. Where would you take him?
just above the surface
high above most of the atmosphere and clouds, in the mesosphere
to the top of Mount Maxwell on the Ishtar continent
in the cloud layers about 50 km above the surface
The process by which Venus became so much hotter than the Earth is called:
radioactivity
ozone depletion
the runaway greenhouse effect
tectonic displacement
the twisted sister effect
The observation that began the 19th and early 20th century fascination with Mars as a place for life was:
the discovery of the Martian moons
Schiaparelli's seeing what seemed to him to be long straight features on the red planet
Percival Lowell's discovery of an entire network of artificial canals built by martians
the images sent back by the Viking spacecraft mission
the landing of Martian spacecraft in New Jersey in 1938
The canals that late 19th and early 20th observers thought they saw on Mars turned out to be:
optical illusions
enormous cracks caused by extensive plate tectonics on Mars
very narrow oceans of water
huge chains of thousands of large volcanoes
The first spacecraft to orbit another planet circled Mars in 1971. It was:
Viking 1
Voyager 1
Apollo 1
Mariner 9
Venera 11
Which of the following would NOT be one of the problems faced by an unprotected Earthling stranded on Mars? (Unprotected meaning no space suit.)
the composition of the atmosphere
the lack of liquid water today on the surface
the low atmospheric pressure
the lack of any ozone layer shielding
the extreme (high) heat at most latitudes
One of the most impressive features of the geology of Mars is an uplifted area about the size of North America, with volcanoes on it, which is called the
Olympus Mountains
Tharsis Bulge
Hellas Basin
Mariner Valley
Valles Marineris is a wide, deep network of chasms stretching for some 2500 miles on the surface of Mars. How do we believe such a big set of canyons formed originally?
it was caused by tectonic pressures from deep within the planet
it was produced suddenly by flooding water some four billion years ago
it was scoured out of the Martian sands by the action of the regular dust storms
it was made by hundreds of impacts from space billions of years ago
On some parts of Mars, it gets cold enough for a gas to freeze out of the atmosphere that does not freeze out by itself at the temperatures and pressures on Earth. This gas makes up some of the polar caps on Mars and is:
water
argon
carbon dioxide
methane
oxygen
Which of the following statements about the atmosphere of Mars today is FALSE?
it is made mostly of carbon dioxide
it is roughly as thin as the Earth's air would be about 30 km up
it has a haze made of carbon dioxide crystals
droplets of liquid water rain irrigate the surface of Mars regularly
there are occasionally great windstorms in the lower atmosphere
Mars rovers (such as Opportunity and Curiosity) have identified evidence that their landing sites were once under water. Which of the following is among the kinds of evidence they have identified?
they found liquid water deposits just under the surface when they dug down a few feet
they found rock formations that show the area was under water and also minerals that only form in water
they found warm salt water spurting up in the form of geysers
they found a lot of water vapor in the martian atmosphere just above their landing sites
Mars appears to have long branching channels that have the appearance of being formed by a flowing liquid. Yet we know that liquids would not stay liquid in the very thin atmosphere we have on the Martian surface? So how can we explain the channels?
they were made by wind-blown dust during the great Martian dust storms
they are made by plate tectonics; by plates in the crust separating
Mars had a thicker atmosphere long ago when the channels formed
they were formed by volcanic lava from Olympus Mons
Astronomers believe that Mars formed with a much thicker atmosphere than it has today. Where did this atmosphere go?
it escaped into space (and some later froze out as Mars got cold)
it was absorbed by the rocks on Mars, which are much more absorbent than on Earth
it was drawn into the crust and mantle of Mars through the enormous cracks of the Mariner Valley canyon system
it is trapped in bubbles inside the rocks on the martian surface
By far the most abundant element in the giant (jovian) planets is:
helium
hydrogen
oxygen
nitrogen
silicon
Much of what we have learned about the jovian planets and their satellites has come from the work of two spacecraft called:
Viking
Magellan
Voyager
Mariner
Enterprise
Which of the following is NOT a way that Jupiter differs from terrestrial planets?
its average density is lower
it is farther away from the Sun
it includes much more gas and liquid
it is larger in diameter
its surface has many more craters from early collisions
What allowed the Voyager 2 spacecraft to make a "tour" of all four of the jovian planets in the late 1970's and the 1980's?
NASA had developed a completely new kind of rocket that could send the craft from planet to planet
the four planets were approximately aligned on one side of the Sun and we used the gravity of each planet to speed up the spacecraft to get to the next one in its path
the spacecraft stopped off to collect fuel on the satellites of each planet before proceeding to the next one
we used laser beams to propel the spacecraft into the outer solar system, where sunlight is dim
Which of the following spacecraft is NOT leaving the solar system?
Pioneer 10
Pioneer 11
Galileo
Voyager 1
Voyager 2
To obtain the wonderful images of the jovian planets in our textbook (out where the sunlight is a lot fainter) what did the Voyager spacecraft cameras have to do as they flew by each world?
use faster (more light sensitive) film
slow down the spacecraft using retro-rockets to get long exposures
swivel the cameras backwards to keep pointing in the same direction as the craft flew by
use more than one camera and combine the light that fell into each one
simply make do with pictures that got worse and worse as we went outward from the Sun; by the time we got to Neptune, the images were quite blurry
The jovian planet that has the longest year (period of revolution) is:
Jupiter
Saturn
Uranus
Neptune
Which of the jovian planets has the shortest period of rotation (the shortest day)?
Jupiter
Saturn
Uranus
Neptune
The planet that orbits "on its side" (i.e. has its rotation axis perpendicular to the plane of its orbit) is:
Uranus
Neptune
Pluto
Jupiter
Saturn
Which of the following statements about the seasons on Jupiter is correct?
Jupiter has seasons pretty much like the Earth; its axis has the same tilt, and each season is about the same length
Jupiter has the same axis tilt as the Earth, but each season on Jupiter is much longer
Jupiter's axis is tilted much more than the Earth's so its seasons are much more intense
Jupiter's axis is hardly tilted so it has no real seasonal variations
Jupiter's orbit brings it much closer to the Sun in summer and much farther from the Sun in
At the moment when the Voyager spacecraft got closest to Uranus, the Sun was shining directly on the planet's south pole. Uranus takes about 17 hours to rotate once on its axis. If Voyager took a photo of the south pole 8.5 hours later, what would it observe?
the south pole was in darkness
the south pole was brightly lit, with the Sun shining down on it
the south pole was in twilight
the south pole was facing directly away from the Sun
Astronomers believe that Jupiter's strong magnetic field is caused by
a core of molten iron and nickel
electric charges from the moon Io
a huge layer of metallic hydrogen inside Jupiter
the circulation of large reddish storms containing magnetic ammonia crystals
Which of the following characteristics distinguishes Uranus from every other planet in our solar system?
it has more than one moon
its atmosphere is made of gases
it rotates on an axis tilted almost 90 degrees to the circle of its orbit
its orbit is significantly tilted relative to the orbits of the other planets
its magnetic axis does not lie in the same direction as its rotation axis
What do the magnetic fields of Jupiter, Uranus, and Neptune have in common?
all three have their magnetic axes offset from the center of the planet
all are weaker than the Earth's magnetic field
all are caused by molten iron and nickel deep within each planet
all are tilted by about 50 or 60 degrees from the planet's axis of rotation
all were discovered by spacecraft that flew by the planets
The primary clouds in the atmospheres of Jupiter and Saturn are composed of:
water vapor
iron and nickel
frozen ammonia crystals
metallic hydrogen
In the far future, a daring interplanetary tourist wants to go "hang-gliding" on the jovian planet with the highest equatorial wind speeds. Which planet would have the fastest wind at its equator?
Jupiter
Saturn
Uranus
Neptune
The Red Spot of Jupiter is:
variable in size
a high pressure storm system in the atmosphere
made of a reddish colored material (but we don't know what gives it the reddish color)
long-lived (observed since the 1600's)
all of the above
What was a surprise to astronomers when they carefully examined Neptune with the Hubble Space Telescope in 1994?
the magnetic field of the planet had reversed (north was now south)
new elements and compounds were found in the upper atmosphere that had not been there
the Great Dark Spot had disappeared
the wind speeds had slowed considerably
Which planet has the biggest moon relative to its own size? Not the biggest moon in terms of kilometers, but the biggest as a percentage of the size of the planet it orbits.
Jupiter
Neptune
Uranus
Saturn
Pluto
What do astronomers think is the origin of the many irregular moons around the outer planets (irregular meaning they are orbiting backwards and/or have eccentric orbits)?
These moons were likely formed elsewhere and captured by the giant planets
These moons are fragments of a much larger moon around each planet that exploded
These moons were expelled by volcanoes on the surfaces of the giant planets
These moons had an early interaction with the rings of the giant planets and were moved to strange orbits as a result
The largest satellite (moon) in the solar system is:
Ganymede
Titan
Earth's Moon
Charon
Io
The satellite which has the thickest atmosphere (so thick that it's quite a surprise for a satellite) is:
Triton
Titan
the Earth's Moon
Europa
Callisto
When astronomers say that Ganymede is a differentiated body, they mean that it:
has a northern hemisphere which is different from its southern hemisphere
has more of the larger crater types than the smaller ones
has a magnetic field that is not centered on its axis of rotation
has a heavier core, surrounded by a lighter, icy mantle and crust
has a color that is surprising among outer solar system satellites
The Galileo spacecraft measured that the moon Ganymede had a magnetic field, indicating that its interior was at least partly melted and warm. What do scientists think is the most likely reason for this?
Ganymede is so far away from Jupiter, it is an independent world, and can compress its core without interference
Ganymede has thousands of volcanoes, which then send material downward to heat up its interior
Ganymede is a relatively small moon, and therefore much easier to heat up than its neighbor moons
Ganymede is heated by tidal forces from Jupiter
What evidence can you give that shows the surface of Jupiter's moon Europa must be relatively young?
there are thousands of active volcanoes on Europa's surface
we see very few craters compared to the surfaces of Callisto and Ganymede
radioactive rocks from Europa that have been brought back to Earth by our probes show that Europa is a young moon
the interior of Europa is made of metals like iron and nickel
Europa was not orbiting Jupiter when Galileo observed its moons, but now it is
What is the cause of its many volcanic/geyser-like eruptions on the moon Io?
its surface is at the triple point of methane, where it can be gas/liquid/solid
Jupiter's magnetic field causes huge bolts of lightning to hit Io and heat the surface
the gravitational stress of being so close to Jupiter and its other large moons heats the Io's inside
there is a metallic magnetic layer inside Io which is explosive
Which element plays the same role on Titan as water does on Earth (existing as gas, liquid, and solid)?
carbon dioxide
methane
ammonia
hydrogen cyanide
propane
The lakes found in the north polar region of Titan are filled with liquid
water
ammonia
methane
nitrogen
Which of the following statements about the geysers on the moon Triton is true?
they are caused by the impact of small comets on Triton's fragile surface
the geysers are sulfur volcanoes which stick out of Triton's crust
they involve plumes of nitrogen on the sunlit side of Triton
they are caused by collisions with the rings of Neptune
they are only visible when it is winter on Triton
Pluto was discovered through the patient searching of
Percival Lowell
Clyde Tombaugh
E. E. Barnard
Gerard Kuiper
Pluto's big satellite is called
Charon
Titan
Ganymede
Christy
Tombaugh
Which of the following statements about Charon is FALSE?
it takes the same amount of time to rotate and revolve
it keeps the same face toward Pluto
it takes the same time to go around Pluto as Pluto takes to rotate
it has a significant atmosphere
it has a retrograde orbit (revolves in a direction opposite to the sense that most satellites in the solar system revolve)
The spacecraft that visited Pluto and send back our first images:
was called New Horizons
got a gravity boost from Jupiter to get it to Pluto faster
used plutonium to keep it warm
is returning to Earth in the 22nd century
more than one of the above
The mountains on Pluto are made of frozen water, which at Pluto temperatures, is as hard as rock. Pluto also has a smooth, round basin which could be thought of as a frozen sea. What material is in the basin (nicknamed Sputnik) likely to be made of?
warmer water
carbon dioxide (dry ice)
nitrogen
helium
The rings of the outer planets consist of
sheets of ice that stretch in round planes millions of miles wide around each planet
billions of chunks (of various sizes) that all orbit the equator of each planet
many large moons, about the size of Jupiter's moon Io, all crowded together
subatomic charged particles, all kept in line by each planet's magnetic field
millions of alien spacecraft, some of which occasionally make it to the Earth and pick up humans to experiment on
The largest and most massive of Saturn's rings is the
A
B
C
D
F
How were the rings of Uranus discovered?
They were seen through a small telescope at the same time the planet was
They were discovered with the Hubble Space Telescope
They were discovered by the Voyager 2 spacecraft when it flew by Uranus
Through the radio waves given off as they interact with the magnetic field
by using the Kuiper Airborne Observatory (the telescope aboard an airplane) to observe Uranus moving in front of a distant star
What makes the rings of Neptune different from those of other planets we know?
they are much thinner
they have gaps and divisions in them
they are much darker
they are clumpy (or bulging) in places
there is more than one ring in the system
How does Saturn's F ring stay so thin (narrow), when the other rings are so wide?
the further away from Saturn a ring is, the narrower it gets
there are 2 shepherding satellites on either side of it
Saturn's huge magnetic field keeps ice boulders from expanding
the F ring is in the same orbit as the moon Enceladus
The first asteroid to be discovered (which is also the largest one) is called
Ceres
Gaspra
Davida
Eros
Fraknoi
How have astronomers learned what different asteroids are made of?
The only way is to send a spacecraft to each asteroid and bring a chunk of it home
They measure the x-rays that all asteroids give off
They wait until the asteroid has a tail of gas behind it and measure that tail
They examine the spectrum of the sunlight that reflects from the asteroid
More than 75% of the known asteroids:
cross the Earth's orbit at least once as they revolve around the Sun
are made of icy material that is highly reflective
were once part of a planet as large as Jupiter
lie farther out from the Sun than the orbit of Saturn
can be found in a belt between Mars and Jupiter
The fact that some asteroids cluster in what are called asteroid families is probably the result of:
resonances with the jovian planets
collisions which broke up larger bodies into a number of smaller ones
comets which pass through the asteroid belt and attract asteroids to them
strong magnetic fields found in some asteroids
Different asteroids reflect different percentages of the light falling on them. This is due to the fact that they have different:
temperatures
compositions
eccentricities
rotation rates
size moons orbiting them
A baseball pitcher wants to impress his girl-friend with how strong his throwing arm is. On which of the following bodies would the pitcher be MOST likely to be able to throw a baseball (a fast ball) so fast it would actually go into orbit?
Earth
Mars
Ganymede
Titan
asteroid Ida
Two small moons in the solar system, known since the 19th century, turn out to be captured asteroids. These two moons are:
Io and Europa around Jupiter
Dione and Titan around Saturn
the Earth's moon and antimoon
Phobos and Deimos around Mars
The first asteroid confirmed to have a satellite (moon) was
Vesta
Eros
Toutatis
Chiron
Ida
The Shoemaker-NEAR spacecraft explored two asteroids, Mathilde and Eros. A big difference between them is that:
Mathilde appears to be pile of 'rubble' (a collection of separate rocks) while Eros is solid
Mathilde is a 'real' asteroid, while Eros is a comet that has lost some of its ice
Mathilde is always inside the orbit of the Earth, while Eros is always outside our planet's orbit
Mathilde is going to impact the Earth, while Eros will never come near our planet
In 2013, a small stony asteroid collided with the Earth above the Russian city of Chelyabinsk. What was the result?
A large earthquake was felt all over Europe and Asia
A fireball briefly brighter than the Sun could be seen in the sky
It broke apart and large pieces of rock fell from the sky, killing thousands of innocent people
The Earth's orbit around the Sun changed in a measurable way
It burned up so high in the atmosphere, absolutely nothing could be felt or seen on the ground
In 2012, NASA's Spaceguard Survey concluded that astronomers had now identified 90% of the asteroids with diameters greater than 1 km. How could astronomers know that they had reached this goal?
Asteroids larger than 1 km are so rare and so big, they have always been easy to keep track of
NASA is now able to keep track of everything in the solar system out to Pluto with great precision; nothing remains to be discovered in that region
Most of the near-Earth objects that big are comets, and they all have big tails which are easy to see
The people doing the survey began to find the same objects over again, indicating they were reaching the limits of their survey
Halley's Comet was given that name because Edmond Halley was
the first person to ever see that comet
the scientist who pointed out that the orbit of the comet was such that it should return every 76 years or so
the chief scientist who designed the probe that flew by the comet
the first person to be hurt by pieces falling off the comet
prime minister of England at the time the comet was discovered
One of the key reasons that professional astronomers (as opposed to the public) are interested in comets is that they
are beautiful to look at
are always omens of disaster
are icy pieces left over from the time that our solar system formed that can give us clues about that early time
are pieces splintered off one of the giant planets, so they can provide us with samples of their composition
are all visitors from other star systems, which can tell us about what conditions are like in distant reaches of the Milky Way Galaxy
The scientist who first proposed that comet nuclei were "dirty snowballs" was:
Edmond Halley
Fred Whipple
Eugene Shoemaker
Isaac Newton
Jan Oort
Which of the following statements about the tails of comets is FALSE?
the tail always points away from the Sun
some comets have both a gas tail and a dust tail
the tail of a comet can sometimes be ahead of the comet in its orbit
a comet always has a nice long tail, even when it is far from the Sun
the Earth can pass through the tail of a comet without suffering any harm
Comets change as they approach the Sun in their orbits. Which of the following statements about a comet approaching the Sun is FALSE?
the solid water ice in a comet begins to evaporate just beyond the orbit of Mars
comets close to the Sun can evaporate enough material to become as large or larger than Jupiter
the gravity of the comet nucleus holds on to the evaporated material, and it all eventually freezes back into the nucleus
when the ice evaporates, some dust frozen into the ice is freed up to join the comet's coma and tail
the evaporation is not always even, but can occur in spurts (where jets of material are seen moving away from the comet nucleus)
The large reservoir of comet nuclei far beyond Pluto, from which we believe new long-period comets come into the inner solar system, is called:
the Lowell reservoir
the Oort Cloud
the Kohoutek Cloud
the Alvarez belt
If our estimates of the number of comets in every part of the solar system are correct, the total mass contained in comets must be:
about the mass of Ceres, the largest asteroid
about the mass of the Earth
about the mass of the Moon
on the order of the mass of all the planets put together
since comets are mostly vapor, their total mass is less than that of the moons of Mars
The comet that broke into more than 20 pieces and then collided with Jupiter in 1994 was
Giacobini-Zinner
Kohoutek
Halley's Comet
Eros
Shoemaker-Levy 9
Which of the following statements about the unusual object Chiron is FALSE?
it is one of the largest asteroids, just a little smaller than Vesta
its path around the Sun carries it from just inside Saturn's orbit almost out to Uranus' orbit
it shows some characteristics of an asteroid and some characteristics of a comet
in 1988, as it came closest to the Sun, it was seen to brighten by a factor of two
its orbit does not appear to be stable
