Question 1

The spacecraft that got the closest to the nucleus of Halley's Comet and sent back dramatic photographs of what the nucleus looked like was:
A) Giotto
B) Venera
C) Pioneer
D) Mariner 13
E) the Enterprise

Accepted Answer

Giotto was the spacecraft that got closest to the nucleus of Halley's Comet, coming within just 596 kilometers in March of 1986. It sent back dramatic photographs of the nucleus, providing scientists with valuable insights into cometary composition and structure.

Question 2

Between 1992 and today, astronomers using large telescopes have discovered many icy pieces that orbit in the same region as the orbit of Pluto. These are believed to be members of the
A) asteroid belt (which have escaped)
B) Kuiper belt
C) Oort cloud
D) ring around Pluto
E) the rock and roll band called Bill Haley and the Comets

Accepted Answer

These icy objects are commonly known as Kuiper Belt objects (KBOs) and are believed to be remnants from the early Solar System. They are found in a disk-shaped region beyond Neptune's orbit, called the Kuiper belt, which is believed to be the source of many short-period comets.

Question 3

According to our textbook, what is the best way to defend ourselves against an asteroid which is on course to collide with the Earth in 7 years?
A) The only thing we could do would be to move some people to the Moon so they could survive
B) If we do it early enough, we could explode something on or near the asteroid to deflect it slightly, so that years later it would then miss the Earth
C) Asteroids are all rubble piles, so the only thing that would protect us would be a huge thermos-nuclear explosion that vaporizes the entire asteroid
D) There is no problem, because all asteroid burn up by friction in the Earth's thick atmosphere
E) There is no possible protection for us; if an asteroid is headed our way, we are all doomed
Section 13.3: The Long-Haired Comets

Accepted Answer

According to the textbook, if an asteroid is on course to collide with the Earth in 7 years, the best way to defend ourselves is to explode something on or near the asteroid to deflect it slightly, so that years later it would then miss the Earth. This approach would need to be done early enough to give the asteroid time to change course.

Question 4

Halley's Comet was given that name because Edmond Halley was
A) the first person to ever see that comet
B) the scientist who pointed out that the orbit of the comet was such that it should return every 76 years or so
C) the chief scientist who designed the probe that flew by the comet
D) the first person to be hurt by pieces falling off the comet
E) prime minister of England at the time the comet was discovered

Accepted Answer

Edmond Halley was the scientist who pointed out that the orbit of the comet was such that it should return every 76 years or so. He predicted the next appearance of the comet, which was later named after him.

Question 5

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?
A) Asteroids larger than 1 km are so rare and so big, they have always been easy to keep track of
B) 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
C) Most of the near-Earth objects that big are comets, and they all have big tails which are easy to see
D) The people doing the survey began to find the same objects over again, indicating they were reaching the limits of their survey
E) This was fake news; in fact, we can't ever know if we have found 90% of the larger near-Earth objects

Accepted Answer

The people doing the survey began to find the same objects over again, indicating they were reaching the limits of their survey. This means that they had already identified almost all of the large near-Earth asteroids, and were running out of new ones to discover.

Question 6

Which of the following statements about NEO's (Near Earth Objects) is TRUE?
A) we have identified just about all NEO's with diameters greater than 1 km
B) no NEO has passed closer to the Earth than the orbit of the Moon
C) it is unlikely that any NEO's have hit the Earth during our planet's history
D) NEO's can include both asteroids and comets that cross the Earth's orbit
E) we are not able to obtain information about the shape or size of any of the NEO's at present

Accepted Answer

NEO's can include both asteroids and comets that cross the Earth's orbit. We have identified most NEO's with diameters greater than 1 km, but not all. Several NEO's have passed closer to Earth than the Moon, and some have even hit our planet in the past. While we have information about the size and shape of some NEO's, there are still many that we know very little about.

Question 7

The scientist who first proposed that comet nuclei were "dirty snowballs" was:
A) Edmond Halley
B) Fred Whipple
C) Eugene Shoemaker
D) Isaac Newton
E) Jan Oort

Accepted Answer

The scientist who first proposed the "dirty snowball" model of comets was Fred Whipple in 1950.

Question 8

One of the key reasons that professional astronomers (as opposed to the public) are interested in comets is that they
A) are beautiful to look at
B) are always omens of disaster
C) are icy pieces left over from the time that our solar system formed that can give us clues about that early time
D) are pieces splintered off one of the giant planets, so they can provide us with samples of their composition
E) are all visitors from other star systems, which can tell us about what conditions are like in distant reaches of the Milky Way Galaxy

Accepted Answer

Comets are thought to be remnants from the formation of the solar system, so studying them can offer insights into the conditions and materials present during that time. This is a key interest for professional astronomers who seek to better understand the origins of our solar system and how it came to be. While comets can be beautiful and have historically been associated with disaster, these are not the primary reasons that astronomers study them.

Question 9

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:
A) the Lowell reservoir
B) the Oort Cloud
C) the Kohoutek Cloud
D) the Alvarez belt
E) Bayonne, New Jersey

Accepted Answer

The reservoir of comet nuclei beyond Pluto is called the Oort Cloud. The other options, such as Lowell reservoir, Kohoutek Cloud, and Alvarez belt are not correct terms for describing the reservoir. Bayonne, New Jersey is a city and not related to the topic.

Question 10

Short-period comets like Comet Halley
A) return to the Oort Cloud during each of their orbits
B) come back again and again at predictable intervals
C) have a long tail visible during their entire orbit around the Sun
D) can never be observed without a telescope
E) you can't fool me, the only short-period comet we know is Halley

Accepted Answer

Short-period comets like Comet Halley come back again and again at predictable intervals. In the case of Halley, it has an orbital period of 76 years.

Question 11

Which of the following statements about the unusual object Chiron is FALSE?
A) it is one of the largest asteroids, just a little smaller than Vesta
B) its path around the Sun carries it from just inside Saturn's orbit almost out to Uranus' orbit
C) it shows some characteristics of an asteroid and some characteristics of a comet
D) in 1988, as it came closest to the Sun, it was seen to brighten by a factor of two
E) its orbit does not appear to be stable

Accepted Answer

Chiron is not one of the largest asteroids, but is instead classified as a minor planet or a centaur.

Question 12

Which of the following statements about the tails of comets is FALSE?
A) the tail always points away from the Sun
B) some comets have both a gas tail and a dust tail
C) the tail of a comet can sometimes be ahead of the comet in its orbit
D) a comet always has a nice long tail, even when it is far from the Sun
E) the Earth can pass through the tail of a comet without suffering any harm

Accepted Answer

Option D is false because a comet's tail only becomes visible when it is close to the Sun, because the heat causes the gas and dust to form a tail that reflects sunlight. When it is far from the Sun, a comet may not have a visible tail.

Question 13

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:
A) about the mass of Ceres, the largest asteroid
B) about the mass of the Earth
C) about the mass of the Moon
D) on the order of the mass of all the planets put together
E) since comets are mostly vapor, their total mass is less than that of the moons of Mars

Accepted Answer

The answer of If our estimates of the number of...

Question 14

In addition to hundreds of smaller objects they have been discovering in the Kuiper Belt recently, astronomers were surprised to find
A) clear evidence of the building blocks of life in their atmospheres and tails
B) larger bodies, with sizes as big as Pluto (now called dwarf planets)
C) objects whose orbits bring them as close to the Sun as Mars
D) objects whose composition indicates that they are made mostly of stone and metal, not ice
E) souvenirs from Earth's tourist attractions, such as Bayonne, New Jersey

Accepted Answer

Astronomers were surprised to find larger bodies, some as big as Pluto, in addition to the hundreds of smaller objects discovered in the Kuiper Belt recently.

Question 15

Comets get significantly brighter in our skies as they approach the Sun because
A) they reflect more sunlight as they get closer to the source of light
B) they get bigger as the ice evaporates
C) they get closer to the Earth than when they were outside the orbit of Mars
D) they move faster and faster
E) more than one of the above

Accepted Answer

Comets get brighter in our skies as they approach the Sun due to a combination of factors. As they get closer to the Sun, they also get closer to Earth, making them appear brighter. Additionally, as the ice and other volatile materials on the comet's surface heat up, they evaporate and release gas and dust, forming a glowing coma and tail that reflects sunlight and makes the comet appear brighter. Finally, as the comet approaches the Sun, it may also speed up due to the Sun's gravitational pull, but this is not the primary factor contributing to its increased brightness.

Question 16

Comets change as they approach the Sun in their orbits. Which of the following statements about a comet approaching the Sun is FALSE?
A) the solid water ice in a comet begins to evaporate just beyond the orbit of Mars
B) comets close to the Sun can evaporate enough material to become as large or larger than Jupiter
C) the gravity of the comet nucleus holds on to the evaporated material, and it all eventually freezes back into the nucleus
D) when the ice evaporates, some dust frozen into the ice is freed up to join the comet's coma and tail
E) the evaporation is not always even, but can occur in spurts (where jets of material are seen moving away from the comet nucleus)

Accepted Answer

The gravity of a comet nucleus is not strong enough to retain the evaporated material, so it does not freeze back into the nucleus. Instead, this material forms the comet's coma and tail, which are lost to space.

Question 17

Astronomers estimate that there may be a trillion (a thousand billion) comet nuclei orbiting beyond Pluto. Why then do we not see more comets in our skies?
A) most comets are so small that millions pass by the Earth completely undetected
B) most comets have orbits that only bring them inward as far as the orbit of Jupiter
C) most comets collide with Jupiter each year and are thus not seen
D) most comets remain in stable orbits beyond Pluto, only a few have their orbits disturbed and come into the inner solar system
E) all the comets astronomers miss are the reason so many people report seeing UFO's

Accepted Answer

Most comets remain in stable orbits beyond Pluto, only a few have their orbits disturbed and come into the inner solar system. This means that while there may be a large number of comet nuclei in the outer solar system, they don't necessarily all become comets that we can see from Earth.

Question 18

The comet that broke into more than 20 pieces and then collided with Jupiter in 1994 was
A) Giacobini-Zinner
B) Kohoutek
C) Halley's Comet
D) Eros
E) Shoemaker-Levy 9

Accepted Answer

The comet that broke into more than 20 pieces and collided with Jupiter in 1994 was Shoemaker-Levy 9.

Question 19

Which part of a comet is the DENSEST?
A) the nucleus
B) the atmosphere (coma)
C) the dust tail
D) the gas tail
E) the hydrogen cloud

Accepted Answer

The nucleus of a comet is the solid, dense core of the comet, made up of ice, rock, and dust. It is the densest part of the comet.

Question 20

Which of the following is NOT an accomplishment of the Rosetta mission to Comet Churyumov-Gerasimenko (C-G)?
A) Rosetta matched orbits with Comet C-G and flew alongside
B) Rosetta dropped the Philae lander on Comet C-G
C) Rosetta took close-up images of Comet C-G and sent them back to Earth
D) Rosetta took samples of the surface material of Comet C-G and sent them back to Earth
E) Rosetta turned off the spacecraft systems to save power far from the Sun, and turned them back on as it got closer to the Sun
Section 13.4: The Origin and Fate of Comets and Related Objects

Accepted Answer

Rosetta did not take samples of the surface material of Comet C-G and send them back to Earth, although it did extensively study and analyze the composition of the comet from close range.

Quiz 13: Comets and Asteroids: Debris of the Solar System

The spacecraft that got the closest to the nucleus of Halley's Comet and sent back dramatic photographs of what the nucleus looked like was:

Between 1992 and today, astronomers using large telescopes have discovered many icy pieces that orbit in the same region as the orbit of Pluto. These are believed to be members of the

According to our textbook, what is the best way to defend ourselves against an asteroid which is on course to collide with the Earth in 7 years?

Halley's Comet was given that name because Edmond Halley was

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?

Which of the following statements about NEO's (Near Earth Objects) is TRUE?

The scientist who first proposed that comet nuclei were "dirty snowballs" was:

One of the key reasons that professional astronomers (as opposed to the public) are interested in comets is that they

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:

Short-period comets like Comet Halley

Which of the following statements about the unusual object Chiron is FALSE?

Which of the following statements about the tails of comets is FALSE?

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:

In addition to hundreds of smaller objects they have been discovering in the Kuiper Belt recently, astronomers were surprised to find

Comets get significantly brighter in our skies as they approach the Sun because

Comets change as they approach the Sun in their orbits. Which of the following statements about a comet approaching the Sun is FALSE?

Astronomers estimate that there may be a trillion (a thousand billion) comet nuclei orbiting beyond Pluto. Why then do we not see more comets in our skies?

The comet that broke into more than 20 pieces and then collided with Jupiter in 1994 was

Which part of a comet is the DENSEST?

Which of the following is NOT an accomplishment of the Rosetta mission to Comet Churyumov-Gerasimenko (C-G) ?