Deck 19: Meteorites, Asteroids, and Comets

Question 1

The density of Comet Halley was found to be about 0.2 g/cm³. This implies that Comet Halley

A) is composed of about 50% rock and 50% frozen water and methane.
B) is loosely packed ices with a small amount of rocky material.
C) formed in the inner solar system and was ejected by Jupiter to the Kuiper belt.
D) is really an S-type asteroid.
E) was once a moon of Neptune and was ripped away by a large impact.

Answer 1

is loosely packed ices with a small amount of rocky material.

Question 2

The diagram below shows the relative size of Earth's moon and the asteroid 10 Hygiea. Based on this diagram, what is the diameter of 10 Hygiea?

A) 460 km
B) 46 km
C) 4600 m
D) 46 m
E) 4600 km

Answer 2

460 km

Question 3

Stony, chondrite, achondrite, and stony-iron meteorite types are classified according to their

A) orbit.
B) distance from the sun.
C) impact history.
D) mineral content.
E) coma.

Answer 3

mineral content.

Question 4

A meteor shower is produced when

A) a large number of sporadic meteors are observed.
B) Earth passes through the asteroid belt.
C) massive particles are carried outward from the sun by the solar wind and enter Earth's atmosphere.
D) Earth passes through the orbital path of a comet.
E) meteors cause condensation in the upper atmosphere that leads to early morning rains.

Question 5

Comets falling into the inner solar system from the ____ are called long-period comets.

A) Oort cloud
B) asteroid belt
C) Roche limit
D) Kuiper belt
E) Widmanstätten region

Question 6

The Widmanstätten patterns found in some meteorites show that the material

A) cooled very slowly.
B) cooled very rapidly.
C) was never heated to the point of being molten.
D) was molten just before it entered Earth's atmosphere.
E) is composed primarily of organic compounds.

Question 7

One currently accepted theory suggests that the bodies in the Oort cloud formed

A) near the present orbits of the terrestrial planets and were then ejected by them.
B) near the present orbits of the Jovian planets and were then ejected by them.
C) right there in the Oort cloud very far from the sun.

Question 8

____ asteroids are the most common and appear to be the source of the most common type of meteorite, the chondrites. They are more common in the inner belt and may be the source of stone meteorites.

A) S-type
B) M-type
C) C-type

Question 9

Carbonaceous chondrites

A) II & III
B) I, II & III
C) II, III & IV
D) I, III, & IV
E) I, II, III, & IV

Question 10

Most short-period comets do not have randomly oriented orbits because

A) they are affected by the sun's gravity.
B) they are affected by the solar wind.
C) they formed in the Kuiper Belt, a belt-shaped region in the plane of the solar system.
D) their orbits are altered by the drag of their tails in the solar wind.
E) they all were originally objects ejected from the asteroid belt.

Question 11

What evidence exists that some of the asteroids were geologically active in the distant past?

A) A few of the larger asteroids show similar reflectance spectra (colors) similar to achondrite stony lava-like meteorites.
B) A few of the larger asteroids show similar reflectance spectra (colors) similar to carbonaceous chondrite meteorites.
C) A few of the larger asteroids show similar reflectance spectra (colors) similar to Jovian planets .

Question 12

After formation, a carbonaceous chondrite asteroid could produce an iron core and a rocky silicate mantle if it melted then

A) differentiated.
B) outgassed.
C) condensed.
D) accreted.
E) sublimed.

Question 13

The gas tail of a comet always

A) trails behind the head along the orbital path.
B) extends ahead of the head along the orbital path.
C) points toward the sun.
D) points away from the sun.
E) points perpendicular to the orbital path.

Question 14

Most of the asteroids orbit the sun in a belt between the orbits of

A) Venus and Earth.
B) Earth and Mars.
C) Jupiter and Saturn.
D) Mercury and Venus.
E) Mars and Jupiter.

Question 15

A(n) ____ is a stony meteorite that contains no chondrules and no volatiles. They appear to have been melted after they formed and resemble solidified lavas.

A) carbonaceous chondrite
B) achondrite
C) breccia
D) Widmanstätten
E) Kuiper belt object

Question 16

The ____ is a disk-shaped cloud of icy bodies believed to extend from about 40 AU (the orbit of Pluto) out to 100 AU. It is believed that most short-period comets originate from this region.

A) Oort cloud
B) Widmanstätten cloud
C) Apollo-Amor
D) Kirkwood region
E) Kuiper belt

Question 17

Chondrites are meteorites that have

A) never been melted since formation from solid particles in the solar nebula.
B) totally melted after formation.
C) been made from hydrogen and helium.
D) never entered Earth's atmosphere.
E) entered Earth's atmosphere but will be destroyed before reaching the ground.

Question 18

A bit of matter that enters Earth's atmosphere and survives to reach the ground is called

A) a meteor.
B) a meteoroid.
C) a meteorite.
D) a minor planet.
E) an asteroid.

Question 19

____ asteroids are more common in the outer asteroid belt where it is cooler. They are darker and may be carbonaceous.

A) S-type
B) M-type
C) C-type

Question 20

____ asteroids appear to have nickel-iron compositions and may be the cores of broken asteroids.

A) S-type
B) M-type
C) C-type

Question 21

Meteorites seem to be primarily composed of material very similar to the material in comets.

Question 22

Meteors seen during a meteor shower appear to come from a point in the sky called the ____________________.

Question 23

What characteristic of long-period comets suggest they come directly from the Oort cloud?

A) They have longer dust tails than short-period comets.
B) Their orbits have random inclinations with respect to the ecliptic plane.
C) Their orbits are nearly circular.
D) They tend to appear larger in diameter than short-period comets.

Question 24

____________________ are regions of the asteroid belt where very few asteroids are found due to gravitational resonance with Jupiter.

Question 25

A typical asteroid has an orbital period around the sun of 5.2 years. How far from the sun is this asteroid?

A) 5.2 AU
B) 10.4 AU
C) 27.0 AU
D) 3.0 AU
E) 2.3 AU

Question 26

Long-period comets are believed to originate in the ____________________.

Question 27

The iron meteorites

A) never fall on the Earth.
B) are only found in the Antarctic.
C) are composed of carbonaceous chondrites.
D) are responsible for most of the meteor craters on the surface of the moon.
E) appear to have formed in the interiors of molten planetesimals.

Question 28

If a large 10-km asteroid or comet struck the Earth in the ocean floor,

A) I & IV
B) II & III
C) I, II, & III
D) I, II, III & IV
E) II, III, & IV

Question 29

How is the coma of a comet produced?

A) Rocky material breaks off from the comet to form the coma.
B) The coma is a cloud of particles that the comet has swept up in its orbital path.
C) Ices vaporize to become gas that form the coma around the comet.
D) Particles in the solar wind get caught in the comet's magnetic field to form the coma.

Question 30

The ____________________ of a comet can be up to a million kilometers in diameter.

Question 31

The ____________________-type asteroids are generally found in the outer portion of the asteroid belt and are very dark.

Question 32

What physical processes have led to the creation of stone and iron meteorites from carbonaceous chondrite asteroids?

A) collision only
B) differentiation only
C) fragmentation only
D) melting only
E) melting, differentiation, collision, fragmentation

Question 33

A(n) ____________________ is produced when Earth passes through the debris left by a comet when it passed through the inner solar system.

Question 34

Widmanstätten patterns are found in ____________________ meteorites.

Question 35

Which of the following is evidence for the connection between comets and meteor showers?

A) Meteor and comets have the same appearance in the sky.
B) Meteor showers always occur when a comet is visible.
C) Meteor showers always occur 6 months after a comet passes Earth.
D) Meteor showers are an annual event. Many of these are known to be when the Earth crosses a comet's orbit.

Question 36

The gas tail of a comet

A) is smooth and featureless with a spectrum identical to that of the sun.
B) is present even when the comet is located in the region of the Kuiper belt.
C) is unaffected by the magnetic field of the sun.
D) always points toward the sun.
E) is streaked and shows emission lines of ionized atoms.

Question 37

A(n) ____________________ occurs when a bit of material enters Earth's atmosphere and becomes incandescent due to friction with the atmosphere.

Question 38

____ are round bits of glass found in some stony meteorites.

A) Chondrites
B) Anthrasites
C) Achondrites
D) Widmanstätten patterns
E) Chondrules

Question 39

The diagram below is a plot of an asteroid's reflected brightness versus its ultraviolet minus visual color (U-V color; redder to the right and gray to the left). In this diagram, which of the asteroids is most likely an S-type asteroid?

A) Object 1
B) Object 2
C) Object 3
D) Object 4
E) Object 5

Question 40

The impact of a large asteroid comet with Earth has been proposed to have caused the extinction of the dinosaurs. The impact site of this comet is in or near

A) Iowa.
B) Hudson Bay.
C) Crater Lake, Oregon.
D) Canberra, Australia.
E) Chicxulub, Mexico.

Question 41

Meteorites seem to be primarily composed of material very similar to the material in asteroids.

Question 42

How might we explain the origin of the different types of meteorites among the asteroids?

Question 43

Achondrites are rich in volatiles.

Question 44

The Kuiper Belt is predicted to be the place where most of the short-period comets formed.

Question 45

Most meteors come from comets, but most meteorites come from asteroids. Explain this statement.

Question 46

Meteors strike Earth's atmosphere every day.

Question 47

The majority of meteorite finds are iron meteorites.

Question 48

Some asteroids show evidence of surface activity such as lava flows.

Question 49

What observational evidence do we have that some meteors are caused by debris from comets?

Question 50

Carbonaceous chondrites have been heated to high temperature at least once since they formed.

Question 51

What does the presence of the Widmanstätten patterns in iron meteorites tell us about their history?

Question 52

Jupiter was probably influential in preventing the formation of a planet at the present location of the asteroid belt.

Question 53

The meteors in meteor showers are believed to be the debris left behind in comet orbits.

Question 54

The meteors in meteor showers are believed to be the debris left behind in comet orbits.

Question 55

Meteorites seem to come from both the asteroid belt and the comets.

Question 56

The existence of the Oort cloud cannot be confirmed observationally from Earth because the objects are too small and distant.

Question 57

Kirkwood's gaps in the asteroid belt are caused by orbital resonances with Mars.

Question 58

The dirty snowball theory suggests that the head of a comet is composed of ices.

Question 59

No asteroids have orbits that cross the Earth's orbit.

Question 60

Iridium is more common in meteorites than in the crust of the Earth.

Question 61

Explain how the impact of a large comet may have caused the extinction of the dinosaurs.

Question 62

What evidence do we have that the orbits of the asteroids are modified by the gravitational influences of the planets?

Question 63

Why might the C-type asteroids be expected to be found in the outer part of the asteroid belt, while the S-type asteroids are found in the inner portion?

Question 64

Describe the observational differences between long-period and short-period comets.

Question 65

What evidence do we have that some asteroids have surfaces modified by geological processes?

Question 66

How does the dirty snowball theory explain the observed characteristics of comets?

Question 67

What processes cause the difference in appearance between gas tails and dust tails in comets?