Deck 18: Asteroid and Comet Impacts

Question 1

What are comets made of?

A)high-magnesium and -iron rocks
B)ice
C)ice and some rock
D)nickel-iron
E)close-packed hydrogen

Answer 1

C

Question 2

On average, how often does a six-meter diameter asteroid collide with Earth?

A)once a year
B)once every five years
C)once every ten years
D)once every fifty years
E)once every century

Answer 2

A

Question 3

Why would astronomers have difficulty spotting a large incoming asteroid headed for Earth?

A)It remains in a fixed position in the sky as it comes in directly, so astronomers cannot see its trajectory.
B)It comes in so fast that they do not have time to see it.
C)It is dark before becoming heated in Earth's atmosphere.
D)It is not an important topic to monitor for most astronomers.
E)It is simply too big to seem as if it is moving.

Answer 3

A

Question 4

About how many asteroids larger than 1 km in diameter are known to be in Earth-crossing orbits (those that pass through Earth's orbit around our sun)?

A)20
B)100
C)500
D)1500
E)5200

Question 5

How fast do comets travel?

A)about 2 to 3 km per minute
B)about 60 km per minute
C)about 2 to 3 km per second
D)about 60 km per second
E)about 500 km per second

Question 6

What are shatter cones?

A)funnel-shaped cones of rock with apex pointing downward, with striations radiating downward and outward
B)funnel-shaped cones of rock with apex pointing upward, with striations radiating downward and outward
C)cone-shaped depressions in and around the crater, caused by hypervelocity impact
D)vertical cracks in rocks, radiating outward from the point of impact
E)rocks that shattered at impact, leaving cone-shaped depressions where the rocks once were

Question 7

How many times in the last century have meteorites struck and killed people in North America?

A)none
B)only one
C)only a few (less than five or so)​
D)about 15
E)about 50 (one every couple of years)

Question 8

What causes an asteroid to drop out of orbit and travel toward Earth?

A)the gravitational influence of planets
B)the gravitational attraction of the sun
C)a change in magnetic characteristics due to its age
D)only the collision with another asteroid.
E)the slow loss of water, causing a change in path

Question 9

Approximately how long ago did the Chesapeake Bay impact occur?

A)5 million years
B)15 million years
C)35 million years
D)45 million years
E)70 million years

Question 10

Asteroid 2004 MN4 (Asteroid Apophis) was expected to pass very close to Earth on Friday, April 13, 2029, with collision odds initially calculated as 1 chance in 37. NASA's further calculations now suggest that odds of a 2029 Earth impact are about how much?

A)one in 1,000
B)one in 10,000
C)one in 50,000
D)one in 100,000
E)one in one million

Question 11

Most asteroids originate from an asteroid belt orbiting the sun between which two planets?

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

Question 12

What is the average diameter of the head of a comet?

A)1-2 km
B)less than 15 km
C)50 km
D)500 km
E)2,500 km

Question 13

Which hazard would NOT be associated with an asteroid impact on Earth?

A)tsunamis
B)earthquakes
C)volcanic eruptions
D)floods far from coastal areas
E)fires

Question 14

How fast do asteroids travel in space?

A)about 2 to 4 km per minute
B)about 15 to 40 km per minute
C)about 2 to 4 km per second
D)about 15 to 25 km per second
E)about 150 to 400 km per second

Question 15

How many mass extinctions do scientists believe have occurred on Earth?

A)one
B)two
C)three
D)four
E)five

Question 16

What is the path of comets around the sun?

A)They range far beyond the planetary part of our solar system and loop past the sun and back into outer space.
B)Their path is the same as Earth.
C)They have a circular orbit around the sun.
D)They orbit Earth, not the sun.
E)They don't orbit the sun; they are pulled to the sun by its gravity and eventually crash into it. ​

Question 17

NASA catalogs near-Earth-objects (NEOs) that are larger than ____ in diameter and come within about 75 million km of Earth.

A)10 m
B)100 m
C)1 km
D)5 km
E)15 km

Question 18

How is the tail of a comet oriented? (Which way does it point?)

A)It points away from the sun.
B)It points toward the sun due to gravitational attraction.
C)It points back from the direction of travel.
D)It points in the direction of its afterburner.
E)It oriented randomly in space.

Question 19

The impact of a large asteroid on Earth will NOT typically result in ____.

A)acid rain
B)tsunami, if the impact occurred in the ocean
C)iridium anomaly
D)melted rock and tiny, hollow spherules
E)high radioactivity in the crater

Question 20

What geological material often forms at about the time of major extinctions, for reasons not understood by scientists today?

A)shocked quartz
B)flood basalts
C)ice layers
D)clay layers
E)stony-iron

Question 21

Large amounts of _______________ blown into the stratosphere from an asteroid impact would block    sunlight, affecting agriculture worldwide.

Question 22

Most meteorites have a(n) _______________, a very thin layer of dark glass formed by heat when it came through Earth's atmosphere.

Question 23

Astronomers believe that asteroids are remnants of a planet that disintegrated after a collision with a comet.

Question 24

Comets are asteroids that have gradually gathered water.

Question 25

A meteorite's coating is very different from its interior.

Question 26

In January, 2002, an object 0.3 km across passed within 800,000 km of Earth, only roughly twice the distance to the moon.

Question 27

An asteroid had a grazing encounter with Earth in _______________ in 1908, destroying 1000 square kilometers of forest and killing animals. No crater was found.

Question 28

A large portion of the _______________ layer, which protects us from the sun's ultraviolet rays, would   likely be destroyed by a moderate asteroid impact on Earth.

Question 29

The Chicxulub crater is thought to be evidence of the meteor impact associated with the extinction of the dinosaurs.

Question 30

Iron meteorites make up 20% of all meteorites.

Question 31

Because meteorites travel faster than the speed of sound, we cannot hear them until they are relatively close.

Question 32

High amounts of nickel which would be spread by the vaporization of a 10-km-diameter   chondritic asteroid would interfere with _______________ production in plants.

Question 33

An anomalous amount of _______________ is found in the boundary clay of the 65 million-year-old K-T event.

Question 34

Stony-iron meteorites make up less than 1% of all meteorites

Question 35

Comets originate from the _____.

Question 36

A small piece of rock that enters Earth's atmosphere and survives to reach the ground is a(n) _______________.

Question 37

Meteor Crater, in Arizona, is approximately 100,000 years old.

Question 38

The giant Manicouagan crater of the eastern Canada is one of the largest impact craters observable on the surface of the Earth, appearing as a striking ring of _______________.

Question 39

Asteroids are more abundant than meteoroids.

Question 40

Sometimes large rocks break up in Earth's atmosphere and fall as a(n) _______________, spread out around the main impact site.

Question 41

What are stony-iron meteorites? Describe the two types of stony meteorites.

Question 42

What are specific characteristics of an asteroid impact seen in rocks surrounding an impact crater? Discuss these characteristics and describe their formation and appearance.

Question 43

The _______________ comet, seen by many in 1997, came within Earth's orbit around the sun (on the other side of the solar system) at about 320 million km away at its nearest point.

Question 44

Describe characteristics of an impact crater.

Question 45

Asteroid 1997 XF11 will pass by Earth at approximately 2.5 times the distance to the moon in the year _______________.

Question 46

What is Cretaceous-Tertiary boundary clay, and where did it form? Describe the conditions under which it formed, and what it looks like.

Question 47

The only well-documented case of someone being hit by a meteorite occurred in 1954 in the state of _______________.

Question 48

Describe the difference between meteors and meteorites.

Question 49

With the impact of a 10-km asteroid, land temperatures would, depending on assumptions, likely drop worldwide to _______________ levels very quickly.

Question 50

A spacecraft stationed near an asteroid so that its tiny mass can slowly pull the asteroid off its trajectory is known as a(n) _______________.