Question 1

What are "dwarf planets"?

Accepted Answer

The answer of What are "dwarf planets"?...

Question 2

Assume that the average rate of 1-km sized asteroids hitting the Earth is about 1 every million years. The chance of the Earth being hit by a 1-km sized asteroid in the next 100 years is about:
A) one in a million.
B) inevitable, it has to happen sometime.
C) zero.
D) one in 100 million.
E) one in ten thousand.

Accepted Answer

The average rate is 1 per million years, so in 100 years, the chance is 100/1,000,000 = 1/10,000.

Question 3

Briefly describe how an impact could lead to a mass extinction.

Accepted Answer

The answer of Briefly describe how an impact could lead...

Question 4

You find yourself in a maelstrom, whipped by winds gusting at 10,000 km/hr, rising and falling in convective currents. On the rare occasions when you can assess your surroundings, you notice a horizon that seems to go on "forever" (or, at least, much farther than the horizon on Earth), and no solid surface anywhere. You get a glimpse of several large moons. The Sun races through your sky, requiring only about 5 hours to rise nearly due east, cross the meridian at an altitude of about 55° in the north, and then set due west.

Accepted Answer

The answer of You find yourself in a maelstrom, whipped...

Question 5

Refer to the following choices to answer the questions below. Chose the answer that best describes the chemical composition of the object.
-Mercury's core
A)nickel and iron
B)80 percent nitrogen, 20 percent oxygen
C)95 percent carbon dioxide
D)mostly hydrogen and helium
E)frozen methane, ammonia, water, and other gases and dust

Accepted Answer

Mercury's core is made up mostly of nickel and iron, similar to Earth's.

Question 6

Refer to the following choices to answer the questions below. Chose the answer that best describes the chemical composition of the object.
-Jupiter
A)nickel and iron
B)80 percent nitrogen, 20 percent oxygen
C)95 percent carbon dioxide
D)mostly hydrogen and helium
E)frozen methane, ammonia, water, and other gases and dust

Accepted Answer

Jupiter is mostly composed of hydrogen and helium gas.

Question 7

Suppose the planet Jupiter had never formed. How do you think the distribution of asteroids and comets in our solar system would be different? Explain.

Accepted Answer

The answer of Suppose the planet Jupiter had never formed....

Question 8

You've been dropped at the edge of a cliff, looking down for what seems to be miles! There's only one way to go from here: up! But it's going to be quite a climb, requiring all of your mountaineering skills. The atmosphere is very thin even at the mean surface level of this place. No matter, though, as you could not breathe this atmosphere anyway because it is mostly carbon dioxide and contains no oxygen. You climb and climb. This mountain must be three times the height of Mt. Everest and much broader at its base. There are clouds around you, and you can find water ice as well. When you try to melt some ice, however, it does not turn to liquid but sublimes to gas.

Accepted Answer

The answer of You've been dropped at the edge of...

Question 9

It is very cold, but otherwise comfortable. You breathe deeply. Although there is no oxygen, the air pressure is quite tolerable and seems almost Earth-like (because it is mostly nitrogen). Your vista includes the breathtaking sights of an ocean of liquid methane and methane-snow-capped mountains (although the atmosphere is very smoggy, and the visibility is limited). Your solar day is about 16 Earth days long. A large, ringed object seems to hang in your sky, never rising or setting; however, it does go through phases from new to full and back to new again with the same 16-day period as the rising and setting of the Sun.

Accepted Answer

The answer of It is very cold, but otherwise comfortable....

Question 10

The last major dinosaurs were wiped out as a consequence of a major impact with the Earth about 65 million years ago. All but one of the following statements would be regarded as evidence for this claim.
A) At least 150 craters from past impacts have been identified, including one of the right age and size in Mexico.
B) A layer of iridium in 65-million year old sediments in the Earth's crust.
C) The fossil record shows a mass extinction event 65 million years ago, where only 25% of the species survived.
D) Multiple historical accounts describe a planetary-level flood and storm that wiped out most living things.

Accepted Answer

Historical accounts are not scientific evidence for events that occurred 65 million years ago, unlike geological and fossil records.

Question 11

Refer to the following choices to answer the questions below. Chose the answer that best describes the chemical composition of the object.
-the atmosphere of Mars
A)nickel and iron
B)80 percent nitrogen, 20 percent oxygen
C)95 percent carbon dioxide
D)mostly hydrogen and helium
E)frozen methane, ammonia, water, and other gases and dust

Accepted Answer

The atmosphere of Mars is composed of 95 percent carbon dioxide.

Question 12

You find yourself on a silent airless world! The of the lack of an atmosphere means that you must be very careful not to look at the Sun so that you will not be blinded by its ultraviolet and X-ray radiation. However, you are able to determine that the Sun has about the same angular size that you are used to on Earth. Although this world is clearly lifeless, you are surprised to find footprints and car tracks etched in the powdery surface.

Accepted Answer

The answer of You find yourself on a silent airless...

Question 13

Briefly describe the evidence suggesting that a 10-km asteroid or comet hit Earth at the time of the dinosaur extinction.

Accepted Answer

The answer of Briefly describe the evidence suggesting that a...

Question 14

It's cold. You are sitting on what appears to be a water ice-covered world. The Sun is low on the horizon and circles the horizon once every 24 hours. Despite the low Sun, you can almost "feel" the Sun's ultraviolet radiation on your exposed face because there is little ozone to protect you. Despite these discomforts, you are pleased to find that the air is quite satisfactory; oxygen seems plentiful and you are able to breathe even without the life-support belt.

Accepted Answer

The answer of It's cold. You are sitting on what...

Question 15

Refer to the following choices to answer the questions below. Chose the answer that best describes the chemical composition of the object.
-a Kuiper-belt object
A)nickel and iron
B)80 percent nitrogen, 20 percent oxygen
C)95 percent carbon dioxide
D)mostly hydrogen and helium
E)frozen methane, ammonia, water, and other gases and dust

Accepted Answer

Kuiper-belt objects are typically composed of a mixture of frozen methane, ammonia, water, and other gases and dust.

Question 16

You are walking on a solid surface. The surface gravity is comfortable, but it is "hot, hot, hot!" Your body is being squeezed in all directions due to the high pressure; its almost like being deep in the ocean. Your life-support belt is corroding. The Sun, barely visible through the haze, is near your meridian. You hope for nightfall (unaware that it would provide no relief), but you already have been stuck on this planet for nearly 72 hours, and the Sun seems not to have moved through the sky (and, if it moved at all, it moved eastward from the meridian).

Accepted Answer

The answer of You are walking on a solid surface....

Question 17

Refer to the following choices to answer the questions below. Chose the answer that best describes the chemical composition of the object.
-Comet Hale-Bopp
A)nickel and iron
B)80 percent nitrogen, 20 percent oxygen
C)95 percent carbon dioxide
D)mostly hydrogen and helium
E)frozen methane, ammonia, water, and other gases and dust

Accepted Answer

Refer to the following scenario for the questions below:
Lost in the Solar System: You have been abducted by an alien being. After performing experiments on you, the alien gives you a "life-support belt", allowing you to survive in any environment, and dumps you somewhere in the solar system. Each question below gives a brief description of a place where you were left by the alien. Identify your location. Be as specific as possible. Include a brief explanation for your answer.

Question 18

If the chance of the Earth being hit by a life-destroying asteroid over the course of one year is one in a million, what is the chance of being hit of the course of one hundred years?
A) One in 100 million
B) One in a million
C) One in ten thousand

Accepted Answer

The probability of an independent event occurring over multiple trials is calculated by multiplying the probability of the event occurring in a single trial by the number of trials. Here, 1/1,000,000 per year over 100 years gives 100/1,000,000, which simplifies to 1/10,000.

Question 19

Refer to the following choices to answer the questions below. Chose the answer that best describes the chemical composition of the object.
-Earth's atmosphere
A)nickel and iron
B)80 percent nitrogen, 20 percent oxygen
C)95 percent carbon dioxide
D)mostly hydrogen and helium
E)frozen methane, ammonia, water, and other gases and dust

Accepted Answer

Earth's atmosphere is composed of 80 percent nitrogen and 20 percent oxygen.

Question 20

Refer to the following choices to answer the questions below. Chose the answer that best describes the chemical composition of the object.
-the atmosphere of Venus
A)nickel and iron
B)80 percent nitrogen, 20 percent oxygen
C)95 percent carbon dioxide
D)mostly hydrogen and helium
E)frozen methane, ammonia, water, and other gases and dust

Accepted Answer

The chemical composition of the atmosphere of Venus is mostly carbon dioxide, with a concentration of about 95 percent.

Quiz 9: Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

What are "dwarf planets"?

Assume that the average rate of 1-km sized asteroids hitting the Earth is about 1 every million years. The chance of the Earth being hit by a 1-km sized asteroid in the next 100 years is about:

Briefly describe how an impact could lead to a mass extinction.

Refer to the following choices to answer the questions below. Chose the answer that best describes the chemical composition of the object. -Mercury's core

Refer to the following choices to answer the questions below. Chose the answer that best describes the chemical composition of the object. -Jupiter

Suppose the planet Jupiter had never formed. How do you think the distribution of asteroids and comets in our solar system would be different? Explain.

The last major dinosaurs were wiped out as a consequence of a major impact with the Earth about 65 million years ago. All but one of the following statements would be regarded as evidence for this claim.

Refer to the following choices to answer the questions below. Chose the answer that best describes the chemical composition of the object. -the atmosphere of Mars

Briefly describe the evidence suggesting that a 10-km asteroid or comet hit Earth at the time of the dinosaur extinction.

Refer to the following choices to answer the questions below. Chose the answer that best describes the chemical composition of the object. -a Kuiper-belt object

Refer to the following choices to answer the questions below. Chose the answer that best describes the chemical composition of the object. -Comet Hale-Bopp

If the chance of the Earth being hit by a life-destroying asteroid over the course of one year is one in a million, what is the chance of being hit of the course of one hundred years?

Refer to the following choices to answer the questions below. Chose the answer that best describes the chemical composition of the object. -Earth's atmosphere

Refer to the following choices to answer the questions below. Chose the answer that best describes the chemical composition of the object. -the atmosphere of Venus