Astronomy test 1

According to the nebular theory of solar system formation, which law best explains why the solar nebula spun faster as it shrank in size?

a. Einstein's law E = mc2

b. The law of conservation of energy

c. The law of universal gravitation

d. The law of conservation of angular momentum

D

According to the nebular theory of solar system formation, which of the following best explains why the solar nebula ended up with a disk shape as it collapsed?

a. The law of conservation of energy.

b. It flattened as a natural consequence of collisions between particles in the nebula

.c. The force of gravity pulled the material downward into a flat disk.

d. It was fairly flat to begin with, and retained this flat shape as it collapsed.

B

What component in a molecular cloud blocks light from passing through?

a. Dust

b. Water

c. Carbon monoxide

d. Hydrogen gas

A

What did left-over inner planetesimals become?

a. comets

b. planets

c. Saturn's rings

d. asteroids

D

What is a good explanation for the many comets that make up the Kuiper Belt?

a. They were originally from outside the Solar System, but were captured by the Sun's gravity

b. They are space junk from an ancient advanced civilization

c. They are the debris of a catastrophic collision of two planets that used to exist past Neptune

d. They are remnants of the formation of the Solar System

D

What is the closest distance ever reached between the Earth (which is 1 AU from the Sun) and Venus (which is 0.7 AU from the Sun) while they orbit the Sun?

a. 1.7 AU

b. 0.7 AU

c. 0.3 AU

d. 1 AU

C

What makes it scientifically reasonable to imagine that a giant impact could have occurred on Earth, causing the formation of our Moon?

a. We have witnessed giant impacts occurring in planetary systems around other stars.

b. We have direct observational evidence of the giant impact, in the form of a huge crater on the Moon.

c. Models indicate that at least a few giant impacts should be expected in the process of planetary formation.

d. Actually, it's not a very reasonable idea, but we can't think of any other way the Moon might have formed.

C

What property distinguishes terrestrial planets from jovian planets?

a. Terrestrial planets have thick atmospheres

b. Terrestrial planets are much younger

c. Terrestrial planets are made from heavy elements

d. Terrestrial planets have many moons

C

When a molecular cloud collapses, they become:

a. Less dense and hotter

b. Denser and hotter

c. Less dense and colder

d. Denser and colder

A

Which of the following are TRUE?

a. Moons mainly orbit retrograde

b. Most planets rotate in the same direction

c. Some planets do not rotate as they orbit the Sun

d. The planets orbit in the same direction, but opposite to the Sun

B

Which of the following is not a general distinction between terrestrial planets and jovian planets?

a. Terrestrial planets are made largely of metal and rock whereas jovian planets are made largely of hydrogen and helium.

b. Jovian planets tend to have many more moons than terrestrial planets.

c. Terrestrial planets formed much closer to the Sun than did the jovian planets.

d. Terrestrial planets have oceans of liquid water and jovian planets do not.

D

Which of the following is not a major pattern of motion in the solar system?

a. The Sun and most of the planets rotate in the same direction in which the planets orbit the Sun.

b. Nearly all comets orbit the Sun in same direction and roughly the same plane.

c. Most of the solar system's large moons orbit in their planet's equatorial plane.

d. All of the planets orbit the Sun in the same direction - counterclockwise as viewed from above Earth's north pole.

B

**Which of the following is not a major pattern of motion in the solar system?

a. Most of the solar system's large moons orbit in their planet's equatorial plane.

b. Nearly all comets orbit the Sun in same direction and roughly the same plane.

c. All of the planets orbit the Sun in the same direction - counterclockwise as viewed from above Earth's north pole.

d. The Sun and most of the planets rotate in the same direction in which the planets orbit the Sun.

B

Which of the following planets do not rotate in the same direction as most other planets?

a. Jupiter

b. Venus

c. Jupiter

d. Saturn

B

Which of the following prevents the Moon from being called a planet?

a. The Moon is spherical

b. The Moon orbits the Earth

c. The Moon has a clear orbit

d. The Moon completes a spin around its axis at the same time as it completes an orbit

B

Why is Mars considered to be a potentially habitable world?

a. Robotic rovers have found evidence of microscopic organisms in the surface soil.

b. We observe seasonal changes indicating the presence of plant life.

c. We have evidence that liquid water existed on its surface in the past.

d. It is about the same size as Earth.

C

You've discovered a new object with your telescope! Over many observations, you've noted several features about this object: 1. The object is spherical in shape; 2. The object orbits the Sun; 3. There are many other objects that follow similar orbits around the Sun. How would you classify your object?

a. Dwarf Planet

b. Asteroid

c. Moon

d. Planet

A

Based on its distance from the Sun and the amount of sunlight absorbed by its surface, calculations predict that without a greenhouse effect, Earth's global average temperature would be

a. slightly above the freezing point of water

b. well above the boiling point of water

c. well below the freezing point of water

d. exactly the same as it is measured to be today

C

Based on our current understanding, where is Earth's magnetic field generated?

a. in the crust

b. in the molten outer core

c. in the mantle

d. in the solid inner core

B

Compared to the average surface temperature on the surface of the Earth, the average surface temperature on the surface of Mars is

a. about the same

b. just slightly lower

c. much higher

d. much lower

D

How do the cores of planets form?

a. Tectonic Separation

b. Accretion

c. Differentiation

d. Planetesimal Collisions

C

How does the greenhouse effect result in temperature increases?

a. As a result of slower planetary rotation, less thermal energy is used and therefore is trapped within a planets atmosphere. This in combination with absorbing solar energy results in significant temperature increases.

b. Thermal energy released from volcanic and tectonic activity during outgassing gets entangled and absorbed by the emitted gasses, resulting in a significantly decreased cooling rates.

c. The greenhouse effect is only a concern for planets that are closer to the Sun.

d. Solar energy absorbed by the planet gets emitted as infrared, which is absorbed by atmospheric gasses, thereby trapping that heat/energy.

D

Studies of volcanic outgassing indicate that Earth has outgassed far more water vapor into its atmosphere than exists in the atmosphere today. Where did this water vapor go?

a. It froze to form the polar caps.

b. It condensed to make the oceans.

c. It became chemically incorporated into rocks in the crust.

d. It escaped into space.

B

The extent to which an atmosphere loses gas to thermal escape depends on ________ of the atmosphere.

a. only the temperature

b. both the temperature and pressure

c. both the temperature and the atomic or molecular weight of the gases

d. only the atomic or molecular weight of the gases

C

The fact that Earth is habitable but Venus is not tells us that one crucial factor in surface habitability is a planet's __________.

a. size

b. rotation rate

c. distance from the Sun

d. composition

C

The most important factor that allowed the solar wind to strip substantial amounts of gas from Mars was probably the

a. formation of the polar caps

b. increasing strength of the solar wind

c. damaging effects of impacts

d. loss of the planet's protective magnetic field as it cooled

D

The relative ages of a planet's surface regions are determined based primarily on ________ in the region.

a. the number of dried-up riverbeds

b. the number of volcanoes

c. the predominant colors of the rock

d. the number of impact craters

D

The relative number of solar system planetesimals remains constant over time.

a. True

b. False

False

Venus has many volcanoes, and its surface has been shaped by volcanic activity and tectonic activity.

a. False

b. True

False

What happens to particles in hot gas?

a. All particles move very fast

b. All particles move in the same direction

c. On average, the particles move very fast

d. The particles themselves are hot

C

What role do planetesimals play in planetary histories?

a. As early solar system leftovers, such as comets and asteroids, they can crash into planets leaving craters across planet surfaces.

b. As smaller freely roaming planets, such as dwarf planets, their gravitational influences can warp planet surfaces.

c. Planetesimals do not play a significant role in planetary histories.

d. As large fragments floating through space, they can accrete onto already formed planets and become mountains on planet surfaces.

A

Which of the following has the strongest magnetic field?

a. Mars

b. Earth

c. Moon

d. Venus

B

Which of the following is correct?

a. Sources of planetary atmospheres are outgassing, evaporation, and impacts & cratering; they each contribute significantly to atmosphere compositions

b. Sources of planetary atmospheres are outgassing, evaporation, and impacts & cratering; but the evaporation is by far the most dominant source

c. Sources of planetary atmospheres are outgassing, evaporation, and impacts & cratering; but the outgassing is by far the most dominant source

d. Sources of planetary atmospheres are outgassing, evaporation, and impacts & cratering; but the impacts & cratering are by far the most dominant source

C

Which of the following is true?

a. S-waves are compression waves that can only move through solids. P-waves are transverse waves that can only move through liquids..

b. P-waves are compression waves that can only move through solids. S-waves are transverse waves that can move through solids, liquids, and gasses

.c. S-waves are compression waves that can move through liquids and gases. P-waves are transverse waves that can move through solids and liquids.

d. P-waves are compression waves that can move through solids, liquids, and gases. S-waves are transverse waves that can only move through solids.

D

Why is Venus's surface temperature so high?

a. Venus has very little carbon dioxide in its atmosphere

b. It has experienced a runaway greenhouse effect

c. It is closer to the Sun than Earth

d. Venus has no liquid ocean

B

You discover two new planets in a different star system: Planet A and Planet B! Planet A has a radius of 2000km, whereas Planet B has a radius of 6000km. With no other information, what can you likely conclude about the planets?

a. Planet A will likely have many moons

b. Planet A is smaller, meaning it has a higher chance of hosting life.

c. Planet B will likely have more volcanoes.

d. Planet A is terrestrial and Planet B is Jovian.

C

How many stars are there in our Solar System?

A) None

B) One

C) A few hundred million

D) Afewhundredbillion

B

Compared to planets in the inner Solar System, planets in the outer Solar System generally:

A) Aresmaller

B) Have thinner atmospheres

C) Are made of lighter elements

D) Areyounger

E) Have fewer moons

C

Scientists announce the discovery of a new planet in another solar system. The planet is the same size as Earth and orbits a star just like the Sun at a distance of 0.9 AU. Based on our own solar system, what can we conclude about this planet?

A) Itwillbehighlygeologicallyactive.

B) It will have a similar climate to Earth.

C) It will have a thin atmosphere.

D) Itwillhaveatleastonemoon.

E) It will be made mainly of rock.

E

Why do molecular clouds collapse?

A. They have a lot of mass.

B. They are very hot.

C. They are very dark.

D. They are very dusty.

E. They are made o fhydrogen and helium.

A

According to the nebular theory of solar system formation, what three major changes occurred in the solar nebula as it shrank in size?

A) Its mass, temperature, and density all increased.

B) It got hotter, its rate of rotation increased, and it flattened into a disk.

C) It gained energy, it gained angular momentum, and it flattened into a disk.

D) Its gas clumped up to form the terrestrial planets, nuclear fusion produced heavy elements to make the jovian planets, and central temperatures rose to more

B

In essence, the nebular theory holds that _________.

A) nebulaearecloudsofgasanddustinspace

B) the planets each formed from the collapse of its own separate nebula

C) the planets formed as a result of a near-collision between our Sun and another star

D) oursolarsystemformedfromthecollapseofaninterstellarcloudof gas and dust

D

Consider a rock that is found to have seven times as much Argon-40 than Potassium-40. Assuming the rock contained no Argon-40 when it first formed, how old is the rock?

*Note the half-life of Potassium-40 is 1.25 Billion Years

A) 1.25Byrold

B) 2.5 Byr old

C) 3.75 Byr old

D) 5Byrold

C

Imagine that a planet and its much smaller moon start at the same temperature. After 1 billion years, which will be cooler

A) The planet because it has a larger surface to radiate from

B) The moon because it generates less internal heat

C) They will be the same temperature

D) Need more information

B

Is a flatter or more cratered surface older on a moon

Flatter

Based only on the sizes and masses of each planet, which statement should be TRUE?

A. Mars should have a closer core than Venus.

B. Mars should have more active volcanoes than Earth.

C. Mars should rotate slower than Venus.

D. Mars should have fewer active volcanoes than Venus.

E. Mars should be hotter inside than Earth.

D

Why is the carbon dioxide cycle important to our existence?

A) It will save us from the otherwise destructive effects of global

warming.

B) It is the cycle responsible for ice ages, which have had profound effects on our evolution.

C) It is the cycle in which carbon dioxide is exhaled by animals and used by plants.

D) Over long periods of time, it acts as a thermostat to keep Earth's temperature in a relatively narrow range.

D

What speed is necessary to escape the surface of Mars? Note that Mars has a mass and radius of 6.39 x 1023 kg and 3389.5 km. The gravitational constant is 6.67 x 10-11 m3 s-2 kg-1.

RECALL: Vesc = (2GM/R)1/2 = √(2GM/R) HINT: Watch units!

a) 2.7 km/s

b) 5.0 km/s

c) 6.3 km/s

d) 7.2 km/s

B

What is the role of the magnetosphere in Earth's habitability?

A) It shields the atmosphere from particles of the solar wind.

B) It blocks the loss of atmospheric gas to thermal escape.

C) It shields Earth from many asteroid and comet impacts that would otherwise occur.

D) It produces the lights of the aurora.

A

How might Venus' runaway greenhouse effect have been prevented?

A) More volcanoes.

B) Faster rotation.

C) Less sunlight.

D) Less gravity.

E) More cratering.

C

Why are larger moons

(nearly) spherical?

a) They were spinning more during planet formation.

b) Higher iron content of the cores.

c) Force of gravity is greater than the strength of the rock/ice.

d) They had more atmosphere which caused erosion.

C

If the moon was twice as massive, then tides would be

A) Largerandtwiceasfrequent

B) Smaller and half the frequency

C) Larger, but the same frequency

D) Theywouldn'tchange

C

Why is Ceres nearly spherical?

A) The collisions of planetesimals that made Ceres came from all directions - so it averaged out.

B) Erosion: it used to have a thick atmosphere and liquid water on the surface.

C)It is large enough the strength of gravity is stronger than the strength of the rock/ice it is made of.

D) Jupiter's nearly circular orbit has rounded it off.

C

Which of the following is the main distinction between an asteroid and a dwarf planet?

A) orbital eccentricity

B) shape

C) age

D) orbital semi-major axis

E) number of objects sharing the same orbit

B

A small meteorite is found that is made mainly from volcanic rock. Where could it have come from?

A) The metallic core of a planet or dwarf planet which was destroyed in a major collision

B) The crust or mantle of a planet or large asteroid

C) The surface of a comet

D) It formed that way in the disk during planet formation.

B

Which of the following is the main distinction between an asteroid and a comet?

A) Orbital eccentricity

B) Shape

C) Age

D) Composition

E) Number of objects sharing the same orbit

D