Astronomy Exam 2

PHYS 185

How does the Sun's mass compare with that of the planets?

It is a thousand times more massive than all the planets combined

Where does nuclear fusion occur in the Sun?

In its core

Which planet, other than Earth, has visible water ice on it?

Mercury

Which of the following observations indicates that conditions on Mars may have been suitable for life in the past?

There are very large extinct volcanoes on Mars.

Which planet has a ring system?

Neptune, Saturn, Uranus, Jupiter (All the Jovian planets)

Which planet could an astronaut visit without the need for a spacesuit (and survive)?

None; an astronaut would need a spacesuit to survive a visit to any other planet in the solar system.

The planet closest in size to Earth is

Venus.

Which of the following is not a characteristic of the inner planets?

They all have substantial atmospheres.

Which of the following is not a characteristic of the outer planets?

They are primarily made of hydrogen and helium.

What are the main constituents of the jovian planets?

hydrogen and helium

breath break!

Where are most of the known asteroids found?

between the orbits of Mars and Jupiter (Asteroid belt)

Which of the following is furthest from the Sun?

a comet in the Oort cloud

Astronomers now classify Pluto as really just a large member of           

The Kuiper Belt

Where did the elements heavier than hydrogen and helium come from?

They were produced inside stars

According to our theory of solar system formation, why do all the planets orbit the Sun in the same direction and in nearly the same plane?

The laws of conservation of energy and conservation of angular momentum ensure that any rotating, collapsing cloud will end up as a spinning disk.

Which of the following has not been detected around other stars in the Galaxy?

Strong stellar winds

The heavy bombardment phase of the solar system lasted…

several hundreds of millions of years.

The age of the solar system can be established by radioactive dating of…

the oldest meteorites.

What do meteorites reveal about the solar system?

That the solar system is about 4.6 mil years old

The first planets around other Sun-like stars were discovered…

around the turn of this century

Planets detected via the Doppler technique have been mostly…

Jupiter-mass, in very close orbits

Which planet search technique is currently best suited to finding Earth-like planets?

Transit method

Why are many of the newly detected extrasolar planets called "hot Jupiters"?

Their mas is very similar to Jupiter

The lithosphere of a planet is the layer that consists of

the rocky material of the crust and uppermost portion of the mantle.

Which of the following best describes convection?   

The produces in which warm material expands and rises while cool material contracts and falls.

The three principal sources of the internal heat of terrestrial planets are

accretion, differentiation, and radioactivity.

What are the conditions necessary for a terrestrial planet to have a strong magnetic field?

both a molten metallic core and reasonably fast rotation

How large is an impact crater compared to the size of the impactor?

A) 10 times larger

The relatively few craters that we see within the lunar maria…    

were formed by impacts that occurred after those that formed most of the craters in the lunar highlands

When we see a region of a planet that is not as heavily cratered as other regions, we conclude that…               

The surface area in the region is younger than the surface in more cratered regions.

Which of the following describes erosion?

The wearing down of building up of geological features by wind, water, ice, and other phenomena of planetary weather.

Which of the following describes volcanism?

the eruption of molten rock from a planet's interior to its surface

What kind of surface features may result from tectonics?

(all of the above)

Valles Marineris is a(n)      

A large canyon on Mars

How have we been able to construct detailed maps of surface features on Venus?          

By using radar from spacecraft that were sent to orbit Venus

Why is Mars red?

Its surface is made of ices that absorb blue light.

What are greenhouse gases?

gasses that absorb infrared light

Sunsets are red because…

Sunlight must pass through more atmosphere, and this scatters even more light at bluer wavelengths, transmitting mostly red light.

Why does Mars have more extreme seasons than Earth?

because it has a more eccentric orbit

In what ways is Earth different from the other terrestrial planets?

All of the above are true

Why is Saturn almost as big as Jupiter, despite its smaller mass?

Jupiter's greater mass compresses it more and increases its density.

How do the jovian planet interiors differ?

All have cores of about the same mass, but differ in the amount of surrounding hydrogen and helium.

Why does Jupiter have several distinct cloud layers?                                                                                    

Different layers represent clouds made of gases that condense at different temperatures.

Why are there no impact craters on the surface of Io?

Io did have impact craters but they have all been buried in lava flows.

Which moon did the Huygens spacecraft land on?

Titan

Which of the following best describes the composition of the particles forming Saturn's rings?

Water Ice

Planetary rings are…

all of the above

What is the Cassini division of Saturn's rings?

a large gap, visible from Earth, produced by an orbital resonance with the moon Mimas

Which of the jovian planets have rings?

All of them

Which of the following statements about comets and asteroids is true?

A) Comets are balls of ice and dust.

What do asteroids and comets have in common?

Most are unchanged since their formation in the solar nebula

How do asteroids differ from comets?

Asteroids are made of rocky material, while comets are made of icy material

A rocky leftover planetesimal orbiting the Sun is…

An asteroid

Why do asteroids and comets differ in composition?

Asteroids are formed inside the frost line, while comets are formed outside

Why aren't small asteroids spherical in shape?

Their strength of gravity is less than the strength of the rock

What is a meteorite?

A fragment of an asteroid from the solar system than has fallen to Earth

What characteristic distinguishes a meteorite from a terrestrial rock?

All of the above are true. Meteorite & terrestrial rocks

Primitive meteorites can be distinguished from other meteorites and terrestrial rocks…

contain a noticeable fraction of pure metallic flakes.

What part of a comet always points most directly away from the Sun?     

The plasma tail

Why does the plasma tail of a comet always point away from the Sun?

Because of solar wind that blows the plasma ions directly away from the sun

What happened to the "Impactor" of the Deep Impact mission?               

It created a small crater on the comet.

Comets with extremely elliptical orbits, like Hyakutake and Hale-Bopp…

Are captured by Jupiter

Approximately how long ago was Pluto discovered?

75 years

Rather than being a planet, Pluto is really just a large member of

The Kuiper Belt

What is Charon?

Pluto's largest moon

What is Eris?

the largest known Kuiper Belt object

Pluto is different from the Jovian planets in all of the following ways except which one?

It formed outside of the frost line in the solar nebula.

What is the name of the largest known Kuiper Belt Object?

Eris

On average, how often do impacts large enough to produce mass extinction on the Earth occur?

Once every 100 Mil years

(True of False)1)     A spacecraft traveling through the asteroid belt has a high risk of being destroyed through a collision.

F

(True or False) All meteorites collected on Earth come from asteroids or comets.

F

(True or False) No spacecraft has ever visited an asteroid or comet

F

(True or False) A spacecraft has captured and brought material to Earth from a comet

T

(True or False) All four of the giant outer planets–Jupiter, Saturn, Uranus, and Neptune–have rings.

T

The jovian planets have no solid surface.

T

The more massive planets in the solar system tend to be less dense than the lower mass planets

F

All planets orbit the Sun in the same direction (counterclockwise as viewed from above Earth's North Pole).

T

Within the frost line, planetesimals were composed entirely of rock and outside the frost line planetesimals were composed entirely of ice.

F

Earth's atmosphere resulted from the impact of icy planetesimals that originated in the outer regions of the Solar System.

T

The sky is blue because molecules in the atmosphere scatter blue light more effectively than red light.

T

Impacts were extremely common in the young solar system but are less common today.

T

Without greenhouse gases, Earth's surface would be frozen over

T