ASTR 100 lesson 3

According to our theory of solar system formation, what are asteroids and comets?

Leftover planetesimals that never accreted into planets

What is a meteorite?

A fragment of an object from the solar system that has fallen to Earth's surface

What is the Great Red Spot?

A long-lived, high-pressure storm on Jupiter

Which of the following regions on the surface of a terrestrial planet is older?

Heavily cratered region

Which statement about Io is true?

It is the most volcanically active body in our solar system.

A typical shooting star in a meteor shower is caused by a ________ entering Earth's atmosphere.

Pea-size particle from a comet

Which of the following best describes the lunar maria?

Relatively smooth, flat plains on the Moon

What do we mean by the period of heavy bombardment in the context of the history of our solar system?

The first few hundred million years after the planets formed, which is when most impact craters were formed

"Your species often refers to the jovian planets as gas giants. In what sense is this term misleading?"

They actually contain relatively little material in a gaseous state

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

They all have substantial atmospheres.

one piece of evidence that can help astronomers sort out how the planets in our solar system formed is

finding circumstellar disks of material around nearby stars

The average age of the surface of Venus has been determined primarily from

the number of impact craters per unit area of surface.

The planet closest in size to Earth is

venus

The planet in our solar system with the highest average surface temperature is ________.

venus

Which two geological processes appear to have been most important in shaping the present surface of Venus?

Volcanoes and tectonics

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

Water ice

Which of the following signs of water is NOT seen on Mars?

Water ice (as opposed to carbon dioxide ice) in the polar caps

Where are most of the known asteroids found?

Between the orbits of Mars and Jupiter

which of the following is NOT a correct statement about the ways the jovian planets differ from the terrestrial planets?

(F) all the jovians have satelites around them and none of the terrestrials (T) the jovians have rings while the terrestrials do not (T) the jovians are typically colder and further from the sun (T) the jovians are made mostly of liquid and gas (T) the jovians are larger

which of the following is evidence that the solar system formed out of a rotating and collapsing clump of gas and dust

(all of the above) all planets are nearly the same plane all planets revolve in the same direction around the sun the sun spins in the same direction as the orbiting planets

The Caloris Basin on Mercury covers a large region of the planet, but few smaller craters have formed on top of it. From this we conclude that

. the Caloris Basin formed toward the end of the solar system's period of heavy bombardment.

How do asteroids differ from comets?

Asteroids are made of rocky material. Comets are made of icy material

Of the four gases CO2, H2O, N2, and O2, which are greenhouse gases?

CO2 and H2O (carbon dioxide and water)

From center to surface, which of the following correctly lists the interior layers of a terrestrial world?

Core, mantle, crust

Suppose you could float in space just a few meters above Saturn's rings. What would you see as you looked down on the rings?

Countless icy particles, ranging in size from dust grains to large boulders

The graph above plots planet mass (in Earth masses) vs. planet distance from the Sun (in AU). In which labeled region of the graph (A, B, C, or D) would you find the ice giants?

D!! A was the terrestrial planets (closer and less massive), B was the jovian (closer and more massive), and C was the jovian and the ice giants.

The Huygens probe took numerous pictures as it descended to Titan's surface in 2005. What did the pictures show?

Features or erosion, including what appeared to be dry river valleys and lakebeds

What do we mean by the frost line when we discuss the formation of planets in the solar nebula?

It is a circle at a particular distance from the Sun, beyond which the temperature was low enough for ices to condense.

Which hemisphere of Mars has an older surface?

Mars' southern hemisphere is heavily cratered, which indicates an older surface.

What atmospheric constituent is responsible for the blue color of Uranus and Neptune?

Methane

What do we mean by accretion in the context of planet formation?

The growth of planetesimals from smaller solid particles that collided and stuck together

What observational evidence supports the idea that Mercury once shrank by some 20 kilometers in radius?

The presence of many long, tall cliffs

What is the greenhouse effect?

Visible light can enter an atmosphere and heat a planet, then the planet emits infrared light that is trapped by the atmosphere

What do we mean when we say that the terrestrial worlds underwent differentiation?

When their interiors were molten, denser materials sank toward their centers and lighter materials rose toward their surfaces.

Olympus Mons is ________.

a huge shield volcano on Mars

According to current evidence, Pluto is best explained as ________

a large member of the Kuiper belt

A rock found on Earth that crashed down from space is called ________.

a meteorite

the average temperature on a planet earth is higher than you would expect just from the heating of sunlight alone. what is the explanation for this?

carbon dioxide (and other gases) in the atmosphere cause a greenhouse effect

The largest asteroid, and probably the only one to be a spherical "world" is

ceres

what makes astronomers believe that mars once had rivers and running water

images from orbiting spacecraft reveal ancient channels that looks like dried-up riverbeds on earth (and our rovers show geological formations made by running water)

according to the geocentric view everything in the heavens had to go around the earth which was the center of the universe. what objects did Galileo discover with his telescope that clearly didn't go around the earth?

moons around the planet jupiter

in ptolemy's system the planets orbit the earth and not the sun. How did the system explain the retrograde motion of planets like mars?

the planets moved on a small circle whose center in turn circled a point near the earth

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

the surface in the region is younger than the surface in more heavily cratered regions

If Saturn takes about 30 years to orbit the Sun, and its rings were seen edge-on in 2009, when will they appear edge-on next?

2024

Which of the following statements best characterizes the surface of the planet Mars?

All of the big volcanoes are in the northern hemisphere, and most of the craters are in the southern hemisphere

How do asteroids differ from comets?

Asteroids are made of rocky material. Comets are made of icy material.

Why do asteroids and comets differ in composition?

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

Which terrestrial planet(s) would you expect to sustain geological activity for the longest time?

Earth & Venus, because they are the largest terrestrials

Why does increasing the amount a greenhouse gas increase the temperature of a planet?

Greenhouse gases emit visible light.

In my solar system, we have a planet that is the innermost to our star that is exactly like the innermost planet in your solar system. The planet has a very large impact crater with a basin that covers a large region of the planet's surface, but few smaller craters have formed on top of it. What can one conclude from this?

The basin formed toward the end of the solar system's period of heavy bombardment.

Which feature is older?

The scarp cuts across the crater, meaning that it formed after the crater was already there.

The solar nebula hypothesis offers what explanation for the different compositions of these two types of planets

The terrestrial planets were formed near the Sun where, because of the high temperatures, only heavier elements were able to condense.

The tail of a comet always points

away from the Sun and becomes longest and brightest at perihelion.

astronomers estimate that about 25 million meteors strike the earths atmosphere each day. how come we haven't run out of meteors in the long history of the earth

meteors are pieces of dirt left over from the formation of our solar system and from old comets; there is a huge supply of small dirt particles from both sources

A typical shooting star in a meteor shower is caused by a ________ entering Earth's atmosphere.

pea-size particle from a comet