Astronomy exam 2

What major feature of Saturn's moon Enceladus led scientists to suspect it might have a subsurface ocean?

fountains of ice spraying out from the surface into space

Which of the following is not a key line of evidence supporting the hypothesis that Mars once had abundant liquid water on its surface?

the canals of Mars mapped by Percival Lowell

When you see the bright flash of a meteor, what are you actually seeing?

the glow from a pea-size particle and the surrounding air as the particle burns up in our atmosphere

What is the importance of the carbon dioxide (CO2) cycle?

It regulates the carbon dioxide concentration of our atmosphere, keeping temperatures moderate.

The two most important processes in heating the interiors of the terrestrial worlds are:

(1) heat deposited by the process of formation; (2) heat released by radioactive decay

According to modern scientific dating techniques, approximately how long ago did Earth and the other planets of our solar system form?

4.5 billion years

Which of the following best describes how the greenhouse effect works?

A planet's surface absorbs visible sunlight and returns this absorbed energy to space as infrared light. Greenhouse gases slow the escape of this infrared radiation, which thereby heats the lower atmosphere.

Asteroids are ___________?

A small rocky body orbiting the sun

Suppose you view the solar system from high above Earth's North Pole. Which of the following statements about planetary orbits will be true?

All the planets orbit counterclockwise around the Sun.

What is Eris?

An icy object that orbits in the Kuiper belt and is more massive than Pluto

Which of the following best describes the primary difference between asteroids and comets?

Asteroids are rocky and comets are ice-rich.

What are the 2 main ways to detect the gravitational rugs on stars due to their planets

Astrometric and Doppler

Venus has a higher average surface temperature than Mercury. Why?

Because it is heated by an extreme greenhouse effect.

Which statement is not thought to be true of all comets in our solar system?

Comets always have tails.

Why does Earth have so little carbon dioxide in its atmosphere compared to Venus?

Earth has just as much carbon dioxide as Venus, but most of it is locked up in carbonate rocks rather than being free in the atmosphere.

What is the name of the feature indicated by the arrow in this photo?

Great Red Spot

Which statement about asteroids is not true?

If we could put all the asteroids together, they would make an object about the size of Earth.

All the following statements are true. Which one is most important in explaining the tremendous tidal heating that occurs on Io?

Io orbits Jupiter on an elliptical orbit, due to orbital resonances with other satellites.

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

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

Which statement about Jupiter's moon Io is true?

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

What is the significance of this image?

It shows an actual disk of material orbiting another star, providing strong evidence the planets really do form in such disks.

Which of the following is a key factor in explaining why many jovian moons have been more geologically active than the Moon or Mercury?

Jovian moons contain much more ice that can melt or deform at lower temperatures than can the rock and metal that make up the Moon and Mercury.

What are all the blue lines connecting to Jupiter supposed to represent in this picture?

Jupiter's magnetic field

Scientists suspect that Mars once had a global magnetic field. Assuming this is true, which of the following could explain why Mars today lacks a global magnetic field like that of Earth?

Mars's interior has cooled so much that its molten core layer no longer undergoes convection.

This photo was taken from orbit around some planet. What planet is it, and how do you know?

Mars, because we see dried up riverbeds

Which of the following lists the planets of our solar system in the correct order from closest to farthest from the Sun?

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

Which of the following statements about the moons of the jovian planets is true?

Most of the moons have the potato-like shapes of asteroids, but a few are large enough to be spherical in shape.

According to current models of solar system formation, why did Uranus and Neptune end up to be much less massive than Jupiter and Saturn?

Particles in the solar nebula were more spread out at greater distances, so that accretion took longer and there was less time to pull in gas before the solar wind cleared the nebula.

What are the a types of asteroids

Primitive and processed

What planet is this, and how do you know?

Saturn, because of its colors and bright, wide rings.

Uranus and Neptune have methane clouds but Jupiter and Saturn do not. Which factor explains why?

Temperatures on Jupiter and Saturn are too high for methane to condense.

Which of the following is not a major difference between the terrestrial and jovian planets in our solar system?

Terrestrial planets contain large quantities of ice and jovian planets do not.

What is the giant impact hypothesis for the origin of the Moon?

The Moon formed from material blasted out of the Earth's mantle and crust by the impact of a Mars-size object.

Where do we believe the long period comets originate from?

The Oort cloud

Which of the following statements about our Sun is not true?

The Sun's diameter is about 5 times that of Earth.

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

Most of the Moon's surface is densely covered with craters, but we find relatively few craters within the lunar maria. What can we conclude?

The maria formed after the heavy bombardment ended.

Which type of tail always points directly away from the sun?

The plasma tail

What parameters are measured by transits

The size of the planet and the size of the orbit

What is the primary basis on which we divide the ingredients of the solar nebula into the four categories hydrogen/helium, hydrogen compounds, rock, and metal?

The temperatures at which various materials can condense from gaseous form to solid form.

Why does Jupiter have three distinct layers of clouds?

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

How do typical wind speeds in Jupiter's atmosphere compare to typical wind speeds on Earth?

They are much faster than hurricane winds on Earth.

Which of the following is a general characteristic of the four jovian planets in our solar system?

They are significantly lower in average density than are the terrestrial planets.

Comets with orbits that take them through the inner solar system shed sand- to pebble-size particles that then follow the comet around its orbit. How do these particles affect Earth?

They are the particles that produce meteor showers.

Which of the following is not a reason that exoplanets are hard to directly image

They can block some of the light from their host star

Which moon has a thick atmosphere made mostly of nitrogen?

Titan

To date, most exoplanets have been discovered using which method

Transits

What key evidence suggests that Triton is a captured moon?

Triton orbits Neptune in a direction opposite that of Neptune's rotation.

Comets only have tails when they are close to the sun. True or false?

True

Which jovian planet has the most extreme seasonal changes, and why?

Uranus, because of its extreme axis tilt

All of the statements below are true. Which one gives the primary reason why the surface of Venus today is some 450°C hotter than the surface of Earth?

Venus has a much stronger greenhouse effect than Earth.

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.

In this photograph, the large and bright object in the sky is:

a comet (You can tell it is a comet by it bright tails (and the fact that it appears to be stationary relative to the stars).)

According to current evidence, Pluto is best described as ______.

a large member of the Kuiper Belt

A terrestrial world's lithosphere is ________.

a layer of relatively strong, rigid rock, encompassing the crust and part of the mantle

What do we mean by a primitive meteorite?

a meteorite that is essentially unchanged since it first condensed and accreted in the solar nebula some 4.6 billion years ago

What is tidal heating?

a source of internal heat caused by varying tidal forces acting on a moon or other object

Among discovered meteorites, we have found some with all the following origins except _________.

being a fragment from Comet Halley

The asteroid belt is located _________.

between the orbits of Mars and Jupiter

Jupiter's colors come in part from its three layers of clouds. Which of the following is not the primary constituent of one of Jupiter's cloud layers?

clouds of sulfuric acid

The processes responsible for virtually all surface geology are _________.

impact cratering, volcanisms, tectonics, and erosion

The cores of the terrestrial worlds are made mostly of metal because ______.

metals sunk to the centers a long time ago when the interiors were molten throughout

A rock found on Earth that crashed down from space is called a(n) ______.

meteorite

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

methane

Compared to the distance between Earth and Mars, the distance between Jupiter and Saturn is _________.

much larger

If the hypothesis tracing the extinction of the dinosaurs to an impact is correct, the dinosaurs died off largely because ______.

of global climate effects initiated by dust and smoke that entered the atmosphere after the impact

In essence, the nebular theory holds that _________.

our solar system formed from the collapse of an interstellar cloud of gas and dust

What are the two geological features that appear to set Earth apart from other terrestrial worlds in our solar system?

plate tectonics and a high level of erosion

Overall, Jupiter's composition is most like that of _________.

sun

In the context of the formation of planets in the solar nebula, the frost line marks the distance from the Sun beyond which _________.

the temperature was low enough for hydrogen compounds to condense into ices