Chapter 10

Approximately how long is a sidereal day on Mars?

1 day

What is the length of a Mercury day in Earth days?

176 days

How many days does it take for Venus to complete one revolution (orbital period) around the Sun?

225 days

What is the approximate length of a solar day on Mars?

24 hours

Approximately how long is a sidereal day on Venus?

243 days

What is the approximate length of a solar day on Venus?

243 days

How many days does it take for Mars to complete one revolution around the Sun?

687 days

The number of major plains in the northern hemisphere of Mars is

7

The largest continental (highland) area on Venus is called:

Aphrodite

Like the Earth, volcanoes on Venus appear in recognizable and distinct chains.

False

What makes astronomers believe that Mars once had rivers and running water?

Images from orbiting spacecraft reveal ancient channels that look like dried-up river beds on Earth (and our rovers show geological formations made by running water)

Why are there no smaller craters on the surface of Venus, only bigger ones?

In Venus' thick atmosphere all smaller chunks of material burn up before they can reach the surface

The spacecraft that sent back the most detailed radar images of Venus and showed us features as small as a football field is:

Magellan

The first spacecraft to orbit another planet circled Mars in 1971. It was:

Mariner 9

Mars appears to have long branching channels that have the appearance of being formed by a flowing liquid. Yet we know that liquids would not stay liquid in the very thin atmosphere we have on the Martian surface? So how can we explain the channels?

Mars had a thicker atmosphere long ago when the channels formed

Why is it so much easier to determine the length of the day on Mars than on Venus?

Mars' atmosphere is generally pretty clear (so the surface is visible) while Venus is always cloudy

The highest mountain on Venus is also the only feature to be named after a man; its namesake is the Scottish scientist who laid the foundations for our understanding of electro-magnetic waves. This is Mount:

Maxwell

Which of the inner planets has the most eccentric orbit?

Mercury

The largest volcano on Mars is called:

Olympus Mons (Mt. Olympus)

The person who really publicized the idea of canals on Mars and impressed it on the public mind was:

Percival Lowell

The observation that began the 19th and early 20th century fascination with Mars as a place for life was:

Schiaparelli's seeing what seemed to him to be long straight features on the red planet

One of the most impressive features of the geology of Mars is an uplifted area about the size of North America, with volcanoes on it, which is called the

Tharsis Bulge

Why does Mars have an overall reddish color when we see its surface from afar?

The material of Mars' surface contains a lot of iron oxide, the same chemistry that makes rusting metals look reddish

Which piece of evidence suggests that the inner planets were formed from the same rotating cloud of gas and dust?

The planets orbit the Sun in the same direction and in almost the same plane.

Craters on Venus appear to be fairly evenly distributed across the planet.

True

The existence of large numbers of craters in the highland areas implies that the highlands, geologically speaking, are much older than the lowland plains.

True

There are significantly more craters in the highland areas than in the lowland plains.

True

The spacecraft that soft-landed successfully on the surface of Venus (and briefly sent back pictures while sitting in that destructive environment) were called

Venera

The planet that most resembles the Earth in size and internal composition is

Venus

What planet can come closest to the Earth in its orbit and look brightest in our skies?

Venus

Most planets in our solar system rotate in a counter-clockwise direction when viewed from above the North pole of the Sun. What is unusual about the rotation of Venus?

Venus rotates in the opposite direction to all other planets

What is unusual about the rotation of Venus?

Venus rotates in the opposite direction to all the other planets

Which planet(s) are found within the Sun's habitable zone?

Venus, Earth and Mars

There was a pair of spacecraft whose components both orbited the planet Mars and landed on its surface in 1976. These spacecraft were called:

Viking

Which of the following is NOT a correct statement about the rotation of Venus? a. Venus rotates in roughly the same time period as Earth b. Venus rotates in a retrograde way (east to west) c. the two definitions of a day (how long it takes for a star to return to the same position in the sky and how long it takes the Sun to return to the same position) do not agree on Venus d. the rotation rate of Venus had to be determined from radar measurements e. Venus has the longest rotation period of any planet in the solar system

a. Venus rotates in roughly the same time period as Earth

Mars rovers (such as Opportunity and Curiosity) have identified evidence that their landing sites were once under water. Which of the following is among the kinds of evidence they have identified? a. they found liquid water deposits just under the surface when they dug down a few feet b. they found rock formations that show the area was under water and also minerals that only form in water c. they found warm salt water spurting up in the form of geysers d. they found a lot of water vapor in the martian atmosphere just above their landing sites e. they found buried ropes and buoys from ancient martian swimming holes

b. they found rock formations that show the area was under water and also minerals that only form in water

Astronomers estimate that the runoff channels seen on Mars must be at least 3.9 billion years old. How do they estimate ages like this?

by counting impact craters in the regions containing these channels

Astronomers estimate that the plains of Venus are only about 500 to 600 million years old. How do they estimate dates like this?

by counting the craters visible on the surface and comparing crater counts to other worlds

Which of the following statements about the planet Venus is true? a. its thick nitrogen-oxygen atmosphere acts like a greenhouse, keeping it hot b. it rotates on its axis in the same direction as the Earth does c. it has a thick layer of clouds containing sulfuric acid droplets d. the atmospheric pressure near the surface is about the same as Earth's e. the "face of Miss Piggy" feature indicates that Venus is inhabited

c. it has a thick layer of clouds containing sulfuric acid droplets

Which of the following is NOT one of the key reasons that so many spacecraft from Earth have visited Venus and Mars? a. they are the two planets closest to the Earth b. they resemble the Earth in a number of significant ways c. their atmospheres are very similar to the Earth in terms of their chemical make-up d. both have tantalized us when seen through a telescope -- one because it is perpetually covered by clouds, the other because it shows seasonal changes e. they each have a solid surface on which we can trace their geological history

c. their atmospheres are very similar to the Earth in terms of their chemical make-up

On some parts of Mars, it gets cold enough for a gas to freeze out of the atmosphere that does not freeze out by itself at the temperatures and pressures on Earth. This gas makes up some of the polar caps on Mars and is:

carbon dioxide

The same gas makes up most of the atmosphere of Mars and Venus. This gas is:

carbon dioxide

The Viking spacecraft were designed -- in part -- to search for life on Mars. Which of the following statements about the results of these experiments is true? a. Viking discovered a form of life on Mars that does not require water to thrive b. Viking did not discover larger life forms on Mars, but did find some Mars bacteria c. Viking did not discover life on Mars today, but did find a lot of fossils indicating Mars had life in the past d. Viking found that the surface of Mars in the two places it searched did not have any life or even life's building blocks e. Viking did find a whole Martian civilization, but they are hiding it from the news media

d. Viking found that the surface of Mars in the two places it searched did not have any life or even life's building blocks

Which of the following statements about the atmosphere of Mars today is FALSE? a. it is made mostly of carbon dioxide b. it is roughly as thin as the Earth's air would be about 30 km up c. it has a haze made of carbon dioxide crystals d. droplets of liquid water rain irrigate the surface of Mars regularly e. there are occasionally great windstorms in the lower atmosphere

d. droplets of liquid water rain irrigate the surface of Mars regularly

Which of the following statements about Valles Marineris, the great "grand canyon system" on Mars is true? a. it is much shorter than the Grand Canyon in Arizona, but much much wider b. it was discovered by Giovanni Schiaparelli in the 19th century c. it was hard to photograph because it is always covered by wind-blown dust d. landslides have helped broaden the canyons since they were first formed e. although the canyons are long and wide, they are very shallow, only a few feet deep

d. landslides have helped broaden the canyons since they were first formed

Which of the following is NOT a way that Venus resembles the Earth? a. its size (diameter) b. its overall density c. the surface gravity (which tells us how much we would weigh there) d. the thickness and pressure of its atmosphere e. you can't fool me; Venus resembles Earth in all of the above ways

d. the thickness and pressure of its atmosphere

Which of the following is evidence for volcanic activity on Venus? a. the fact that the lava plains are only 500 million or so years old b. the existence of large volcanic mountains such as Sif Mons c. the discovery of thousands of small volcanic cones of the surface of Venus d. the pancake domes of Venus e. all of the above

e. all of the above

Which of the following is NOT a way we have studied the planet Mars so far? a. observing it through telescopes from Earth b. sending a spacecraft into orbit around it c. landing a spacecraft on the surface and examining the soil in an automated laboratory d. studying samples of Mars that were blasted off Mars by impacts long ago, and found later on Earth e. sending spacecraft to Mars which have brought samples of the planet back to Earth

e. sending spacecraft to Mars which have brought samples of the planet back to Earth

Which of the following would NOT be one of the problems faced by an unprotected Earthling stranded on Mars? (Unprotected meaning no space suit.) a. the composition of the atmosphere b. the lack of liquid water today on the surface c. the low atmospheric pressure d. the lack of any ozone layer shielding e. the extreme (high) heat at most latitudes

e. the extreme (high) heat at most latitudes

The Magellan spacecraft revealed a wide variety of volcanic features on Venus, including some that looked like ticks and spiders. What instrument aboard Magellan was used for these investigations?

imaging radar

A very rich and eccentric tourist in the future hires you to fly him to a region of Venus' atmosphere where the temperatures and pressures are the most Earth-like. Where would you take him?

in the cloud layers about 50 km above the surface

Astronomers believe that Mars formed with a much thicker atmosphere than it has today. Where did this atmosphere go?

it escaped into space (and some later froze out as Mars got cold)

Valles Marineris is a wide, deep network of chasms stretching for some 2500 miles on the surface of Mars. How do we believe such a big set of canyons formed originally?

it was caused by tectonic pressures from deep within the planet

The large circular coronae on Venus are:

large regions where hot magma rising from the interior of Venus puts pressure on the surface material

About 75% of the surface of Venus consists of

lowland lava plains

A crucial difference that helps explain why Venus is so hot and the Earth isn't is that:

on Venus, there was eventually no ocean to remove carbon dioxide from the atmosphere

The canals that late 19th and early 20th observers thought they saw on Mars turned out to be:

optical illusions

The heavily cratered highland areas of Mars are located

primarily in the south with some significant sections in the north

I want to examine the surface of a planet which is completely covered by a thick layer of clouds all the time. What wavelength of electromagnetic radiation would I be smartest to use:

radio waves (like radar)

The surrounding terrain in Chryse Planitia, the landing area for Mars Pathfinder, is best described as:

relatively flat and rocky

The troposphere (the lowest layer in the atmosphere) of Venus

resembles being about a kilometer or so under the Earth's ocean -- a huge mass of air keeps temperatures pretty much the same all over the planet

The total surface area of planet Mars is roughly equal to the

surface area of the Earth's continents

Scientists have clearly noted the relatively random distribution of volcanoes on Venus. The most likely reason for this is believed to be due to

the lack of tectonic plates on venus

One way in which Mars closely resembles the Earth is:

the length of its day (period of rotation)

The process by which Venus became so much hotter than the Earth is called:

the runaway greenhouse effect

Small craters less than 10 km (6.2 mi) in diameter are scarce on the surface of Venus because:

the thick atmosphere filters out the smaller asteroids before they hit the surface

What is one way that we humans are currently making the atmosphere of the Earth more like that of Venus?

we are adding carbon dioxide and other greenhouse gases to the atmosphere, which is leading to global warming