AST 220 Chapter 6
Terms in this set (87)
Venus' rotation period is longer than its period of revolution around the Sun.
Mercury, Venus, and Earth have similar densities.
The density of Mars is very similar to that of the other terrestrial planets.
Venus can appear as a crescent through the telescope.
Mercury's rotation and revolution are an example of a 3:2 resonance.
Although it has no liquid water, Mercury has a tidal bulge.
Compared to Earth, Venus spins very rapidly on its axis.
Atmospheric pressure on Mars is roughly half that of Earth's at sea level.
Venus' surface temperature cools off at night, much like Mercury's does.
Mercury has the widest variation in surface temperatures between night and day of any planet in the solar system.
The scarps on Mercury are extremely similar to the cratered lunar highlands in appearance.
We now know of polar caps on Mercury, the Moon, Earth, and Mars.
The surface temperature of Venus is 730K, even hotter than Mercury.
The polar caps and dust storms of Mars can be seen with Earth-based telescopes.
The Moon's far side is more ancient and heavily cratered; on Mars, the same is true of its southern hemisphere.
Mars appears red in color because of refraction of light by its atmosphere, much like the color of the totally eclipsed Moon.
There is new evidence that water has flowed as mud on Mars in recent times.
Because of its axial tilt and more elliptical orbit, Mars' polar caps change size even more than the Earth's do.
The seasonal polar caps on Mars, which grow and shrink over the year, are primarily carbon dioxide.
Winds on Mars give rise to planet-wide dust storms.
The low surface gravity helps Martian volcanoes grow to great heights.
Mercury has an unusually small core.
Mars has a weak magnetic field.
The Mars Rover found undisputed microfossils, proving life once existed on Mars.
Venus and Mercury both have magnetic fields similar to Earth's.
Carbon dioxide is the predominant atmospheric gas on Venus.
Running water continues to be the major erosive factor of Mars today.
Running water played a major role in shaping Mars in ancient times.
Which of these gets so bright as to be seen in daylight at times?
Which three worlds have almost identical densities?
Mercury, Venus, and Earth
Which planet shows the widest range of surface temperatures between day and night?
How does Mercury's rotation relate to the Sun?
Its rotation rate is 2/3 as long as its year, due to tidal resonances.
Venus' rotation on its axis
Is clockwise, unlike most other solar system objects
The atmospheric pressure on Venus
Is much higher than on Earth
What is the main constituent of the atmosphere of Venus?
The main constituent of the Martian atmosphere is
Why are Mars' seasons more extreme than those of the earth?
All of these contribute to the huge seasonal changes that Mars experiences
Mercury's surface most resembles which of these?
The lunar far side
The scarps on Mercury were probably caused by
the crust cooling and shrinking
What did radar astronomers find in the polar regions of Mercury?
temperatures cold enough to allow thin sheets of water ice
Our most detailed maps of Venus come from
The Magellan space probe
The surface of Venus can be observed with
All of these have provided detailed observations about the surface of our sister planet
Which body has the densest atmosphere?
Which statement is true of Venus' surface?
There are two continent sized uplands
Valles Marineris is the most striking example of a
The deepest depression found on the surface of Mars is the
We have not yet found meteoroids and meteorites derived from
The name of the NASA mission(s) that landed on Mars in 1976 was
Viking I and II
What is true of Mars?
Iron oxide on the surface is responsible for its reddish color
That the Tharsis region on Mars has so few craters
suggests it is the youngest region on the planet
The largest difference between Mars' northern and southern hemispheres is that
the southern appears older, with more impact craters
The presence of a Mercurian magnetic field surprised the planetary scientists on the Mariner 10 team because
the dynamo theory predicted that Mercury was spinning to slowly for one
Much of the water on Mars
is thought to be in a layer of permafrost just below the surface
Of all the planets know in antiquity, _____ is the hardest to observe visually.
Compared to the orbits of Venus and Earth, the orbits of both Mercury and Mars have much _____ eccentricity.
The only two planets which can transit the Sun are _____
Mercury and Venus
The Sun's tidal pull has slowed Mercury's rotation down to a period _____ that of its year.
The direction of the rotation of Venus is exceptional because it is in a _____ direction.
The planet which shows us the widest range of surface temperatures between day and night is _____.
Of all the planets, the axial tilt and rotational period of _____ is most like our own.
While featureless in visible light, we can see some detail in Venus' clouds using _____.
Because of their low surface gravities, the Moon and Mercury lack _____.
The clouds on Venus are made primarily of _____.
_____ are great wrinkle marks on Mercury's crust, due to its core contracting.
The surface of Mercury looks very similar to _____.
The most effective wavelengths to see through the clouds of Venus the surface are _____.
Smooth rolling plains, modest highlands and lowlands, and no water describes the surface of _____.
Unlike our Moon and Mars, all the impact craters found on Venus are _____ in size.
In age, the surface of Venus is much _____ than even the lunar mare.
As with the lunar mare and Earth's ocean basins, the chief rock in the low plains of Venus is _____.
Mars appears red due to _____ on its surface.
Of all the planets, only _____ has surface features easily seen from Earth with ground-based telescopes.
The largest volcano in the solar system, _____, is found on Mars.
Directly opposite the Tharsis uplift and volcanoes on Mars lies the deep _____, perhaps suggesting impact cause and volcanic effect.
Mercury's core is unusually _____, which may help explain its magnetic field.
The planet _____ has the least variation in temperatures on the surface between day and night.
Carbon dioxide dominates the atmospheres of Venus and Mars, but on Earth most of it lies underground as _____.
The ALH84001 meteorite discovered in Antarctica, came from _____, and suggests it may once have had life.
The greatest rift valley system yet found is _____ on Mars.
While _____ gas is the main atmospheric component of both Mars and Venus, its density means it plays a far larger role in heating Venus.
The great barometric changes accompany the sublimation of carbon dioxide in the Martian spring and summer, creating planet-wide _____.
If Mars' atmosphere is mostly carbon dioxide, why isn't it as hot as Venus?
Although it has a carbon dioxide atmosphere, Mars' atmosphere is very thin, much less dense than Venus' or even Earth's.
Other than its atmosphere, name two properties of Venus that are unique among the terrestrial planets.
Venus rotates clockwise and has not been shown to have a magnetic field.
While surface conditions differ greatly, name three ways that Venus and Earth are indeed "sister planets."
No other two planets in the solar system are so similar in size, mass, density, and surface gravity.
How are surfaces of Mercury and the Moon similar? Different? Why?
Both Mercury and the Moon have a similarly heavily cratered surface, this is because of impacts with objects when the Moon and Mercury were being formed and the lack of a heavy atmosphere to erode the objects impacting the surface. Both the Moon and Mercury have no plate tectonics.
Mercury is denser, has a strong magnetic field and is hotter during the day. Its gravity is higher and its atmosphere, though thin, is denser than the Moon's. It's a planet rather than a Moon. There are large, smooth plains of solid lava on the Moon, unlike Mercury, which is more heavily cratered.
Mars is often called a "midway world," similar in some respects to Earth, and in others to our Moon. Explain.
Like our Moon, much of Mars is ancient cratered terrain, and its density is closer to that of the Moon than Earth. But like us, Mars has seasonal variations, polar caps, clouds, an atmosphere, dust storms, and signs of past liquid water and erosion.
Water is one of the most common substances in the universe, and vital to us on Earth. What happened to it on Venus? What happened to it on Mars?
On Venus, ultraviolet light split the water molecules, and the hydrogen then escaped to space. On Mars, the atmosphere became too thin for greenhouse gases to keep the water liquid. Most water froze in the polar caps or as tundra underground