Astronomy 4 Answers – Flashcards
Unlock all answers in this set
Unlock answersquestion
Why does the Moon have a layer of "powdery soil" on its surface?
answer
It is the result of countless tiny impacts by small particles striking the Moon.
question
What observational evidence supports the idea that Mercury once shrank by some 20 kilometers in radius?
answer
the presence of many long, tall cliffs
question
Olympus Mons is ________.
answer
a huge shield volcano on Mars
question
Which of the following does not provide evidence that Mars once had abundant liquid water on its surface? - the presence of features that look like dried up river beds - the presence of tiny spherical rocks made of the mineral hematite (that forms in water) - the presence of very old craters that appear to have been eroded by rain - the presence of canali, discovered in the late 1800s by Giovanni Schiaparelli and mapped by Percival Lowell
answer
The presence of canali, discovered in the late 1800s by Giovanni Schiaparelli and mapped by Percival Lowell
question
How does seafloor crust differ from continental crust?
answer
Seafloor crust is thinner, younger, and higher in density.
question
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?
answer
The maria formed after the heavy bombardment ended.
question
Which of the following is the underlying reason why Venus has so little wind erosion? - its small size - its thick atmosphere - its slow rotation - its relatively close distance to the Sun
answer
its slow rotation
question
All the following statements about Venus are true. Which one offers evidence of a global repaving about a billion years ago? Venus has relatively few impact craters and these craters are distributed fairly evenly over the entire planet. Venus has many circular features, called coronae, which appear to be tectonic in origin. Venus's largest features are three elevated regions that look somewhat like continents. Venus appears to lack any water that could lubricate the flow of rock in its crust and mantle.
answer
Venus has relatively few impact craters and these craters are distributed fairly evenly over the entire planet.
question
Why are there fewer large impact craters on the Earth's seafloor than on the continents?
answer
Seafloor crust is younger than continental crust, so it has had less time in which to suffer impacts.
question
Based on all we know about the terrestrial worlds, what single factor appears to play the most important role in a terrestrial planet's geological destiny?
answer
its size
question
Earth is the only planet in the solar system known to have plate tectonics.
answer
True
question
Mars has virtually no magnetic field.
answer
True
question
Erosion is the most important geological process on Venus.
answer
False
question
In the inner Solar System, the largest surface features are found on the largest planets.
answer
False
question
The process in which one plate slides under another is called subduction and is marked by deep ocean trenches.
answer
True
question
Why do we think Mercury contracted within about a billion years after it formed?
answer
The surface has long cliffs due to tectonic compression. There's no features that show evidence to tectonic stretching. We can then predict there was a contraction rather than expansion.
