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22 Cards in this Set
- Front
- Back
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15. What are the two kinds of seismic waves? How are they different? How are they similar? Which travels faster? How is this speed difference useful?
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Pressure waves and sheer waves. Pressure waves (sound waves) are compressional; the material changes density and pressure as the waves pass. They can travel through any material. Sheer waves are transverse; the material oscillates side to side as the waves pass (can only travel through solids).
P waves travel faster then S waves. Measuring the delay between the two tells you the distance between the tremor and the seismograph station. |
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16. What are crustal plates? What is continental drift? What is plate tectonics? Are they the same? What types of geologic activity is associated with the edges of the plates?
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The crust is broken up into many plates floating on top of the mantel
Continental drift is…. Plate tectonics is when the plates of the crust are carried along in a slow motion as they ride on top of the mantle. The edges of plates can form mountains, faults… |
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17. Why is ocean crust young? Why are the continents old?
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The ocean crust is constantly being formed and subducted back into the mantle.
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18. What are the main chemical components of Earth's atmosphere? Which gases are considered "greenhouse gases"?
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The atmosphere is made up of mostly nitrogen with some oxygen and little amounts of water vapor, argon, and carbon dioxide. Water vapor and carbon dioxide are considered greenhouse gases.
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19. What is the difference between "weather" and "climate"? In which part of the atmosphere does weather occur? Where is most water vapor in the atmosphere?
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Weather is the day to day change the atmosphere undergoes in temperature, water vapor content, and wind speed. Weather occurs in the troposphere. Climate is the weather averaged over a year or more. Most water vapor is in the troposphere.
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20. What is convection? How does it affect the heat and water vapor in Earth's atmosphere?
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Convection is the process in which warm, humid air close to the ground is floating and rises and is then replaced by sinking, drier and colder air. It drives most weather on Earth.
Water condenses into rain or ice, releasing heat; heat is transported into the upper atmosphere. Water evaporates from oceans and land into dry air; sunlit warm water and land heats the air. |
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21. What is the Coriolis effect? What produces the Coriolis effect on Earth? What effect does the Coriolis effect have on large storms? On toilets? Why one and not the other?
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Any object moving northward in the northern hemisphere is moving faster to the east then the ground it is traveling over. Its motion bends eastward relative to the ground. Likewise, an object moving southward in the southern hemisphere is also deflected eastward.
The Earth’s rotation produces the C/E on Earth. It can create cyclones in extreme low pressure regions where air spirals in the center of a storm. The C/E has no effect on toilets b/c the distance the water travels is too small to affect the motion. |
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22. What is the "ozone layer"? How did it form? What does it do?
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The ozone layer blocks solar ultra violet light that is energetic and harmful. It’s in the stratosphere. It formed two billion years ago. It allows life for plants and animals.
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23. What generates Earth's magnetic field? What does Earth's magnetic field do? What is the aurora and where does it occur? Why is it more commonly visible near the poles?
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Earth’s magnetic field is generated by the rotating liquid iron core of the planet (dynamo theory). It protects Earth from solar wind. The liquid iron is slightly electrically charged because the temp of the core is so high.
At the top of the atmosphere energetic protons and electrons from the Sun collide with atoms of oxygen and nitrogen and cause the atoms to emit light called the aurora (aka false dawn). It is commonly visible near the poles because…. |
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24. What causes the Moon's phases? What is an eclipse? How are phases and eclipses different from each other? Why don't we see an eclipse every New and Full Moon?
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The moon’s shape appears to change as it orbits Earth because you see the moon by reflected sunlight and sunlight illuminates different amounts of the side facing Earth. A lunar eclipse occurs at a full moon when the moon moves through the Earth’s shadow. A solar eclipse occurs when the moon moves between Earth and the sun.
The moon’s orbit crosses the ecliptic at 2 locations called nodes and eclipses can only occur when the sun is crossing a node (eclipse seasons). |
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25. What is tidal locking or synchronous rotation? What effect does it have on the Moon's rotation rate? What is the Moon's rotation rate? How long is a day on the Moon?
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The Moon’s rotation period is equal to its orbit (1:1). Mercury rotates 3 times every 2 orbits (3:2). The Moons rotation is 27 days (about a month) and one day on the Moon is 27 Earth days long.
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26. What are the main geologic forces that have shaped the Moon's surface? What are the two major surface types on the Moon? What characterizes each? How did they form? What causes the Moon's terrain to look so rounded and smooth? What is the approximate average age of the lunar surface?
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• Heavily cratered (Cratered Highlands, from heavy bombardment period in the early history of the solar system, abundant on far side)
• Dark and smooth (large dark, flat areas called the Maria, use to be bodies of water) • Craters on lunar surface date back to a billion years ago |
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27. What is the currently accepted theory for the formation of the Moon? What evidence is there that supports this theory?
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The giant impact hypothesis states that an impact between a Mar’s size object and the Earth caused enough material (mostly from the mantle) to be ejected into Earth’s orbit and the material from the disk of debris containing silicate rock condensed to form the Moon. Evidence:
• Small metal core of the Moon • Absence of volatile elements in the Moon • Rapid rotation of the Earth • Tilt of the Moon’s orbit relative to Earth |
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28. Does the Moon have a magnetic field? If not, why not? What evidence do we see that the Moon has cooled and shrunk? Why did the Moon cool faster than Earth?
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No, the Moon is geologically dead. The Moon is an airless world with little gravity. It has wrinkled ridges (most on the maria) to show shrinkage. The Moon experiences extreme temperature changes because it has no atmosphere. The Moon cooled faster then the Earth because it’s a lot smaller.
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29. Why don't the Moon and Mercury have any atmospheres? What effect does the lack of an atmosphere have on surface temperatures? What are surface temperatures like on these two worlds?
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The gravity is too week to contain an atmosphere. They have no clouds to reflect sunlight during the day (extremely hot) and when in the shade (extremely cold). It is about 300-400*K during day and 100*K at night (dynamic temps).
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30. Why do Mercury and Venus always appear close to the Sun in the sky? Why is Venus so bright?
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Both planets are closer to the Sun than the Earth so they appear closer to the sun in the sky. Venus is b/c ¾ the sunlight received is reflected by clouds.
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31. Approximately how fast do Mercury and Venus rotate compared to Earth? Is Mercury tidally locked to the Sun? How do we know?
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Mercury rotates 3 times while it goes around the Sun twice. Mercury isn’t tidally locked to the Sun because observations showed that the “dark side” was actually very hot. Venus rotates once every 243 Earth days and the direction of the rotation is opposite from all the other planets.
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32. What generates Mercury's magnetic field? What explains Venus' lack of magnetic field?
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Mercury’s magnetic field is generated by its solid iron core acting like a giant permanent bar magnet. Venus’ core doesn’t generate a magnetic field because it rotates so slowly.
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33. What are the most common geologic features on Mercury? How is the surface of Mercury similar to the Moon's? How are they different? How is the geologic history of Mercury similar to the Moon's? How are they different?
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The surface is characterized by craters and ejecta. The crater density isn’t as high as the Moon’s. The surface is covered in wrinkled ridges which suggests something is erasing craters. The floor of Caloris Basin was flooded like the maria on the Moon. Mercury is also probably geologically dead.
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34. Why is Venus considered Earth's twin? What are the major types of terrain on Venus? How is the surface of Venus similar to Earth's? How are they different? How is the geologic history of Venus similar to Earth's? How are they different? What appears to be the most common geologic process that shapes Venus' surface?
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They have a similar radius, diameter, density, mass, surface gravity and escape speed. The Earth’s magnetic field is strong and Venus’ is weak. Venus also rotates slower. Venus is mainly smooth plains like the ocean’s floor. Both have a lot of volcanoes. Venus’ two large terras are similar to the Earth’s continents. However Venus is dry and has no water. Most common geologic process that shapes Venus’ surface is volcanoes.
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35. What is the atmosphere of Venus composed of? What are surface conditions like on Venus? How did Venus' atmosphere become the way it is? What happened to the water on Venus? How did the loss of water change the way the atmosphere and crust behave?
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The atmosphere is mostly carbon dioxide (97%). The conditions are hellish: yellow, orange, red, sulfuric acid clouds and very hot. It became this way b/c of the runaway greenhouse affect (atmosphere trapped in water and carbon dioxide). The trapped water evaporated, the atmosphere thickened, greenhouse effect increased, and Venus became very hot and dry which made the crust very rigid and strong.
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36. What are the two theories of the evolution of Venus' crust? What evidence are they based on? How are the two theories different?
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One theory states that volcanic activity was slow and continuous (buried old craters) (uniformism) and the other states that it all occurred at once during a brief period (castrophism). This is why Venus has few craters, b/c something has been covering them up.
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