What is Rayleigh scattering, and what are its most noticeable effects for us on Earth?
Rayleigh scattering: light scattered by Earth's atmosphere. When the Sun is near the horizon it must pass through more atmosphere, blue light is easily scattered and replaced by reds and yellows.
What is the greenhouse effect, and what is its importance to the surface temperature of the Earth?
Light not reflected by clouds reach Earth's surface and radiate back but is absorbed by CO2 in atmosphere causing temperatures to rise. (More CO2 means more radiation trapped in atmosphere and thus higher temperatures.)
What is convection, and how does it affect the Earth's atmosphere?
Convection: rising of warm air and falling of cool air--transfers heat from lower (hotter) areas to higher (cooler) areas. (weather and wind are the result)
Explain how the Moon produces tides.
Gravitational force of moon interacts with oceans (near and far side of Earth). On the opposite side, ocean water is left behind as Earth is pulled closer to the Moon.
By comparison with its average density, what do the densities of water and the Earth's crust tell us about the interior?
Interior has higher temperatures and is more dense--core must be rich in nickel-iron.
Granite and Basalt make up most of the crust--low density lets the crust "float" atop the denser matter of the mantle and core.
Describe the Earth's magnetosphere, and describe how it was discovered.
Magnetosphere: region around a planet influenced by the magnetic field. Discovered by artificial satellites in the 50's.
Poles are roughly aligned with Earth's spin axis but drift at a rate of 10 km a year. Field lines indicate the strength and direction
How do geologists use earthquakes to map the Earth's interior?
Seismographs monitor earth's tremors which move depending on the density of matter it travels through--by measuring speed of wave we can measure density of matter.
Compare and contrast P-waves and S-waves, and explain how they are useful in geology.
P-waves (pressure): travels through liquids and solids, faster than S-waves, vibrate in a direction parallel to direction of motion of wave.
S-waves (shear): motion perpendicular to direction of wave travel, pushes material side to side.
Give two reasons for thinking the Earth's core is liquid.
Shadow zones and dynamo theory (depends on a liquid metal core)
What does differentiation tell us about the Earth's history?
Earth was molten at one time, higher density matter sank to core, lower density replaced on surface.
How does convection affect the interior of the Earth?
Warm mantle rock rises and squeezes through cracks in crust producing geysers or volcanoes. Some warm rock also cools and falls back to lower levels (circulation patterns). Riding atop these circulation patterns are the plates.
How did radioactive decay heat the Earth early in its history, and when did this heating end?
Radioactivity: the release of energy by rare heavy elements.
These elements release energy and heat their surroundings as their nuclei decay into simpler lighter ones. With enough time and atoms heat builds up in the interior, adding to the energy left to
What process is responsible for the large-scale features on the Earth's surface (mountains, oceanic trenches, and so forth)?
Continental drift or plate tectonics
What conditions are needed for there to be a dynamo in the core of the Earth, and what does this dynamo produce?
A spinning, electrically conducting liquid metal core.
Employ the concept of escape speed to explain why the Moon has no atmosphere.
The Moon does not have an atmosphere because of its weak gravitational field. (Massive objects retain atmospheres because a larger escape speed is needed for atoms to escape gravitational pull).
In what sense are the lunar 'maria' seas?
Darker areas resemble the earth's seas, but they are actually flat areas that resulted from lava flows during an earlier time.
What is a synchronous orbit, and how did the orbit of the Moon come to be this way?
Synchronous orbit: the spin of one body is precisely equal to its revolution around another body (same face always facing)
Earth's tidal forces were much stronger when the Moon was closer to Earth, the distortion from the tidal influences could have synch
Unlike the Earth, the surface of the Moon undergoes extreme temperature changes. Why?
It doesn't have an atmosphere.
Describe a widely accepted theory of the Moon's origin.
Impact theory: A collision (glancing blow) between Earth and Mars-sized object long ago. Debris was captured by gravity and set into orbit. Could explain similarities between Earth and Moon.
How is the varying thickness of the Moon's crust related to the presence or absence of maria?
Highland rocks less dense than maria rocks--they represent the Moon's crust. Maria rocks are Moon's old mantle.
Why is Mercury rarely seen with the naked eye?
It rarely strays far from Sun (orbits inside of us).
What does it mean to say that Mercury is in a 3:2 spin-orbit resonance? Why didn't Mercury settle into a 1:1 spin-orbit resonance with the Sun like the Moon did with Earth?
3:2 resonance: the rotation period is exactly two-thirds the planet's orbital period. It cannot settle into a 1:1 resonance (like Moon-Earth) because its orbit around the Sun is eccentric.
What is a scarp? How are scarps thought to have formed? What is the basis for believing that the scarps on Mercury formed after most meteoritic bombardment had ended?
Scarp or cliff, formed when the interior cooled and shrank long ago. (Not volcanic or meteoric).
Unlike the Earth, the surface of Mercury undergoes extreme temperature changes. Why?
It doesn't have an atmosphere and is very close to the Sun.
Why does Venus appear so bright in the sky? On what does the brightness of a planet depend?
It is highly reflective (high altitude clouds)
Describe one observational problem associated with Venus's near resonance of rotation and orbit.
Venus rotates almost five times between one closest approach to Earth and the next; as a result it always presents nearly the same face to Earth at closest approach. Observations of the planet's surface only cover one side.
What is our current best explanation of Venus's slow, retrograde rotation?
The planet was struck by a large body, and the impact slowed the planet's spin to almost zero.
How do the continents of Venus differ from Earth's continents?
Not the result of plate tectonics, rather volcanic activity. The surface appears young, meaning older surfaces were resurfaced within the past few million years.
What is the evidence for active volcanoes on Venus?
High levels of fluctuating sulfur dioxide above Venus' clouds (result of volcanic eruptions).
Given that Venus like Earth has a partially melted iron core, why doesn't it have a magnetic field like Earth's?
The planet rotates too slowly for a dynamo effect to take place.
What did ultraviolet images returned by Pioneer Venus show about the planet's high-level clouds?
90 percent of atmosphere lies within 50 km of the surface. 3 distinct layers of clouds. Above clouds is a high-speed jet stream.
Name three ways in which the atmosphere of Venus differs from that of Earth.
Surface temperatures and pressure are higher on Venus. Atmosphere on Venus extends higher than on Earth.
What are the main constituents of Venus's atmosphere? What are the clouds in the upper atmosphere made of?
High to low: sulfuric acid clouds (high speed jet stream), troposphere (where clouds are), sulfuric acid haze.
What component of Venus's atmosphere causes the planet to be so hot? Explain why there is so much of this gas in the atmosphere of Venus compared with its presence in Earth's atmosphere. What happened to all the water that Venus must have had when the pla
Carbon dioxide (96 % of atmosphere), clouds composed of sulfuric acid, greenhouse effect is very prominent, leading to higher temperatures.
On Earth, sunlight split nitrogen-rich compounds, releasing nitrogen into the air. Water condensed into oceans and
How do the impact craters on Venus differ from those on other bodies in the solar system?
They are volcanic, not meteoric.
What is the evidence that volcanism of various types has changed the surface of Venus?
Larger craters, presence of coronae, lava domes, shield volcanoes.
Why is opposition the best time to see Mars from Earth?
Opposition: when Earth lies between Mars and the Sun.
Mars has an eccentric orbit, it is closest to Earth at opposition, thus it is easier to see.
How were the masses of Mars's moon measured, and what did these measurements tell us about their origin?
Estimated based on measurements of gravitational effect on Viking orbiter. Densities are less than any other planet--they are probably asteroids captured by Mars early in history.
What are the Martian 'canals'?
Evidence supporting theory that Mars once had liquid water.
What is the evidence that Mars never melted as extensively as did Earth?
Lack of current volcanism, absence of magnetic field, low density, high abundance of surface iron.
Why is Mars red?
Planet is covered in iron oxide. Reflects the red part of the light spectrum once carried into the atmosphere.
Why are Martian volcanoes so large?
Mars has low surface gravity, height of volcanoes depend on how much weight it can support, lower gravity means less weight and higher mountains.
Describe the major large-scale features on the surface of Mars.
Tharis bulge: near the equator, caused by upwelling material in mantel.
Olympus Mons: the largest known volcano in solar system.
Valles Marineris: a huge crack in the surface.
Tharsis in the Hellas basin: site of violent meteoric impact.