Jacob
Terms
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- galaxy
- a large group of stars held together by gravity
- Milky Way
- Our outer galaxy
- spectrum
- a band of colors made when white light is broken up
- expansion redshift
- the shift of a spectrum of a galaxy toward longer(redder)wavelengths due to the expansion of space
- big bang
- the beginning of the universe, when the density of the universe was very high
- background radiation
- electromagnetic radiation left over from the big bang
- quasar
- an extremely bright, extremely distant, high-energy source
- crust
- Earth's solid, rocky surface containing the continents and ocean floor
- original horizontality
- the idea that many kinds of rocks form in flat, horizontal layers
- continental drift
- the idea that a supercontinent split apart into pieces, the continents, which drifted in time to their present locations
- sea-floor spreading
- the idea that new crust is forming at ridges in the sea floor, spreading apart the crust on either side of the ridges
- magma
- hot,molten rock below Earth's surface
- plate tectonics
- the idea that Earth's surface is broken into plates that move
- mantle
- Earth's layer beneath the crust
- subduction
- where plates collide, the sliding of a denser ocean plate under another plate
- fault
- a huge in the crust, at or below the surface, the sides of which may show evidence of motion
- focus
- the point where an earthquake starts, where rocks begin to slice past each other
- seismic wave
- a vibration that spreads out away from a focus when an earthquake happens
- epicenter
- the point on Earth's surface directly above the focus
- aftershock
- the shaking of the crust after the the initial shaking of an earthquake
- seismograph
- a sensitive device that detects the shaking of the crust
- magnitude
- the amount of energy released by an earthquake
- hot spot
- a very hot part of the mantle, where magma can melt through a plate moving above it
- vent
- a central opening in a volcanic area through which magma may escape
- lava
- magma that reaches Earth's surface and flows out of a vent
- crater
- a cuplike hollow that forms at the top of a volcano around the vent
- cinder-cone volcano
- a steep-sided cone that forms from e eruptions of hot rocks, ranging from particles to boulders
- shield volcano
- a wide, gently sloped cone that forms from flows of lava
- composite volcano
- a cone formed from e eruptions of hot rocks followed by a flow of lava, over and over
- geothermal energy
- heat from below Earth's surface
- fold mountain
- a mountain made mostly of rock layers folded by being squeezed together
- fault-block mountain
- a mountain made by huge tilted blocks of rocks separated from surrounding rocks by faults
- weathering
- the breaking down of rocks into smaller pieces by natural processes
- erosion
- the picking up and removal of rock particles
- soil
- a mixture of weathered rock, decayed plant and animal matter, living things, air, and water
- soil horizon
- any of the layers of soil from the surface to the bedrock below
- groundwater
- water that soaks into the soil and rock by collecting in spaces between rock particles
- humus
- material in soil formed by the breakdown of plant and animal material
- mass wasting
- the downhill movement of Earth material caused by gravity
- desposition
- the dropping off of sediment
- glacier
- a huge sheet of ice and snow that moves slowly over the land
- till
- a jumble of many sizes of sediment deposited by a glacier
- moraine
- a deposit of many sizes of sediment in front of or along the sides of a glacier