| A | B |
|---|
| earth science | The study of astronomy, geology, meteorology, oceanography, and human interactions with each. |
| retrograde motion | The apparent backwards motion of a planet as it crosses our sky. |
| geocentric | A model of the universe in which all objects in space are believed to revolve around the Earth in perfect circles. |
| heliocentric | A model of our solar system that places the sun at the center and planets orbiting it in concentric circles. |
| parallax | The most basic way of measuring the distance to an object in space by comparing its shift in apparent position over a period of time. |
| red shift | The shift toward the red end (higher wavelength) of the visible spectrum that happens over time as a star moves farther away from us. |
| cosmic microwave background radiation | Remnant heat left over from the Big Bang that creates "noise" in space. |
| focus | point within the earth where an earthquake originates |
| epicenter | location on the surface of the earth directly above the focus |
| Elastic Rebound Hypothesis | states that most earthquakes are produced by the rapid release of energy stored in rocks when they've been subjected to forces that exceed their strength |
| foreshock | small releases of energy prior to an earthquake |
| aftershock | release of the last bit of elastic energy following an earthquake |
| primary, or p wave | type of seismic wave that travels as a compressional wave at a high rate of speed; can travel through all states of matter |
| secondary, or s wave | slower moving seismic wave that travels as a transverse wave; can only travel through solids |
| surface wave | most destructive of seismic waves; produced when body waves reach the surface |
| seismograph | instrument that records seismic waves |
| Moment Magnitude Scale | new method of measuring the strength of an earthquake based on estimated energy released from the rocks using fault displacement measurements |
| slip | short, sudden movement of a fault |
| liquefaction | uneven settling of structures due to effect of earthquake on heavily saturated soil and rock |
| tsunami | high energy wave formed when an earthquake pushes up a slab of ocean floor |
| lithosphere | combination of the Earth's crust and the top, rigid portion of the upper mantle |
| asthenosphere | portion of the upper mantle that is acutally partially melted (molten) and able to flow |
| Mohorovicic Discontinuity | boundary between the Earth's crust and the upper mantle |
| hypothesis of continental drift | stated that at one time all the continents were joined together in one supercontinent |
| hypothesis of seafloor spreading | stated that new crust is formed at the ridges and destroyed at the trenches |
| Theory of Plate Tectonics | provides the mechanism for continental drift |
| convergent boundary | place where 2 continental plates are moving together |
| divergent boundary | place where 2 continental plates are moving apart |
| transform fault | place where 2 continental plates slide horizontally past each other |
| relative dating | how old a rock is as compared to surrounding rocks |
| absolute dating | actual number of years since a rock was formed |
| igneous rock | formed by magma |
| sedimentary rock | formed by the erosion of existing rocks by wind, water, or ice |
| metamorphic rock | formed when existing rocks are subjected to intense heat and pressure |
| uniformitarianism | states that physical, chemical and biological laws operating today were also operating in the geological past |
| Law of Superposition | states that in an undisturbed sequency of sediment, the older layers are on the bottom |
| uncomformity | surface between 2 layers that were NOT laid down in an unbroken sequence (ex: weathering) |
| disconformity | occurs where 2 sedimentary layers are separated by an erosional surface |
| fault | area of rock cut by plate tectonics |
| Principle of cross-cutting | states that a fault is younger than the rocks it cuts |
| Principle of fossil succession | states that organisms succeed one another in a definite and determinate order |
| index fossil | fossils that are widespread, abundant and limited to a short time span |
| ecological indicator | fossil from an organism that must live in a specific environment to survive |
| fossil | preserved or petrified remains, molds, casts, carbon film, or impression of organisms from the geological past |
| accretion | Process where particles collide and stick together in a solar nebula. Gravity is NOT involved. |
| differentiation | Process in planet formation where the homogeneous interior begins to separate out into layers of different compositions/densities. |
| Asteroid Belt | Large field of asteroids situated between Mars & Jupiter. |
| Kuiper Belt | Large field of ice, rock material, and comets located out beyond the gas giants. |
| dwarf planet | A protoplanet, such as Pluto, that has high enough gravity to pull itself into a spherical shape but not to sweep its neighborhood. |
| Oort Cloud | Spherical shell around the entire solar system and containing comets with orbits outside the plane of the planets. |
| meteor | A meteoroid that enters a planet's atmosphere. |
| meteorite | Any portion of a meteoroid that reaches a planet's surface. |
| Giant Impact Theory | Moon formed from ejected debris caused by impact of Mars-sized planetesimal with Earth. |
| regolith | Layer of soil-like debris on the moon. |
| rayed craters | Thin layer of recent impact debris that covers the moon's surface. |
| parallax | The most basic way of measuring the distance to an object in space by comparing its shift in apparent position over a period of time. |
| apparent magnitude | The perceived brightness of a star as viewed from Earth. |
| absolute magnitude | The actual brightness of a star based on an imagined distance of exactly 32.6 light years. |
| nebula | A cloud of gas and dust in space from which stars are born. |
| main sequence star | A star that whose inward gravitational force is exactly balanced by its outward force of pressure from nuclear reactions. |
| planetary nebula | The outer layers of a red giant are being gently "puffed" off in pulses, creating dusty rings around the star. |
| astronomical unit | A measurement of distance equal to the mean distance from the earth to our sun. |
| light year | A measure of distance equal to how far light travels in a year. |
| Hertzprung-Russell Diagram | A graphical representation of stars that shows the relationship between its spectral class (color) and its absolute magnitude. |
| spiral galaxy | A galaxy shaped like a flat disk with a central bulge, spiral arms, and a surrounding halo. |
| elliptical galaxy | Formed by mostly old stars with little gas/dust and range from spherical to football-shaped. |
| the Local Group | Cluster of about 30 galaxies, including our own. |
| Andromeda Galaxy | The closest galaxy to our own and with which we are on a collision course. |
| the Virgo Cluster | A giant galaxy cluster toward which the Local Group is "falling." |
| decompression melting | melting in the lower lithosphere due to a drop in pressure that ocurs as molten rock in the asthenosphere rises |
| Ring of Fire | long belt of volcanoes encircling the Pacific Ocean |
| hot spot | believed to be form within a plate due to hot mantle plumes over which a plate moves, creating a chain of volcanoes in which only the most recent is active |
| pahoehoe lava | hot, fast-flowing lava that forms smooth, braided surfaces |
| ah ah | cooler, slower-moving lava that forms rough surfaced, jagged & sharp surfaces |
| pyroclastic material | any solid particle produced in a volcanic eruption and ejected into the air by that eruption |
| pipe | cylinder-shaped pathway from magma chamber to the opening of the volcano |
| vent | fissure or crack in the surface through which magma escapes |
| shield volcano | broad, dome-shaped structure formed by basaltic lavas |
| cinder cone volcano | short-lived, small, steep-sided structures formed by gas-rich lavas that eject pyroclastic materials as opposed to lava |
| composite cone volcano | large, nearly symmetrical volcanic mountains composed of layers of lava and pyroclastic materials |
| caldera | a depression in a volcanic mountain formed by the collapse of the volcano's top |
| volcanic neck | Exposed pipe of an ancient volcano after the cone is eroded away |
| lava plateau | forms when lava leaks out through fissures, spreading out across a wide area instead of forming a cone |
| isotope | atoms of the same element with the same number of protons but different numbers of neutrons |
| radiocarbon dating | process used to date organic (living) remains less than 75,000 years old |
