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51 Cards in this Set
- Front
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-the earth rotates or it spins around on its axis for 24 hours. -the tilt of the rotationary axis is 23.5 degrees -perpendicular to the Earth's orbital plane |
rotation (short term Earth motions: Day and yearly cycles) |
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-earth completes one full orbit around the sun every 365.25 days -which time the distance to the sun changes |
revolution (short term earth motions) |
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-earth is closest to the sun in January -this means winter is in the northern hemi -the season cannot be caused by the sun's proximity to the Earth |
seasons |
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-northern and southern hemi alternate receiving (on a yearly cycle) the majority of direct light from the sun - leads to the seasons |
seasons |
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-solstices (about June 21 and Decemeber 21) when the sun rises at the most extreme north and south points |
solstices and equinoxes |
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-equinoxes (equal day and night and March 21 and September 22) are when Sun rises directly east |
solstices and equinoxes |
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-changes in the orientation of earth's axail tilt (26,000 year cycle) |
precession (long term earth motions) (milankovitch cycles) |
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-changes in the angles of earth's axail tilt (40,000 year cycles) |
obliquity (long term earth motions) (milankovitch cycles) |
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-changes in the shape of earth's orbit around the sun (100,000 year cycles) |
eccentricity (long term earth motions) (milankovitch cycles) |
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-is found especially in oxygen |
isotopic ratios in rocks and ice |
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-indicate environment of deposition |
rock types |
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-consistently throughtout the past 500 million years , and on average temperatures were 8-15 degrees C warmer than today |
climate on earth |
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-current ice age/ warm age cycle started aout 2.5 millio years ago and the last ice age ended about 10,000 years ago |
ice age/warm age cycles |
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-forces the reshape the earth's surface -forces that change the amount of solar input from the sun -changes in the composition of the atmosphere |
natural causes of climate change |
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-re positioning of the continents and oceans due to moving tectonic plates |
plate tectonics |
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-volcanic explosions that eject carbon & greenhouse gases into the atmosphere causing the temp. to rise -v. explosions & large meteorite impacts eject large amounts of ash & dust in the stratosphere which reflect light & cool the surface |
volcanism |
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-burning fossil fuels: release CO2 -deforestation -methane, nitrous oxides, CFCs: also released into the atmosphere |
increased levels of greenhouse gasses (anthropogenic climate change) |
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-sulfates aerosols and other particles reflect sunlight & lead to localized cooling |
increased levels of aerosols |
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-20th century average global surface temperature has increased 0.8C & projected to increase over the next century at a faster rate |
global warming |
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-warmer atmosphere: more evaporation -changes to cyclonic storms (stronger hurricanes) |
atmospheric impacts of global warming |
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-sea level rise (water expands as it warms, glaciers over continents & oceans melt -half of the worlds population lives near sea level |
atmos. temp. rises lead to |
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-the use of models & observations, they were the first to explain the workings of the heavens -the general east to west motion of objects in the sky, geocentric theories were developed |
geocentric models (ancient greek astronomers) |
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-a planet will move from east to west relative to the stars |
retrograde motion |
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-lack of detectable stellar parallax |
greek (proof) that the earth is the center of the universe (stellar parallax) |
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-near stars should appear to shift in comparison with further stars throughtout our orbit |
stellar parallax |
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-ptolemy of alexandria improves the geocentric model by incorporating the retrograde motion in epicycles |
claudius ptolemy |
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-reconsidered aristarchus's heliocentric model with the sun at the center of the solar system -was not a better model because planetary motion was in perfect circles |
nicholas copernicus |
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-designed instruments of greater accuracy, hired kepler |
tycho brahe |
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-using tycho's data -showed the orbit to be an ellipse |
johannes kepler |
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-planets move in elliptical orbits with the sun at one focus of the ellipse -the planet will sweep out equal areas in equal time intervals; the closer a planet is to the sun the faster it moves -the amount of time a planet takes to orbit the sun is related to its orbits size |
keplers 3 laws of plantetary motions |
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-first person to use the telescope to study the heavens & show the true nature of the solar system -the sun has spots: the sun is not perfect -Jupiter has four objects orbiting it: objects are moon and they are not circling the earth -venus undergoes full phase cycle: venus must circle sun |
galileo |
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-made major advances in math, physics, and astronomy & wrote 3 laws of motion that describe motion on earth & in space |
isaac newton |
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-gives the universe its structure & controls astronomical motion -it is a universal force that causes all objects to pull on all other objects everywhere, older astronomers did not connect gravity & astronomical motion |
gravity |
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-objects in motion tend to stay in motion |
galileo established the idea of inertia |
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-planets move along curved (elliptical) paths, or orbits. -due to the external force of gravity -at a sufficiently high speed, an object travels so far that the ground curves out from under it -the object, now in orbit, still experiences that pull of gravity |
inertia (newtons first law of motion) (orbital motion) |
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-a force will cause an object to have non-uniform motion, a changing velocity -a: acceleration is defined as a change in velocity -m:mass should not be confused with weight, which is a force related to gravity weight may change from place to place, but mass does not F=Gm1m2/r2 |
F=ma (newtons second law of motion) (universal gravitation) |
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-when two object interact, they create equal and opposite forces on each other. this is true for any two objects, including the sun and the earth -(surface gravity) the acceleration a mass undergoes at the surafce of an object -determines the weight of a mass at a celestial objects surface -influences that shape of celestial objects |
surface gravity (newtons third law of motion) (action and reaction) |
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-to overcome a celestial objects gravitational force and escape into space, a mass must obtain a critical speed called the escape velocity - influences whether or not a celestial object has an atmosphere |
escape velocity (newtons third law of motion) (action and reaction) |
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-our_____ is 1/4 the earth;s diameter, & approximately 1/100 of the mass |
the moon's unusual size & mass |
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-the moons size & crated appearance give us evidence of its formation -the giant impact theory provides an explanation on why our moon us very large compared to the earth |
giant impact theory of lunar formation |
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-our moon orbits the earth every 29.5 days, or roughly once a "moonth" which creates lunar phases -the moons illumination is reflected light from the sun shining on half of the moon |
lunar phases |
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-the moon is between the earth & sun, casting a shadow on the earth |
solar eclipse |
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-the earth is between the sun and the moon, casting a shadow on the moon |
lunar eclipse |
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-a phase of the moon must be full (lunar) or new (solar) & these phases must occur at the same time as the moons orbit the crosses into the same plane as the sun (or node) -only a small area on the surface experiences a full eclipse, and area around that experiences a partial |
eclipses |
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-the moons gravity pulls harder on near side of earth that on far side -magnitude of the tides is dependent upon the phase of the moon |
tides |
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-strong, gravitational forces from sun and moon pull, in the same direction -phase is new or full |
spring tide |
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-weak, gravitational forces from sun and moon work against each other -phase is first or third quarter |
neap tide |
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-_________ gradually slows earths rotation, the moon rotation, and makes the moon move farther from earth |
tidal friction |
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-the moon currently rotates only once during its entire orbit around the earth |
synchronous rotation |
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-spaceflight endeavor that landed the first humans on earth moon |
NASA |
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- the goal was accomplished during Apollo 11 mission on July 20, 1969 with the landing of astronauts Neil Armstrong and Buzz Aldrin, while Michael Collins remained in lunar orbit |
NASA & the Apollo missions |
