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66 Cards in this Set
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An imaginary sphere of arbitrarily large radius, concentric with the Earth and rotating upon the same axis. Projected upward from Earth's equator and poles are the celestial equator and the celestial poles. |
Celestial Sphere |
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The apparent path that the Sun follows through the sky over the course of the year, relative to the stars, as seen from the vantage point of the Earth. It is traced on the imaginary celestial sphere |
Ecliptic |
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Equivalent of geographic longitude. Measured in hours, minutes and seconds from the point where the ecliptic meets the celestial equator and moving towards the east. Each hour corresponds to 15 degrees of arc and 24 hours corresponds to 360 degrees. |
Right Ascension |
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Comparable to geographic latitude. Measured in degrees north and south of the celestial equator. |
Declination |
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Two imaginary points in the sky where the Earth's axis of rotation, indefinitely extended, intersects the celestial sphere. |
Celestial Poles |
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An imaginary point directly "above" a particular location, on the imaginary celestial sphere. |
Zenith |
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The angle of the object around the horizon, usually measured from the north increasing towards the east. |
Azimuth |
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Sometimes referred to as elevation, is the angle between the object and the observer's local horizon. It is expressed as an angle between 0 degrees to 90 degrees |
Altitude |
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A circle of twelve 30° divisions of celestial longitude that are centered upon the ecliptic. Historically, these twelve divisions are called signs. |
Zodiac |
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An internationally defined area of the celestial sphere grouped around patternsformed by prominent stars within apparent proximity to one another on Earth's night sky. |
Constellations |
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What causes the seasons? |
The Axial Tilt/Obliquity |
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Precession changes ____ ____ and ______ ____ |
North Star; Zodiac dates |
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What are three factors of long term climate change? |
-Precession -Change in elliptical orbit -change in obliquity |
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The Sidereal day is ______ than the Solar day |
shorter |
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_____ and ______ represent points in the _____ (path of the Sun) |
Equinoxes; Solstices ecliptic |
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When the moon rotates in 27.3 days around the earth and in relation to the Stars |
Sidereal Month |
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When the moon rotates in 29.5 days in relation to the Sun and complete phase change |
Synodic Month |
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The phases of the moon change every: |
29.5 days |
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What are the phases of the moon in order? (8 total) |
1) New 2) Waxing Crescent 3) First Quarter 4) Waxing Gibbous 5) Full Moon 6) Waning Gibbous 7) Third Quarter 8) Waning Crescent |
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The moon is tilted in relation to place of Ecliptic by __ degrees |
5 degrees |
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The idea that Earth as the center of the Universe. Main Explanation by Ptolemy with his epicycles. |
Geocentrism |
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Ptolemy is famous for: |
geocentrism and epicycles |
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The idea that the Sun as the center of the Universe. Main proponent was Copernicus. Theory proven by Galileo |
Heliocentrism |
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Revived Heliocentric theory; he believed that the Earth rotating on its axis caused the visual effect of celestial bodies revolving around the Earth. |
Copernicus (Polish, 15-16th Centuries) |
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Galileo (Italian, 16th century) is famous for: |
- First astronomical use of the telescope - Discovered 4 moons of Jupiter - Discovered geographic features of the moon - Discovered Sun spots and rotation of the Sun -Discovered phases of Venus, proving Heliocentric theory |
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Planets orbit the Sun on elliptical paths. The Sun occupies one of the two foci |
Kepler's First Law of Planetary Motion (Law of Elliptic Orbits) |
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An imaginary line connecting the Sun to a planet sweeps out equal areas in equal intervals of time. This means that given elliptical orbits where a planet will have a closest approach to the Sun, will travel fastest in its orbit at that time. |
Kepler's Second Law of Planetary Motion (Law of Areas) |
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The square of a planet's period is proportional to the cube of its mean distance from the Sun. |
Kepler's Third Law of Planetary Motion (The Harmonic Law) |
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Unless acted on by an external force, a body at rest will remain at rest. Unless acted on by an external force, a body in motion will continue to do so in a straight line at constant speed. |
Newton's First Law of Motion |
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A body acted on by an external force will accelerate in the direction of the applied force. The greater the force, or the smaller the mass, the greater the acceleration will be. |
Newton's Second Law of Motion |
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For every force, there is an equal magnitude, but oppositely directed, force. |
Newton's Third Law of Motion |
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The rate of change of position. Both magnitude and direction must bespecified. |
Velocity |
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The rate of change of velocity. Both magnitude and direction must be specified. a=F/m |
Acceleration |
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All objects in the universe attract all other objects with a force dependent upon the mass of the two objects and the distance between them. |
Newton's Law of Universal Gravitation |
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There are ___ standard constellations recognized by the International Astronomical Union (IAU) since 1922. The majority of these go back to the __ constellations defined by Ptolemy in his Almagest (2nd century). |
88; 48 |
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Points north of the celestial equator have _____ declinations, while those to the south have ____ declinations. |
Positive; negative |
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The study of all matter and energy in the universe |
Astronomy |
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A great ring stones in the Salisbury plain in Southern England. Each significant stone lines up with another to point to some extreme position of the Sun and Moon. A set of holes around the perimeter probably was used to predict eclipses |
Stonehenge (2800-1075 BC) |
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They knew (also Babylonians, Assyrians, and Egyptians) 1 year = 365.25 days Determined the Moon's orbital period Recorded Halley's Comet (467BC) Recorded "Crab Nebula" supernova in 1054 AD |
The Chinese (1000 BC) |
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The _____ and ____ ____ _____ had calendars and "medicine wheels" showing extreme annual positions of key celestial objects. |
Mayan; Native American Indians |
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Was the first to believe in a heliocentric universe. Thought the stars were at a great distance from the Earth and we couldn't detect their annual motion. |
Aristarchus (Greek, 3rd century BC) |
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Was the first to measure the Earth's circumference. |
Eratosthenes (Greek, 3rd century BC) |
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Two scientists who extolled the geocentric universe |
Hipparchus and Ptolemy (Greek, 2nd century BC) |
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Made extensive and accurate observations of the positions of the planets, particularly Mars (w/o a telescope), which led to Kepler's formation of his laws of orbital motion |
Tycho Brahe (Danish, 16th Century) |
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Discovered that the planets' orbit around the Sun were ellipses |
Johannes Kepler (German, 16th century) |
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-Believed in immense universe with no particular center. -He thought the Earth orbited the Sun. -Believed in the possibility of life elsewhere |
Bruno (Italian, 16th century) |
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Formulated integral calculus; the laws of mechanics and gravitation; invented the first reflecting telescope. |
Isaac Newton (English, 17th century) |
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Studied comet orbit records, which suggested to him that the comets of 1531, 1607, and 1682 were the same comet returning. Predicted it would return in 1758. Financed the publishing of Newton's the Prinicipia |
Edmund Halley (English, 17th century) |
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The spinning of a celestial body about its (internal) rotational axis |
Rotation |
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Proofs of the Earth's rotation: |
Foucault pendulum Coriolis Force Aritificial Satellite |
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The orbiting of a body around a more massive "parent" body, that is, motion around an external axis. |
Revolution |
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The closest approach of a planet to the Sun in its orbit around the Sun. |
Perihelion |
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The farthest distance of a planet from the Sun in its orbit around the Sun. |
Aphelion |
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Proofs of the Earth's Revolution: |
Parallactic motion of the stars Variation in the radial velocity of a star Aberration of starlight |
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The slow, Westward wobbling of the Earth's rotational axis due to the gravitational pull of the Sun and the Moon on the Earth's equatorial bulge. |
Precession |
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Current pole star is: |
Polaris |
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The time it takes for one (360 degree) rotation of a planet with respect to the fixed stars. 23h 56 min |
Sidereal Day |
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The time it rakes for one (360 degree) rotation of a planet with respect to the Sun as a reference. Avg: 24h 0min |
Solar Day |
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The position of the Sun at the same time of the day to map out a figure 8 in the sky over 1 year |
analemma
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The moon has a "locked" or _____ rotation, keeping the same face toward the Earth all the time. |
Synchronous |
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The closest approach of a satellite to the Earth in its orbit around the Earth |
Perigee |
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The furthest distance of a satellite from the Earth in its orbit around the Earth. |
Apogee |
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The shadow zone where sunlight is completely cut off |
Umbra |
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The shadow zone where sunlight is partially cut off |
Penumbra |
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When the moon is too far away from the Earth and/or the Earth is too close to the Sun for the Moon to cover the face of the Sun completely despite being properly centered. |
Annular eclipses |
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When a celestial body with a large angular size in our sky passes b/w the Earth and a celestial body with a smaller apparent size in the sky. |
Occultations |