ASTR 1345: Chapter 1 Discovering the Night Sky
46 Cards in this Set
Front | Back |
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Speed of Light
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- 300,000 km/sec or 186,000 miles/sec
- fastest speed known
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Light from the Sun reaches Earth in ____
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8min
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Light from the Sun reaches Pluto in ____
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5 hours 30 mins
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Nearest Star
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Proxima Centauri
- 4.2 light years away
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Diameter of the Milky Way
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100,000 light years
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Sun rises in the ___, and sets in the ___
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Sun rises in the east, and sets in the west
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Moon, planets and stars rise in the ___ and set in the ____
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Moon, planets and stars rise in the east, and set in the west
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The cycle of day and night goes with ___
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The cycle of day and night goes on with the rising and setting of the Sun
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Seasons ___ throughout the year
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Seasons change throughout the year
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Constellations ___ throughout the year
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Constellations change throughout the year
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Rotation
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Earth spins on its axis
- 24 hours
- Day to day changes: formation of day and night
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Revolution
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Earths orbit around the sun
- 365.25 days
- Seasonal changes: winters and summers
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Astronomy
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study of the entire universe
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Universe
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totality of all space, time, matter and energy
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Day
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Earth's rotation
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Month
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Moon's revolution around Earth
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Year
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Earth's revolution around the Sun
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Astronomy: importance and usefulness
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- Time
- Calender
- Religion
- Artificial satellites (communication)
- Physics/Chemistry/Geology/Geophysics/Biology
- Event predictions (eclipse, meteor showers etc.)
- Celestial Navigation (one's position on Earth)
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How many stars are there in our Solar System?
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One (Sun)
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How many stars are in our galaxy?
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Billions
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Is the Milky Way a part of our Solar System?
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False
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Arrange the Sun, the Moon, Stars, and Pluto in order to most distance from Earth?
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Earth, Moon, Sun, Pluto, Stars
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In what direction does our Earth spin?
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West to East
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The formation of Seasons is due to?
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- Earth's orbital motion
- Tilt of Earth's axis to the ecliptic
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When is Earth closest to the Sun?
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January
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Vernal/Spring Equinox
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- March 21st
- Sun crosses the celestial equator moving North
- Equal day and night on the entire Earth
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Summer Solstice
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- June 21st
- Sun is in northernmost point
- Longest day in the Northern hemisphere
- 24 hours of daylight in the Arctic regions near the North Pole
- 24 hours of nighttime in the Antarctic regions near the South Pole
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Autumnal/Fall equinox
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- September 21st
- Sun moves into the Southern Hemisphere
- Equal day and night on the entire Earth
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Winter Solstice
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- December 21st
- Sun is at the southernmost point
- The shortest day in the Northern hemisphere
- 24 hours of night in the Arctic regions near the North Pole
- 24 of daylight in the Antarctic region near the South Pole
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Subsolar Point
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The location on Earth where the Sun rays come directly, at an angle of 90 degrees
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1º (degree) = _____
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60 minutes
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Arcminute
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1
1' = ------- degrees
60
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Constellations
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- Names based on Greek astronomy (brightest stars having proper names from antiquity of Arbic or Latin orgin)
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Celestial Equator is at ____ declination
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0º declination
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Lines of Right Ascension
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Run from North to South from 0 hours and 0 minutes around glove to 23 hours 59 minutes
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Lines of Declination
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Run around the globe in concentric circles from -90º at the South Celestial Pole to +90º at the North Celestial Pole
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New Moon is at __º
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0º
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Waxing Crescent is at ___º
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0º to 90º
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Full Moon is at ___º
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180º
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3rd Quarter Moon is at ___º
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270º
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1st Quarter
Moon is at ___º
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90º
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Waxing Gibbous is at __º
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90º to 180º
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Waning Gibbous is at __º
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180º <
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When the Moon is on the right side it's the ___ cycle
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Waxing cycle
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When the Moon is on the left side it's the ___ cycle
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Waning cycle
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What time does our solar eclipse occur?
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Anytime from sunrise to sunset
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