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166 Cards in this Set
- Front
- Back
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On a clear night, approx how many stars may be visible to the naked eye?
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more than 2,000
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What is the term for a region of the sky with well-defined borders?
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A Constellation
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How many official constellations are there?
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88
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Who and when were the names of the 88 official constellations chosen?
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1928 by the members of the International Astronomical Union
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T or F
Stars in a particualr constellation appear to lie close to one another but may be quite far apart in reality, because they may lie at diferent distances from Earth |
True
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What is the term for the illusional area that surrounds the Earth that houses the stars?
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Celestial Sphere
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List the 4 special point and circles that make up the celestial sphere that helps us locate the constellations?
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1. North celestial pole
2. South Celestial pole 3. Celestial equator 4. The Ecliptic |
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Name the point in the celestial sphere that is directly over the Earth's North Pole?
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North Celestial Pole
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Name the point in the celestial sphere that is directly over the Earth's South Pole?
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South Celestial Pole
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Re: the Celestial sphere
Name the projection of the Earth's equator into space and makes a complete circle around the celestial sphere? |
Celestial Equator
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Re: the Celestial sphere
Name the path the Sun follows as it appears to circle around the celestial sphere once each year. |
Ecliptic
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At what angle does the Ecliptic cross the celestial equator?
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23 1/2 degree angle
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Why is the angle of the Ecliptic crossing over the celestial equator 23 1/2 degrees?
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Because it is the amount of the tilt of the Earth's axis
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Name the band of light that circles all the way around the sky, passing through more than a dozen constellations?
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The Milky Way
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What is the relationship between the Milky Way in the sky and the Milky Way Galaxy?
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It traces our glaxay's disk of stars - the galactic plane- as it appears from our location in the outskirts of the galaxy.
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T or F
We see far fewer stars and relatively little gas and dust in our own galaxy when we look in directions pointing away from the galactic disk. |
True
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Where is the Milky Way we see in the sky the widest?
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Near the Sagittarius constellation
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What prevents us from seeing more than a few thousand light years into the Milky Way Galaxy?
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1. Milky Way's abundant gas
2. Milky Way's abundant dust |
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What is the term for the sky as seen from where you happen to be standing?
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Local Sky
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What is the term for the boundary between Wearth and sky?
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Horizon
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What is the term for the point directly overhead in the Local Sky?
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Zenith
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What is the term for the imaginery half-circle stretching from the horion due south, through the zenith to the horizon due north?
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Meridian
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How can we pinpoint the position of any object in the local sky?
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By stating its direction in degrees clockwise from due north, and its altitude above the horizon
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What is another word for direction in degrees closkwise from due north in the Local Sky that is used to pinpoint an object's position?
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Azimuth
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What is the altitude and direction for the zenith in the Local Sky?
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90 degree altitude
but NO direction!!!!!! |
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T or F
We have no way to judge the true sizes or seperations of the objects we see in the sky unaided. |
True
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What causes us to be unable to judge sizes in the night sky?
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Lack of depth perception
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What is the term for the angle an object appears to span in your field of view?
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Angular size
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What 2 objects in our sky have roughly the same angular size?
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Sun and Moon
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What is the angular size for the Sun and the Moon?
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@ 1/2 degree.
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T or F
The further away an object is, the larger it will look in angular size. |
False.
The further away an object is, the smaller it will look in angular size. |
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What is the angular size of the Moon based on?
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1. Its actual size
2. Its distance from the Earth |
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What is the term for the angle that appears to separate a pair of objects in the sky?
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Angular Distance
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How are degrees divided when discussing altitude in the sky?
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Each degree has 60 arcminutes
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How are arcminutes divided?
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Each arcminute has 60 arcseconds
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How can u remember degrees, arcminutes, and arcseconds?
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Think of a degree has an hour with 60 minutes, each minute having 60 seconds
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What is the corrallary to a degree?
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An hour on a clock
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How often does every object in the celestial sphere appear to circle around the Earth?
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Once per day
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What direction does the Earth rotate?
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From West to East
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What direction does the celestial sphere appear to rotate?
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It appears to rotate from East to West
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T or F
Stars relatively near the north celestial pole remain perpetually aboe the horizon. |
True
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What is the term for stars that appear to never rise or set in the celestial sphere but instead make daily conterclockwixe circles around the north celestial pole?
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Circumpolar
(circulating around the pole) |
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T or F
Stars relatively near the south celestial pole always rise above the horizon. |
False
Stars relatively neart the south celestial pole never rise above the horizon at all. |
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Which direction as viewed from the above the North Pole does the Earth rotate?
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Counter-clockwise
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What is the formula to determine the physical size, angular size, and distance of an object knowing 2 of the 3?
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angular size/ 360 degrees =
physical size/ 2pi X distance |
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What is the term that measures north-south position on Earth and is defined to 0 degrees at the equator and increases northward and southward?
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Latitude
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What is the latitude of the North Pole?
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90 degrees N (north)
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What is the latitude of the South Pole?
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90 degrees S (south)
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What are the imaginary circles running parallel to the equator?
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"lines of latitude"
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What is the term that measures east-west positions
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Longitude
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What is the term for the imaginary semicircles (halfcircles) extending from the North Pole to the South Pole?
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"lines of longitude"
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Where is the line of longitude that is 0 degrees?
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Greenwich, England
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What is the term for the 0 degree longitude?
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Prime Meridian
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How is a location pinpointed on the Earth?
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Stating its latitude and longitude
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T or F
The sky varies with longitude and does not vary with latitude. |
False,
The sky varies with latitude and does not vary with longitude |
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T or F
Charleston, SC and San Diego have the same latitude and people see the same constellations at night. |
True
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T or F
Longitude only affects when you see particular stars. |
True
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T or F
The Sun remains above the horion for 6 months at the North |
True
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T or F
The altitude of the celestial pole in your sky is euqal to your latitude. |
True
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If the north celstial pole appears in your sky at an altitude of 40 degrees above your north horizon, what is your altitude?
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40 degrees North
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If the south celedstial pole appears in yoru sky at an altitude of 34 degrees above your south horizon, what is your latitude?
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34 degrees South
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Where is the north celestial polie located close to?
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The North Star or Polaris
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What is another name for the North Star?
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Polaris
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In the southern hemisphere where is the south celestial pole located near?
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The Southern Cross
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What is the term for the constellations that lie along the ecliptic?
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The Zodiac
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Officially, how many zodiac constellations are there?
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13
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Traditionally, how many zodiac constellations are there?
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12, corresponding to the Juian caledar, sort of, from @ the 20th of each month to the 20th of the next month
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What determines which constellations we see at night?
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The Sun's apparent location along the ecliptic
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When the Sun appears to be in a zodiac constellation, can we see that constellation in the night sky? Why?
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No, because the constellation moves with the Sun through the daytime sky.
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What is the precise length of the Earth's rotation period?
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23 hours
56 minutes 4.09 seconds |
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Astronomically, how many types of days are there?
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2
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Describe the 2 types of days we have astronomically speaking:
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1. 23 hr 56 min; and
2. the length of time it takes any star to make one full circuit through our sky |
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What is the term for the length of time that it takes any star to make one full circuit through our sky?
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Sidereal Day
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What is the term that means "related to the stars"
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Sidereal
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What is the term for the type of astronomical day that is 24 hrs long?
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Solar Day
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T or F
Earth's axis point in different directions in space during the year. |
False.
Earth's axis points in the same direction in space all year round. |
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What happens to the Earth's orientation relative to the Sun during the year?
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The Earth's orientation relative to the Sun changes as Earth orbits the Sun
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Why does the Earth's 2 hemispheres experience opposite seasons?
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When one hemisphere is tipped towards the Sun while the other is tipped away.
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Which hemisphere has summer when the Northern hemisphere is tipped towards the Sun?
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Northern Hemisphere
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Which hemisphere has winter when the Northern hemisphere is tipped towards the Sun?
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Southern hemisphere
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What causes warmer days in the summer for a hemisphere?
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The steeper the angle means the sunlight is more concentrated
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What causes the days to be longer and Sun is higher through a summer sky?
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the steeper angle of the sun's light hitting the Earth in that hemisphere
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T or F
The seasons on Earth are caused by the change in the Earth's distance from the Sun. |
False.
The seasons on Earth are caused ONLY BY the axis tilt |
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How much is the difference between Earth's distance from the Sun at its nearest and farthest points?
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3%.
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When does the summer solstice occur?
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@ June 21.
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What is the term given to the moment when the Northern Hemisphere receives its most direct sunlight?
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Summer Solstice
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When does the winter solstice occur?
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@ December 21
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What is the term for the moment when the Northern Hemipshere receives its least direct sunlight?
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Winter Solstice
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When is the Spring Equinox?
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@ March 21
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What is the term for the moment when the Northern Hemisphere goes from being tipped slightly away from the Sun to beig tipped slightly toward the Sun?
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Spring Equinox
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When is the Fall Equinox?
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@ September 22
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What is the term for the moment when the Northern Hemisphere forst starts to be tipped away from the Sun?
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Fall Equinox
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What is another term for the Spring Equinox?
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Vernal Equinox
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What is another term for the Fall Equinox?
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Autumnal Equinox
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T or F
The exact dates & times for the solstices and equinoxes vary from year to year. |
True
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What is calculted into our modern calendars to keep solstices and equinoxes around the same dates each year?
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A "Leap Year" on February 29th is added every fourth year unless the century is divisable by 400.
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What two days is it known that the Sun rises precisely due east and set precisely due west?
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The Fall and Spring Equinoxes
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When are the only 2 days that sunlight falls equally on both hemispheres?
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The Fall and Spring Equinoxes
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When does the Sun follow its longest and highest path through the Northern Hemisphere sky?
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Summer Solstice
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When does the Sun follow its shortest and lowest path through the Southern hemisphere?
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Summer Solstice
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When does the noon Sun reach reaches its highest point in the Northern Hemisphere sky?
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Summer Solstice
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When does the noon Sun reach its highest point in the Southern Hemisphere?
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Winter Solstice
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What marks the "first day" of a season?
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The day that the equinoxes and solstices occur.
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When does MidSummer occur?
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@ late July or early August
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What does Midsummer really represent?
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When the Northern Hemisphere has finally warmed and heated up which takes.
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T or F
People living at or near the equator don't experience four seasons in the same way as people living at mid-latitudes. |
True
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What happens to the Sun in the celestial sky at high latitudes?
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The Sun becomes cirumpolar, never "setting"
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What regions are the "lands of the Midnight Sun"?
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The higher latitudes
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What is the term for the gradual "wobble" that the changes the Earth's axis in space?
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Precession
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T or F
Precession occurs with many rotating objects. |
True
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How long is each cyle of the Earth's precession take?
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@26,000 years
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In 13,000 years what star will be the closest to true north?
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Vega
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Does precession change the amount of the axis?
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No.
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T or F
Precession affects the the patterns of the seasons. |
False.
Precession does NOT affect the patterns of the seasons. |
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What causes precession?
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Gravity's effect on a tilted, rotating object that is NOT a perfect sphere.
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Beside the Sun, what is the brightest and nmost noticeable object in our sky?
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The Moon
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What is the term for the latitude at which the Sun is directly overhead on the summer solstice(23 1/2 degrees)?
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Tropic of Cancer
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On the celestial sphere, the Moon appears to rise in the ________, and set in the _______.
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The Moon appears to rise in the East and set in the West.
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At night, the Moon appears to move_______ through the constellation of the zodiac.
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At night, the Moon appears to move eastward through the constellations of the zodiac
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How long roughly, is each ciruit through the constellations does the Moon take?
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@ 27 1/2 days
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What is the term for the phases of the Moon on any given day depending on its position relative to the Sun as it orbits Earth?
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Lunar phases
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Approx. how long is each complete cycle of lunar phases?
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Approx. 29 1/2 days
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What phase of the Moon rises @ sunset, reaches its highest point in the sky @ midnight and sets @ sunrise?
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Full Moon
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What phase of the Moon rises @ noon, reaches its highest point @ 6 pm, and sets @ midnight?
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First quarter Moon when the Moon is @ 90 degrees east of the Sun in our sky.
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T or F
We always see the same face of the Moon? |
True
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What is meant by "waxing"
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When phases of the moon are increasing, from new to full
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What is meant by "waning"?
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When phases of the moon are decreasing, from full to new.
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What is the name of the lunar phases just before and after new moons?
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Crescent moons
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What is the name of the lunar phases just before and after full moons?
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Gibbous
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What is the term for when the Sun, Earth, and Moon fall into a sgtraight line?
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Eclipses
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What type of eclipse occurs when Earth lies directly between the Sun and Moon, so that Earth's shadow falls on the Moon?
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Lunar Eclipse
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What type of eclipse occurs when the Moon lies directly between the Sun and Earth, so that the Moon's shadow falls on Earth?
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Solar Eclipse
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What will people living within the area covered by the Moon's shadow during a solar eclipse?
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They will see the Sun blocked or partially blocked from view
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What is the term for the two points in each orbit at which the Moon crosses the surface?
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The Nodes of the Moon's orbit
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What two conditions must occur for an eclipse to occur?
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1. Full or New moons
2. Full or new moons must occur duing one of the periods when the nodes of the Moon's orbit are aligned with the Sun and Earth. |
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What is the term for the region where sunlight is completely blocked during an eclipse?
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Umbra
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What is the term for the region where sunlight is only partially blocked during an eclipse?
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Penumbra
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What type of eclipse occurs when the Sun, Earth, and Moon are nearly perfectly aligned, and the Moon passes through Earth's umbra?
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Total Lunar Eclipse
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What type of eclipse occurs when the alignment is less perfect, onl part of the full moon passes through the umbra?
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Partial Lunar Eclipse
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What type of eclipse occurs when the alignment is less perfect, the Moon passes only through Earth's penumbra?
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Penumbral lunar eclipse
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Which eclipses are more common, penumbral or total lunar?
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Penumbral
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During the totality of a total lunar eclipse what color does the Moon become?
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Red because the Earth's atmosphere bends some of the red light from the Sun towards the Moon.
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How many solar eclipses are there?
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3
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Name the 3 types of lunar eclipses:
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1. total lunar
2. partial lunar 3. penumbral lunar |
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List the 3 types of solar eclipses:
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1. total solar
2. partial solar 3. annular eclipse |
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What type of eclipse is seen when a ring of sunlight surrounds the disk of the Moon?
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Annular eclipse
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What causes the Moon's umbral and penumbral shadows to race across the face of Earth at sppeds @ 1700 km/hr?
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1. Earth's rotation
2. Orbital rotation of the Moon |
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What is the term for the two periods each year when the nodes of the Moon orbit are nearly aligned with the Sun
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Eclipse Seasons
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How long does each eclipse season last?
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A few weeks
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What is the term for the points where the Moon's orbit crosses the ecliptic plane?
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Nodes
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When do eclipse seasons occur?
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Slightly less than 6 months apart.
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When do eclipses recur in a cycle?
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Every 18 years, 11 days
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What is the term given to the recuring eclipse cycles that occur every 18 years?
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Saros Cycle
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Name the 5 planets that are easy to to find with the naked eye?
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1. Mercury
2. Venus 3. Mars 4. Jupiter 5. Saturn |
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When is Mercury visible with the naked eye?
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Infrequently, only just after sunset or just before sunrise because it is so close to the Sun
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When & where do you see Venus with the naked eye?
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Early evening in the the west or before dawn in the east.
It is the bright "star" in the early evening and early morning |
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Describe seeing Jupiter by the naked eye?
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Beside the Moon and Venus, it is brightest object in the sky
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Describe seeing Mars by the naked eye?
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Recognized by its reddish color, but you should check a star map to bake sure you aren't looking at a bright red star
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Describe seeing Saturn by the naked eye?
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Its as bright as many stars so it helps to know where to look for it.
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T or F
Planets move through the night sky just like the stars, rising in the east and setting in the west. |
True
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T or F
Planets wander slowly through the constellations. |
True
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What does the word "planet" come from in Greek?
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Means "wandering star"
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T or F
Planets always move in the same direction. |
False.
Planets occasionally reverse course copletely, sometiming moving westward rather than eastward. |
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What is the term given to the periods of time that planets reverse their motion in the night sky?
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Apparent Retrograde Motion
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Name the Greek stronomer who first suggested a Sun-centered solar system?
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Aristarchus in 260 BC
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What is the term for the apparent shift in the postioin of a nearby star as we look at it from different places in Earth's orbit?
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Stellar Parallax
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