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166 Cards in this Set

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On a clear night, approx how many stars may be visible to the naked eye?
more than 2,000
What is the term for a region of the sky with well-defined borders?
A Constellation
How many official constellations are there?
88
Who and when were the names of the 88 official constellations chosen?
1928 by the members of the International Astronomical Union
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
What is the term for the illusional area that surrounds the Earth that houses the stars?
Celestial Sphere
List the 4 special point and circles that make up the celestial sphere that helps us locate the constellations?
1. North celestial pole
2. South Celestial pole
3. Celestial equator
4. The Ecliptic
Name the point in the celestial sphere that is directly over the Earth's North Pole?
North Celestial Pole
Name the point in the celestial sphere that is directly over the Earth's South Pole?
South Celestial Pole
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
Re: the Celestial sphere
Name the path the Sun follows as it appears to circle around the celestial sphere once each year.
Ecliptic
At what angle does the Ecliptic cross the celestial equator?
23 1/2 degree angle
Why is the angle of the Ecliptic crossing over the celestial equator 23 1/2 degrees?
Because it is the amount of the tilt of the Earth's axis
Name the band of light that circles all the way around the sky, passing through more than a dozen constellations?
The Milky Way
What is the relationship between the Milky Way in the sky and the Milky Way Galaxy?
It traces our glaxay's disk of stars - the galactic plane- as it appears from our location in the outskirts of the galaxy.
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
Where is the Milky Way we see in the sky the widest?
Near the Sagittarius constellation
What prevents us from seeing more than a few thousand light years into the Milky Way Galaxy?
1. Milky Way's abundant gas
2. Milky Way's abundant dust
What is the term for the sky as seen from where you happen to be standing?
Local Sky
What is the term for the boundary between Wearth and sky?
Horizon
What is the term for the point directly overhead in the Local Sky?
Zenith
What is the term for the imaginery half-circle stretching from the horion due south, through the zenith to the horizon due north?
Meridian
How can we pinpoint the position of any object in the local sky?
By stating its direction in degrees clockwise from due north, and its altitude above the horizon
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?
Azimuth
What is the altitude and direction for the zenith in the Local Sky?
90 degree altitude
but NO direction!!!!!!
T or F
We have no way to judge the true sizes or seperations of the objects we see in the sky unaided.
True
What causes us to be unable to judge sizes in the night sky?
Lack of depth perception
What is the term for the angle an object appears to span in your field of view?
Angular size
What 2 objects in our sky have roughly the same angular size?
Sun and Moon
What is the angular size for the Sun and the Moon?
@ 1/2 degree.
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.
What is the angular size of the Moon based on?
1. Its actual size
2. Its distance from the Earth
What is the term for the angle that appears to separate a pair of objects in the sky?
Angular Distance
How are degrees divided when discussing altitude in the sky?
Each degree has 60 arcminutes
How are arcminutes divided?
Each arcminute has 60 arcseconds
How can u remember degrees, arcminutes, and arcseconds?
Think of a degree has an hour with 60 minutes, each minute having 60 seconds
What is the corrallary to a degree?
An hour on a clock
How often does every object in the celestial sphere appear to circle around the Earth?
Once per day
What direction does the Earth rotate?
From West to East
What direction does the celestial sphere appear to rotate?
It appears to rotate from East to West
T or F
Stars relatively near the north celestial pole remain perpetually aboe the horizon.
True
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?
Circumpolar
(circulating around the pole)
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.
Which direction as viewed from the above the North Pole does the Earth rotate?
Counter-clockwise
What is the formula to determine the physical size, angular size, and distance of an object knowing 2 of the 3?
angular size/ 360 degrees =

physical size/ 2pi X distance
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?
Latitude
What is the latitude of the North Pole?
90 degrees N (north)
What is the latitude of the South Pole?
90 degrees S (south)
What are the imaginary circles running parallel to the equator?
"lines of latitude"
What is the term that measures east-west positions
Longitude
What is the term for the imaginary semicircles (halfcircles) extending from the North Pole to the South Pole?
"lines of longitude"
Where is the line of longitude that is 0 degrees?
Greenwich, England
What is the term for the 0 degree longitude?
Prime Meridian
How is a location pinpointed on the Earth?
Stating its latitude and longitude
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
T or F
Charleston, SC and San Diego have the same latitude and people see the same constellations at night.
True
T or F
Longitude only affects when you see particular stars.
True
T or F
The Sun remains above the horion for 6 months at the North
True
T or F
The altitude of the celestial pole in your sky is euqal to your latitude.
True
If the north celstial pole appears in your sky at an altitude of 40 degrees above your north horizon, what is your altitude?
40 degrees North
If the south celedstial pole appears in yoru sky at an altitude of 34 degrees above your south horizon, what is your latitude?
34 degrees South
Where is the north celestial polie located close to?
The North Star or Polaris
What is another name for the North Star?
Polaris
In the southern hemisphere where is the south celestial pole located near?
The Southern Cross
What is the term for the constellations that lie along the ecliptic?
The Zodiac
Officially, how many zodiac constellations are there?
13
Traditionally, how many zodiac constellations are there?
12, corresponding to the Juian caledar, sort of, from @ the 20th of each month to the 20th of the next month
What determines which constellations we see at night?
The Sun's apparent location along the ecliptic
When the Sun appears to be in a zodiac constellation, can we see that constellation in the night sky? Why?
No, because the constellation moves with the Sun through the daytime sky.
What is the precise length of the Earth's rotation period?
23 hours
56 minutes
4.09 seconds
Astronomically, how many types of days are there?
2
Describe the 2 types of days we have astronomically speaking:
1. 23 hr 56 min; and
2. the length of time it takes any star to make one full circuit through our sky
What is the term for the length of time that it takes any star to make one full circuit through our sky?
Sidereal Day
What is the term that means "related to the stars"
Sidereal
What is the term for the type of astronomical day that is 24 hrs long?
Solar Day
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.
What happens to the Earth's orientation relative to the Sun during the year?
The Earth's orientation relative to the Sun changes as Earth orbits the Sun
Why does the Earth's 2 hemispheres experience opposite seasons?
When one hemisphere is tipped towards the Sun while the other is tipped away.
Which hemisphere has summer when the Northern hemisphere is tipped towards the Sun?
Northern Hemisphere
Which hemisphere has winter when the Northern hemisphere is tipped towards the Sun?
Southern hemisphere
What causes warmer days in the summer for a hemisphere?
The steeper the angle means the sunlight is more concentrated
What causes the days to be longer and Sun is higher through a summer sky?
the steeper angle of the sun's light hitting the Earth in that hemisphere
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
How much is the difference between Earth's distance from the Sun at its nearest and farthest points?
3%.
When does the summer solstice occur?
@ June 21.
What is the term given to the moment when the Northern Hemisphere receives its most direct sunlight?
Summer Solstice
When does the winter solstice occur?
@ December 21
What is the term for the moment when the Northern Hemipshere receives its least direct sunlight?
Winter Solstice
When is the Spring Equinox?
@ March 21
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?
Spring Equinox
When is the Fall Equinox?
@ September 22
What is the term for the moment when the Northern Hemisphere forst starts to be tipped away from the Sun?
Fall Equinox
What is another term for the Spring Equinox?
Vernal Equinox
What is another term for the Fall Equinox?
Autumnal Equinox
T or F
The exact dates & times for the solstices and equinoxes vary from year to year.
True
What is calculted into our modern calendars to keep solstices and equinoxes around the same dates each year?
A "Leap Year" on February 29th is added every fourth year unless the century is divisable by 400.
What two days is it known that the Sun rises precisely due east and set precisely due west?
The Fall and Spring Equinoxes
When are the only 2 days that sunlight falls equally on both hemispheres?
The Fall and Spring Equinoxes
When does the Sun follow its longest and highest path through the Northern Hemisphere sky?
Summer Solstice
When does the Sun follow its shortest and lowest path through the Southern hemisphere?
Summer Solstice
When does the noon Sun reach reaches its highest point in the Northern Hemisphere sky?
Summer Solstice
When does the noon Sun reach its highest point in the Southern Hemisphere?
Winter Solstice
What marks the "first day" of a season?
The day that the equinoxes and solstices occur.
When does MidSummer occur?
@ late July or early August
What does Midsummer really represent?
When the Northern Hemisphere has finally warmed and heated up which takes.
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
What happens to the Sun in the celestial sky at high latitudes?
The Sun becomes cirumpolar, never "setting"
What regions are the "lands of the Midnight Sun"?
The higher latitudes
What is the term for the gradual "wobble" that the changes the Earth's axis in space?
Precession
T or F
Precession occurs with many rotating objects.
True
How long is each cyle of the Earth's precession take?
@26,000 years
In 13,000 years what star will be the closest to true north?
Vega
Does precession change the amount of the axis?
No.
T or F
Precession affects the the patterns of the seasons.
False.
Precession does NOT affect the patterns of the seasons.
What causes precession?
Gravity's effect on a tilted, rotating object that is NOT a perfect sphere.
Beside the Sun, what is the brightest and nmost noticeable object in our sky?
The Moon
What is the term for the latitude at which the Sun is directly overhead on the summer solstice(23 1/2 degrees)?
Tropic of Cancer
On the celestial sphere, the Moon appears to rise in the ________, and set in the _______.
The Moon appears to rise in the East and set in the West.
At night, the Moon appears to move_______ through the constellation of the zodiac.
At night, the Moon appears to move eastward through the constellations of the zodiac
How long roughly, is each ciruit through the constellations does the Moon take?
@ 27 1/2 days
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?
Lunar phases
Approx. how long is each complete cycle of lunar phases?
Approx. 29 1/2 days
What phase of the Moon rises @ sunset, reaches its highest point in the sky @ midnight and sets @ sunrise?
Full Moon
What phase of the Moon rises @ noon, reaches its highest point @ 6 pm, and sets @ midnight?
First quarter Moon when the Moon is @ 90 degrees east of the Sun in our sky.
T or F
We always see the same face of the Moon?
True
What is meant by "waxing"
When phases of the moon are increasing, from new to full
What is meant by "waning"?
When phases of the moon are decreasing, from full to new.
What is the name of the lunar phases just before and after new moons?
Crescent moons
What is the name of the lunar phases just before and after full moons?
Gibbous
What is the term for when the Sun, Earth, and Moon fall into a sgtraight line?
Eclipses
What type of eclipse occurs when Earth lies directly between the Sun and Moon, so that Earth's shadow falls on the Moon?
Lunar Eclipse
What type of eclipse occurs when the Moon lies directly between the Sun and Earth, so that the Moon's shadow falls on Earth?
Solar Eclipse
What will people living within the area covered by the Moon's shadow during a solar eclipse?
They will see the Sun blocked or partially blocked from view
What is the term for the two points in each orbit at which the Moon crosses the surface?
The Nodes of the Moon's orbit
What two conditions must occur for an eclipse to occur?
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.
What is the term for the region where sunlight is completely blocked during an eclipse?
Umbra
What is the term for the region where sunlight is only partially blocked during an eclipse?
Penumbra
What type of eclipse occurs when the Sun, Earth, and Moon are nearly perfectly aligned, and the Moon passes through Earth's umbra?
Total Lunar Eclipse
What type of eclipse occurs when the alignment is less perfect, onl part of the full moon passes through the umbra?
Partial Lunar Eclipse
What type of eclipse occurs when the alignment is less perfect, the Moon passes only through Earth's penumbra?
Penumbral lunar eclipse
Which eclipses are more common, penumbral or total lunar?
Penumbral
During the totality of a total lunar eclipse what color does the Moon become?
Red because the Earth's atmosphere bends some of the red light from the Sun towards the Moon.
How many solar eclipses are there?
3
Name the 3 types of lunar eclipses:
1. total lunar
2. partial lunar
3. penumbral lunar
List the 3 types of solar eclipses:
1. total solar
2. partial solar
3. annular eclipse
What type of eclipse is seen when a ring of sunlight surrounds the disk of the Moon?
Annular eclipse
What causes the Moon's umbral and penumbral shadows to race across the face of Earth at sppeds @ 1700 km/hr?
1. Earth's rotation
2. Orbital rotation of the Moon
What is the term for the two periods each year when the nodes of the Moon orbit are nearly aligned with the Sun
Eclipse Seasons
How long does each eclipse season last?
A few weeks
What is the term for the points where the Moon's orbit crosses the ecliptic plane?
Nodes
When do eclipse seasons occur?
Slightly less than 6 months apart.
When do eclipses recur in a cycle?
Every 18 years, 11 days
What is the term given to the recuring eclipse cycles that occur every 18 years?
Saros Cycle
Name the 5 planets that are easy to to find with the naked eye?
1. Mercury
2. Venus
3. Mars
4. Jupiter
5. Saturn
When is Mercury visible with the naked eye?
Infrequently, only just after sunset or just before sunrise because it is so close to the Sun
When & where do you see Venus with the naked eye?
Early evening in the the west or before dawn in the east.
It is the bright "star" in the early evening and early morning
Describe seeing Jupiter by the naked eye?
Beside the Moon and Venus, it is brightest object in the sky
Describe seeing Mars by the naked eye?
Recognized by its reddish color, but you should check a star map to bake sure you aren't looking at a bright red star
Describe seeing Saturn by the naked eye?
Its as bright as many stars so it helps to know where to look for it.
T or F
Planets move through the night sky just like the stars, rising in the east and setting in the west.
True
T or F
Planets wander slowly through the constellations.
True
What does the word "planet" come from in Greek?
Means "wandering star"
T or F
Planets always move in the same direction.
False.
Planets occasionally reverse course copletely, sometiming moving westward rather than eastward.
What is the term given to the periods of time that planets reverse their motion in the night sky?
Apparent Retrograde Motion
Name the Greek stronomer who first suggested a Sun-centered solar system?
Aristarchus in 260 BC
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?
Stellar Parallax