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Astronomy Ch. 2 Textbook Qs

Terms in this set (108)

Earth rotates from
west to east
Objects in the sky appear to move from
east to west
What is the celestial sphere?
The imaginary sphere on which objects in the sky appear to reside when observed from Earth.
What is the North Celestial Pole?
The point on the celestial sphere directly above Earth's North Pole.
What is the South Celestial Pole?
The point on the celestial sphere directly below Earth's South Pole
What is the the apparent path of the Sun in the sky throughout the year?
the ecliptic
The __ divides the northern half and southern half and projects Earth's equator into space.
the celestial equator
The celestial poles are __ degrees from the celestial equator.
90
__ is the point of the sky directly above wherever you are.
Zenith
__ is the point directly below wherever you are.
Nadir
The __ is the circle that is 90 degrees from the zenith.
horizon
What is the imaginary north-south line that goes through the zenith and divides the sky into east and west half?
meridian
How many degrees is the Earth tilted?
23.5 degrees
The __ of Earth determines the apparent patterns and daily motions of celestial objects like the Sun and stars.
rotation
__ stars don't rise or set and are always seen above the horizon.
circumpolar
From the North Pole, stars appear to move __ around the NCP.
counterclockwise
From the South Pole, stars appear to move __ around the SCP.
clockwise
From the North Pole, we always
see the same half of the sky
From the South Pole, we see the __
half that is hidden from view from the North Pole
At the __, every star is circumpolar.
North and South Poles
At the __, no star is circumpolar and you can see the entire sky over the course of 24 hours.
equator
At 30 degrees N latitude, some stars are
circumpolar, some not
__ measures how far north or south of the equator you are from Earth.
latitude
At higher latitudes where the NCP is higher in the sky, most stars are __.
circumpolar
At lower latitude where the NCP is closer to the horizon, __ stars are circumpolar.
fewer
When the celestial equator intersects the horizon due east and due west, stars on the celestial equator __
rises due east and sets due west.
Stars located north of the celestial equator rise ___ and set __
north of east; north of west.
Stars located south of the celestial equator rise __ and set __.
south of east; south of west
Regardless of the poles, regardless of where you are on Earth, __ of the celestial equator is always visible above the horizon.
half
Any object located on the celestial is visible for __
half the time (12 hours)
Objects above the hemisphere are visible for __
more than half the day
The __ the star, the less time it stays up
more south
What is the bright star that is close to the NCP and used for navigation?
Polaris
The altitude of Polaris is nearly the same as the __ of the observer.
latitude
If you were standing at Earth's North Pole, where would you see the north celestial pole?
a. at the zenith
b. on the eastern horizon
c. 23.5 degrees south of the horizon
d. none of the above (the NCP can't be seen from there)
a. at the zenith
The __ determines the changing constellations and zodiacs in the night sky.
revolution of Earth around the Sun
Earth's revolution around the Sun is
counterclockwise
The stars overhead at midnight 6 months ago will now be
overhead at noon today
The __ is Earth's orbit around the Sun.
ecliptic plane
The constellations that lie along the ecliptic are called the constellations of the __
zodiac
How do you know which zodiac it is?
look at whichever constellation that the sun is in
Earth's __ determines the seasons.
tilted axis
Seasons are _____ in Northern and Southern hemispheres
opposites
If Earth's axis weren't tilted, __
there would be no seasons
In the summer, the north pole is tilted towards the Sun, so __
the Sun is north of the celestial equator and is visible above the horizon for more than 12 hours a day
The the winter, the north pole is tilted away from the Sun, so __
the Sun is south of the celestial equator and is visible above the horizon for less than 12 hours a day
Since the Sun is higher in the sky in summer than winter, __
sunlight strikes the ground more directly in summer than winter
The main reason why it's hotter in summer than winter is because
your location is more perpendicular to the Sun, so energy becomes more intense
The longest day when the Sun is highest in the sky and rises farthest north of east and sets farthest north of west is called __
the summer solstice
The summer solstice is on
June 21
The summer solstice means that it is
summer in the Northern Hemisphere and winter in the Southern Hemisphere
The shortest day of the year is
the winter solstice
The winter solstice is on
December 21
The winter solstice means that it is
winter in the Northern Hemisphere and summer in the Southern Hemisphere
__ is when there is an equal amount of day and night.
Equinox
The autumnal equinox is on
September 22
The vernal equinox is on
March 20
Equinoxes happen when
the celestial equator intersects with the ecliptic when it is about halfway from the winter and summer solstice
The __ measures from one specific equinox to the exact next one.
tropical year
How long is a tropical year?
365.2422 days
Why do we have leap years?
each year has an extra 1/4 day so that after 4 years we add a day to the year (due to tropical year)
Days and nights are 12 hours on the __ throughout the year.
equator
The change of position of the equinox, due to the wobble of Earth is called the __.
precession of the equinoxes
The tilt of Jupiter's rotational axis with respect to its orbital plane is 3 degrees. If Earth's axis had this tilt, then the seasons on Earth
a. would be much more extreme
b. would be much less extreme
c. would be pretty much the same
d. would occur much differently every year, depending on the alignments
b. would be much less extreme
What causes the phases of the moon?
The changing relative positions of the moon, Earth, and sun; the moon's revolution around Earth
What is synchronous rotation?
the moon rotates exactly once with each orbit
What causes the Moon's synchronous rotation?
the Moon is elongated and Earth's gravity constantly pulls on the near side
The __ occurs when the Moon is between Earth and the Sun and the far side is only illuminated.
New Moon
When does a New Moon rise?
sunrise (6am)
Why is the New Moon up during the day?
it's in the direction of the Sun
The __ happens a few days after the New Moon.
waxing crescent (light is increasing, less than 50% and in the right)
The __ happens a few days after the waxing crescent.
first quarter (light is 50% and in the right)
When does the first quarter moon rise?
noon (12pm)
The __ happens a few days after the first quarter.
waxing gibbous (light is increasing, over 50% and on right)
The __ happens a few days after the waxing gibbous.
full moon (light is 100%)
When does the full moon rise?
sunset (6pm)
The __ happens a few days after the full moon.
Waning gibbous (light is decreasing, over 50%, on left)
The __ happens a few days after waning gibbous.
third quarter (50% light, on left)
When does the third quarter moon rise?
midnight
The __ happens a few days after the third quarter.
waning crescent (decreasing light, less than 50%, on left)
You see the first quarter Moon on the meridian. Where is the Sun?
a. on the western horizon
b. on the eastern horizon
c. below the horizon
d. on the meridian
a. on the western horizon
A __ occurs when the Moon completely blocks the disk of the Sun.
total solar eclipse
A __ occurs when the Moon partially covers the disk of the Sun in part of the Earth's umbra.
partial solar eclipse
A __ occurs when the Moon is slightly farther away from Earth in its noncircular orbit, so it appears slightly smaller in the sky.
annular solar eclipse
A __ occurs when the Moon is partly or entirely in Earth's shadow.
Lunar eclipse
A __ occurs when the Moon is entirely in Earth's shadow.
total lunar eclipse
A __ occurs when Earth's shadow incompletely covers the Moon and some of the disk of the Moon remains bright while some remains in shadow.
Partial lunar eclipse
If the Moon were in the same orbital plane as Earth's orbit around the Sun, which of the following would happen?
a. the phases of the Moon would remain unchanged
b. there would be a solar eclipse every lunar orbit (roughly every month)
c. there would be a lunar eclipse every lunar orbit (roughly every month)
d. the Moon's cycle of phases would not occur
b and c
T/F: The celestial sphere is not an actual object in the sky.
True
T/F: eclipses happen somewhere on earth every month
False
T/F: the phases of the moon are caused by the relative positions of earth, the moon, and the sun
True
T/F: if a star rises north of east, it will set south of west
False
T/F: from the north pole, all stars in the night sky are circumpolar stars
True
The Sun, Moon, and stars
a. change their relative positions over time
b. appear to move each day because the celestial sphere rotates about Earth
c. rise north or south of east and set north or south of west, depending on their location in the celestial sphere
d. always remain in the same position relative to each other
a. change their relative positions over time
Which stars we see at night depend on
a. our location on Earth
b. Earth's location in its orbit
c. the time of the observation
d. the motion of stars relative to one another over the course of the year
a, b, c
You see the Moon rising just as the Sun is setting. What phase is the Moon in?
a. full
b. new
c. first quarter
d. third quarter
c. waning crescent
a. full
Where on Earth can you stand and, over the course of a year, see the entire sky?
a. only at the North Pole
b. at either pole
c. at the equator
d. anywhere
c. at the equator
You do not see eclipses every month because
a. all eclipses happen at night
b. the sun, earth, and the moon line up only twice a year
c. the sun, earth, and the moon line up only once a year
d. eclipses happen randomly and are unpredictable
b. the sun, earth, and the moon line up only twice a year
The tilt of the Earth's axis causes the seasons because
a. one hemisphere of earth is closer to the sun than in summer
b. the days are longer in summer
c. the rays of light strike the ground more directly in summer
d. a and b
e. b and c
e. b and c
On the vernal and autumnal equinoxes,
a. the entire earth has 12 hours of daylight and 12 hours of darkness
b. the sun rises due east and sets due west
c. the sun is located on the celestial equator
d. all of the above
e. none of the above
d. all of the above
We always see the same side of the moon because
a. the moon doesn't rotate on its axis
b. the moon rotates once each revolution
c. when the other side of the moon is facing towards us, it is unlit
d. when the other side of the Moon is facing earth, it is on the opposite side of earth
e. none of the above
b. the moon rotates once each revolution
You see the moon on the meridian at sunrise. The phase of the moon is
a. waxing gibbous
b. full
c. new
d. first quarter
e. third quarter
e. third quarter
A lunar eclipse occurs when the __ shadow falls on the __.
a. Earth's; moon
b. moon's; earth
c. sun's; moon
d. sun's; earth
a. Earth's; moon
You see the full Moon on the meridian. From this information, you can determine that the time where you are is
a. noon
b. sunrise (6am)
c. sunset (6pm)
d. midnight
d. midnight
What do we call the group of constellations through which the sun appears to move over the course of a year?
a. the celestial equator
b. the ecliptic
c. the line of nodes
d. the zodiac
d. the zodiac
If you were standing at earth's south pole, which stars would you see rising and setting?
a. all of them
b. all the stars north of the Antarctic circle
c. all of the stars south of the Antarctic circle
d. none of them
d. none of them
On the summer solstice in the Northern Hemisphere, the sun
a. rises due east, passes through its highest point on the meridian, and sets due west
b. rises north of east, passes through its highest point on the meridian, and sets north of west
c. rises north of east, passes through its highest point on the meridian, and sets south of west
d. rises south of east, passes through its highest point on the meridian, and sets south of west
e. none of the above
b. rises north of east, passes through its highest point on the meridian, and sets north of west
In the tropics,
a. the sun is directly overhead twice per year
b. the sun's rays strike earth precisely perpendicularly twice per year
c. the seasons vary less than elsewhere on earth
d. all of the above
d. all of the above
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