How many stars can you see with your naked eye on a clear, moonless night from a dark location?
a few thousand
Which of the following best describes the modern definition of a constellation?
a region of the celestial sphere
Which of the following statements about the celestial sphere is not true?
The "celestial sphere" is just another name for our universe
Which of the following statements about the celestial equator is true at all latitudes?
it represents an extension of Earth's equator onto the celestial sphere.
What is the ecliptic?
the Sun's apparent path along the celestial sphere
When we look into the band of light in our sky that we call the Milky Way, can we see distant galaxies? Why or why not?
No, because the stars, gas and dust of the Milky Way block us from seeing them
Which of the following correctly describes the meridian in your sky?
a half-circle extending from your horizon due north, through your zenith, to your horizon due south
If it is midnight in New York, it is
daytime in Sydney, Australia
How many arcseconds are in 1 degree?
3,6000
Which of the following statements does not use the term angular size or angular distance correctly?
The angular distance between those two bright stars in the sky is about 2 meters
What is a circumpolar star?
a star that always remains above your horizon
Which of the following statements about circumpolar stars is true at all latitudes?
they always remain above your horizon
We describe a position on Earth's surface by stating its
latitude and longitude
What makes the North Star, Polaris, Special?
It appears very near the north celestial pole
You are standing on Earth's equator. Which way is Polaris, the North star?
on the northern horizon
By locating the north celestial pole in the sky, how can you determine your latitude?
the altitude of the NCP is the same as your latitude
Orion is visible on winter evenings but not summer evenings because of
the location of Earth in its orbit
Why do we have seasons on Earth?
As Earth goes around the Sun and Earth's axis remains pointed toward Polaris, the Northern and Southern hemispheres alternatively receive more and less direct sunlight
Why is it summer in the Northern Hemisphere when it is winter in the Southern Hemisphere?
The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight
Which of the following statements is true?
Both the Northern and Southern hemispheres receive the same amount of sunlight on the equinoxes AND The Northern Hemisphere receives the most direct sunlight on the summer solstice
Which of the following statements about constellations is false?
Most constellations will be unrecognizable hundreds of years from now
Which of the following statements about lunar phases is true?
It is possible to have two full Moons during January, but not during February
Which of the following is not a phase of the Moon?
half Moon
When someone on Earth observes the Moon in the first-quarter phase, someone on the Moon facing Earth observes Earth in the
third-quarter Earth phase
If the Moon is setting at 6 A.M., the phase of the Moon must be
full
If the Moon is setting at noon, the phase of the Moon must be
third quarter
If the Moon is rising at midnight, the phase of the Moon must be
third quarter
At approximately what time would a full Moon be on your meridian?
Midnight
At approximately what time would a first quarter Moon rise?
noon
If the Moon rises around 3 A.M., its phase must be
waning crescent
In which direction does a quarter Moon rise?
east
Why do we see essentially the same face of the Moon at all times?
because the Moon's rotational and orbital periods are equal
Which of the following statements about the Moon is true?
The Moon's distance from Earth varies during its orbit
Suppose you live on the Moon. How long is a day (from sunrise to sunrise)
a lunar month
Ashen light or (earth shine) is
sunlight reflected by Earth that illuminates the "dark" portion of the Moon
All of the following statements are true. Which one explains the reason why there is not a solar eclipse at every new Moon?
the orbital plane of the Moon is tilted by about 5 degrees to the ecliptic plane
What effect or effects would be most significant if the Moon's orbital plane were exactly the same as the ecliptic plane?
solar eclipses would be much more frequent
What conditions are required for a solar eclipse?
The phase of the Moon must be new, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun
What conditions are required for a lunar eclipse?
the phase of the Moon must be full, and the nodes of the Moon's orbit must be nearly aligned with the Earth and the Sun
In addition to the conditions required for any solar eclipse, what must also be true in order for you to observe a total solar eclipse?
The moon's umbra must touch the area where you are located
If part of the full Moon passes through Earth's umbra, we will see a
partial lunar eclipse
If the Moon is relatively far from Earth, so that the umbra does not reach Earth, someone directly behind the umbra will see
an annular eclipse
When are eclipse seasons?
When the nodes of the Moon's orbit are nearly aligned with the SUn
The procession of the Moon's nodes means that
the eclipse seasons occur less than 6 months apart
What is the Saros cycle?
the 18-year cycle over which the pattern of eclipses repeats
Ancient people who knew the Saros cycle could
predict when an eclipse would happen, but not necessarily what type and where it would be visible
What happens during the apparent retrograde motion of a planet?
The planet appears to move westward with respect to the stars over a period of many nights
Why are lunar eclipses more commonly seen than solar eclipses?
the Earth casts a bigger shadow than the Moon
What causes the apparent retrograde motion of the planets?
As Earth passes another planet, the other planet appears to move backward with respect to the background stars, but the planet's motion does not really change
Which of the following never goes in retrograde motion?
the Sun
Which of the following statements about parallax is not true?
The technique of stellar parallax was used by Hubble to determine that the Andromeda Galaxy (M 31) is about 2 million light-years away
Which of the following statements about stellar parallax is true?
The closer a star is to us, the more parallax it exhibits
We can't detect stellar parallax with naked-eye observations. Which of the following would make parallax easier to observe?
increasing the size of Earth's orbit
Why were ancient peoples unable to detect stellar parallax?
they did not have the ability to measure very small angles
About how many stars are visible to the naked eye on a clear, dark night away from city lights?
a couple thousand
What do astronomers mean by a constellation?
a constellation is a region in the sky as seen from Earth
What is the ecliptic?
the path the Sun appears to trace around the celestial sphere each year
What do we mean when we talk about the Milky Way in our sky?
the patchy band of light that outlines the plane of the Milky Way Galaxy as seen from Earth
Which of the following correctly describes the meridian in your local sky?
a half-circle extending from your horizon due north, through your zenith, to your horizon due south
The point directly over your head is called
the zenith
We describe a location on Earth's surface by stating its
latitude and longitude
If you are located in the Northern Hemisphere, which of the following correctly describes a relationship between the sky and your location?
The altitude of the north celestial pole equals your latitude
Which of the following best describes why we have seasons on Earth?
the tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year
Each choice below describes how a few astronomical phenomena are related to time periods. Which list is entirely correct?
Earth's rotation defines a day.
The cycle of the Moon's phases takes about a month.
Earth's orbit defines a year.
Earth's cycle of axis precession takes 26,000 years.
If we have a new Moon today, when will we have the next full Moon?
in about 2 weeks
We cannot see a new moon in our sky because
a new moon is quite near the Sun in the sky
The Moon always shows nearly the same face to Earth because
the Moon rotates once in the same amount of time that it takes the Moon to orbit Earth once
Lunar eclipses can occur only during a
full moon
What is the saros cycle?
the roughly 18-year cycle over which the pattern of eclipses repeats
During the time that a planet is in its period of apparent retrograde motion
over many days or weeks, the planet moves westward relative to the stars, rather than the usual eastward relative to the stars
What is stellar parallax?
it is the slight back-and-forth shifting of star positions that occurs as we view the stars from different positions in Earth's orbit of the sun
Which of the following statements about the celestial sphere is NOT true?
the "celestial sphere" is another name for our universe
The Andromeda Galaxy is faintly visible to the naked eye in the constellation Andromeda. Suppose instead it were located in the same direction in space as the center of the Milky Way Galaxy (but still at its current distance). How would it appear to the eye in that case?
We could not see it at all
An angle of 1 arcsecond is
less than the thickness of a human hair held at arm's length
When traveling north from the United States into Canada, you'll see the North Star (Polaris) getting
higher in the sky
Suppose you use the Southern Cross to determine that the south celestial pole appears 40 degrees above your horizon. Then you must be located at
latitude 40 degrees south
Suppose you are facing north and you see the Big Dipper close to your northern horizon, with Polaris (and the Little Dipper) above it. Where will you see the Big Dipper in six hours?
to the right of Polaris; that is, 90 degrees counterclockwise from its current position
In any particular place on Earth, certain constellations are visible in the evening only at certain times of the year because
our evening view of space depends on where Earth is located in its orbit around the Sun
The sun's path as viewed from the equator is highest in the sky on
the spring and fall equinoxes
Suppose Earth's axis tilt was significantly greater than its current 23.5 degrees, but Earth's rotation period and orbital period were unchanged. Which statement below would not be true?
the length of each season (for example, the number of days from the summer solstice to the fall equinox) would be significantly longer than it is now
If our year were twice as long (that is, if Earth took twice as many days to complete each orbit around the sun), but Earth's rotation period and axis tilt were unchanged, then
the four seasons would each be twice as long as they are now
How does Earth's varying distance from the Sun affect our seasons?
It doesn't--Earth's orbital distance plays no significant role in the seasons
Suppose you live in the US and you see a crescent Moon in your evening sky tonight. What will a friend in South America see tonight?
Your friend will also see a crescent Moon
Suppose it is a full Moon. What phase of Earth would someone on the Moon see at this time?
New Earth
It is 6 AM and the Moon is at its highest point in your sky (crossing the meridian). What is the Moon's phase
third quarter
You observe a full Moon rising at sunset. What will you see at midnight?
a full Moon high in the sky
All of the following statements are true. Which one explains the reason that there is not a solar eclipse at every new Moon?
the orbital plane of the Moon is tilted slightly (about 5 degrees) to the ecliptic plane
For most of history, the lack of observable stellar parallax was interpreted to mean that
Earth is stationary at the center of the universe
During the period each year when we see Mars undergoing apparent retrograde motion in our sky, what is really going on in space?
Earth is catching up with and passing by Mars in their respective orbits
Suppose you see a photo showing Jupiter half in sunlight and half in shadow (that is, a first quarter Jupiter). This photo might have been taken by
the Galileo spacecraft that orbited Jupiter in the 1990s
