Mastering Astronomy Chapter 2 Flashcards
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Which of the following statements about the celestial sphere is NOT true?
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The "celestial sphere" is another name for our universe.
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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?
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we could not see it at all
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An angle of 1 arcsecond is
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less than the thickness of a human hair held at arm's length
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When traveling north from the United States into Canada, you'll see the North Star (Polaris) getting
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higher in the sky
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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
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latitude 40 degrees south
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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?
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To the right of Polaris; that is, 90 degrees counterclockwise from its current position
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In any particular place on Earth, certain constellations are visible in the evening only at certain times of the year because
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our evening view of space depends on where Earth is located in its orbit around the Sun
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The Sun's path, as viewed from the equator, is highest in the sky on
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the spring and fall equinoxes
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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?
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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.
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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
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the four seasons would each be twice as long as they are now
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How does Earth's varying distance from the Sun affect our seasons?
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It doesn't --- Earth's orbital distance plays no significant role in the seasons.
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Suppose you live in the United States and you see a crescent moon in your evening sky tonight. What will a friend in South America see tonight?
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Your friend will also see a crescent moon.
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Suppose it is full moon. What phase of Earth would someone on the Moon see at this time?
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new Earth
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It's 6 am and the Moon is at its highest point in your sky (crossing the meridian). What is the Moon's phase?
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third quater
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You observe a full moon rising at sunset. What will you see at midnight?
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A full moon high in the sky
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All the following statements are true. Which one explains the reason that there is not a solar eclipse at every new moon?
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The orbital plane of the Moon is tilted slightly (by about 5 degrees) to the ecliptic plane.
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For most of history, the lack of observable stellar parallax was interpreted to mean that
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Earth is stationary at the center of the universe
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During the period each year when we see Mars undergoing apparent retrograde motion in our sky, what is really going on in space?
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Earth is catching up with and passing by Mars in their respective orbits.
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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
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the Galileo spacecraft that orbited Jupiter in the 1990s
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When it is summer in Australia, the season in the United States is
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winter
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Why do we always see the same face of the Moon?
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We always see the same face of the Moon because the Moon displays synchronous rotation, meaning that the Moon's rotation period and its orbital period around Earth are the same.
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Beijing and Philadelphia have about the same latitude but very different longitudes. Therefore, tonight's night sky in these two places:
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will look about the same.
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When I looked into the dark lanes of the Milky Way with my binoculars, I saw what must have been a cluster of distant galaxies.
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This statement does not make sense because we cannot see through the band of light we call the Milky Way to external galaxies; the dark fissure is gas and dust blocking our view.
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The North Celestial Pole is 35.0? above your northern horizon. This tells you that:
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you are at latitude 35.0? N.
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What do astronomers mean by a constellation?
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A constellation is a region in the sky as seen from Earth.
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When we see Saturn going through a period of apparent retrograde motion, it means
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Earth is passing Saturn in its orbit, with both planets on the same side of the Sun.
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If the Sun rises precisely due east:
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it must be the day of either the spring or fall equinox.
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If you are located in the Northern Hemisphere, which of the following correctly describes a relationship between the sky and your location?
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The altitude of the north celestial pole equals your latitude.
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In winter, Earth's axis points toward the star Polaris. In spring:
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the axis also points toward Polaris.
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Which of the following statements does NOT use the term angular size or angular distance correctly?
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The angular distance between those two bright stars in the sky is about 2 meters.
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If we have a new moon today, when we will have the next full moon?
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in about 2 weeks
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A week after full moon, the Moon's phase is:
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third quarter
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Stars that are visible in the local sky on any clear night of the year, at any time of the night, are called
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circumpolar
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What is the ecliptic?
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the path the Sun appears to trace around the celestial sphere each year
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Which of the following celestial objects do NOT rise in the east and set in the west, as viewed from Earth? (Assume that all of these objects are visible from your location on Earth, and that none of them are circumpolar.)
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All of these objects rise in the east and set in the west
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Two stars that are in the same constellation:
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may actually be very far away from each other.
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Angular size of an object is the ___ it appears to span in you field of view. It has nothing to do with the distance of the object. You can measure angular distance using ___
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angle, your hand/fingers
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Angular distance between a pair of objects is the ___ that appears to separate them. One degree = 60arcmin. One arcmin = 60arcsec
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angle
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The circumpolar stars in the southern hemisphere rotate ___
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clockwise
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Calculate the real diameter given the angular size (diameter)
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physical size(diameter) = angular size * ( (2pi*distance)/360deg. )
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Latitude is measured ___ or ___ of the equator. (It is 0 at the equator, increasing to 90degreesN at the North Pole and 90degrees S).
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north, south
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Longitude is measured ___ or ___ of the prime meridian (Greenwich at 0 degrees)
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east, west
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The sky varies with ____ because different parts of the sky are seen at different latitudes. Everyone at the same latitude would have the same view of the sky at some point during the 24 hours.
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latitude
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The altitude of the celestial pole in your sky is equal to your latitude. For example, if you see the north celestial pole at an altitude of 40 degrees above your north horizon, your latitude is
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40 degrees N
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The Northern hemisphere is tipped toward the sun in ___ and away in ___. The opposite is true for the southern hemisphere.
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June, December
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A sidereal day depends on the stars. It is ___ than a solar day
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shorter
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On the march and september equinoxes, the sun
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shines equally on both hemispheres
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On the june solstice, the sun
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faces the northern hemisphere more (northern is tipped toward)
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Sun directly overhead (23.5 degrees N) on the ___
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June solstice
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Moon orbits every ____ days. New moon --> waxing crescent --> first quarter --> waxing gibbous --> full moon --> waning gibbous --> third quarter --> waning crescent
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29.5
