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24 Cards in this Set
- Front
- Back
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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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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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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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A week after full moon, the Moon's phase is:
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3rd quarter
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Some type of lunar or solar eclipse (not necessarily a total eclipse) occurs
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at least four times a year
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If there is going to be a total lunar eclipse tonight, then you know that:
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the Moon's phase is full.
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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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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.
When we look in the sky, the stars all appear to be located on the celestial sphere. The celestial sphere does not exist physically. The Earth is placed at the center of the celestial sphere. The celestial sphere is not another name for our universe. Rather, it is an imaginary device for locating objects by their direction in the sky as seen from Earth. |
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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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Remember that the altitude of the north celestial pole in your sky is equal to your latitude, and think about how latitude changes as you travel north.
** Remember that the altitude of the north celestial pole in the local sky is equal to your latitude, so traveling north (to higher latitude) means the North Star will move higher in your 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
* The altitude of the south celestial pole is equal to your latitude; because you see the south celestial pole at altitude 40 degrees, you must be located at 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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Facing north, the sky appears to turn counterclockwise. In 6 hours, the sky will turn ¼ of the way around a full circle, so you all stars will appear to have moved 90 degrees counterclockwise around the north celestial pole.
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
*As we orbit the Sun, the direction we are looking in space at any particular time of day is constantly changing. |
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The Sun's path, as viewed from the equator, is highest in the sky on _________.
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winter solstice-sun pointed south
summer solstice- sun pointed north spring and fall equinox *At the equator, the Sun passes through the zenith just twice each year: at noon on 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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Summers and winters would be more severe (for example, hotter and colder, respectively) than they are now.
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. Polaris would not be our North star. The region of Earth where the Sun does not rise on the winter solstice would be larger (extending farther south) than it is now *The length of the seasons would be unaffected, because this is determined by Earth's orbital period. |
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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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-Rise and set is determined by rotation period, not the orbital period.
-Precession is related to Earth's rotation, which the question said was unchanged. (Precession, however, is affected by the Sun's gravity, so if Earth were farther from the Sun, precession might actually be slower, but certainly not faster. ) *As long as the axis is tilted, there will be four seasons during a year, so a longer year means longer seasons. 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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The difference in distance over the course of the year is not enough to affect Earth's seasons; seasons on Earth are caused by the tilt of Earth's axis.
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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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The phase of the Moon depends only on the relative positions of the Earth, Moon, and Sun.
On a given day, everyone only on Earth sees the same phase of the moon. 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
We see full moon when the Moon is opposite the Sun in our sky. So at this time, observers on the Moon would be looking at the night side of Earth, which means they would see 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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First quarter moon is visible in the evening, not in the morning.
Full moon is highest in the sky around midnight. Third quarter moon rises around midnight, reaches its highest point around 6am, and sets around noon. That is why you can see the third-quarter moon in the morning 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 Moon goes through a complete cycle of phases about every 29 1/2 days.
The orbital plane of the Moon is tilted slightly (by about 5 degrees) to the ecliptic plane. The Moon is only about 1/4 as large as Earth in diameter. The nodes of the moon's orbit precess with an 18-year period. Because the angular size of the Moon as seen from Earth is only about half a degree, the 5 degree tilt of the Moon's orbit ensures that on most orbits, the Moon passes either slightly above or below the Sun in our sky. |
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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
The Greeks were aware that stellar parallax should occur if Earth orbits the Sun - and we now know that it does indeed occur. However, the stars are so far away that ancient people could not detect parallax; the Greeks mistakenly took this lack of detectable parallax as evidence in favor of their Earth-centered model, rather than as evidence that the stars are really far away. |
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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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This is true during only part of the period of apparent retrograde motion, and it is also the case during some periods when Mars is not seen in apparent retrograde motion.
(earth and mars getting closer...not the answer) Earth is catching up with and passing by Mars in their respective orbits. In other words, we see apparent retrograde motion as we "lap" Mars in going around our orbit. |
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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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