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15 Cards in this Set
- Front
- Back
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Which of the following years will be a leap year?:
A: 2054 B: 2100 C: 2102 D: 2400 E: (None of the above.) |
D. 2400
Reason: A year is a leap year if it is divided by 4 unless it is a century year, in which case it is a leap year if it is divided by 400. |
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An observer at the Earth's South Pole sees the stars:
A: rising and setting every day. B: neither rising nor setting. C: rising and setting for only half the year. D: rising and setting at intervals that depend on the seasons. E: (None of the above.) |
B. Neither rising nor setting.
Reason: At the Earth's South Pole your horizon is the celestial equator and your zenith is the celestial south pole. You will be able to see all the stars in the south celestial sphere moving in circular orbits around the celestial south pole; these orbits are parallel to the celestial equator. Therefore none of the stars will be rising or setting. |
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At the time of the equinox the Sun is located..?
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On the celestial equator.
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For an observer in the northern hemisphere summers are warmer than winters mainly because..?
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The Sun's altitude in the sky is higher during summer.
Reason: The Earth is actually farther from the Sun during winter and the days are longer during the summer. The Sun's energy output does not depend on the seasons and reflected sunlight from the Moon has nothing to do with seasons. |
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When does a planet move westward with respect to the distant stars?
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During it's retrograde.
Reason: A planet's direction of motion around the Sun does not change. Planets, like the stars, the Sun, and the Moon, rise in the east and set in the west. With respect to the distant stars, the Sun and the Moon move eastward, but the planets sometimes stop their eastward motion and move westward for a while (retrograde motion). |
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The celestial coordinates of the autumnal equinox are..?
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0 degrees declination, 12 hours right ascension.
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The number 50,000 written in power-of-ten notation is ________ .
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5´104
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A light-year is..?
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the distance light travels in a year. It is therefore a unit of distance. It is about 63,000 astronomical units. Choice C is the definition of the astronomical unit, which is about 150 million kilometers.
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On a scale where the Sun is the size of a basketball, the nearest star is....?
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About 7000 kilometers away.
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Compared to the astronomical unit, the size of Texas (about 800 miles) is
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About five orders of magnitude smaller.
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What is a nebula?
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An interstellar region of dust and/or gas
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During a total lunar eclipse, an astronaut on the near side of the Moon observes..?
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A total solar eclipse.
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An observer on Earth always sees the full Moon..?
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Rising about the time the Sun sets.
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The shortest time that a lunar eclipse can occur after a solar eclipse is about..?
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Two weeks.
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The elongation of the Moon when it is in its full phase is about
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80 degrees.
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