Astronomy 1,2 – Flashcards
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Why did early civilizations observe constellations?
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for practical reasons, such as navigation and helping to determine seasons
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What conditions are necessary for a total solar eclipse?
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new moon on ecliptic near perigee
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The parallax shift of a star would be greater if viewed from Mars than from Earth.
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true
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The orbits of most of the planets in our solar system have eccentricities close to zero.
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true
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If Earth rotated twice as fast as it currently does, but its motion around the Sun stayed the same, then
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the night would be half as long.
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What conditions must exist for a solar eclipse to occur?
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The phase of the Moon must be new and the Moon must be passing through Earth's orbital plane.
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What conditions must exist for a lunar eclipse to occur?
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The phase of the Moon must be full and the Moon must be passing through Earth's orbital plane.
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If you could change the layout of the solar system, which of the following would cause a lunar eclipse to occur at least once every month in this hypothetical situation?
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Change the Moon's orbital plane so it is in the same plane as Earth's orbit around the Sun.
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From Earth, the Sun and Moon have about the same angular diameter.
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true
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Combining Newton's and Kepler's laws, we can weigh the Sun, provided we know:
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the size of the A.U. and exact length of the year.
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Newton's modification of Kepler's Laws allows us to find the ________ of the planets, if we can observe satellites in orbit about them.
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masses
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If the distance between two asteroids is doubled, the gravitational force they exert on each other will:
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be one fourth as great.
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Kepler based his theories on the precise planetary observations of Tycho Brahe.
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true
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Where on Earth would you be if Polaris was at your zenith?
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north pole
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On which of these assumptions do Ptolemy and Copernicus agree?
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All orbits must be perfect circles.
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Galileo found the rotation period of the Sun was approximately:
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a month.
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Like the Sun and the Moon, the stars appear to move from west to east from one day to the next
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true
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A planet whose distance from the Sun is 3 A.U. would have an orbital period of how many Earth-years?
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square root of 27
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Galileo's observations of sunspots proved the Sun was rotating, like the Earth.
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true
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What conditions are necessary for an annular solar eclipse?
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new moon on ecliptic at apogee
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Only at the equator are all the stars visible over the course of the year.
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true
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Today we rely largely on what technique to precisely measure distances in the solar system?
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radar echo timings
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About how many stars are visible on a clear, dark night with the naked eye alone?
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a few thousand
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Compared to orbital velocity, escape velocity is about:
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40% more.
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Halley's comet has a perihelion distance of 0.6 AU AU and an orbital period of 76 years. What is the aphelion distance of Halley's comet from the Sun?
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35 AU
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The places where the Sun crosses the equator are called the:
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equinoxes.
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From a location in the United States of America, a star is observed to be rising due East. Where will this star be located 6 hours later?
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high in the southern sky
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An accurate sketch of Jupiter's orbit around the Sun would show
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a nearly perfect circle.
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The place the Sun stops its northward motion along the ecliptic is the:
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summer solstice.
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The place in a planet's orbit that is closest to the Sun is called:
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perihelion.
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Escape velocity is the speed required to:
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overcome the gravitational pull of an object.
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If you are in the Moon's umbral shadow, then you will witness:
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a total solar eclipse.
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The greatest contribution of the Greeks to modern thought was:
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the development of scientific inquiry and model building.
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When the Sun rises, it is located in the constellation Gemini. When the Sun sets later that same day, it will be:
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in the constellation Gemini.
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While watching a star, you see it moves 15 degrees across the sky. How long have you been watching it?
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15 minutes
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Kepler's second law implies what about planetary motion?
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A planet moves faster when it is closer to the Sun.
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A star with a large parallax:
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is at a short distance from Earth.
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You note that a particular star is directly overhead. It will be directly overhead again in:
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23 hours 56 minutes.
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The angular size of an object depends on which two quantities?
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the object's actual size and its distance from us
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The Ptolemaic model probably persisted for all these reasons EXCEPT:
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it accounted well for Galileo's observations of the phase cycle of Venus.
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The last quarter phase of the Moon:
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crosses the meridian at sunrise.
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Which of the choices below correctly lists things in order from largest to smallest?
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Universe, Local Group, Milky Way, Solar System
