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Related Flashcards
Related Topics
Cards In This Set
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Light year definition and what it's useful for
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The distance light travels, moving at the speed of light, in one year. Useful for measuring distances between stars.
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Astronomical unit (AU) definition and what it's useful for
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The average distance between the sun and the Earth. Useful for measuring distances between the sun and planets in our solar system.
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Parsec definition and what it's useful for
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Distance at which the separation (or paralax) angle between the Earth and the sun equals one arc second (1/3600 degree) of angle. Useful for measuring distances to galaxies
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Celestial sphere
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The imaginary bowl of the sky that surrounds Earth and and carries the stars attached to the sphere.
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Moon
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Orbits a planet
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Planet
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Orbits a star
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Star
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A huge sphere of hot gases held together by gravity
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Solar system
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A star orbited by planets
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Galaxy
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A grouping of billions of stars held together by gravity
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Universe
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The totality of all space, time, matter, and energy
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Solstice
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First day of the summer or winter season
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Equinox
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First day of the spring (vernal) or autumn (autumnal) season
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Ecliptic plane
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The plane of Earths orbit around the sun
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New moon
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Phase of the moon where none of the lunar disc is visible
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Full moon
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Phase of the moon where the entire lunar disc is visible
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