3714419343 | constellation | a region of the sky with well-defined borders | 0 | |
3714421094 | celestial sphere | the illusion that all stars lie on the edge of a sphere around Earth that occurs because we lack depth perception | 1 | |
3714425267 | north celestial pole | the point directly above Earth's North Pole | 2 | |
3714431491 | south celestial pole | the point directly above Earth's South Pole | 3 | |
3714432914 | celestial equator | a projection of Earth's equator into space, which makes a complete circle around the celestial sphere | 4 | |
3714435533 | ecliptic | the path the Sun follows as it appears to circle around the celestial sphere once each year | 5 | |
3714438880 | local sky | the sky as seen from where you happen to be standing | 6 | |
3714440575 | horizon | the boundary between Earth and the sky | 7 | |
3714442304 | zenith | the point directly overhead in the sky | 8 | |
3714443891 | meridian | an imaginary half-circle stretching from the horizon due south, through the zenith, to the horizon due north | 9 | |
3714447356 | direction (local sky) | one of the two coordinates needed to pinpoint an object in the local sky | 10 | |
3714449621 | altitude | the angular distance between the horizon and an object in the sky | 11 | |
3714451180 | angular size (or angular distance) | a measure of the angle formed by extending imaginary lines outward from our eyes to span an object (or the space between two objects) | 12 | |
3714451870 | arcminute | 1/60 of 1 degree | 13 | |
3714451871 | circumpolar star | a star that always remains above the horizon for a particular latitude | 14 | |
3714451872 | latitude | the angular north-south distance between Earth's equator and a location on Earth's surface | 15 | |
3714452803 | longitude | the angular east-west distance between the prime meridian and a location on Earth's surface | 16 | |
3714454158 | prime meridian | the meridian of longitude that passes through Greenwich, England; defined to be longitude 0 degrees | 17 | |
3714454159 | zodiac | the constellations on the celestial sphere through which the ecliptic passes | 18 | |
3718896318 | June solstice | the moment when the Northern Hemisphere is tipped most directly toward the Sun and receives the most direct sunlight | 19 | |
3718896319 | December solstice | the moment when the Northern Hemisphere receives the least direct sunlight | 20 | |
3718896989 | March equinox | the moment when the Northern Hemisphere goes from being tipped slightly away from the Sun to being tipped slightly toward the Sun | 21 | |
3718897943 | September equinox | the moment in when the Northern Hemisphere first starts to be tipped away from the Sun | 22 | |
3718897944 | precession | the gradual wobble of the axis of a rotating object around a vertical line | 23 | |
3718898996 | lunar phases | the state determined by the portion of the visible face of the Moon that is illuminated by sunlight; cycles through waxing crescent, first-quarter, waxing gibbous, full, waning gibbous, third-quarter, waning crescent, and back to new | 24 | |
3718900954 | synchronous rotation | the rotation of an object that always shows the same face to an object that it is orbiting because its rotation period and orbital period are equal | 25 | |
3718900955 | eclipse | an event in which one astronomical object casts a shadow on another or crosses our line of sight to the other object | 26 | |
3718902024 | lunar eclipse | an event that occurs when the Moon passes through Earth's shadow, which can occur only at full moon | 27 | |
3718902025 | solar eclipse | an event that occurs when the Moon's shadow falls on Earth, which can occur only at a new moon | 28 | |
3718902026 | nodes | the two points in the Moon's orbit where it crosses the ecliptic plane | 29 | |
3718902027 | umbra | the dark central region of a shadow | 30 | |
3718904174 | penumbra | the lighter, outlying regions of a shadow | 31 | |
3718904175 | total lunar eclipse | a lunar eclipse in which the Moon becomes fully covered by Earth's umbral shadow | 32 | |
3718904812 | partial lunar eclipse | a lunar eclipse during which the Moon becomes only partially covered by Earth's umbral shadow | 33 | |
3718904813 | penumbral lunar eclipse | a lunar eclipse during which the Moon passes only within Earth's penumbral shadow and does not fall within the umbra | 34 | |
3718906356 | totality | the portion of a total lunar eclipse during which the Moon is fully within Earth's umbral shadow or a total solar eclipse during which the Sun's disk is fully blocked by the Moon | 35 | |
3718906357 | total solar eclipse | a solar eclipse during which the Sun becomes fully blocked by the disk of the Moon | 36 | |
3718907763 | annular eclipse | a solar eclipse during which the Moon is directly in front of the Sun but its angular size is not large enough to fully block the Sun; thus, a ring of sunlight is still visible around the Moon's disk | 37 | |
3718907764 | partial solar eclipse | a solar eclipse during which the Sun becomes only partially blocked by the disk of the Moon | 38 | |
3718910329 | saros cycle | the period over which the basic pattern of eclipses repeats, which is about 18 years and 11 1/3 days | 39 | |
3718910889 | apparent retrograde motion | the apparent motion of a planet, as viewed from Earth, during the period of a few weeks or months when it moves westward relative to the stars in our sky | 40 | |
3718912901 | stellar parallax | the apparent shift in the position of a nearby star (relative to distant objects) that occurs as we view the star from different positions in Earth's orbit of the Sun each year | 41 |
The Essential Cosmic Perspective - Chapter 2 Flashcards
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