Cycles of the Sun and Moon Chapter 3 PDF

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Rotation: the turning of a body on its axis ● Causes the cycle of day and night VS. Revolution: the motion of a body around a point outside the body ● Motion around the sun in its orbit that defines the year Ecliptic: The apparent path of the sun against the background of stars Earth has seasons because its axis of rotation is tipped 23.4 degrees from the perpendicular to its orbit. ● The sun moves into the northern sky in the spring, and into the southern sky in the fall. ● Goes through seasons because of the changes in the amount of solar energy that Earth’s northern and southern hemispheres receive at different times of the year. ● When one hemisphere receives more solar energy than the other, it grows rapidly warmer Common misconceptions about seasons: ● The seasons don't occur because the earth moves closer to or farther from the sun. If that was the case, both of Earth’s hemispheres would experience winter at the same time, which doesn’t happen Planet: comes from Greek word meaning “wanderer” Evening Star: any planet visible in the evening sky Morning Star: Any planet visible in the sky shortly before sunrise Vernal Equinox: The place on the celestial sphere where the sun crosses the celestial equator moving northward; also, the time of year where the sun crosses this point, spring begins in the Northern Hemisphere. (March 20) Summer Solstice: The point on the celestial sphere where the sun is at its most northerly point; also, the time when the sun passes this point, about June 22, and summer begins in the Northern Hemisphere. (June 22) Autumnal Equinox: The point on the celestial sphere where the sun crosses the celestial equator going southward. Also, the time when the sun reaches this point and autumn begins in the NOrthern hemisphere. (September 22) Winter Solstice: The point on the celestial sphere where the sim os farthest south; Also, the time of year when the sun passes this point, winter begins in the Northern Hemisphere. (December 21) Equinox comes from the word “equal”; the day if ab equinox has equal amounts of daylight and

darkness. Solstice comes from the words meaning “sun” and “stationary” Vernal comes from the word “green.”; the green equinox marks the beginning of spring in the northern hemisphere Light from the summer solstice sun strikes northern latitudes from nearly overhead and is concentrated. Light from the winter solstice sun strikes northern latitudes at a much steeper angle and spreads out. Perihelion: The orbital point of closest approach to the sun; 1.7 percent closer than average Aphelion: The orbital point of greatest distance from the sun; 1.7 percent farther than average ●

Small variation does not significantly affect the seasons

Astrology: Based on the cycles of the sun and planets around the sky ● Zodiac: a band around the sky extending 9 degrees above and below the ecliptic ● Horoscope: a diagram showing the location of the sun, moon, and planets around the ecliptic and their position above or below the horizon for a given date and time. Subtle changes in the annual motion can have dramatic affects on climate. ● Dont notice these changes during your lifetime ● Over thousands of years, they can bury continents under glaciers Milankovitch Hypothesis: The hypothesis that small changes in Earth's orbital and rotational motions cause the ice ages ● Meteorologist Milutin Milankovitch Scientific Argument: An honest, logical discussion of observations and theories intended to reach a valid conclusion. The moon revolves counterclockwise around Earth. ● In 24 hours, the moon moves 13 degrees ● EAch night you see the moon 13 degrees eastward of its location the night before ● Monthlong cycle 1. The moon always keeps the same side facing earth 2. The changing shape of the moon as it passes through its cycle of phases is produced by sunlight illuminating different parts of the side of the moon you can see

Lunar Eclipse: Can occur at full moon of the moon moves through the shadow of Earth. Earths shadow consists of 2 parts: Umbra: the region of total shadow Penumbra: Partial shadow; you would see the sun peeking around the edge of Earth Totlality: the period of total eclipse Sidereal Period: The period of rotation or revolution of an astronomical body relative to the stars ● How long the moon takes to circle the sky once and return to the same position among the stars Synodic Period: A complete cyle of lunar phases Solar Eclipse: The moon is just the right size to cover the bright disk of the sun and cause a solar eclipse Photosphere: The bright visible surface of the sun Chromosphere: when the moon covers the photosphere Corona: the suns outer atmosphere Annular Eclipse: a solar eclipse in which a ring of the photosphere is visible around the disk of the moon Saros Cylce:An 18 year 11 ⅓ day period after which the pattern of lunar and solar eclipses repeats...