module 2

• astronomy - the science of the universe outside of our planet
• astronomy - branch of science dealing with heavenly bodies
• moon - a natural object that orbits a larger object
• eclipse - when one celestial body such as a moon or planet moves into the shadow of another celestail body
• solar eclipse - a type of eclipse that occurs when the moon passes between the sun and earth; an the moon fullu or partially blocks the light of the sun
• lunar phase - one of the cyclically recurring phases of the moon
• gibbous - the figure of the moon that is more than half full, looking swollen on one side
• crescent - the figure of the moon that appears as a curve with pointy ends
• waxing - growing ; describes the moon when the illuminated portion is increasing
• waning - shrinking; describes the moon when the illuminated portion is decreasing
• planet - a larger round object that orbits the sun and has cleared out most of the object in its orbit
• solar system - the sun and all of the planets, comets, etc. that revolves around it
• ancient astronomers were able to observe the following:2. point where the Sun rises and sets in the horizon varies in a year,3. phases of the moon,4. lunar eclipse,5. solar eclipse,6. daily and annual motion of the stars, and7. planets Mercury, Venus, Mars, Jupiter, and Saturn..rising and setting of the Sun in the east and the west, respective
• gnomon - a primitive version of a sundial that is used by babylonian and egyptians
• gnomon - a pointer, especially one used to indicate the direction of the sun or the stars
• sun rises and sets on the horizon varies over a year and these variations happen peiodically
• seasonal changes in climate happen during a course of one year
• earths orbit around the sun is sligthly elliptical
• sun travels across the sky at slightly different speeds from day to day depending upon where earth is in its orit
• earth's axis is also not perpendicular to the plane of its orbit
• earth is tilted on its axis approximately 23.4 degree
• the earth is tilted which gives us the season on earth
• earth's tilt explains why the longest day of the year occurs on the summer solstice (usually around june 21), andthe shortest occurs on winter solstice ( usually around december 21)
• the combination of earths elliptical orbit and the tilt of its axis results in the sun taking different paths across the sky which gives us different sunrise and sunset
• a moon is also called a satellite
• earths moon is the 5th biggest moon in the solar system
• the distance between the earth and the moon is 384,000 kilometer
• the moon is about four times smaller than the width of the earth
• as the moon orbits the earth, we see a different phase of the moon
• it takes 27 days 7 hours and 43 minutes for our moon to complete one orbit around the earth
• it takes our moon about 29.5 days to complete one cycle of phases ( from full moon to full moon)
• sidereal month - is the time it takes for the Earth to complete one orbit of the Sun
• the full moon falls on either the 14th or 15th day of the lunar month
• new moon - only appears when the moon is on the side of the earth most directly in line with the sun
• new moon - no light, no tides, no wind, no rain, no photosynthesis
• first quarter - half side of the moon facing the earth appears illuminated
• full moon - the whole side of the moon is now illuminated to the viewers
• third quarter or last quarter - like the first quarter half is illuminated
• third quarter - rises about midnight, is highest at dawn and sets about noon
• in the morning the thrid quarter moon is in the western sky