1. The Earth exhibits two main motions: Rotation the turning, or spinning, of a body on its axis. Revolution the motion of a body, such as a planet or moon, along its orbit around some point in space. The Earth also has another very slow motion. Precession the wobbling of a body around its axis of rotation.

2. The main results of the Earthsrotation (W to E) are day andnight. Takes about 24 hours movingapprox. 1000 mph! Axis of rotation tilted about 23.5 We can measure Earths day in2 ways: Synodic (Solar) one completerotation with respect to the Sun 24 hours. Sidereal one complete rotationwith respect to distant stars 23 hours, 56 minutes. 3. http://astro.unl.edu/classaction/animations/lunarcycles/synodiclag.html 4. Earth revolves around the Sun in a veryslight elliptical orbit. (Keplers 1st Law) Takes 365.25 days traveling at an average speed of 67,000 mph! Average distance of 93 million miles. However, due to its slightly ellipticalorbit, Earths distance from the Sunvaries. Perihelion Earth is closest to the Sun. 91 million miles. Aphelion Earth is farthest from the Sun. 95 million miles. 5. Winter Solstice Summer Solstice December 21 June 21 SDR 23.5 S SDR 23.5 N(Tropic of Capricorn) (Tropic of Cancer) 10 hrs. day, 14 hrs. night 14 hrs. day, 10 hrs. night Spring (Vernal) Equinox Fall (Autumnal) Equinox March 21 September 21 SDR Equator SDR Equator 12 hrs. day, 12 hrs. night 12 hrs. day, 12 hrs. nighthttp://astro.unl.edu/classaction/animations/coordsmotion/eclipticsimulator.html 6. The motion of Earths axis A lot of astronomers linkas it traces out a circle on climate change to this.the sky. Presently, the axis of the Earth points to the star, Polaris Amount of time it takes to (North Star).complete one circle is In about 13,000 years, it will26,000 years!point to Vega! 7. Earth has one natural satellite, themoon (Luna), which also makes anelliptical orbit around the Earth. Due to this, its distance from Earth varies fromtime to time. Perigee moon is closest to Earth. Apogee moon is farthest away from Earth. The motions of the Earth-moon systemconstantly change in relation to the Sun,Earth, and moon. This is why the moon appears differentlythroughout each month. 8. The lunar phases are caused by the changes in how much of the illuminated (sunlit) side of the moon faces Earth. Half the moon is always illuminated! Themoon produces none of its own light. 9. 1st Phase NEW MOON None of the moon appears illuminated asviewed from Earth. Waxing phases during which thelit portion of the moon increasesfrom the RIGHT. Waning phases during which thelit portion of the moon decreasesand only the LEFT hand sideremains illuminated. 10. Thecycle of the moon through all 8 phases takes 29.5 days. This is one complete revolution with respect to the sun and is called a synodic month. Thetrue period of revolution for the moon is actually 27.3 days. This revolution is known as a sidereal month, since it iswith respect to distant stars. The reason it takes longer to go through the phases isbecause as the moon is revolving around Earth, theEarth-moon system is also revolving around the Sun. 11. Themoon is not only revolving around the Earth, but also rotating upon its own axis. One complete rotation on its axis takes27.3 days. You may recall this number is thesidereal month time. Therefore, the moon revolves around the Earth at the same rate it rotates on its axis. This is called synchronous rotation. 12. Due to the moonssynchronous rotation, itssurface experiences periodsof daylight and darknesslasting about 2 weeks each. This, along with noatmosphere on the moonaccounts for thetemperature extremes of127 C (261 F) on the dayside of the moon and -173C (-279 F) on the night side. 13. Throughout early astronomy, the Greeksrealized shadows on certain celestial bodiessuch as the Earth and moon. When the moon moves in aline directly between Earthand the Sun, it casts a darkshadow on Earth and isknown as a solar eclipse. Occur during the new moonphase, as viewed from Earth. 14. Whenthe Earth is positioned between theSun and the moon, Earth casts its shadow onthe moon, and a lunar eclipse occurs. Occur during the full moon phase, asviewed from the Earth. On average, there are 4 eclipseseach year, 2 of each kind (solarand lunar). The zone of full shadow is known asthe umbra. The zone of partial shadow is knownas the penumbra. 15. ABSolar Eclipse Lunar Eclipse 16. Why doesnt a solar eclipse occur with every new moon and a lunar eclipse occur with every full moon? They would if theorbit of the moon layexactly along theplane of Earths orbitaround the Sun. However, the tilt ofthe moons patharound Earth is 5 . 17. During a total solar eclipse, the moon completely blocks out the solar disk of the Sun for up to seven minutes. Temperature sharply decreases a few degrees during this time. Visible only to people within the moons umbra. A partial eclipse is seen by those in penumbra. Total solar eclipses are very rare at any location. Next one visible from the United States 8-21-17 18. During a total lunar eclipse, the moon is completely within Earths umbra, but is still visible as a reddish-orange disk. This is due to Earths atmosphere scattering sunlight. Longer, red wavelengths reflect Visible to anyone on the side of the Earth facing the moon. Total lunar eclipse can last up to almost 2 hours! 19. Our natural satellite, the moon,is about 1/4 the diameter ofEarth. Much of what we know about themoon comes from the Apollomissions. Six Apollo spacecraft landed on themoon between 1969 and 1972. Gravitational attraction at thelunar surface is 1/6 of thatexperienced on Earths surface. Example: 150 lb. person on Earthweighs only 25 lb. on the moon. 20. Most widely accepted theory for the origin of the moon is when the solar system was forming, an object the size of Mars impacted the Earth. Debris was ejected from this collision and eventually entered orbit around Earth, combining to form the moon. This is known as the Giant Impact Hypothesis. 21. Themost obvious feature of the moons surface are craters, which are round depressions in the surface of the moon. Larger craters are about 250 km. in diameter (width of Indiana). Most craters were produced by the impact of rapidly moving debris or meteoroids from space. 22. In contrast, the Earthssurface only has about adozen easily recognizedcraters. Friction with Earthsatmosphere burns up smallVredefort: 250-300 km.debris prior to making impactwith Earths surface. Three largest on Earthssurface include: Vredefort (South Africa) Sudbury: 200 km. Sudbury (Canada) Chicxulub (Mexico)Chicxulub: 170 km. 23. Mostof the moons surface is made of densely cratered, light-colored areas known as highlands. They cover most of the surface on the far side of the moon. The highlands consist of mountain ranges made from lunar material. 24. When Galileo first viewed the moon from his telescope, he noticed dark areas, which he thought looked like seas. We now term these dark, relatively smooth areas on the moons surface maria, which is the Latin for sea. These beds of old lava flows formed when meteoroids punctured the moons surface, allowing magma to bleed out. Long channels called rilles, are associated with maria may be remnants of ancient lava flows. 25. The first manned mission to successfully land on the moonwas the Apollo 11 mission (July 20, 1969) This mission carried three astronauts:Neil Armstrong, Buzz Aldrin, and Michael Collins. Of those 3, only 2 walked on the moon (Armstrong first, then Aldrin).Collins stayed in the command module. This fulfilled President John F. Kennedys dream (speech in 1961).