PERIODIC EVENTS Warm Up 1.Name the original crew of Apollo What was the mission objective for Apollo 13? 3.Why was Ken Mattingly scrubbed from the mission? 4.Who replaced Ken Mattingly on Apollo 13? Warm Up 1.Name and define Newtons three laws of planetary motion. 2.Name and define Newtons law of gravity. Warm Up 1.On Planet X, a 50 gram weight is suspended from string that is 23 centimeters long. The weight pendulums 58 times in 60 seconds. What is the acceleration due to gravity on Planet X? 2.On Planet O, a 100 gram weight is suspended from string that is 50 centimeters long. The weight pendulums 45 times in 60 seconds. What is the acceleration due to gravity on Planet O? Warm Up 1.What elements do you need to form an ellipse? 2.What does ellipticity mean? 3.What causes day and night to occur? 4.What happens to the relationship between the Sun and Earth for spring, summer, winter and summer to occur? 5.What happens to the lengths of the days and nights as the year progresses? Day solsticeeclipse Night umbra precession Seasonpenumbra moon phases Equinoxannularpartial revolutionrotationtotal Warm Up-09/23/13 1.What causes the seasons? 2.What is a solstice? 3.When do they occur? 4.What is an equinox? 5.When do they occur? Periodic Events: Index SeasonsSolar Eclipses Precession Lunar Eclipses Lunar CyclesDay and Night Because of the clock-like order of our Universe, certain astronomical phenomenon repeat themselves. Day and Night Day and night are caused by the Earths rotation of its axis. Days are longer in the summer and shorter in the winter./LengthofDay.swf Seasons Many people believe that the seasons are caused by the Earth traveling closer to and farther away from the Sun. Seasons At its closest (aphelion), the sun is 91.4 million miles away from us. At its farthest (perihelion), the sun is 94.5 million miles away. That might sound like a lot, but it isnt. The Earths temperature barely changes from it. The real reason for the seasons is.. Seasons the tilt of the Earth on its axis!!! As the Earth orbits the Sun, the orientation of its axis remains fixed. Warm Up 1.What events correspond to the following dates: 6/21, 9/21, 12/21 and 3/ Describe the lengths of the days on the above dates. 3.During what season is the Sun the highest in the sky? 4.During what season is the Sun the lowest in the sky? 5.How does the Earths axial tilt determine the seasons? Seasons During June, the northern hemisphere tilts toward the Sun. The more direct sunlight heats the northern hemisphere more than the southern hemisphere, where it is Winter. Length of Day/LengthofDay.swf Seasons During December, the northern hemisphere tilts away from the Sun. The more direct sunlight in the southern hemisphere heats it up more than the northern hemisphere, where it is now Winter. Seasons During Autumn and Spring, the Sun shines on both hemispheres of the Earth equally which results in the mild weather associated with those seasons. mations/01_EarthSun.htmlhttp://www.mesoscale.iastate.edu/agron206/ani mations/01_EarthSun.htmlarth.htmhttp://www.educypedia.be/education/spacejavae arth.htmerc/content/visualizations/es1704/es1704page0 1.cfm?chapter_no=visualization Suns Azimuthasons/index.html Precession The Earth's rotation axis is not fixed in space. Like a rotating toy top, the direction of the rotation axis executes a slow precession with a period of 26,000 years Precession/LengthofDay.swf Precession Thus, Polaris will not always be the Pole Star or North Star. The Earth's rotation axis happens to be pointing almost exactly at Polaris now, but in 13,000 years the precession of the rotation axis will mean that the bright star Vega in the constellation Lyra will be approximately at the North Celestial Pole (which is perpendicular to the celestial equator), while in 26,000 more years Polaris will once again be the Pole Star. Precession Since the rotation axis is precessing in space, the orientation of the Celestial Equator (which lies in the same plane as the terrestrial equator) also precesses with the same period. This means that the position of the equinoxes is changing slowly with respect to the background stars. This precession of the equinoxes means that the right ascension and declination of objects changes very slowly over a 26,000 year period. This effect is negligibly small for casual observing, but is an important correction for precise observations. Precession Because of the precession of the equinoxes, the vernal equinox moves through all the constellations of the Zodiac over the 26,000 year precession period. Presently the vernal equinox is in the constellation Pisces and is slowly approaching Aquarius. Precession Around the year 130 BC, Hipparchus compared ancient observations to his own and concluded that in the preceding 169 years heavenly bodies had moved by 2 degrees. How could Hipparchus know the position of the Sun among the stars so exactly, when stars are not visible in the daytime? By using not the Sun but the shadow cast by the Earth on the moon, during an eclipse of the Moon! During an eclipse, Sun, Earth and Moon form a straight line, and therefore the center of the Earth's shadow is at the point on the celestial sphere, which is exactly opposite that of the Sun. Precession Hipparchus concluded that the intersection marking the equinox slowly crept forward along the ecliptic (the plain defined by the Earths orbit around the Sun), and called that motion "the precession of the equinoxes. " The rate is about one full circle in years. In ancient times the intersection marking the spring equinox was in the constellation of Aries, the ram, and for that reason the intersection (wherever it might be) is still sometimes called "the first point in Aries. Precession Around the year 1 it moved into the constellation of Pisces and currently it is again in transition, to the constellation of Aquarius, the water carrier. If you ever heard the song "The dawning of the age of Aquarius" from the musical "Hair," that is what it is all about. To believers of astrology, the "dawning of the age of Aquarius" is a great portent marking the beginning of a completely new era. Precession Warm Up 1.What are the eight phases of the moon? 2.What time does the full moon rise? 3.What time does the full moon set? 4.What time is the full moon straight overhead? Lunar Cycles The moon goes through the following phases every 30 days. These phase changes always occur from right to left. VA/moonphase.html Lunar Cycles The initial phase is called the new moon. The new moon is completely dark. As light begins to cover more and more of the moons surface, the moon is said to be waxing. As darkness begins to cover more and more of the full moons surface, the moon is said to be waning. Lunar Cycles The phase of the Moon can tell you the time of day. For example, because a full Moon is seen when the Moon is on the opposite side of the Earth from the Sun, an observer on the Earth will see the Moon rise just as the Sun sets. The next day, the Moon will rise approximately one hour later (because the Moon will have moved farther along on its orbit). This means that a waning half Moon will rise at midnight, a new moon at dawn, etc... Warm Up 1.List and diagram the eight phases of the moon. 2.Define waxing and waning. 3.You see the full moon just rising above the horizon. What time is it? 4.Do we ever see the new moon? Why or why not? 5.You see the first quarter moon setting. What time is it? What time will it rise? 6.You see the third quarter moon just rising above the horizon. What time is it? What time will it set? Warm Up-09/26/13 The last new moon was ! 1.What is the current phase of the moon? 2.What time does it rise? Set? 3.It is 3 PM and the moon is straight overhead, what is the moon phase? What time did it rise and set? 4.It is 6 PM and the moon is just rising, what is its phase? What time will it set? 5.It is 3 AM and the moon is just setting, what is its phase? What time did it rise? 6.What time does the waxing crescent rise and set? 7.What time does the new moon rise and set? 8.How can you differentiate the 1 st quarter moon from the 3 rd quarter moon? Creating a White Sheet! What topics should be included? What specific information should be listed under each topic? Do I need any math formulas? Do I know how to use the math formulas? Eclipses The Two Types of Eclipses: Solar eclipses- When the Sun grows dark when covered by the moon and Lunar eclipses- When the moon grows dark when covered by the shadow of the Earth. NASA Eclipse Web Site Lunar eclipses Solar eclipses There are three kinds of solar eclipses: Total eclipse Partial eclipse and Annular eclipse Solar eclipses Total Eclipse During a total eclipse, the moon completely covers the Sun and all you can see is the Suns corona. This only occurs when the moon is a certain distance from the Earth. The moon castes two kinds of shadows on the Earths surface: The umbra: The dark, internal portion of the shadow and The penumbra: The lighter shadow formed outside the umbra. Partial Eclipse During partial eclipses, the sky never darkens and the moon never completely covers the Sun. These photographs were taken during a partial eclipse and show some of the strange effects to shadows caused by the eclipse. Annular Eclipse When the moon is farther away during a total eclipse alignment, an annular eclipse occurs. During an annular eclipse, the moon passed in front of the Sun, but because it is further away from the Earth, it casts a smaller shadow. During an annular eclipse the Sun is not completely obscured by the moon and the fringes of the Sun may be seen. The Earths Moon The End