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Unformatted text preview: The term light year scientific method Scientific theories are not proven; Earth and the celestial The rotational axis of the Earth is tilted at 23 degrees. The position of sunrise on the horizon at the equinoxes is due east. The sun sets due west after 12 hours (equinox means equal night with day). From College Park on the summer solstice the Sun rises in the NE and sets NW remaining above the horizon the greatest number of hours of any day (about 15 hrs.). On the winter solstice the Sun rises in the SE and sets SW remaining above the horizon for the fewest number of hours (about 9 hrs.). The seasons were explained in terms of the causeaxis tilt and effectschanging day length and changing altitude of the Sun. The moon shines by reflecting sunlight. lunar phases and eclipses TERMS: laws of nature, zenith, altitude, latitude, midnight Sun, solstices, equinoxes, 1. Describe the position of the Earth in the Solar System. " in the galaxy. " in the universe. 3. How do scientists use the scientific method to acquire knowledge? 4. Why does an observer at the N. Pole see only circumpolar stars? 5. Why doesnt an observer at the equator see any circumpolar stars? 6. Compare how the sky would appear to an observer at the N. Pole, at the equator, and in College Park. constructed calendars using solstices/equinoxes, star positions, or the lunar cycle. The raising of stone markers (like Stonehenge) demonstrates these abilities. Pyramids in Egypt and the Americas are oriented precisely to locations in the heavens. The ability to predict eclipses seems to appear independently in the eastern (China [2700 years ago]; Babylon, Greece and India about 100 yrs later) and western hemispheres (Mayas [1500 years ago]). The geocentric theory was formally proposed by Aristotle in 350 BC, refined by Ptolemy in 140 AD and adopted by the Catholic Church in the 13 cThe theory was believable due to accuracy in prediction of planetary positions (within 2 degrees per century) and the inability of people to detect stellar parallax. TERMS: , lunar phases (new, crescent, first quarter, gibbous, last quartersynchronous rotation, , annular eclipse, umbra, penumbra, , precession, , epicycle, stellar parallax 1. Make a sketch showing the positions of Sun, Earth and Moon during last quarter moon (or any other phase given to you). What time would the Moon rise and set? When would you expect the Moon to rise the following night? (You should be able to answer questions like theseespecially after completing the Lunar Phases Lab.) 3. Where do you have to be on Earth to observe a total solar eclipse? a partial solar eclipse? --an annular eclipse? 5. Why dont two eclipses (one lunar and one solar) occur every month? 6. Be able to illustrate what ancient people knew about the sky using examples that the study of archeoastronomy has provided....
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This note was uploaded on 05/18/2008 for the course ASTR 101 taught by Professor Deming during the Spring '07 term at Maryland.
- Spring '07