Moon stuff

1. Moon stuff • Made easy by Bill Frye • Moon phases • Tides • Eclipse stuff

2. Fryesheet numbers for quiz • Fryesheet #8: 10 – 20, 48 - 52 • Fryesheet #10: 1 – 15, 26, 30 – 32, and 43 – 57

4. New (couple days)Waxing Crescent (several days)1st QuarterWaxing Gibbous (several days) FullWaning Gibbous (several days)3rd QuarterWaning Crescent (several days)New Phases:Observing and Identifying http://www.lpi.usra.edu/education/skytellers/moon_phases/about.shtml

5. Percent (%) illumination • Gibbous - greater than 50% illumination • Crescent – less than 50% illumination

6. Waxing and Waning • Waxing means “to grow” • Waning – means “to shrink”

7. Percent (%) illumination? • What phase is 100% illumination? • Full Moon • What phase has 0% illumination? • New moon • http://aa.usno.navy.mil/data/docs/MoonFraction.php

8. moon phase diagram http://www.mpasd.net/cms/lib6/PA14000136/Centricity/ModuleInstance/2289/my%20moon%20phase%20diagram.bmp • See the link above

9. Where did the term “month” come from? • The old English word “moonth.”

10. Solar day vs. Sidereal day • Solar = 24 hours long • Sidereal = 23h 56min. 4s (p.24 in text) • http://www.youtube.com/watch?v=lwVf-AvD8ds

11. sidereal month • It takes the moon 27 1/3 days to revolve one time around the Earth FS#8-52 page 205

12. synodic month • 29 ½ days for one – the time between two New Moons (p.205) • FS#8-52

13. Why do we see a Full Moon but cannot see a New Moon? • Because the Moon’s orbit is inclined to the ecliptic 5.2°

14. The Moon rises 52 minutes later each day. This is because the Moon has to “play catch-up” to the Earth as the Earth-Moon system orbits the Sun.

15. Couple more terms • Earthshine – when the earth’s atmosphere reflects sunlight to the Moon illuminating the unlit portion • FS#8-12 • http://www.youtube.com/watch?v=zhZ4zgJE2sI

16. Blue moon • – second full moon in a month • http://en.wikipedia.org/wiki/Blue_moon

17. Syzygy • when 3 (or more) celestial bodies line up (p.205) • FS#8-50

18. Actual path of Earth in spaceFS#10-8

19. Synchronous rotation • always keeps same side facing you because it rotates at the same rate that it revolves

20. Tides • The Moon’s gravity tugs on the Earth. • It pulls the most on the part of Earth closest, which raises the atmosphere, the oceans, and even the rocks (a little) • It pulls the least on the part of Earth that’s farthest, which allows the oceans and atmosphere to be further from the Moon (and higher) • The Sun’s gravity does the same thing, but to a lesser extent

21. Tides and the Moon

22. NASA videoclip - tides • http://www.youtube.com/watch?v=l37ofe9haMU

23. TIDES • High tide is always in the direction of the Moon and on the other side of the Earth • Direct high – towards Moon • Indirect high – on other side of Earth

24. Spring • occurs at new and full phases, results in higher than normal high tide, lower than normal low tide

25. Neap • occurs at the quarter phases and results in lower than normal high, higher than normal low tide

26. Slack water • “neutral” water level between tides (inter-tidal water level)

27. “Frye’s Tide Post

28. Tidal bore • When the tide from the ocean pushes into waterways • http://www.youtube.com/watch?v=LWumonz87rA

32. Which sides have high tide?

33. Which sides have low tide?

34. http://starchildgsfc.nasa.gov/docs/StarChild/questions/question3.htmlhttp://starchildgsfc.nasa.gov/docs/StarChild/questions/question3.html

35. starchild.gsfc.nasa.gov/docs/StarChild/questions/phases.html

36. Eclipses • The Sun and Moon occasionally line up so that we have an eclipse. • Eclipses happen every year • To see a solar eclipse, you need to be on a particular part of the Earth • websites

37. Eclipses • Two parts of a shadow • Umbra – dark part • Penumbra – light part

38. ECLIPSES – p.275Lunar – • occurs at Full Moon • longer duration • safe to look at • several types

39. Total lunar • Moon is completely hidden in Earth’s umbra (dark part of the shadow)

40. When the Earth’s shadow covers the Moon, we have a lunar eclipse

41. Three types of Lunar Eclipses • Penumbral lunar eclipse—the Moon only passes through the penumbra of Earth’s shadow • Partial lunar eclipse—part of the Moon passes through the umbra of Earth’s shadow • Total lunar eclipse—the entire Moon passes through the umbra of Earth’s shadow • websites

42. Who on Earth will be able to see a lunar eclipse? Anyone who can see the Moon (anyone who is on the nighttime side of the Earth during the eclipse)

43. websites

44. Why is the Moon red during an eclipse? • The Earth’s atmosphere filters some sunlight and allows it to reach the Moon’s surface • Remaining light is red or orange • Some of this remaining light is bent or refracted so that a small fraction of it reaches the Moon • Exact appearance depends on dust and clouds in the Earth’s atmosphere

45. Why is a lunar eclipse reddish? • The atmosphere bends different colors of light at different angles…..

46. Light through a prism…

47. Frye’s wonderful artwork!

48. Upcoming Lunar Eclipses • Apr. 25, 2013, Partial eclipse (not visible in US) • May 25, 2013, Penumbral eclipse • Oct. 18, 2013, Penumbral eclipse • Apr 15, 2014, TOTAL ECLIPSE –visible here • websites

49. Penumbral • Moon is in the penumbra – appears dull reddish-brown

50. Partial • Moon is between umbra and penumbra