General Astronomy

1. General Astronomy Earth and Moon

2. The Double Planet The Earth-Moon system is unique in this solar system in that Earth's moon is the largest in relation to its planet.

3. Earth, Terra, Sol III What's in a name? This is where you live. This is where all of your ancestors have ever lived. Yours may be the first generation who's children may live elsewhere. Apollo 17

4. The Moon, Luna, Selene This is where some may live in the future Taylor Observatory Stockton 5" Celestron

5. Physical Parameters Before comparing the planets, let's look as some of the physical characteristics: Density – Mass divided by volume This gives us an idea of the composition of the body. If we can measure the radius and (from Kepler's 3rd Law) the mass, then we can get the density. Some densities: (in grams/cubic centimeter) Of course, a planet is a mixture – so the actual density depends on how much of each type of item is present.

6. Physical Parameters Obliquity – The 'tilt' of the north-south (rotational) axis with respect to the Ecliptic. Earth's inclination is 23.5 degrees Inclination – The 'tilt' of the orbit with respect to the Ecliptic

7. .40 .60 1.0 0.0 Physical Parameters Oblateness - The flattening at the poles Albedo - The amount of light reflected from the surface expressed as a fraction; eg, 100% reflection = 1.0

8. Earth Physical Characterstics Radius 6,371 Km Density 5.52 g/cc Rotation 23h56m04s Inclination 0º Obliquity 23º 27' Oblateness 1/298.2 Albedo 0.39 Escape Vel. 11.2 Km/s

9. The Moon Physical Characterstics Radius 1,738 Km Density 3.34 g/cc Albedo 0.12 Escape Vel. 1.9 Km/s

10. Lunar Features

11. The Far Side It's easy to see that the far side of the Moon is much rougher. There are many more impact craters and much fewer marias. This makes sense when you realize the Earth has been 'protecting' the near side

12. Ice on the Moon? • A recent mission called Lunar Prospector has reported possible evidence for ice on the Moon: • The Moon has permanently shadowed polar craters too. • Data showed slightly enhanced Hydrogen in these areas. • Not confirmed by radar images as on Mercury. • H could be from solar wind or some other process and • might not be the "H" in H2O. • Big implications for space exploration.

13. Lunar Water – Sept 2009 NASA's Moon Mineralogy Mapper, an instrument on the Indian Space Research Organization's Chandrayaan-1 mission, took this image of Earth's moon. It is a three-color composite of reflected near-infrared radiation from the sun, and illustrates the extent to which different materials are mapped across the side of the moon that faces Earth.Small amounts of water were detected on the surface of the moon at various locations. This image illustrates their distribution at high latitudes toward the poles.Blue shows the signature of water, green shows the brightness of the surface as measured by reflected infrared radiation from the sun and red shows an iron-bearing mineral called pyroxene.

14. Lunar Water – Sept 2009

15. Lunar Water – Sept 2009 On the left is an image showing brightness at shorter infrared wavelengths. On the right, the distribution of water-rich minerals (light blue) is shown around a small crater. Both water- and hydroxyl-rich (red) materials were found to be associated with material ejected from the crater.

16. Lunar Cratering

17. Buzz Aldrin (photo by Neil Armstrong)

18. Retroreflector Left on the lunar surface by the Apollo astronauts, this instrument is used to reflect laser beams back to Earth and accurately measure the moon's distance. Hard to do if the Moon landings were a hoax.

19. Moon Factoids • A blue moon is when more than one full moon occurs in the same calendar month. The 2nd occurance is the blue moon • The moon undergoes synchronous rotation and revolution (i.e. the periods of rotation and revolution are identical), so one side of the moon always faces the Earth. • The harvest moon involves the rising of the full moon in late September and early October.

20. Moon Myths • The phase of the moon has no effect on human behavior. • There is no such thing as the “darkside of the moon.” • We did indeed land humans on the moon in the six Apollo landings between July 1969 and December 1972.

21. Mythbusters! There is no relationship between the full moon and the number of births

22. Earth-Moon Interactions Obvious interactions we must examine are: • Phases of the Moon (Reprise) • Eclipses • Tides

23. Sunset evening afternoon Midnight Noon N.P. morning night Sunrise

24. New

25. New Sunset

26. Waxing Crescent

27. Waxing Crescent Sunset

28. First Quarter

29. First Quarter Sunset

30. Waxing Gibbous

31. Waxing Gibbous Sunset

32. Full

33. Full Sunset

34. Full Sunrise

35. Waning Gibbous

36. Waning Gibbous Sunrise

37. Last Quarter

38. Last Quarter Sunrise

39. Waning Crescent

40. Waning Crescent Sunrise

41. New

42. New Sunrise

43. New Waxing Crescent First Quarter Waxing Gibbous Full Waning Gibbous Last Quarter Waning Crescent New Lunar Phases Lunar or Synodic Month: 29 1/2 days

44. The Earth's Shadow The Earth will cast two shadows. One where all the light is blocked and a second where only part of the light is blocked The darker, innermost shadow is the Umbra The lighter, surrounding shadow is the Penumbra

45. Lunar Eclipse

46. Lunar Eclipse When the Moon enters the Earth's shadow, we have a lunar eclipse This, of course, can only occur at the time of the Full Moon Moon

47. Lunar Eclipse A total eclipse of the moon.

48. Solar Eclipse At the time of the New Moon, the Moon casts its shadow(s) on the Earth The Moon's shadows are much smaller and only cover a small area on the Earth. If you are in the penumbra, you see a Partial Eclipse If you are in the umbra, you see a Total Eclipse

49. Example of a Solar Eclipse Path

50. Total Solar Eclipse of 21 June 2001 from Zimbabwe Bailey’s Beads Solar Corona “Diamond Ring”