2. Mercury images- Similar to our Moon

4. Venus & Mercury 2-8-07

5. I. Mercury A. 0.4 AU from sun

6. 1. A.U.= Astronomical unit = 93,000,000 miles This is the distance of Earth from Sun so we compare all planets to our distance.

7. 2. close to sun in sky a) morning or evening “star” a) morning or evening “star” ( not a star but looks like one. )

12. b) poor photos Earth’s atmosphere distorts image Earth’s atmosphere distorts image

14. Earth View

15. B. Rotation 1. once in 59 Earth days 1. once in 59 Earth days (siderial period) Siderial means with respect to stars.

16. C. Revolution 1. once in 88 Earth days 1. once in 88 Earth days Time to go once around the Sun.

19. D. Length of day (solar rotation) (solar rotation) 1. 176 Earth days 1. 176 Earth days This is a strange effect. Look at the diagrams and I will explain it when I return.

20. 2. One Mercury day = 2 Mercury years

21. 3. Determine motion by RADAR Radio detection and ranging

23. E. Temperature 800 o F 800 o F -280 o F -280 o F

24. F. Albedo= 1. Light reflected 1. Light reflected Light received Light received

25. 2. Mirror albedo is 90% Black is 0% Black is 0% Mercury is 6% Mercury is 6%

26. 3. Dark, like moon

27. G. Mass 1. 5.5% of Earth 1. 5.5% of Earth

29. H. Density 1. same as Earth 1. same as Earth 2. must have iron core 2. must have iron core

30. I. Spacecraft Observations 1. unmanned 1. unmanned

31. 2. Mariner 10 a) 3 flybys a) 3 flybys b) 1974 b) 1974

32. 3. Messenger Mission Left Earth August 2004 Arrived at Mercury in 2011 Still There

33. 4. Photographs a) craters a) craters flatter than moon flatter than moon

35. Why? greater gravity softer surface eroded

36. b) maria c) scarps cliffs hundreds of miles long cliffs hundreds of miles long

39. Scarps are wrinkles.... Cracks in the crust

41. scarp

43. scarp

44. 4-22-13

45. d) Weird Terrain Grooved areas with smooth area in between Grooved areas with smooth area in between

46. weird terrain

50. Cause? 180 o from large crater

52. recombined shock waves from meteorite impact created Weird Terrain

53. 5. Atmosphere a) small a) small b) sodium, helium b) sodium, helium

54. c) coming from craters?

55. 6. Magnetic field a) yes a) yes

57. 6. No moons 7. origin very different from moon

58. I. Mercury A. 0.4 AU from sun

59. Spider Crater Views from Messenger at Mercury