1. Planets (inner)

2. Mercury
Roman’s-swift-footed messenger god. Merchants prayed to for quick success
Greek’s-winged shoes

3. Mercury

4. Similar Bodies
Moon
Mercury

5. Mercury Facts
Diameter…4880 Km
radius……2/5
Distance to sun….. .4A.U.
Gravity…… 2.8
Axis tilt….. 0o
Density…… g/cm3

6. Mercury Facts
Rotation…. 59 days
Revolution…

29. Slow Rotation: Mercury makes only 3 rotations every 2 orbits.
One solar day on Mercury is 176 Earth days!
So 2 years for every 1 day (you would have
1 &1/2 birthdays in 1 day on Mercury)
This is an example of spin-orbit resonance. Its day is twice as long as its year Go FIGURE

30. Mercury Facts
Tilt of Axis…… 0.0o
Orbital Inclination…. 7.0o
Surface Pressure…… 0

32. Mercury Rising

34. Mercury’s Atmosphere
almost none
weak gravity and very hot => gasses escape
sodium, potassium from rocks out-gassing
hydrogen and helium from Sun
no weather =====> very little erosion ====> old surface

35. Atmospheric composition He….. 42% Sodium…. 42 % Oxygen…… 15%
Mercury Facts
Atmospheric composition
He….. 42%
Sodium…. 42 %
Oxygen…… 15%
Other…. 1%

39. Why a thin Mantle?
To hot for lighter elements to collect
Collision with large planetisimal knocked mantle away
Very powerful solar wind blew mantle away

40. Mercury in transit

41. Mercury in transit

42. The next transit of Mercury will be November 11, 2019 On average transits of Mercury happen once every 7 years!

43. Mercury Mercury has phases like our Moon.
Mercury is always seen near the Sun as a "morning star" or "evening star".
Surface Features
Impact Craters
Scarps (or cliffs)
Almost No Atmosphere
Crater Rays

44. lots of impacts!
bad neighborhood?

47. Caloris (very hot) Basin
Largest Crater on Mercury

55. Mercury was first imaged by the Mariner 10 spacecraft.

57. Mariner 10
Launched – 1973
Flybys – 1974 and 1975

58. Messenger space craft http://solarsystem. nasa. gov/missions/profile
Launched – 2004
Orbital insertion – 2011
Mission is still going on today!!!

59. End of Chapter.