Moon

• Moon

  • Surface dominated by impact craters
  • Some filled with volcanic flows (maria)
  • No atmosphere
  • Same side always faces the earth (tidally locked)

  
• Moon is smaller in density than Venus, Mars, and Earth
• Gravity on the Moon is 1/6th that of Earth
• Moon's orbital period matches its tidally locked rotation

  
• Intense engineering designs are required to counteract the Moon's cold and warm conditions

  
• Phases of the Moon


  Cyclical changes in the Moon's appearance as seen from Earth

  
• Moon's gravitational pull on Earth and oceans

  Creates high and low tides

  
• High tide is always aligned with the Moon

  
• Lunar exploration programs

  • USSR Luna program (1959-1976)
  • US Ranger, Lunar Orbiter, and Surveyor missions (1961-1968)
  • Lunar Reconnaissance Orbiter (2009)
  • Chang'e 3 / Yutu (2013)
  • Chang'e-5 spacecraft (2020)
• Over 100 spacecraft have been launched to explore the Moon
• The USSR Luna program was the first to visit the Moon

  
• The US Ranger, Lunar Orbiter, and Surveyor missions paved the way for human exploration
• China's Chang'e 3 / Yutu was the third nation to successfully land a spacecraft on the Moon
• China's Chang'e-5 spacecraft returned lunar samples in 2020
• The Apollo missions (1969-1972) landed 12 astronauts on the Moon and returned 382 kg of rock and soil
• Lunar rock types

  • Anorthosite
  • Basalt
  • Breccia
  • Regolith (lunar soil)
  • Glass
• Lunar near side

  • Lunar Maria - Basaltic lava emplaced from fissures, relatively young (formed ~4 – 3.2 Ga)
• Lunar far side

  • Terrae (highlands) - Local relief of 5000m, abundant craters (50 - 1000 km), anorthosite and feldspar-rich rocks, covers 80% of surface

  
• Lunar volcanic features

  • Very fluid lavas
  • Sinuous rills (similar to lava tubes)
  • Smooth low domes
• Lunar tectonic features

  • Linear rills (flat-floored, steep-walled troughs similar to grabens)
  • Wrinkle ridges (compressional features from contraction as moon cooled)

  
• Formation of the Moon (4.6-4.5 Gy)

  1. Mars-sized object impacting differentiated Earth

  2. Debris from Earth and impactor accumulating to form the Moon

  3. Global magma ocean

  4. Differentiation: Less dense rocks migrating upward, cooling, and forming lunar crust