The Moon Basics Cheat Sheet

1. Overview of the Moon

• Type: Natural satellite
• Orbiting Body: Earth
• Distance from Earth: ~384,400 km (238,855 miles)
• Orbital Period: 27.3 days (sidereal month)
• Synodic Period (Full Moon Cycle): 29.5 days
• Rotation Period: 27.3 days (synchronous rotation – same side always faces Earth)
• Diameter: 3,474 km (27% of Earth’s)
• Gravity: 1.62 m/s² (16.5% of Earth’s)
• Temperature:
  • Daytime: Up to 127°C (260°F)
  • Nighttime: Down to -173°C (-280°F)
• Moons: None (The Moon itself is Earth’s moon)

2. Key Characteristics

• Shape: Nearly spherical with a slight bulge at the equator.
• Surface: Covered in dust, rocks, and craters.
• Color: Grey and dusty appearance.
• Atmosphere: Extremely thin exosphere (trace amounts of hydrogen, helium, neon).
• Axial Tilt: 1.5° (minimal seasonal changes).

3. Phases of the Moon

4. Lunar Surface and Features

• Maria (Seas): Dark, flat plains formed by ancient volcanic eruptions (e.g., Mare Tranquillitatis).
• Highlands: Lighter, mountainous, and heavily cratered regions.
• Craters: Formed by meteorite impacts (e.g., Tycho Crater).
• Rilles: Channels or grooves caused by lava flows.
• Mountains: Tall peaks such as Mons Huygens (highest mountain, 5.5 km tall).

5. Moon’s Orbit and Rotation

• Synchronous Rotation: The Moon rotates on its axis at the same rate it orbits Earth, showing the same face to Earth.
• Libration: Slight wobble allowing us to see about 59% of the Moon’s surface over time.
• Orbit Shape: Elliptical (slightly oval-shaped).
• Closest Point (Perigee): ~363,300 km (226,000 miles)
• Farthest Point (Apogee): ~405,500 km (252,000 miles)

6. Eclipses

• Solar Eclipse: Moon passes between Earth and the Sun, blocking sunlight.
• Lunar Eclipse: Earth passes between the Sun and the Moon, casting a shadow on the Moon.
• Types of Lunar Eclipses:
  • Total Eclipse: Moon is completely covered by Earth’s shadow.
  • Partial Eclipse: Only part of the Moon enters the shadow.
  • Penumbral Eclipse: Moon passes through Earth’s outer shadow (less noticeable).

7. Formation of the Moon

• Giant Impact Hypothesis:
  • The Moon likely formed around 4.5 billion years ago when a Mars-sized body (Theia) collided with Earth.
  • Debris from the collision coalesced to form the Moon.

8. Exploration of the Moon

• First Flyby: Luna 1 (1959, USSR) – First spacecraft to fly past the Moon.
• First Landing: Luna 2 (1959, USSR) – First human-made object to impact the Moon.
• First Human Landing: Apollo 11 (1969, USA) – Neil Armstrong and Buzz Aldrin walked on the Moon.
• Recent Missions:
  • Chang’e 4 (China, 2019) – First landing on the far side of the Moon.
  • Artemis Program (NASA) – Plans to return humans to the Moon in the 2020s.

9. Interesting Facts

• Only Natural Satellite: Earth’s only natural satellite.
• Tidal Effects:
  • Causes ocean tides through gravitational pull.
  • Slows Earth’s rotation by about 1.5 milliseconds per century.
• Moonquakes: Quakes occur beneath the surface, likely caused by gravitational interaction with Earth.
• No Atmosphere: No sound or weather occurs on the Moon.
• Moon Dust: Fine, sharp particles cling to equipment and are hazardous to health.

10. Why is the Moon Important?

• Tides and Stability: Regulates Earth’s tides and stabilizes its axial tilt, influencing climate.
• Space Exploration: A stepping stone for deep space missions.
• Scientific Research: Provides insight into the solar system’s formation and early Earth history.

11. Key Measurements

12. The Moon in Mythology and Culture

• Named After: “Luna” (Roman goddess of the Moon).
• Symbol: ☽
• Astrological Significance: Represents emotions, intuition, and the subconscious.
• Cultural References: Prominent in mythology, literature, and art across civilizations.

13. Differences Between the Moon and Earth

14. Can the Moon Support Life?

• Surface: Hostile to life – lacks water, atmosphere, and protection from radiation.
• Potential for Colonization:
  • Water ice at the poles may provide resources for future missions.
  • Moon bases could serve as launch points for Mars and beyond.