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THE MOON

LESSON 5:  STRUCTURE | ORBITS | PHASES

INSIDE THE MOON

FOR YOUR NOTEBOOK:

Lesson 4:  The Moon's Structure | Facts | Figures

Surface

  • Albedo- the percentage of incoming sunlight that its surface reflects (only about 7% compared to 31% on Earth)

  • Maria/Mare- dark, relatively smooth plains (about 3 km lower in elevation)

  • Rilles- valley-like structures that may be collapsed lava tubes

  • Impact craters- formed when objects from space crashed into the lunar surface

  • Ejecta- the material blasted out during these impacts that fell back to the Moon’s surface

Composition

  • Made up mostly of silicates

  • The highlands are predominantly lunar breccias (rocks formed by the fusion of smaller pieces of angular rock during impacts) 

  • The maria are mainly basalt (does not contain water)

  • Crust- varies in thickness, is thickest on the far side of the moon (away from Earth)

  • Upper mantle- solid

  • Lower mantle- partially molten

  • Core- solid iron

Formation

  • Giant impact theory: the Moon formed as a result of a collision between Earth and a Mars-sized object about 4.5 billion years ago. Materials from the incoming body and Earth’s outer layers were ejected into space where they began to orbit (trapped by Earth’s gravity). Over time the materials merged to form the Moon.

    BEST ORBIT AND LUNAR PHASE VIDEO I COULD FIND

    Draw and label the diagrams!  This will help you study!

    FOR YOUR NOTEBOOK:

    Lesson 4:  Orbits and Phases

    • New Moon → Waxing Crescent → First Quarter → Waxing Gibbous → Full Moon → Waning Gibbous → Third Quarter → Waning Crescent → [restart cycle]

    • Earth’s gravity may have slowed the Moon’s spin to achieve synchronous rotation

    • Synchronous rotation- both the orbital and rotational periods of the Moon are equal

    • The Moon orbits counterclockwise around the Earth in a slightly elliptical (Oval) orbit

      • Apogee- most distant point from Earth during its orbit (Looks slightly smaller)

      • Perigee- closest point to Earth during its orbit (Looks slightly bigger)

      READING FOR UNDERSTANDING

      Now that you've drawn the Moon's Structure and added some detail, see what else you can add from this article from EarthSky.

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