The Moon

Formation

• Formed about 4.5 billion years ago.• A large object hit Earth and caused large and

small chunks to be removed.– The moon is lower in density because most of the

heavy metals on Earth had already sunk to the core when impact happened.

• These chunks coalesced into the moon.

Formation

• The moon was bombarded over time by small body space objects causing craters to form.

• Larger bombardments caused lava flows causing plateaus, river valley formations, and seas or plains.– Ancient lava flows appear darker in color on the surface on

the near side and are called maria or seas.– Some happened as recent as when dinosaurs roamed the

Earth.• The crust on the near side of the moon is thinner than

the crust on the far side of the moon because of magma ocean tidal pull from the Earth during its formation.

Formation

• https://www.youtube.com/watch?v=hahpE8b6fDI

• https://www.youtube.com/watch?v=UIKmSQqp8wY

• https://www.youtube.com/watch?v=2iSZMv64wuU

Moon Phases

• New moon every 29.5 days• Orbits Earth in a counterclockwise motion• The moon orbits and revolves at the same

rate, so the same side is always facing us.

Moon Phases

Eclipses

• The moon’s orbit is tilted 5 ° off of the ecliptic plane causing infrequent, but predictable eclipses.

• Solar Eclipse = the Sun gets blocked from view by the Moon.

• Lunar Eclipse = the Moon gets blocked from sunlight by Earth.

• We would have higher high tides during eclipses.

Eclipses

Eclipses

• https://www.youtube.com/watch?v=rVE8PFYlwSM

Tides

• Daily changes in the elevation of ocean surfaces.

• Caused by gravitational forces of celestial bodies - the Sun and the Moon.

• The moon causes a bulge on Earth on the side nearest the moon and an equal size bulge on the opposite side of Earth.

• The Sun’s tide generating effect is only about 46% that of the moon.

Spring Tides

• Occur during New and Full Moons• Sun, Moon, and Earth are aligned so forces are

added together• Causes higher high tides and lower low tides.

Spring Tides

Neap Tides

• First and Third quarter moon phases.• Sun and Moon act on right angles and partially

offset the other’s influence.• Daily tidal range is less.

Neap Tides

Tides

The End