Origin of the MoonOrigin of the Moon • Approx. 4.6 billion years ago Earth collided with an Approx. 4.6 billion years ago Earth collided with an

object the size of Mars. It is believed that Earth had a object the size of Mars. It is believed that Earth had a hard crust, but the inside was molten rock (still liquid). hard crust, but the inside was molten rock (still liquid). This collision caused a large mass of liquid rock to be This collision caused a large mass of liquid rock to be thrown into space. It cooled and hardened into what thrown into space. It cooled and hardened into what we know as the moon. (THEORY – NOT FACT)we know as the moon. (THEORY – NOT FACT)

• Since the moon has no atmosphere to protect it from Since the moon has no atmosphere to protect it from debris floating in space, its surface is covered with debris floating in space, its surface is covered with impact cratersimpact craters

50 miles

LUNAR MOVEMENTLUNAR MOVEMENT

• revolves around Earth in an elliptical orbit that it completes in 27 days⅓

• Since the orbit is elliptical, the moon is at times closest to Earth (perigee), and at other times farthest from Earth (apogee)

• The moon rises in the east and sets in the west, just like the sun (remember, this is caused by Earth’s rotation)

Perigee

356,410 km

Apogee

406,700 km

PHASES OF THE MOONPHASES OF THE MOON• beginning phases is called NEW MOON

– During this phase the moon’s surface is not visible • The moon’s surface will then appear to become more

visible each night until the FULL MOON phase – During this time when the surface becomes more visible, the

moon is said to be WAXING – Once the full moon is reached, the moon’s surface will get less

visible each night until the new moon phase is again reached• During this time when the surface becomes less visible,

the moon is said to be WANING

……PHASESPHASES

• *Important, the moon gets lighter from right to left, and gets darker from right to left

• (think like the Karate Kid…wax on, wane off)

• Go outside at night and practice determining if the moon is waxing or waning!

• The time it takes the moon to go from one new moon phase to the next new moon phase is called a lunar month. This takes 29½ days

SUN

LIG

HT

SUN

LIG

HT

Blue Moon…

A blue moon is when there are 2 full moons in one month. The moon isn’t actually blue though!

• Lunar eclipse – this occurs when the moon passes through Earth’s shadow cast into space

• The moon is blocked from view

• This only happens in the FULL MOON PHASE!!!

• Solar eclipse – this occurs when the moon passes between the sun and Earth

• The moon’s shadow is cast onto Earth’s surface

• The sun is blocked from view

• This only happens in the NEW MOON PHASE!!!!

TIDESTIDES

• the rising and falling of the levels of water caused by the pull of the moon’s (and to some extent the sun’s) gravity

• On average, many locations receive two high and two low tides each day (approx. six hours apart)

• Spring tides are when the high tides are especially high, and the low tides are especially low

• This occurs during the new moon and full moon phases, because the pull of the moon’s and sun’s gravity are working together

Benedictine Abbey – Bay of Fundy (Nova Scotia, Canada) – founded in 708, highest tidal range in the world!

Same Abbey @ High Tide –

Man-made causeway added in 1992

• Neap tides are when the high tides are not very high, and the low tides are not very low (small tidal range)

• this happens twice a month during the waxing quarter and waning quarter, because the sun’s gravity is working against the moon’s gravity

Low Tide and High Tide @ Hilton Head, SC

A tidal bore is a wall of water that moves up certain low-lying rivers due to an incoming tide. Tidal bores form when an incoming tide rushes up a river, developing a steep forward slope due to resistance to the tide's advance by the river, which is flowing in the opposite direction.