Phases, & Eclipses Chapter 1: Earth, Moon, & Sun

Motions of the Moon

Why is the “day” on the moon the same length as a “year” on the moon? Rotation : Day :: Revolution : year Rotation : Day :: Revolution : year Since it takes 27.3 Earth days for the moon to rotate (day) and 27.3 Earth days for the moon to revolve (year), the day and a year are the same length Since it takes 27.3 Earth days for the moon to rotate (day) and 27.3 Earth days for the moon to revolve (year), the day and a year are the same length

Checkpoint: How many days does it take the moon to revolve once around Earth? It takes the moon 27.3 Earth days to revolve around Earth. It takes the moon 27.3 Earth days to revolve around Earth. It also takes the moon 27.3 Earth days to rotate It also takes the moon 27.3 Earth days to rotate

Phases of the Moon

The different shapes of the moon you see from Earth are called _____. phases phases

The moon goes through its whole set of phases each time it _____ around Earth, or about once a _____. revolves revolves month month

Guide For Reading:What causes the phases of the moon? The phases of the moon are caused by the change of the relative positions of Earth, the moon, and sun. The phases of the moon are caused by the change of the relative positions of Earth, the moon, and sun. Since the moon revolves around Earth we see it from different angles Since the moon revolves around Earth we see it from different angles The ½ of the moon that faces Earth is not always the ½ lit up by the sun causing the moon’s shape to appear to change The ½ of the moon that faces Earth is not always the ½ lit up by the sun causing the moon’s shape to appear to change The phase of the moon you see depends on how much of the sunlit side of the moon faces Earth The phase of the moon you see depends on how much of the sunlit side of the moon faces Earth

What is the length of time from a new moon to the next new moon? 29.5 Earth days 29.5 Earth days Since Earth is revolving it takes an extra 2.2 Earth days for the sun, moon and Earth to line up, causing the next new moon Since Earth is revolving it takes an extra 2.2 Earth days for the sun, moon and Earth to line up, causing the next new moon

Checkpoint: Since the moon does not produce light, how can you see it? Light from the sun reflects off the moon, enabling it to be seen from Earth. Light from the sun reflects off the moon, enabling it to be seen from Earth.

Eclipses

Figure 6: Interpreting Diagrams How large is the angle between Earth’s orbit and the moon’ s orbit? The angle between Earth’s orbit and that of the of the moon is 5º The angle between Earth’s orbit and that of the of the moon is 5º

When does an eclipse occur? In a rare occasion when the moon or Earth becomes directly between the sun and the other and cast a shadow on that object In a rare occasion when the moon or Earth becomes directly between the sun and the other and cast a shadow on that object

The two types of eclipses are ______ & ______. lunar lunar solar solar

Solar Eclipses

Solar Eclipse A solar eclipse occurs when the moon comes directly between the sun and Earth A solar eclipse occurs when the moon comes directly between the sun and Earth The moon blocks Earth from sunlight and cast a shadow The moon blocks Earth from sunlight and cast a shadow Earth’s sky becomes darker and you can only see the corona of the sun Earth’s sky becomes darker and you can only see the corona of the sun

At what phase of the moon could a solar eclipse occur? A new moon when the moon becomes directly between the sun and Earth A new moon when the moon becomes directly between the sun and Earth

The darkest part of the moon’s shadow is called the _________. Umbra Umbra

Why are the people in the umbra the only ones that experience a total solar eclipse? The umbra is the darkest part of the moon’s shadow The umbra is the darkest part of the moon’s shadow People who are in the umbra are in the darkest part of the shadow where the moon is almost completely blocking sunlight from reaching Earth, except for the sun’s corona People who are in the umbra are in the darkest part of the shadow where the moon is almost completely blocking sunlight from reaching Earth, except for the sun’s corona

Penumbra The larger less dark shadow cast by the moon during a solar eclipse and by Earth during a lunar eclipse The larger less dark shadow cast by the moon during a solar eclipse and by Earth during a lunar eclipse

Lunar Eclipses

What is a lunar eclipse? A lunar eclipse occurs when Earth comes directly between the sun and moon A lunar eclipse occurs when Earth comes directly between the sun and moon Earth blocks the moon from sunlight and cast a shadow Earth blocks the moon from sunlight and cast a shadow The moon turns a red/orange color The moon turns a red/orange color

Figure 8: Interpreting Diagrams: What is the difference between Earth’s umbra and penumbra? The umbra is in the area of total darkness, the penumbra is the area of partial darkness The umbra is in the area of total darkness, the penumbra is the area of partial darkness

Checkpoint: Why do lunar eclipses occur only at full moon? Earth must come between the sun and the moon during a lunar eclipse; this only happens during the full moon phase. Earth must come between the sun and the moon during a lunar eclipse; this only happens during the full moon phase.

Guide For Reading: What causes solar and lunar eclipses? When the moon’s shadow hits Earth or Earth’s shadow hits the moon, an eclipse occurs. When the moon’s shadow hits Earth or Earth’s shadow hits the moon, an eclipse occurs. Eclipses occur when the moon’s orbit which is usually tilted becomes not tilted and the sun, moon and Earth line up perfectly Eclipses occur when the moon’s orbit which is usually tilted becomes not tilted and the sun, moon and Earth line up perfectly