Phases, & Eclipses Phases, & Eclipses

Chapter 1: Earth, Moon, & SunChapter 1: Earth, Moon, & Sun

Motions of the MoonMotions of the Moon

Why is the “day” on the moon Why is the “day” on the moon the same length as a “year” on the same length as a “year” on

the moon?the moon?

Rotation : Day :: Revolution : yearRotation : Day :: Revolution : year

Since it takes 27.3 Earth days for Since it takes 27.3 Earth days for the moon to rotate (day) and 27.3 the moon to rotate (day) and 27.3 Earth days for the moon to revolve Earth days for the moon to revolve (year), the day and a year are the (year), the day and a year are the same lengthsame length

Checkpoint: How many days Checkpoint: How many days does it take the moon to does it take the moon to revolve once around Earth?revolve once around Earth?

It takes the moon 27.3 Earth It takes the moon 27.3 Earth days to revolve around Earth.days to revolve around Earth.

It also takes the moon 27.3 Earth It also takes the moon 27.3 Earth days to rotatedays to rotate

Phases of the MoonPhases of the Moon

The different shapes of the The different shapes of the moon you see from Earth are moon you see from Earth are

called _____.called _____.

phases phases

The moon goes through its The moon goes through its whole set of phases each time it whole set of phases each time it _____ around Earth, or about _____ around Earth, or about

once a _____.once a _____. revolves revolves

monthmonth

Guide For Reading:Guide For Reading:What What causes the phases of the causes the phases of the moon?moon?

The phases of the moon are caused by The phases of the moon are caused by the change of the relative positions of the change of the relative positions of Earth, the moon, and sun.Earth, the moon, and sun.

Since the moon revolves around Earth we Since the moon revolves around Earth we see it from different angles see it from different angles

The ½ of the moon that faces Earth is The ½ of the moon that faces Earth is notnot always the ½ lit up by the sun causing always the ½ lit up by the sun causing the moon’s shape to appear to changethe moon’s shape to appear to change

The phase of the moon you see depends The phase of the moon you see depends on how much of the sunlit side of the on how much of the sunlit side of the moon faces Earthmoon faces Earth

What is the length of time What is the length of time from a new moon to the next from a new moon to the next new moon?new moon?

29.5 Earth days29.5 Earth days

Since Earth is revolving it takes an Since Earth is revolving it takes an extra 2.2 Earth days for the sun, extra 2.2 Earth days for the sun, moon and Earth to line up, causing moon and Earth to line up, causing the next new moonthe next new moon

Checkpoint: Since the moon Checkpoint: Since the moon does not produce light, how does not produce light, how can you see it?can you see it?

Light from the sun reflectsLight from the sun reflects off off the moon, enabling it to be the moon, enabling it to be seen from Earth.seen from Earth.

EclipsesEclipses

Figure 6: Figure 6: Interpreting DiagramsInterpreting DiagramsHow large is the angle between How large is the angle between Earth’s orbit and the moon’ s Earth’s orbit and the moon’ s

orbit?orbit?

The angle The angle between Earth’s between Earth’s orbit and that of orbit and that of the of the moon is the of the moon is 55ºº

When does an eclipse When does an eclipse occur?occur?

In a rare occasion when the moon In a rare occasion when the moon or Earth becomes directly between or Earth becomes directly between the sun and the other and cast a the sun and the other and cast a shadow on that objectshadow on that object

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

lunarlunarsolar solar

Solar EclipsesSolar Eclipses

Solar EclipseSolar Eclipse

A solar eclipse occurs when the A solar eclipse occurs when the moon comes directly between the moon comes directly between the sun and Earthsun and Earth

The moon blocks Earth from The moon blocks Earth from sunlight and cast a shadowsunlight and cast a shadow

Earth’s sky becomes darker and Earth’s sky becomes darker and you can only see the corona of the you can only see the corona of the sunsun

At what phase of the moon At what phase of the moon could a solar eclipse occur?could a solar eclipse occur?

A new moon when the moon A new moon when the moon becomes directly between the sun becomes directly between the sun and Earthand Earth

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

UmbraUmbra

Why are the people in the umbra Why are the people in the umbra the only ones that experience a the only ones that experience a total solar eclipse?total solar eclipse?

The umbra is the darkest part of The umbra is the darkest part of the moon’s shadowthe moon’s shadow

People who are in the umbra are in People who are in the umbra are in the darkest part of the shadow the darkest part of the shadow where the moon is almost where the moon is almost completely blocking sunlight from completely blocking sunlight from reaching Earth, except for the reaching Earth, except for the sun’s coronasun’s corona

PenumbraPenumbra

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

Lunar EclipsesLunar Eclipses

What is a lunar eclipse? What is a lunar eclipse?

A lunar eclipse occurs when Earth A lunar eclipse occurs when Earth comes directly between the sun comes directly between the sun and moonand moon

Earth blocks the moon from Earth blocks the moon from sunlight and cast a shadowsunlight and cast a shadow

The moon turns a red/orange colorThe moon turns a red/orange color

Figure 8: Figure 8: Interpreting DiagramsInterpreting Diagrams: : What is the difference between What is the difference between Earth’s umbra and penumbra?Earth’s umbra and penumbra?

The umbra is in The umbra is in the area of total the area of total darkness, the darkness, the penumbra is the penumbra is the area of partial area of partial darknessdarkness

Checkpoint: Checkpoint: Why do lunar Why do lunar eclipses occur only at full eclipses occur only at full moon?moon?

Earth must come between the Earth must come between the sun and the moon during a lunar sun and the moon during a lunar eclipse; this only happens during eclipse; this only happens during the full moon phase.the full moon phase.

Guide For Reading: What Guide For Reading: What causes solar and lunar causes solar and lunar eclipses?eclipses?

When the moon’s shadow hits When the moon’s shadow hits Earth or Earth’s shadow hits Earth or Earth’s shadow hits the moon, an eclipse occurs.the moon, an eclipse occurs.

Eclipses occur when the moon’s Eclipses occur when the moon’s orbit which is usually tilted orbit which is usually tilted becomes not tilted and the sun, becomes not tilted and the sun, moon and Earth line up moon and Earth line up perfectlyperfectly