AstronomyAstronomy

Ch. 19 Earth, Moon, and Sun

Ch. 19 Earth, Moon, and Sun

This amazing Earthrise above the moon's horizon was seen by astronaut Michael Collins in the Apollo 11 moon orbiter Columbia.

This amazing Earthrise above the moon's horizon was seen by astronaut Michael Collins in the Apollo 11 moon orbiter Columbia.

ObjectivesObjectives

Identify the effects of Earth’s rotation and revolution.

Explain the causes of the seasons on Earth.

Identify the effects of Earth’s rotation and revolution.

Explain the causes of the seasons on Earth.

19.1 Earth in Space19.1 Earth in Space

Discover Activity - p. 636

Why Does Earth Have Day and Night?

Discover Activity - p. 636

Why Does Earth Have Day and Night?

IntroductionIntroduction

Egyptian farmers planted their crops after the floods every year. They noticed that the star Sirius became visible before the floods. That’s when they could start predicting the floods.

The Egyptians were the first people to study the stars.

Egyptian farmers planted their crops after the floods every year. They noticed that the star Sirius became visible before the floods. That’s when they could start predicting the floods.

The Egyptians were the first people to study the stars.

Days and Years Days and Years

Astronomy is the study of the moon, stars, and other objects in space.

Astronomy is the study of the moon, stars, and other objects in space.

RotationRotation Axis - the

imaginary line that passes through Earth’s center and the North and South poles.

Rotation - the spinning of Earth on its axis.

A point on the equator rotates at about 1,600 km per hour.

Axis - the imaginary line that passes through Earth’s center and the North and South poles.

Rotation - the spinning of Earth on its axis.

A point on the equator rotates at about 1,600 km per hour.

RotationRotation

Earth’s rotation on its axis causes day and night.

Earth rotates eastward. It takes 24 hours to rotate

once on its axis. This is called a day.

Earth’s rotation on its axis causes day and night.

Earth rotates eastward. It takes 24 hours to rotate

once on its axis. This is called a day.

RevolutionRevolution

Earth also travels around the sun.

Revolution - the movement of one object around another object.

Earth’s orbit is a oval shape.

Earth also travels around the sun.

Revolution - the movement of one object around another object.

Earth’s orbit is a oval shape.

CalendarsCalendarsThe Egyptians counted the number

of days between Sirius stars which was about 365.

Earth’s orbit around the sun is about 365 1/4 days.

Four years of 365 1/4 days each can be approx. by taking 3 years of 365 days and a fourth year of 366 days. This is known as leap year.

On a leap year, one extra day in February is added for 29 days.

The Egyptians counted the number of days between Sirius stars which was about 365.

Earth’s orbit around the sun is about 365 1/4 days.

Four years of 365 1/4 days each can be approx. by taking 3 years of 365 days and a fourth year of 366 days. This is known as leap year.

On a leap year, one extra day in February is added for 29 days.

CalendarsCalendarsDividing the year into smaller

parts (months) was difficult. Early people used the moon

cycle which is 29 1/2 days but this only added up to 354.

The Egyptians had a plan to have 12 months of 30 days and 5 extra days.

The Romans borrowed the calendar and devised the one that we have today with 11 months of 30 to 31 days and February with 28 or 29 days.

Dividing the year into smaller parts (months) was difficult.

Early people used the moon cycle which is 29 1/2 days but this only added up to 354.

The Egyptians had a plan to have 12 months of 30 days and 5 extra days.

The Romans borrowed the calendar and devised the one that we have today with 11 months of 30 to 31 days and February with 28 or 29 days.

Seasons on EarthSeasons on Earth

Most places have four seasons: winter, spring, summer, and autumn.

Most places have four seasons: winter, spring, summer, and autumn.

Earth’s Tilted AxisEarth’s Tilted Axis

Earth has seasons because its axis is tilted as it move around the sun.

Earth has seasons because its axis is tilted as it move around the sun.

Earth in JuneEarth in June

The north end of Earth’s axis is tilted toward the sun. It is summer in the Northern Hemisphere and winter in the Southern Hemisphere.

The north end of Earth’s axis is tilted toward the sun. It is summer in the Northern Hemisphere and winter in the Southern Hemisphere.

Earth in DecemberEarth in December

The south end of Earth’s axis is tilted toward the sun. It is summer in the Southern Hemisphere and winter in the Northern Hemisphere.

The south end of Earth’s axis is tilted toward the sun. It is summer in the Southern Hemisphere and winter in the Northern Hemisphere.

Both in June and December

Both in June and December

Summer solstice - longest day of the year (June 21).

Winter solstice - shortest day of the year (December 21).

Both of the these are in the Northern Hemisphere and the opposite in the Southern Hemisphere.

Summer solstice - longest day of the year (June 21).

Winter solstice - shortest day of the year (December 21).

Both of the these are in the Northern Hemisphere and the opposite in the Southern Hemisphere.

Earth in March & September

Earth in March & September

Neither hemisphere is tilted toward or away from the sun. So the days and nights are in a equinox which is equal.

Neither hemisphere is tilted toward or away from the sun. So the days and nights are in a equinox which is equal.

Earth in March and September

Earth in March and September

Vernal equinox, or spring equinox, occurs around March 21 and is the first day of spring.

Autumnal equinox, or fall equinox, occurs around September 23 and is the first day of fall.

Vernal equinox, or spring equinox, occurs around March 21 and is the first day of spring.

Autumnal equinox, or fall equinox, occurs around September 23 and is the first day of fall.

Plants and AnimalsPlants and Animals

Plants and animals are effected by the amount of day light hours.

In the spring and summer, plants grow, animals feed on the plants, insects and animals get more food.

In the winter, animals go dormant and birds travel to warmer climates to find food.

Plants and animals are effected by the amount of day light hours.

In the spring and summer, plants grow, animals feed on the plants, insects and animals get more food.

In the winter, animals go dormant and birds travel to warmer climates to find food.

Reasons for the Seasons

Reasons for the Seasons

LabBooks, Styrofoam balls

and flashlights.

LabBooks, Styrofoam balls

and flashlights.

Phases, Eclipses, and Tides

Phases, Eclipses, and Tides

ObjectivesObjectives

Describe the causes of the moon’s phases.

Explain what causes solar and lunar eclipses.

Identify the cause of the tides.

Describe the causes of the moon’s phases.

Explain what causes solar and lunar eclipses.

Identify the cause of the tides.

Engage/ExploreEngage/Explore

When does the moon appear?

Moon Rise and Set

When does the moon appear?

Moon Rise and Set

Discover ActivityDiscover Activity

How Does the Moon Move?Quarter &

pennyP. 646

How Does the Moon Move?Quarter &

pennyP. 646

Motions of the MoonMotions of the Moon

The moon revolves around Earth and rotates on its own axis.

It takes 27.3 days to revolve around Earth.

The same side of the moon always faces the Earth.

The moon revolves around Earth and rotates on its own axis.

It takes 27.3 days to revolve around Earth.

The same side of the moon always faces the Earth.

Phases of the MoonPhases of the Moon

Phases of the moon are seen by the reflection of the sun on the moon’s surface.

The different shapes of the moon you see from Earth are called phases. The moon goes through its whole set of phases each time it revolves around the Earth, about once a month.

Phases of the moon are seen by the reflection of the sun on the moon’s surface.

The different shapes of the moon you see from Earth are called phases. The moon goes through its whole set of phases each time it revolves around the Earth, about once a month.

What Causes Phases?

What Causes Phases?

Phases are caused by changes in the relative positions of the moon, Earth, and the sun.

P. 648

Phases are caused by changes in the relative positions of the moon, Earth, and the sun.

P. 648

The Cycle of the Phases of the Moon

The Cycle of the Phases of the Moon

EclipsesEclipses

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

Two types of eclipses: solar and lunar

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

Two types of eclipses: solar and lunar

Solar EclipseSolar Eclipse

Solar EclipsesSolar Eclipses

During a new moon, most of the time the moon is a little above or below the sun in the sky.

A solar eclipse occurs when the moon passes between Earth and the sun, blocking the sunlight from reaching Earth.

It is really a new moon that blocks your view of the sun.

During a new moon, most of the time the moon is a little above or below the sun in the sky.

A solar eclipse occurs when the moon passes between Earth and the sun, blocking the sunlight from reaching Earth.

It is really a new moon that blocks your view of the sun.

Solar Eclipses Solar Eclipses

Total Solar EclipsesTotal Solar Eclipses

Umbra - the darkest pat of the moon’s shadow that is cone-shaped. The point of the cone can reach a small part of Earth’s surface.

Umbra - the darkest pat of the moon’s shadow that is cone-shaped. The point of the cone can reach a small part of Earth’s surface.

Partial Solar EclipsesPartial Solar Eclipses

Penumbra - larger part of the shadow which is more visible on Earth. During a partial eclipse, part of the sun is visible.

It is not safe to look at a partial eclipse.

Penumbra - larger part of the shadow which is more visible on Earth. During a partial eclipse, part of the sun is visible.

It is not safe to look at a partial eclipse.

Solar EclipseSolar Eclipse

August 11, 1999August 11, 1999

Lunar EclipsesLunar Eclipses

A lunar eclipse occurs at a full moon when Earth is between the moon and the sun. Earth blocks sunlight from reaching the moon.

A lunar eclipse occurs at a full moon when Earth is between the moon and the sun. Earth blocks sunlight from reaching the moon.

Total Lunar EclipseTotal Lunar Eclipse

When the moon is in Earth’s umbra, you see a total lunar eclipse. You are more likely to see a total lunar eclipse than a total solar eclipse.

When the moon is in Earth’s umbra, you see a total lunar eclipse. You are more likely to see a total lunar eclipse than a total solar eclipse.

Partial Lunar EclipsesPartial Lunar Eclipses

Occurs when the moon passes partly into the umbra of Earth’s shadow. The edge of the shadow appears blurry and you can watch it pass across the moon for up to two or three hours.

Occurs when the moon passes partly into the umbra of Earth’s shadow. The edge of the shadow appears blurry and you can watch it pass across the moon for up to two or three hours.

TidesTides

Two high tides and two low tides occur daily, over 24 hours.

Two high tides and two low tides occur daily, over 24 hours.

19. 3 Rockets and Satellites

19. 3 Rockets and Satellites

19.4 Earth’s Moon19.4 Earth’s Moon

The End of Ch. 19The End of Ch. 19