THE MOON AND SURROUNDING PLANETS

MRS. ANTON

Solar System

1. It’s the sun and all the objects that orbit (go around) the sun2. The sun’s family is:

a. nine planetsb. 2 groups – inner ad outer planets

Mercury, Venus, Earth, Mars – innerJupiter, Saturn, Uranus, Neptune, maybe Pluto - outer

Theories of How it Began

1. Solar system began with a NEBULA - spinning cloud of hot gases.

• VERY SLOW PROCESSa. it shrank, contracted, to form the sun,

planets, and other objects

Shape of Orbit

• The Earth travels around the sun in an ELLIPTICAL orbit (oval shape).

• The Earth is not the same distance from the sun all of the time during the year.

• In January – perihelion – closest to the sun• In July – aphelion – farthest from the sun

Revolution and Rotation

Rotation – like a ballerina…rotates on an axisin one spotRevolution – revolving or going around an object

What Revolves and what rotates?

• The moon revolves around the Earth• It also rotates around the Earth but VERY slowly.• Takes 28 days for the moon to revolve around the

Earth• It takes 28 days for the moon to rotate one time.• We only see one side of the moon. If it rotated on

its axis faster, we would see the other side. • At the same time, the Earth rotates and revolves

around the sun

Phases of the moon

• New Moon• Waxing

Crescent-------------------------------------------------------------------------

• 1st Quarter• Waxing Gibbous -----------------------------• Full Moon • Waning Gibbous• Last Quarter• Waning Crescent

Waning and Waxing• Waxing – to increase in size gradually• Waning – To decrease in size gradually • Umbra – darker part of moon• Penumbra – lighter part of moon that we see• Maria – dark smooth area on moon’s surface• Crater – saucer like on the moon

Satellites• Satellite – Body orbiting another of larger

size• Our moon is our only natural satellite• Other satellites are man made and help us

with communications around the world.

Why planets orbit the sun?• -The reason is gravity – force of attraction

between objects in space• -pulls a ball to the ground. Pulls all objects

toward the center of Earth•-All objects in motion stay in motion but gravity pulls them DOWN. So..two motions happen – forward THEN down. •- Causes a curved path

MORE ON Gravity•

-Gravitation happens between the sun and all its planets. Planets pulled toward sun as they move through space.

• -Instead of flying off into space they move in curved orbits around the sun.

• -The closer two objects are two each other, the greater the gravitational PULL.

• -SO…the closer a planet is to the sun, gravity is greater. • The closer to the sun it gets, the faster the planet moves. • -Further away from sun, planet moves __________.- A planet moves fastest during perihelion.- A planet moves slowest during _____________.•

What Causes Day and Night??

• -Remember – Earth moves in an orbit around the sun – revolving. Also spins on its axis – rotation (remember ballerina.)

• -Sun shines on only one side of Earth at a time- Side of Earth facing sun – get daylight•- Facing away from sun - night

More on day and night

• -Daylight hours change during the year. - During summer – more hours of daylight - During winter – more hours of darkness- Changes because EARTH’S AXIS IS TILTED- Earth’s axis tilted – 23 ½ degrees- If Earth was not tilted we would have 12 hours of daylight

and 12 hours of night

SEASONS• The seasons have NOTHING TO DO WITH how close the Earth is to the

sun.• Seasons – caused by the tilt of Earth’s axis.• Earth is tilted toward the sun for part of year.• Earth is tilted away from sun for other part of year. • We are in the Northern hemisphere.• So….when the Northern part is tilted toward the sun we have more hours of daylight, more of a chance to heat up our Earth……..Its summer.

More on seasons• While Northern part of Earth is pointed toward the sun(summer)

southern part is pointed away from Earth so…….they get fewer hours of daylight and sun so it’s winter.

Solstices and Equinoxes• They both mark the beginning of seasons• Solstice – means “sun stop” • when the North pole points toward or away from the sun “• Equinox – means “equal night”. Day when the sun shines directly on the

equator. • 1. SUMMER SOLSTICE • a. On June 21.. North Pole points DIRECTLY toward sun.• b. North Pole has 24 hours of daylight • c. At same time, South Pole has 24 hours of night

More on Solstices• Winter Solstice• - December 21 - First day of winter in Northern part

of Earth• - North Pole – points away from Sun- South Pole has 24 hours of darkness?- What would you see if you were at the North Pole on

December 21?

• RECAP •2 SOLSTICES –Summer and Winter.•North pole points toward or away from sun

••

• What kind of solstice is this?

• How do you know this is a winter solstice?

Equinoxes- The sun shines directly on the equator

MORE EQUINOXES• Happens two days of the year- Spring and Fall• Spring Equinox and Fall Equinox• Spring (also called Vernal)• Fall (also called autumnal)• Autumnal – first day of fall• Vernal – first day of spring• Since the sun is hitting the equator all of Earth gets

equal daylight and equal darkness. How many hours would that be for the Earth?

Why does the moon and sun look like it rises and sets?

Because the Earth rotates it looks like the moon is rising in the east and setting in the west. Because the Earth rotates it looks like the sun is rising in the east and setting in the west. http://www.youtube.com/watch?v=L-jLgSE2sKo

ECLIPSES

-Lunar Eclipse – moon passes through Earth’s shadow. In other words…Like Chelsea passing through Ethan’s shadow on the lawn. Ethan is in the way of the light. That’s why he has a shadow.

Earth is in the way of the sun shining on the moon.

More Eclipses• Picture the moon revolving around the Earth.

• It usually passes above or below the shadow the Earth makes. But NOT ALWAYS.

• When sunlight is blocked from reaching the moon it’s a lunar eclipse.

Partial and Total Eclipses

• Partial Eclipse -When only a part of moon moves into the earth’s shadow. Then the Earth is only blocking the sun from reaching the moon a little. Which is which?

Total Eclipse

• Total Eclipse – when the moon moves entirely into the Earth’s shadow. All sunlight is blocked from reaching the moon.