Part One: Earth’s Place in Part One: Earth’s Place in Space Space This PowerPoint Presentation is from the Gaston County This PowerPoint Presentation is from the Gaston County

Schools Secondary Science WebsiteSchools Secondary Science Website

• Earth rotates and revolves around the Sun, even though it Earth rotates and revolves around the Sun, even though it appears as though the Sun is moving! The Sun is the force appears as though the Sun is moving! The Sun is the force which keeps our solar system together!which keeps our solar system together!• Rotation – spinning of Earth on its axis (23 degrees), Rotation – spinning of Earth on its axis (23 degrees),

which occurs once every 24 hours. which occurs once every 24 hours. • Earth moves around the Sun in a regular, curved path Earth moves around the Sun in a regular, curved path

called an orbitcalled an orbit• It takes about one year for Earth’s revolution around the It takes about one year for Earth’s revolution around the

SunSun• We have leap years because our planet rotates exactly 365.24 times in We have leap years because our planet rotates exactly 365.24 times in

one revolution. So we have leap years to make up for that extra time!one revolution. So we have leap years to make up for that extra time!

• SEASONS occur due to Earth’s tilted axis and its SEASONS occur due to Earth’s tilted axis and its revolution around the Sun revolution around the Sun

TERMS TO KNOW….TERMS TO KNOW….

• Rotation: When an object spins on its Rotation: When an object spins on its axis (Think of a basketball spinning on a axis (Think of a basketball spinning on a finger)finger)

• Revolution: When an object travels Revolution: When an object travels around another objectaround another object

• Orbit: The path that an object takes as it Orbit: The path that an object takes as it revolves around anotherrevolves around another

A Day on Earth

The SeasonsThe Seasons• Change of seasons is a result of the Change of seasons is a result of the tilttilt of the of the

Earth’s rotation axis (23 degree slant) with Earth’s rotation axis (23 degree slant) with respect to the plane of the respect to the plane of the ecliptic.ecliptic.

• Sun, moon, planets run along the Sun, moon, planets run along the ecliptic ecliptic (their paths)(their paths)

• We experience summer, when we tilt towards the sun.

• We experience winterwinter, when we tilt away from the sun.

The Seasons

Motion of the MoonMotion of the Moon• Moon shines not by its own light but by reflected light of SunMoon shines not by its own light but by reflected light of Sun• Moon revolves around the EarthMoon revolves around the Earth• Moon’s period of rotation = 27.3 days Moon’s period of rotation = 27.3 days • Period of revolution =Period of revolution =27.3 days• The Tides of the oceans are caused by the moon’s pull on Earth• The Moon’s changing shapes are known as phasesThe Moon’s changing shapes are known as phases

The Moon

Phases of the Moon Phases of the Moon (THE LUNAR (THE LUNAR CYCLE) CYCLE)

Caused by the position of the Caused by the position of the Earth, the Moon, and the SunEarth, the Moon, and the Sun

new to full = waxing new to full = waxing

full to new = waning full to new = waning

……and the phases…with Oreos!and the phases…with Oreos!Copy this into your notesCopy this into your notes

EclipsesEclipses

• One celestial object hidden by other or in the One celestial object hidden by other or in the shadow of anothershadow of another

• Solar eclipse: sun hidden by the Moon, as Solar eclipse: sun hidden by the Moon, as Moon is between the Sun and Earth and the Moon is between the Sun and Earth and the Moon’s shadow falls on EarthMoon’s shadow falls on Earth

• Lunar eclipse: Earth is between the Moon Lunar eclipse: Earth is between the Moon and the Sun and Earth’s shadow falls on the and the Sun and Earth’s shadow falls on the MoonMoon

• Most spectacular because moon and sun Most spectacular because moon and sun appear appear to be the same size from earthto be the same size from earth

Solar Eclipses Solar Eclipses

• UmbraUmbra – region of total shadow – region of total shadow

• PenumbraPenumbra – region of partial shadow – region of partial shadow

• Totality lasts only a few minutes!Totality lasts only a few minutes!

SolarSolar

Lunar Eclipses Lunar Eclipses Moon moves Moon moves

into earth’s into earth’s shadow…shadow…

Part One ReviewPart One Review1.1. What is the gravitational force that keeps our solar What is the gravitational force that keeps our solar

system together? Explain.system together? Explain.

2.2. How are rotation, revolution, and orbit different?How are rotation, revolution, and orbit different?

3.3. Explain how the seasons occur. When do we experience Explain how the seasons occur. When do we experience summer and winter?summer and winter?

4.4. Explain why we have leap years.Explain why we have leap years.

5.5. How do we see the moon? List the phases of the moon How do we see the moon? List the phases of the moon beginning with a new moon.beginning with a new moon.

6.6. What causes the tides of the earth?What causes the tides of the earth?

7.7. What are eclipses? Identify and describe the differences What are eclipses? Identify and describe the differences between the two we discussed.between the two we discussed.

PART TWO: OUR SOLAR PART TWO: OUR SOLAR SYSTEMSYSTEM

THE MILKY WAYTHE MILKY WAY

Our Solar SystemOur Solar System

• Earth orbits the Sun as the solar Earth orbits the Sun as the solar system revolves within the Milky system revolves within the Milky Way, which is among billions of Way, which is among billions of galaxies that make up the universegalaxies that make up the universe

• Introduction to the Solar System – Introduction to the Solar System – VIDEO CLIPVIDEO CLIP

Our Solar System is filled with Our Solar System is filled with eight major planets, the Sun, and eight major planets, the Sun, and other objects that orbit the Sunother objects that orbit the Sun

• MercuryMercury• VenusVenus• EarthEarth• MarsMars• JupiterJupiter• SaturnSaturn• UranusUranus• NeptuneNeptune• Pluto (not classified as a Pluto (not classified as a

planet any longer!)planet any longer!)

THE SUNTHE SUN

The SunThe Sun• The Sun is one of one-hundred The Sun is one of one-hundred

billion stars in our galaxy.billion stars in our galaxy.• It is the brightest object in the sky.It is the brightest object in the sky.• The sun is by far the largest object The sun is by far the largest object

in our solar system.in our solar system.• It is the sun’s gravitational pull It is the sun’s gravitational pull

which holds our planets in order.which holds our planets in order.

Inner PlanetsInner Planets

• Solid, with minerals similar to those Solid, with minerals similar to those on Earthon Earth

• Include Mercury, Venus, Earth, and Include Mercury, Venus, Earth, and MarsMars

MERCURYMERCURY

MercuryMercury

• Mercury is the closest planet to the sun Mercury is the closest planet to the sun and is the smallest planet now that and is the smallest planet now that Pluto is deemed a “dwarf planet”Pluto is deemed a “dwarf planet”

• There is little to no atmosphere, There is little to no atmosphere, resulting in extremes of temperature; resulting in extremes of temperature; can reach 430 degrees Celsius during can reach 430 degrees Celsius during the day and drop to –180 degrees the day and drop to –180 degrees Celsius at night!Celsius at night!

Mercury FactsMercury Facts

VENUSVENUS

VenusVenus

• Venus is the third brightest object in the sky.Venus is the third brightest object in the sky.• It is the second closest planet from the sun and is It is the second closest planet from the sun and is

the sixth largest.the sixth largest.• Heavy cloud layer; clouds trap solar energy, Heavy cloud layer; clouds trap solar energy,

making the planet extremely hot ~ 470 degrees making the planet extremely hot ~ 470 degrees Celsius!Celsius!

• Considered to be Earth’s twin because it’s similar Considered to be Earth’s twin because it’s similar in size.in size.

Venus FactsVenus Facts

EARTHEARTH

EarthEarth• Earth is the third planet from the sun and is Earth is the third planet from the sun and is

the fifth largest.the fifth largest.• This planet is the densest major body in our This planet is the densest major body in our

solar system.solar system.• The Earth’s atmosphere protects its life The Earth’s atmosphere protects its life

from the harmful rays of the sun.from the harmful rays of the sun.• Life on Earth is possible because of water Life on Earth is possible because of water

availability and the stability of temperatures.availability and the stability of temperatures. Earth FactsEarth Facts

MARSMARS

MarsMars• Mars is the fourth planet from the sun and Mars is the fourth planet from the sun and

is the seventh largest.is the seventh largest.• The first space craft to visit Mars was the The first space craft to visit Mars was the

Mariner 4 in 1965.Mariner 4 in 1965.• Has seasons and polar ice caps; may have Has seasons and polar ice caps; may have

water shaping its surfacewater shaping its surface• Red due to rocks containing iron oxideRed due to rocks containing iron oxide• Two small moonsTwo small moons Exploring MarsExploring Mars

Asteroid BeltAsteroid Belt• Separates the inner (rocky) and outer (gas Separates the inner (rocky) and outer (gas

giants with lots of moons and rings) planetsgiants with lots of moons and rings) planets• It is located between the planets of Uranus and It is located between the planets of Uranus and

Neptune Neptune • Pieces of rock made of minerals similar to Pieces of rock made of minerals similar to

those that formed the rocky planets and moonthose that formed the rocky planets and moon• Jupiter’s huge gravitational force might have Jupiter’s huge gravitational force might have

prevented a small planet from forming in the prevented a small planet from forming in the area of the asteroid beltarea of the asteroid belt

JUPITERJUPITER

JupiterJupiter

• Jupiter is the fifth planet from the Jupiter is the fifth planet from the sun and is by far the largest planet.sun and is by far the largest planet.

• Jupiter is the fourth brightest object Jupiter is the fourth brightest object in the sky.in the sky.

• 28 moons; Giant Red Spot is a giant 28 moons; Giant Red Spot is a giant storm on the planet’s surfacestorm on the planet’s surface

Jupiter FactsJupiter Facts

SATURNSATURN

SaturnSaturn

• Saturn is the sixth planet from the sun Saturn is the sixth planet from the sun and is the second largest.and is the second largest.

• Saturn is the least dense of all the Saturn is the least dense of all the planets because it is mostly composed planets because it is mostly composed of gases (hydrogen and helium)of gases (hydrogen and helium)

• Has 30 moons; several broad rings of Has 30 moons; several broad rings of ice and dust.ice and dust.

Saturn FactsSaturn Facts

URANUSURANUS

UranusUranus

• Uranus is the seventh planet from Uranus is the seventh planet from the sun and the third largest.the sun and the third largest.

• Uranus has only been visited one Uranus has only been visited one time, by the Voyager 2 in 1986.time, by the Voyager 2 in 1986.

• Axis makes the planet spin nearly Axis makes the planet spin nearly sideways; has rings and 21 moonssideways; has rings and 21 moons

Exploring UranusExploring Uranus

NEPTUNENEPTUNE

NeptuneNeptune

• Neptune is the eighth planet from Neptune is the eighth planet from the sun and is the fourth largest.the sun and is the fourth largest.

• Neptune has 8 moons.Neptune has 8 moons.• Atmosphere is composed of Atmosphere is composed of

hydrogen, helium, and methane hydrogen, helium, and methane (make planet blue)(make planet blue)

Neptune FactsNeptune Facts

PLUTOPLUTO

PlutoPluto

• Pluto is the farthest object from Pluto is the farthest object from the sun and is by far the the sun and is by far the smallest.smallest.

• Pluto is the only dwarf planet Pluto is the only dwarf planet that has not been visited by a that has not been visited by a space craft.space craft.

Exploring PlutoExploring Pluto

All planets move in same plane All planets move in same plane except Plutoexcept Pluto

Is Pluto a planet?Is Pluto a planet?

• Orbit too Orbit too weirdweird

• Too smallToo small

• Today Pluto Today Pluto may not be may not be classified as classified as a planet.a planet.

CometsComets

• Large body of frozen ice and rock that travels Large body of frozen ice and rock that travels toward the center of the solar systemtoward the center of the solar system

• As a comet approaches the Sun, radiation As a comet approaches the Sun, radiation vaporizes some of the material; solar winds blow vaporizes some of the material; solar winds blow vaporized gas and dust away from the comet, vaporized gas and dust away from the comet, forming what appears from Earth as a bright, forming what appears from Earth as a bright, glowing tailglowing tail

MeteoritesMeteorites• Fragments of space material that land Fragments of space material that land

on Earth’s surfaceon Earth’s surface

• Pieces may be iron, rock, or bothPieces may be iron, rock, or both

• Age (4.5 billion years) provides a clue to Age (4.5 billion years) provides a clue to the Solar System’s agethe Solar System’s age

StarsStars• About About 50005000 stars visible with naked eye stars visible with naked eye• About About 35003500 of them from the northern hemisphere of them from the northern hemisphere

• Stars that Stars that appearappear to be close are grouped together to be close are grouped together into into constellationsconstellations

• Officially 88 constellations Officially 88 constellations • Names range from Names range from

• mythologicalmythological (Perseus, Cassiopeia)(Perseus, Cassiopeia)• technical (Air Pump, Compass)technical (Air Pump, Compass)

Lives of StarsLives of Stars

• A star has a life that depends on its sizeA star has a life that depends on its size• Stars begin their lives as huge clouds of gas Stars begin their lives as huge clouds of gas

and dustand dust• Force of gravity causes dust and gases to Force of gravity causes dust and gases to

move closer togethermove closer together• Temperatures within the cloud begin to riseTemperatures within the cloud begin to rise• Star is formed when this cloud gets so dense Star is formed when this cloud gets so dense

and hot that the atoms within it merge (fusion)and hot that the atoms within it merge (fusion)

GalaxiesGalaxies• Group of stars, gas, and dust held together Group of stars, gas, and dust held together

by gravityby gravity• Earth is in a spiral galaxy called the Milky WayEarth is in a spiral galaxy called the Milky Way• 100 billion galaxies might exist ~ all these 100 billion galaxies might exist ~ all these

galaxies with all their stars make up the galaxies with all their stars make up the UNIVERSE!UNIVERSE!