Chapter 7 Earth in Space.Section 1

Earth’s Motion and the Seasons

Earth’s Shape

• It’s a sphere (Almost!)– A 3D shape with all surface points the same

distance from the center.– Gravity is centered at the core of the earth• Pulls all objects on earth toward the center.

– It bulges somewhat at the equator and is flattened a little near the poles. • Due to the rotation of Earth on its axis.

Perfect Sphere Actual Sphere

Motions of Earth

• Earth…..– Rotates on its axis.• The imaginary line between the North and South Pole.• Tilted 23.5 ° away from vertical.• Causes day and night.

– Revolves around the sun.• Along with the tilt, causes parts of Earth to experience

seasonal change.• Takes 365 ¼ days to complete one revolution.

Earth is actually closer to the sun..

• in January.• and furthest from the sun in July.

Solstices

• Summer and Winter– Summer Solstice

• June 21 or 22• The sun is at its highest in the sky and the longest day of

the year.• Sun rays directly hitting the Tropic of Cancer.

– Winter Solstice• December 21 or 22• The sun is at its lowest in the South sky and the shortest

day of the year.• Sun rays directly hitting the Tropic of Capricorn.

A View From The North Pole!

A View From The Side.

Equinoxes

• Spring (Vernal)– March 21 or 22– Earth’s tilt is neither to nor away from the sun.– Sun rays hit equator.

• Autumnal– September 21 or 22– Same as above.

Explain everything you know about numbers 1-4.

Section 2 Earth’s Moon

• The Moon– Aka. Luna

• Moon Features– Dark colored low land areas• Maria- (Galileo) Latin word for seas.

– Light colored highland areas.– Craters• Depressions formed from meteorite collisions.

The Moon’s Interior.

• Apollo missions left seismographs, earthquake measuring devices, on the moon to measure moonquakes!

• A model of the interior of the moon was formed.• The Moon has:– Crust

• 60 km thick facing the earth• 100 km thick away from the earth

– Solid Mantle– Iron Rich Solid Core

Moon Motion!

• 27.3– The number of days it takes the moon to revolve

around the earth.– Also, the number of days it takes the moon to

rotate one turn on it’s axis.– Therefore, we only ever see one side of the moon

from Earth.

Moon Phases.

• Why do we see different phases of the moon?– THE SUN!

• As the moon revolves around the Earth, the sun always lights one half of it.

• We don’t always see the entire lighted part.• The part that we do see is the phase or

position of the moon.

• New Moon– Moon is between Earth and Sun– We don’t see any of the moon– Seen during the day.

• Full Moon– Earth is between Moon and Sun– We see the entire lighted half

• Waxing Moon– The lighted side of moon is increasing each night.– Period between a new moon and a full moon.

• Waning Moon– The lighted side of moon is decreasing each night.– Period between a full moon and a new moon.

• Crescent– A phase in the waxing and waning stages that looks like a crescent roll. Shows

1/8 of the Moon’s lit surface.• Gibbous

– A phase in the waxing and waning stages that shows ¾ of the moon’s lighted surface.

Eclipses!

• Occur only when the Sun, the Moon, and the Earth are lined up perfectly.

• A few times per year.• Most of the time the Moon’s shadow misses

the Earth.– And the Earth’s shadow misses the moon.

Solar Eclipse

• Occurs during the new moon phase.• Earth moves into the shadow of the Moon.• The Moon blocks the sunlight from reaching

certain points on Earth. • During a total solar eclipse the stars can be

seen and the earth is dark. • Lasts a few minutes. Why?

Small dark region = umbra, total solar eclipseShaded region = penumbra, partial solar eclipse

Lunar Eclipse

• Occurs during a Full Moon.• The Moon moves into the Earth’s shadow.• Moon usually appears to be dark red• Can see the edge of the Earth’s shadow

moving through the moon.

Total Lunar Eclipse Partial Lunar Eclipse

Lunar EclipseNotice how the Sun’s Rays bend around the Earth.

Dark Area = UmbraShaded Area = Penumbra

Section 3: Our Solar System

• Found in which Galaxy?

The Inner Planets

• Mercury– Closest to the sun.– Has no atmosphere.– Daytime temps. can

reach 880 ° F.– Nighttime temps.

with no atmosphere to hold in heat can reach – 275 ° F.

Venus• 2nd planet from the sun.

• Earth’s twin in size, shape, and mass.

• Thick atmosphere made of Carbon Dioxide.

• Greenhouse effect causes temps. to reach 880° F.

Earth• Water can exist as

solid, liquid, and gas.

• Atmosphere is made of Ozone (O3).

• Perfections that enable life.– Ozone

layer/atmosphere.– Orbit/distance from

the sun.– Temperatures.– Presence of water.

• All this by chance? You decide.

Mars

• The Red Planet.• The 4th planet from the sun.• Iron Oxide/ Rust causes the red color.• Olympus Mons – largest volcano in solar system.• Polar ice caps.• 2 moons.– Phobos– Deimos

The Outer Planets

• Jupiter– Number 5– Largest planet.– The Great Red Spot.

• A giant storm that has raged for over 300 years.

– 61 moons.• Why?• 4 largest - Galilean Satelites

– Io– Europa– Ganymede– Callisto

• Saturn– Number 6– Ring system that circles the planet– Rings made of ice and rock.– At least 31 moons.• Largest = Titan

• Uranus– Number 7– Methane in atmosphere makes planet bluish

green!– At least 27 moons.– Axis points to sun.– Faint rings.

• Neptune– Number 8– The rocky

core is as big as Earth.

– Fast winds in the gaseous atmosphere.

– At least 11 satellites.• Triton has

nitrogen geysers

• Pluto– Number 9. (Maybe?)– Only traveled 20% of orbit since discovery in 1930.– 3 moons. • Charon = largest

– Dwarf planet.• Member of Kuiper belt.

– 134340 Pluto• New name.

Other Objects in Solar System.

• Asteroids– Small rocky

objects that mostly lie in a belt located between Mars and Jupiter.

– Divide the inner and outer planets.

• Comets– Made of rocky particles and ice.– Form tails when parts of the comet vaporize.– Found in:• Kuiper belt – beyond Neptune (Pluto)• Oort Cloud – far beyond Pluto

– Haley’s Comet• Comes by Earth every 76 years.• 1986

It’s a bird, it’s a plane, it’s a meteor. I think?

• Meteoroid– Small objects from comets and asteroids in the

solar system• Meteor– When the meteoroid enters the atmosphere of

Earth.• Meteorite– When they fall to earth.

Meteoroid

Meteor

Meteorite