Earth Science NotesEarth Science NotesThe Earth, Moon, and SunThe Earth, Moon, and Sun

Properties of the EarthProperties of the Earth

RotationRotation refers to the spinning of refers to the spinning of earth on its axisearth on its axis

When Earth spins on axis it When Earth spins on axis it causes causes dayday and and nightnight

Properties of the EarthProperties of the Earth

RevolutionRevolution refers to the orbiting refers to the orbiting of earth around the sunof earth around the sun

Earth’s orbit is an Earth’s orbit is an ellipseellipse

Properties of the EarthProperties of the Earth

Change in seasons are caused by Change in seasons are caused by the the tilttilt of the earths axis as it of the earths axis as it revolves around the sunrevolves around the sun– The hemisphere that is tilted The hemisphere that is tilted

towardtoward the sun received more the sun received more sunlight (has longer days)sunlight (has longer days)

The SeasonsThe Seasons

Properties of the EarthProperties of the Earth

SolsticeSolstice is the day the sun is the day the sun reaches its greatest distance reaches its greatest distance north or south of the equatornorth or south of the equator– Winter solstice and summer solstice Winter solstice and summer solstice

Properties of the EarthProperties of the Earth

EquinoxesEquinoxes occur when the sun is occur when the sun is directly above the Earth’s equator directly above the Earth’s equator – Sunlight hours are equal during this Sunlight hours are equal during this

timetime

– Fall and Spring EquinoxFall and Spring Equinox

Properties of the EarthProperties of the Earth The earth The earth bulgesbulges slightly at slightly at

the equatorthe equator– Gravity contracts earth into sphereGravity contracts earth into sphere– Rotation cause Earth’s sphere to Rotation cause Earth’s sphere to

bulgebulge– Pull of moon creates tidal bulgePull of moon creates tidal bulge

Properties of the EarthProperties of the Earth

Earth has a Earth has a magneticmagnetic polespoles Moving material inside the earth Moving material inside the earth

as well as Earth’s rotation may as well as Earth’s rotation may generate the magnetic fieldgenerate the magnetic field

The poles change over timeThe poles change over time– Recall magnetic reversals as Recall magnetic reversals as

evidence of seafloor spreadingevidence of seafloor spreading

The MoonThe MoonMoon phasesMoon phases Different forms that the moon Different forms that the moon

takes in appearancetakes in appearance

The MoonThe MoonMoon Phases - Moon Phases - depend on the depend on the

relative relative positionposition of the Earth, Moon, and of the Earth, Moon, and Sun.Sun.

New Moon Moon is between earth and the sun – no light is reflected

Waxing Crescent first thumbnail shaped portion of the moon seen

First Quarter one quarter of the moon is reflecting the sun light

Waxing Gibbous means more of the illuminated half can be seen each night

Moon PhasesMoon Phases

Moon Phases Moon Phases (cont.)(cont.)

Full Moon moon surface that faces earth reflects all light from sun

Waning Gibbous means less of the illuminated half can be seen each night

Third Quarter one quarter of the moon is reflecting the sun light

Waning Crescent last thumbnail shaped portion of the moon seen

Moon PhasesMoon Phases

The MoonThe Moon SolarSolar eclipse occurs when the eclipse occurs when the

moon moves directly between the moon moves directly between the sun and the earth.sun and the earth.

Solar Eclipse Solar Eclipse

The MoonThe Moon Lunar Lunar eclipse occurs when the eclipse occurs when the

earth falls directly between the earth falls directly between the sun and the moonsun and the moon

The MoonThe Moon

Structure of the moonStructure of the moon Models for moon’s Models for moon’s

interior derived from interior derived from seismic activity (i.e. seismic activity (i.e. moonquakes)moonquakes)

The moon is made up The moon is made up of crust, upper mantle, of crust, upper mantle, lower mantle, and core.lower mantle, and core.

The MoonThe MoonOrigin of the MoonOrigin of the Moon Various theories had been Various theories had been

proposed for the formation proposed for the formation of the Moon. of the Moon.

Fission TheoryFission Theory – moon – moon somehow separated from somehow separated from the earth the earth – Location – pacific basinLocation – pacific basin– Evidence – moon is made of Evidence – moon is made of

materials similar to Earth’s materials similar to Earth’s mantlemantle

– Problem – cast off of moon Problem – cast off of moon would be do to rapid spinning would be do to rapid spinning of Earth – no fossil evidence of of Earth – no fossil evidence of thisthis

The MoonThe Moon

Origin of the MoonOrigin of the Moon Capture Theory: Moon was formed

somewhere else in the solar system, and was later captured by the gravitational field of the Earth

The MoonThe Moon

Origin of the MoonOrigin of the Moon• The Condensation

Theory: the Moon and the Earth condensed individually from the nebula that formed the solar system. • Problem – if the Moon

formed near Earth it should have nearly the same composition. Specifically, it should possess a significant iron core, and it does not.

The MoonThe MoonOrigin of the MoonOrigin of the Moon The Giant Impactor TheoryThe Giant Impactor Theory: : proposes that a small proposes that a small

planet the size of Mars struck the Earth just after the formation planet the size of Mars struck the Earth just after the formation of the solar system, ejecting large volumes of heated material of the solar system, ejecting large volumes of heated material from the outer layers of both objects. A disk of orbiting material from the outer layers of both objects. A disk of orbiting material was formed, and this matter eventually stuck together to form was formed, and this matter eventually stuck together to form the Moon in orbit around the Earth.the Moon in orbit around the Earth.

–This theory can This theory can explain why the explain why the Moon is made Moon is made mostly of rock and mostly of rock and how the rock was how the rock was excessively excessively heated. heated. Furthermore, we Furthermore, we see evidence in see evidence in many places in the many places in the solar system that solar system that such collisions such collisions were common late were common late in the formative in the formative stages of the solar stages of the solar system. system.

Giant Impactor TheoryGiant Impactor Theory

Trips to the MoonTrips to the Moon

Click the link to learn more about these missionsClick the link to learn more about these missions

http://www.lpi.usra.edu/expmoon/apollo_landings.htmlhttp://www.lpi.usra.edu/expmoon/apollo_landings.html

The Sun The Sun Structure of the SunStructure of the Sun

The SunThe Sun

Structure of the SunStructure of the Sun Corona – largest layer of the sun’s atmosphere, extends

millions of km out into space

Chromosphere – transition zone between the photosphere and the coronaPhotosphere – lowest layer of the sun’s atmosphere, where light is given off, 6000 K.

The SunThe Sun

Convention layer – heat energy rises – heat energy rises and falls in this layer as gases rise, cool, and falls in this layer as gases rise, cool, and then falland then fall

Radiation zoneRadiation zone – – energy from the energy from the suns core is suns core is transferred to the transferred to the conduction zoneconduction zoneCore Core – source of – source of suns energy, where suns energy, where nuclear fusion nuclear fusion takes placetakes place

The SunThe Sun

Surface Features of Surface Features of SunSun

SunspotsSunspots – spots on – spots on the sun that are the sun that are darker because they darker because they are coolerare cooler

The SunThe Sun

Surface Features of Surface Features of SunSun

ProminencesProminences – – arching columns of arching columns of gasgas– Maybe caused by Sun’s Maybe caused by Sun’s

magnetic fieldmagnetic field

The SunThe SunAuroras Auroras Created as a result of electrically charged Created as a result of electrically charged

particles from the sun’s corona hitting the earth’s particles from the sun’s corona hitting the earth’s atmosphere and ionizing gases there.atmosphere and ionizing gases there.

The SunThe Sun

The sun is an average star. It The sun is an average star. It emits average heat and light emits average heat and light energyenergy

Summary Summary

How does rotation and revolution How does rotation and revolution differ? What are the effects of each?differ? What are the effects of each?

Explain why we have seasons.Explain why we have seasons. What are the phases of the moon?What are the phases of the moon? What is the difference between solar What is the difference between solar

and lunar eclipses?and lunar eclipses? Explain different theories regarding Explain different theories regarding

the origin of the moon.the origin of the moon. Describe the Sun’s structures and its Describe the Sun’s structures and its

features.features.