Earth andMoon

Full Earth from Apollo 17

Earth DataEarth Data• Mean Distance from the sunMean Distance from the sun

• 93,200,000 miles93,200,000 miles• 1.0 AU1.0 AU

• MoonsMoons• 11

• Diameter at the EquatorDiameter at the Equator• 7926 miles 7926 miles

• Length of Year Length of Year (revolution (revolution around the sun)around the sun)• 365.26 Earth days365.26 Earth days

• Diameter if Earth = 1Diameter if Earth = 1• 11

• Length of DayLength of Day• Solar: 24 hoursSolar: 24 hours• Sidereal: 23 hr. 56 min. 4.1 Sidereal: 23 hr. 56 min. 4.1

sec. sec.

• Mass if Earth = 1Mass if Earth = 1• 11

• Planet SymbolPlanet Symbol

• Surface Gravity if Earth = 1Surface Gravity if Earth = 1• 11

http://www.charlesgilchrist.com/SGEO/Square/Earth.jpg

Earth as a PlanetEarth as a PlanetRecognitionRecognition: It was not until the time of : It was not until the time of

Copernicus (the 1500’s) that it was Copernicus (the 1500’s) that it was understood that the earth is another understood that the earth is another planet.planet.

http://www.nasa.gov/centers/glenn/images/content/84036main_solrwalk.jpg

What Makes the Earth Unique?What Makes the Earth Unique?NameName: Earth is the only planet whose : Earth is the only planet whose

English name does not derive from English name does not derive from Greek/Roman mythology. Greek/Roman mythology.

Name derives from Old English and Name derives from Old English and Germanic. Germanic.

In Roman mythology, the goddess of earth In Roman mythology, the goddess of earth was Tellus (Greek: Gaia). was Tellus (Greek: Gaia).

WaterWaterLiquid WaterLiquid Water: Oceans like ours, that cover : Oceans like ours, that cover

about ¾ of the globe, exist nowhere else about ¾ of the globe, exist nowhere else in the solar systemin the solar system

Liquid water may lie beneath the surface Liquid water may lie beneath the surface on other, icier bodies (such as Jupiter’s on other, icier bodies (such as Jupiter’s moons), and rivers and lakes may once moons), and rivers and lakes may once have existed on Mars. have existed on Mars.

Goldilocks PlanetGoldilocks PlanetLocationLocation: Not too close to the sun like hot : Not too close to the sun like hot

Mercury or too far from the sun like cold Mercury or too far from the sun like cold MarsMars

Our distance allows liquid water to exist on Our distance allows liquid water to exist on the surface and provides a comfortable the surface and provides a comfortable environmentenvironment

http://www.bbc.co.uk/radio4/science/media/goldilocks.jpg

AtmosphereAtmosphere AtmosphereAtmosphere: Consisting : Consisting

mostly of Nitrogen mostly of Nitrogen (78%) and oxygen (78%) and oxygen (21%). (21%).

Earth’s oxygen Earth’s oxygen atmosphere was likely atmosphere was likely created by plants early created by plants early in earth historyin earth history

Plate TectonicsPlate Tectonics Continental DriftContinental Drift: The continents may have once : The continents may have once

been connected together in a single landmass been connected together in a single landmass named Pangaea. named Pangaea.

Plate TectonicsPlate Tectonics: The earth’s outer crust is : The earth’s outer crust is broken into about a dozen platesbroken into about a dozen plates

These plates move slowly, growing in some These plates move slowly, growing in some areas and sinking back into the earthareas and sinking back into the earth

Edges of plates feature earthquakes, volcanoes, Edges of plates feature earthquakes, volcanoes, and mountainsand mountains

Continental DriftContinental Drift•The continents shift and move slowly over time.

•At one point, the continents are believed to have been together, in the form of a supercontinent called Pangaea.

•This supercontinent then separated into smaller continental plates.

•Some plates separated further, creating mid-oceanic ridges, while others collided, creating large mountain ranges.

•Eventually the familiar continents of today emerged.

The Earth’s Major Tectonic Plates

The boundaries of Earth’s tectonic plates show different motions

Sliding past one anotherSliding past one another

SeparatingSeparating

CollidingColliding

Magnetic FieldMagnetic FieldEarth’s magnetic field is strongEarth’s magnetic field is strongThe field protects life from excess solar The field protects life from excess solar

radiationradiation Interaction between the earth’s magnetic Interaction between the earth’s magnetic

field, atmosphere, and solar radiation field, atmosphere, and solar radiation (solar wind) create the northern lights(solar wind) create the northern lights

Earth is surrounded by a magnetic Earth is surrounded by a magnetic field believed to be produced by field believed to be produced by convection in its molten iron core. convection in its molten iron core.

The magnetic field produced is similar to that of a bar magnet.

The axis of the Earth’s magnetic field differs from the axis of rotation by 11°, placing the north magnetic pole in a different location than the geographic (true) North Pole.

The Earth’s Magnetic Field Protects us The Earth’s Magnetic Field Protects us from the Solar Windfrom the Solar Wind

Near the magnetic poles, these particles sometimes leak into our atmosphere, causing the gases to glow. This is known as the aurora or northern lights.

Earth’s MoonEarth’s MoonEarth’s MoonEarth’s Moon: Of the four inner planets, : Of the four inner planets,

earth alone features a large satelliteearth alone features a large satelliteThe moon likely formed early in earth The moon likely formed early in earth

history when our planet was struck by a history when our planet was struck by a Mars-sized objectMars-sized object

This impact ejected material to form the This impact ejected material to form the moonmoon

LifeLifeLifeLife: Earth is the only place in the universe : Earth is the only place in the universe

where life is known to exist. where life is known to exist. Life may have existed once on Mars (this Life may have existed once on Mars (this

is still unproven)is still unproven)Organic molecules (e.g., amino acids) Organic molecules (e.g., amino acids)

exist in comets and meteoritesexist in comets and meteorites It is likely that the components of life came It is likely that the components of life came

from space, perhaps from meteorites or from space, perhaps from meteorites or cometscomets

Moon DataMoon DataMean Distance from EarthMean Distance from Earth

238,900 miles238,900 miles

• Diameter at the EquatorDiameter at the Equator2,160 miles2,160 miles

• Length of “Year” Length of “Year” (revolution (revolution around the earth)around the earth)

29.5 earth days29.5 earth days

• Diameter if Earth = 1Diameter if Earth = 10.270.27

• Length of “Day”Length of “Day”29.5 earth days 29.5 earth days

• Mass if Earth = 1Mass if Earth = 10.012 0.012

• SymbolSymbol

• Surface Gravity if Earth = 1Surface Gravity if Earth = 10.170.17

http://www.vegaattractions.com/astrology/symbols.html

www.solarviews.com/cap/moon/vmoon1.htm

PerspectivePerspectiveEarth to MoonEarth to Moon: About 250,000 miles: About 250,000 milesRoughly the distance between New York Roughly the distance between New York

City and Los Angeles. City and Los Angeles.

DiscoveryDiscoveryThe moon is the second brightest object in The moon is the second brightest object in

the sky after the sun. the sky after the sun. The moon is actually made of dark The moon is actually made of dark

material, its albedo is 11%material, its albedo is 11%

Moon’s RevolutionMoon’s Revolution Lunar phases result Lunar phases result

from the moon’s from the moon’s revolution around the revolution around the earthearth

Main Phases:Main Phases: New moonNew moon First quarterFirst quarter Full moonFull moon Last quarterLast quarter

Waxing PhasesWaxing Phases

Animation: The Moon’s RotationAnimation: The Moon’s RotationAnimation 6.5: The Moon’s RotationAnimation 6.5: The Moon’s Rotation

MotionsMotions Synchronous: The moon rotates on its axis and Synchronous: The moon rotates on its axis and

revolves around the earth in 29.5 daysrevolves around the earth in 29.5 days Apogee, closest to earthApogee, closest to earth Perigee, farthest from earthPerigee, farthest from earth Due to its synchronous rotation and revolution, Due to its synchronous rotation and revolution,

the moon always presents the same face the moon always presents the same face towards the earthtowards the earth

The back side of the moon was first imaged by a The back side of the moon was first imaged by a Russian robotic space mission in 1959 (Luna 3)Russian robotic space mission in 1959 (Luna 3)

Perigee and ApogeePerigee and Apogee

Apogee and perigee cause the moon to be slightly larger or smaller throughout the year

LibrationLibration The moon appears to The moon appears to

“rock” and “nod” due “rock” and “nod” due to its elliptical orbit to its elliptical orbit and tilt compared to and tilt compared to earthearth

As a result, 56% of As a result, 56% of the moon’s surface is the moon’s surface is visible from earthvisible from earth

Libration SimulationLibration Simulation Libration: Apparent Libration: Apparent

“rocking”“rocking” Perigee & Apogee: Perigee & Apogee:

Larger and smaller Larger and smaller appearanceappearance

http://antwrp.gsfc.nasa.gov/apod/image/0709/lunation_ajc.gif

20 Full Moons20 Full Moons

Lunar TerrainLunar Terrain Lunar TerrainLunar Terrain: Two : Two

types, mare and types, mare and highlands highlands

MareMare: Dark, younger : Dark, younger (less cratered), (less cratered), consists of immense consists of immense lava flows (lunar seas)lava flows (lunar seas)

HighlandsHighlands: Bright, old : Bright, old (heavily cratered), (heavily cratered), moon’s original crustmoon’s original crust

Highlands, upper half of image, maria below

Harvest Moon RisingHarvest Moon Rising Identify Identify

highlands, mariahighlands, maria

http://www.stargazing.net/david/moon/moonrise20050917.html

Lunar SeasLunar SeasThe maria make up the shape of the “man The maria make up the shape of the “man

in the moon” or the “rabbit in the moon.”in the moon” or the “rabbit in the moon.”Latin for “sea”. Latin for “sea”. Apollo 11 landed at Mare Tranquilitatis, Apollo 11 landed at Mare Tranquilitatis,

the “Sea of Tranquility”the “Sea of Tranquility”Originally immense impact basins, later Originally immense impact basins, later

filled with molten lavafilled with molten lava

Lunar Maria (Seas)Lunar Maria (Seas)NameName MeaningMeaning

Mare CrisiumMare Crisium Sea of CrisesSea of Crises

Mare FecunditatisMare Fecunditatis Sea of FertilitySea of Fertility

Mare SerenitatisMare Serenitatis Sea of SerenitySea of Serenity

Mare TranquilitatisMare Tranquilitatis Sea of TranquilitySea of Tranquility

Mare NectarisMare Nectaris Sea of NectarSea of Nectar

Mare VaporumMare Vaporum Sea of VaporsSea of Vapors

Mare FrigorisMare Frigoris Sea of ColdSea of Cold

Mare ImbriumMare Imbrium Sea of RainsSea of Rains

Oceanus ProcellarumOceanus Procellarum Ocean of StormsOcean of Storms

Mare InsularumMare Insularum Sea of IslesSea of Isles

Mare CognitumMare Cognitum Known SeaKnown Sea

Mare HumorumMare Humorum Sea of MoistureSea of Moisture

Mare NubiumMare Nubium Sea of CloudsSea of Clouds

CratersCratersThousands of cratersThousands of cratersMost result of meteorite impactsMost result of meteorite impactsUp to 100 miles in diameterUp to 100 miles in diameterCan exhibit central mountains and bright Can exhibit central mountains and bright

streaks of ejectastreaks of ejectaGalileo was the first scientist to observe Galileo was the first scientist to observe

lunar craters with a telescope (1609)lunar craters with a telescope (1609)

CopernicusCopernicus

http://www.usno.navy.mil/pao/Digipix/coper041007_20041007_1029_001.jpg

Galileo’s Moon Paintings, Galileo’s Moon Paintings, SketchSketch

http://www.mhhe.com/physsci/astronomy/fix/student/images/09f18.jpg

MountainsMountainsOften surround edge of mareOften surround edge of mareThese mountains are the edges of These mountains are the edges of

immense impact basins that later filled immense impact basins that later filled with lava with lava

Named after prominent mountain ranges Named after prominent mountain ranges on earthon earth

For example, there are lunar Appenines For example, there are lunar Appenines and Alpsand Alps

Lunar FeaturesLunar FeaturesTerminatorTerminator: The line separating : The line separating

lunar day and nightlunar day and nightCraters are visible due to long Craters are visible due to long

shadowsshadows Interesting in telescopeInteresting in telescope

Lunar NomenclatureLunar NomenclatureLunar NamesLunar Names: Named for famous figures : Named for famous figures

in the history of science such as Tycho, in the history of science such as Tycho, Copernicus, and Ptolemaeus (Ptolemy) Copernicus, and Ptolemaeus (Ptolemy)

Most are menMost are menFeatures on Venus are named for women Features on Venus are named for women

Sinus IridumSinus Iridum

Sinus Iridum NamedSinus Iridum Named

http://www.webcam-astrophotography.com/moon/sinus-iridum.html

Far SideFar Side Back of the Back of the

moon, never moon, never visible from visible from earthearth

Same side of Same side of moon always moon always faces earthfaces earth

Mostly Mostly highlands, highlands, mysterymystery

Lunar ExplorationLunar ExplorationMoon the only extraterrestrial body ever Moon the only extraterrestrial body ever

to have been visited by humans.to have been visited by humans.Apollo 8, in Dec 1968, first men to orbitApollo 8, in Dec 1968, first men to orbitFirst landing on the moon was July 20, First landing on the moon was July 20,

1969 (Apollo 11), the last was in 1969 (Apollo 11), the last was in December 1972 (Apollo 17). December 1972 (Apollo 17).

12 men walked on the moon (6 12 men walked on the moon (6 missions)missions)

Apollo: Men on the MoonApollo: Men on the Moon Apollo 8Apollo 8

Launched Dec 21, 1968Launched Dec 21, 1968 Astronauts: Frank Borman, James Lovell, William AndersAstronauts: Frank Borman, James Lovell, William Anders First to leave earth’s gravity, orbit moon and return First to leave earth’s gravity, orbit moon and return

Apollo 11Apollo 11 Landed July 20, 1969Landed July 20, 1969 Astronauts: Neil Armstrong, Buzz Aldrin, Michael Collins (Command Astronauts: Neil Armstrong, Buzz Aldrin, Michael Collins (Command

Module)Module) Location: Mare TranquilitatusLocation: Mare Tranquilitatus First men on moon, fulfilled Kennedy’s dreamFirst men on moon, fulfilled Kennedy’s dream

Apollo 12Apollo 12 Landed Nov 19, 1969Landed Nov 19, 1969 Astronauts: Charles Conrad, Alan Bean, Richard Gordon (CM)Astronauts: Charles Conrad, Alan Bean, Richard Gordon (CM) Location: Oceanus ProcellarumLocation: Oceanus Procellarum First pinpoint landing, returned pieces of Surveyor IIIFirst pinpoint landing, returned pieces of Surveyor III

Apollo MissionsApollo Missions Apollo 14Apollo 14

Landed Feb 5, 1971Landed Feb 5, 1971 Astronauts: Alan Shepard, Edgar Mitchell, Stuart Roosa (CM) Astronauts: Alan Shepard, Edgar Mitchell, Stuart Roosa (CM) Location: Fra Mauro CraterLocation: Fra Mauro Crater Landed in location planned for Apollo 13, Shepard hit two golf Landed in location planned for Apollo 13, Shepard hit two golf

balls on the moon, returned 42.9 kg of moon rocksballs on the moon, returned 42.9 kg of moon rocks Apollo 15Apollo 15

Landed July 30, 1971Landed July 30, 1971 Astronauts: David Scott, James Irwin, Alfred Worden (CM)Astronauts: David Scott, James Irwin, Alfred Worden (CM) Location: Hadley Rille in the lunar ApenninesLocation: Hadley Rille in the lunar Apennines First use of LRV, Lunar Roving VehicleFirst use of LRV, Lunar Roving Vehicle

Apollo Missions, Cont.Apollo Missions, Cont. Apollo 16Apollo 16

Landed April 21, 1972Landed April 21, 1972 Astronauts: John Young, Charlie Duke, Thomas Mattingly (CM) Astronauts: John Young, Charlie Duke, Thomas Mattingly (CM) Location: Descartes CraterLocation: Descartes Crater Astronauts spent 71 hours on the moon, explored for 20 hours, Astronauts spent 71 hours on the moon, explored for 20 hours,

collected 95 kg of moon rocks using LRVcollected 95 kg of moon rocks using LRV Apollo 17Apollo 17

Landed Dec 11, 1972Landed Dec 11, 1972 Astronauts: Eugene Cernan, Harrison Schmidt, Ronald Evans Astronauts: Eugene Cernan, Harrison Schmidt, Ronald Evans

(CM)(CM) Location: Taurus-LittrowLocation: Taurus-Littrow First geologist (Schmidt) on the moon, last man on the moon First geologist (Schmidt) on the moon, last man on the moon

(Cernan)(Cernan)

http://www.nasm.si.edu/collections/imagery/apollo/FIGURES/LandingSitesMaps.jpg

Apollo SlidesApollo SlidesClickClick

Moon RocksMoon Rocks Three types returned Three types returned

by astronauts:by astronauts: Basalts-hardened lavaBasalts-hardened lava Anorthosite-light Anorthosite-light

colored, moon’s colored, moon’s original crust (Genesis original crust (Genesis Rock)Rock)

Breccia-fused debris Breccia-fused debris from many impactsfrom many impacts

Meteorites from the MoonMeteorites from the Moon MacAlpine Hills 88105 MacAlpine Hills 88105

is a lunar meteorite is a lunar meteorite found in found in Antarctica in 1989Antarctica in 1989

Meteorites from Mars Meteorites from Mars have also been have also been identifiedidentified

List: List: http://meteorites.wustl.ehttp://meteorites.wustl.edu/lunar/moon_meteoritdu/lunar/moon_meteorites_list_alpha.htmes_list_alpha.htm

How the Moon FormedHow the Moon Formed Formation of the MoonFormation of the Moon: There are four major : There are four major

theories :theories :1.1. Co-AccretionCo-Accretion: The earth and moon formed : The earth and moon formed

individually and at the same time from the solar individually and at the same time from the solar nebulanebula

2.2. FissionFission: The moon split off from the earth: The moon split off from the earth3.3. CaptureCapture: The moon formed elsewhere and was later : The moon formed elsewhere and was later

captured by the earthcaptured by the earth4.4. ImpactImpact: The earth collided with a Mars-sized body : The earth collided with a Mars-sized body

(not the planet Mars!) and the moon formed from the (not the planet Mars!) and the moon formed from the ejected material. This theory is now widely accepted.ejected material. This theory is now widely accepted.

The similarity in materials making up the Earth and Moon suggest that the Moon may have been created from Earth material ejected after a collision with a large planetesimal.

EARTH

MOON

This computer simulation shows how the This computer simulation shows how the Moon could have been formed in a Moon could have been formed in a collision between the Earth and a large collision between the Earth and a large planetesimal. planetesimal.

AnimationAnimation: Formation of the Moon: Formation of the Moon

Formation of the MoonFormation of the Moon