The Earth’s MoonThe Earth’s Moon

SatellitesSatellites Satell ite: Any body that Satell i te: Any body that orbitsorbits a a

larger bodylarger body 1957: First artif icial satell i te, 1957: First artif icial satell i te,

Sputnik,Sputnik, launched by the Soviets launched by the Soviets Earth’s only Earth’s only naturalnatural satell i te is the satell i te is the

moon.moon.

The MoonThe Moon Force of gravity is 1/6Force of gravity is 1/6 t ht h that of that of

Earth’s Earth’s

Lack of atmosphere also means that there is a huge temperature range: 134oC in the day, -170oC at night

Very little gravity so it has no atmosphere; Very little gravity so it has no atmosphere; therefore it has no weathertherefore it has no weather

The MoonThe Moon

Your weight would Your weight would change, but not change, but not your massyour mass

The MoonThe Moon 1969-1972: The US sent 6 1969-1972: The US sent 6 ApolloApollo

missions to the moonmissions to the moon

Moon rotates once every 27.3 days, but appears to take 29.5 days.It needs time to “catch up” from the delay crated by the rotation of the earth

The Lunar SurfaceThe Lunar Surface

From youngest to oldest -From youngest to oldest -Rilles : collapsed lava tubesRil les : collapsed lava tubesMaria: dark areas on the moon; Maria: dark areas on the moon; made of solidif ied lavamade of solidif ied lava

– Remains of ancient volcanoesRemains of ancient volcanoes– Looks l ike riverbeds but no water ever Looks l ike riverbeds but no water ever

on moonon moonHighlands: l ight areas; created from Highlands: l ight areas; created from meteorites hitt ing the moonmeteorites hitt ing the moon

Rilles – collapsed lava tubesRilles – collapsed lava tubes

Straight rille

Sinous rille

MariaMaria

The Lunar SurfaceThe Lunar Surface Craters: bowl-shaped depressions, Craters: bowl-shaped depressions,

most from the moons early most from the moons early formation; named for famous formation; named for famous scientistsscientists

Rays: streaks that extend from the Rays: streaks that extend from the impact sitesimpact sites – Most formed 4 billion of years ago from debris

that bombarded all other bodies in solar system

Moon FormationsMoon Formations PBS:PBS: http://mass.pbslearningmedia.org/resourchttp://mass.pbslearningmedia.org/resourc

e/npls12.sci.ess.eiu.tourmoon/tour-of-the-e/npls12.sci.ess.eiu.tourmoon/tour-of-the-moon/moon/

Rays - streaksRays - streaks

Lunar RocksLunar Rocks regolithregolith - layer of dust and ground - layer of dust and ground

up rock created from meteorite up rock created from meteorite impactsimpacts

Moons rocks are similar to Earth Moons rocks are similar to Earth rocks –rocks –sil icatessil icates

Galileo Was RightGalileo Was Right From the Earth to the Moon: Part 10From the Earth to the Moon: Part 10

– Gathering of lunar rocksGathering of lunar rocks

Interior of the MoonInterior of the Moon Information found using Information found using

seismographsseismographs Less dense than the interior of the Less dense than the interior of the

EarthEarth– Density = mass / volumeDensity = mass / volume

Interior of the MoonInterior of the Moon Crust is thinner on the Earth-facing Crust is thinner on the Earth-facing

sidesideMantle pulled closer on Earth-Mantle pulled closer on Earth-

facing side when ancient magma facing side when ancient magma below surface existed – making below surface existed – making crust thinnercrust thinner

Interior of the MoonInterior of the Moon Core – made of ironCore – made of iron

Determined the iron is solid, unlike Earth’s Determined the iron is solid, unlike Earth’s core, because it is not magneticcore, because it is not magneticLack of magnetism is due to lack of Lack of magnetism is due to lack of convectionconvection

Moon’s crustMoon’s crust

Current Theory of Moon’s Current Theory of Moon’s CreationCreation

Giant impact theory: formed when Giant impact theory: formed when a Mars-sized object struck the a Mars-sized object struck the EarthEarth– Fragments ejected from the Earth Fragments ejected from the Earth

(mostly less dense crust and mantle)(mostly less dense crust and mantle)– Eventually formed moonEventually formed moon

Explains why the moon is less Explains why the moon is less dense than the Earthdense than the Earth

Impact TheoryImpact Theory

Impact TheoryImpact Theory Supported by moon rocksSupported by moon rocks

– Anothrocite – “Genisis Rock”Anothrocite – “Genisis Rock”– Chemical analysis of the Genesis Rock

indicated it is an anorthosite, composed mostly of a type of plagioclase feldspar 

– formed in the early stages of the solar system, at least 4 billion years ago. 

– recovered in a crater of the Moon, near other rocks of its kind.

Genesis RockGenesis Rock

Impact TheoryImpact Theory

11 s ts t phase: Mars-sized object struck phase: Mars-sized object struck the Earththe Earth

22 n dn d phase: moon was covered with phase: moon was covered with molten lava – densest material molten lava – densest material moved to the centermoved to the center

33 r dr d phase: meteorite impact phase: meteorite impact “punches” through thin crust; l iquid “punches” through thin crust; l iquid rock seeps throughrock seeps through

Current phase: less loose material Current phase: less loose material in solar system; only rayed craters in solar system; only rayed craters formform

http://www.youtube.com/watch?http://www.youtube.com/watch?v=WGTBJHFNywIv=WGTBJHFNywI

Impact TheoryImpact Theory

New Theory (2012)New Theory (2012) Impact of Mars-sized Impact of Mars-sized meteoritemeteorite (Theia) (Theia) not not

likelylikely New study of samples of the Moon are New study of samples of the Moon are

virtually identical with the Earthvirtually identical with the Earth Studied titanium isotopesStudied titanium isotopes Meteorite sample shown extremely Meteorite sample shown extremely

diverse titanium isotope compositiondiverse titanium isotope composition

New Theory (2012)New Theory (2012) Scientists theorize that Theia might have Scientists theorize that Theia might have

been made solely of icebeen made solely of ice Or that a proto-Earth was spinning much Or that a proto-Earth was spinning much

faster, allowing more mixing of faster, allowing more mixing of compositioncomposition