A look at our nearest neighbor in Space!
The Moon A look at our nearest neighbor in Space! Free powerpoints at What is the Moon? A natural satellite
One of more than 96 moons in our Solar System The only moon of the planet Earth Location, location, location!
About 384,000 km (240,000 miles) from Earth 3,468 km (2,155 miles) in diameter (about the size of Earth) Theories for Origin of Moon
Fission: originally part of Earth but torn free Problem: would have fallen back or been flung into space, not into orbit. Fails to explain why lunar chemistry differs from Earth's Co-Creation: formed in its present orbit can not explain why lunar chemistry differs from Earth's Capture: formed as a separate planet but captured by Earth Conditions for successful capture very stringent Impact: formed from Mega-Impact of Mars-sized planet Computer modeling suggests SS forms 100 or so small planets, then collide to make larger objects can explain differences in chemistry: impact occurred after chemical differentiation in Earth; therefore, not as much iron was part of the Moon high temperatures during impact would have vaporized the volatile and water vapor in rocks Currently favored model Birth of the Moon Born 4-5 billion years ago
Formed from impact of Mars-sized planetesimal on Earth Debris from both objects melted together to form the Moon Computer Simulation of Formation of Moon
Moon may have formed by a Mars-sized object impact on Earth Some of thematerial does not fall back onto the Earth, but forms a satellite of Earth Cut to the Core 3 major divisions of the Lunar interior
Crust - average thickness of about 70 kilometers Mantle Core - radius is between 300 and 425 kilometers Moons interior structure
crust is thicker on non-Earth facing side iron-rich core like Earth asthenosphere layer: somewhat pliable plastic layer solid layer just below surface no plate tectonics smaller planet than Earth less internal energy, less geological activity! moon probably had a weak magnetic field early in history - core is now solid, so no current is generated Moonquakes: Studying the Moons Interior
~ 3000 quakes/year much lower intensity than Earth: Richter indicate that Moons interior is more rigid than Earths (some plasticity) Seismometer placed on Moon by lunar astronauts The Moons Surface No atmosphere No liquid water Extreme temperatures
Daytime = 130C (265F) Nighttime = -190C (-310 F) 1/6 Earths gravity Lunar Features - Highlands
Mountains up to 7500 m (25,000 ft) tall Rilles (trenchlike valleys) Lunar Features - Craters
Up to 2500 km (1,553 miles) across Most formed by meteorite impact on the Moon Some formed by volcanic action inside the Moon Lunar Geological Features
Craters ~30,000 visible with small telescopes from Earth millions visible from lunar orbiting satellites origin: interplanetary debris sizes: largest 100s km across a result of fast moving impact rocks of only a few kms across! large craters often produce central peak craters Clavius Crater diameter = 232 km depth of 16,000 feet Lunar Features - Maria Originally thought to be seas by early astronomers Darkest parts of lunar landscape Filled by lava after crash of huge meteorites on lunar surface 3-4 billion years ago Mostly basalt rock Limb Terminator Craters Can you see the rays? Maria Does this photo show us a limb or terminator line? Color-coded images illustrate surface geography
Galileo data flyby in 1989 blue lowland marias red - highlands Movements of the Moon Revolution Moon orbits the Earth every 271/3 days The moon rises in the east and sets in the west The moon rises and sets 50 minutes later each day Rotation Moon turns on its axis every 27 days Same side of Moon always faces Earth Moon Rocks: Sampling the Surface of the Moon
surface material: regolith pulverized by constant impacts ~2500 samples brought back by astronauts; ~850 lbs total!! all rocks are IGNEOUS (i.e., from molten processes) totally dry rocks (no water) all rocks older than 3 Byr Far Side of the Moon First seen by Luna 3 Russian space probe in 1959
Surface features different from near side More craters Very few maria Thicker crust Its Just a Phase Moonlight is reflected sunlight
Half the moons surface is always reflecting light From Earth we see different amounts of the Moons lit surface The amount seen is called a phase Waxing and Waning New moon Waxing Crescent moon First Quarter moon
Waxing Gibbous moon Full moon Waning Gibbous moon Third Quarter moon Waning Crescent moon FOUR MAIN SHAPES FULL Four Basic Shapes CRESCENT GIBBOUS QUARTER Rising/Meridian/Setting Times
Phase Rising Meridian Setting New 6 am Noon 6 pm Waxing Crescent 9 am 3 pm 9 pm First Quarter Midnight 3 am Full Waning Gibbous Third Quarter Waning Crescent *Assuming the moon is always on the celestial equator and above the horizon 12 hours per day. Earth Plane of earths orbit Moon Plane of lunar orbit Moon Lunar Eclipses Moon moves into Earths shadow this shadow darkens the Moon Umbra Penumbra About 2-3 per year Last up to 4 hours Solar Eclipses Moon moves between Earth and Sun
Moon casts a shadow on part of the Earth Total eclipses rare only once every 360 years from one location! The Tides Tides caused by pull of Moons gravity on Earth High tide
Side facing Moon and side away from Moon Every 12 hours, 25 minutes Low tide On sides of Earth Exploring the Moon 1950s to 1960s - probes
Neil ArmstrongFirst man on the Moon July 20, 1969 Six Apollo missions ( ) 382 kg (842 lbs) rocks 12 Americans have walked on the moon When will we return? Ice on the Moon? 1994 Clementine probe 1998 Lunar Prospector Moon base of the future? What would you need to live there? The Lunar Challenge! Name this phase! Full Moon What time does this phase rise and set? Name these features. Craters Maria Name these features. Does this image show us the near side or far side of the moon?
How can you tell? Is this line the limb or terminator? Name this phase! First Quarter Name this phase! Waxing Crescent Does this image show the near side or the far side of the moon? Name this phase! Waning Gibbous Name this phase! Third Quarter From what direction does the moon rise?
The East Name this phase! Waxing Gibbous Name this phase! Waning Crescent What might be happening in this image?
Lunar Eclipse Is this line the limb or the terminator? Name this phase! Look closely! Waxing Gibbous The Far Side and the Dark Side of the moon are the same thing.
True or False: The Far Side and the Dark Side of the moon are the same thing. False! Name this phase! Full Moon Name this phase! New Moon Does the moon rise or set in the west?
It sets in the west. Name this phase! Waning Gibbous Name this phase! Waning Crescent Name this phase! Waning Gibbous