The Moon

Theories on moon’s creation The Fission Theory: – Part of earth – Thrown out due to extreme rotation – Basin in Pacific Ocean – Earth’s gravity pulled it in – Composition resembles earth’s composition

2. Capture Theory – – Moon made in solar system – Came into contact with earth’s gravitational field – Pulled into orbit around earth 3. Condensation Theory – – both condensed from gases at the beginning of the solar system

4. Giant Impact Theory – ( most believed) – Small planet impacted earth after it was first made – Material was thrown into space – Material congealed to make a small planetoid – Earth’s gravity captured the small planetoid to orbit earth

Moon rocks Rocks made of basalt from volcanic eruptions and minerals, such as plagioclase feldspar and olivine, No organic materials It's gray with very fine grained particles like sand or even dust and extremely dry because there is no water on the moon

Lunar Breccia These fragments are the white pieces visible in the rock and are composed of feldspar. feldspar, pyroxene, and olivine.

basalt

Moon’s orbit Ellipse Rotation rate: once every 27.3 days – This keeps one side of the moon facing the earth at all times Revolution rate: – 27.3 days

Moon’s orbit Apogee – point in moon’s orbit furthest from earth Perigee – point in moon’s orbit closest to earth

Moon phases Waning moon – moon is getting smaller Waxing moon – moon is getting larger Length – 29.5 days – Extra days from revolution due to position of S E and M to return to starting position

Tides – Rise and fall of the sea level due to the gravitational pull of the moon and sun on the earth’s waters and solid crust. - moon has a greater effect due to its distance to the earth.

Kinds of tides Spring tides – when the sun and moon are both on the same side of the earth. - high tides

Neap tides – when the moon and sun are at rt. angles to each other Gravitational pull is against each other Low tides

Since the moon moves around the Earth, it is not always in the same place at the same time each day. So, each day, the times for high and low tides change by 50 minutes.

Causes of tides: 1. position of moon and sun to earth 2. gravitational pull of moon and sun on earth’s waters 3. rotation of earth in and out of the waters

Moon’s light Moon light is light reflected from the sun off the moon’s surface. Libration: wiggling of moon in its orbit b/c of this we see 59% of the moon. /watch?v=3f_21N3wcX8

Regolith – lunar soil On the Moon, regolith occurs as a mixture of powdery dust and broken rock. Lunar regolith is formed by the impact of meteorites on the body’s surface. meteorites

Lunar gravity = 1/6 of earth Weight: pull of gravity on an object. Mass: amt. Of matter in an obj. Since the Moon is smaller, and has much less mass, it pulls with less gravity.

Lunar eclipse Moon passes into the shadow of the earth Umbra – darkest part of the shadow – complete eclipse Penumbra – lighter part of the shadow -partial eclipse Two lunar eclipses each year Duration – 1 hour

Solar eclipse when the earth moves into the moon’s shadow. Small area on earth in umbra. Total eclipse in umbra Lasts 8 minutes

Annular eclipse – when moon’s shadow does not touch the earth’s surface.

Solar eclipse

Moon features Mares – Lt. seas smooth dark areas on moon - lava flows - youngest rocks

Craters – depressions made from impact of meteors Copernicus Plato Crater Walls – surround crater

Chained craters – craters joined together

Rays – light colored material extending outward from crater - splash material from impact

Rilles - Rilles are trenches a few kilometers wide and hundreds of meters deep. Straight rilles are faults in the lunar crust whereas sinuous rilles are collapsed lava tubes.

Wrinkled ridges – found in maria result from cooling

Domes – small swelling on surface - domed volcanoes - laccoliths pushing upward

Mountain ranges- mountains on the moon

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