Formation of the Moon

What properties were known about the moon prior to Apollo? Orbital Period Mass and Size and therefore Density Gravity was 1/6 as strong as Earth No atmosphere, no oceans Albedo = 7% Very hot on the day side, cold on night side Maria were dark, highlands were lighter

Anatomy of the Moon

Highlands. Rough terrain many craters. 3.9 to 4.4 by Anorthosite Breccia

Maria (Seas) –flat –roughly circular –not many craters –rocks are like basalt –3.1 to 3.8 by.

Regolith –Lunar soil –Physically Weathered rock

Craters

–Meteor impacts –Methods to determine age Superposition Amount of weathering

Phases of the Moon

Near Side

Far Side

Lunar Landing Locations

Model for the Formation of the Solar System

Models for the Formation of the Moon Fission Theory –Earth had a baby –Poor model Why did it come out Where did is come out

Models for the Formation of the Moon Capture Theory –Asteroid was passing by the Earth and got caught in its gravitational pull. –Is the accepted model for the formation of small moons of Mars and big planets

Models for the Formation of the Moon Co-Accretion, Condensation or Colliding Planetesimals Theory –Earth had a sister –Planet and moon formed at the same time, same way Large moons on large planets are believed to have formed this way

Models for the Formation of the Moon Collision-Ejection or Ejected Ring Theory –Impact from a large object tour off a large piece of the Earth which was ejected into orbit around the Earth. This material reformed into the moon.

What properties were known about the moon since Apollo? 4.5 BY Highlands are made of Anorthosite Maria are made of Basalt Rock has very little volatile material –No Water –The ice found recently at the lunar north pole is from comets – found in the cold shaded craters.

Short History of the Moon Formed 4.6 billion years ago (bya) at about the same time as the Earth with continuous and intense meteor bombardment. By 4.2 bya the solid solidified, bombardment continued. By 3.8 to 3.1 bya the seas are formed by massive lava flows 3.o bys to present, the moon is geologically dead