The Moon

Formation Hypotheses Co-Accretion – Earth and Moon formed near each other at same time. Fission – Rapidly rotating Proto-Earth released material that formed the Moon. Capture – Moon formed elsewhere in the Solar System and was captured by Earth’s gravity. Giant Impact (Collision ejection) – Mars-sized object struck early Earth and “splashed” material into space that formed the Moon. Giant Impact (Collision ejection)

Features Maria (Mare) – _____ – large, dark plains on the Moon’s surface. – Caused by volcanic activity, basaltic rock – Cover 16% of the Moon’s surface – Mostly on “our” side of the Moon __________ (Terrea/Terra)– lighter surface, more visible, Older “Seas” Highlands

_________ – caused by __________. Named for astronomers, mathematicians and philosophers. – 30,000 visible with telescope. Most between 1km and 100km – Ejecta Blanket – debris released from impact. Light – ______________ Dark – _________________________ ______ – Collapsed lava tubes or lava channels ________ – fine grained layer of pulverized material. Varies from 2m deep to 20m deep. Craters Rilles Regolith impacts More recent older – longer exposure to solar wind

Craters

Rilles

Craters and Rilles

Regolith

This image of the lunar farside from NASA's Lunar Reconnaissance Orbiter shows the moon's topography with the highest elevations (above 20,000 feet) in red and the lowest areas in blue. Image credit: NASA/Goddard.