Earth’s Moon Key Concepts What features are found on the moon’s surface? What are some characteristics of the moon? How did the moon form?
Key Terms • Telescope • Craters • Maria • meteoroids
The Moon’s Surface • Maria – dark, flat areas; hardened rock formed from lava flows 3-4 billion years ago • Craters – large round pits caused by impacts of meteoroids (chunks of rock or dust from space) • Highlands – light colored features, mountains that cover much of the moon’s surface
9 Main Maria on Near side I'm Sure That Croaking Frogs Never Need Hair Pieces
Characteristics of the Moon • Distance from Earth – about 384,000 km • Size – 3,476 km in diameter (1/4 Earth’s diameter) • Density - 1/80 the mass of earth, Earth has dense core and less dense outer layers. Whole moon’s density is similar to • Earth’s outer layers.
Characteristics of the Moon • Temperature and Atmosphere – surface = 130C in direct sunlight, -180C at night • Reason for such is extremes is that the moon has no atmosphere • Moon’s surface gravity is so weak that gases escape into space • Water – No liquid water, but evidence of solid (ice) water at poles and in craters where areas are shielded from sunlight and remain frozen
Water on Moon • October, 2009 L-CROSS (lunar crater observation and sensing satellite) probe found significant amounts of water ice (solid water) when it was crashed into the moon’s south pole • Debris from the impact was viewed by lunar reconnaissance orbiter, LRO and other space and ground based telescopes • Chemicals in debris were analyzed by spectrometers which measures light waves absorbed by different chemicals
Origin of the Moon Collision-ring theory – Present theory that best fits the data • a planet sized object (Theia) collided with the Earth. • Materials from the object and Earth’s outer layers was ejected into orbit around Earth • Formed a ring, gravity eventually caused it to combine and form the moon