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SlideshowReport

Two Views of Mercury

Description
Lunar surface
Maria (singular, mare), Latin for “sea”
Dark regions
Fairly smooth lowlands
Originated from asteroid impacts and lava flooding the surface

Highlands
Bright, densely cratered regions
Make up most of the Moon
Make up all of the “back” side of the Moon
Older than maria
Craters
Most are produced by an impact from a meteoroid which produces
Ejecta
Occasional rays (associated with younger craters)

Lunar regolith
Covers all lunar terrains
Gray, unconsolidated debris
Composed of
Igneous rocks
Breccia
Glass beads
Fine lunar dust
“Soil-like” layer produced by meteoric bombardment

Lunar history
Hypothesis suggests that a giant asteroid collided with Earth to produce the Moon
Older areas have a higher density
Younger areas are still smooth

Moon evolved in three phases
Original crust (highlands)
As Moon formed, its outer shell melted, cooled, solidified, and became the highlands
About 4.5 billion years old

Formation of maria basins
Younger than highlands
Between 3.2 and 3.8 billion years old
Formation of rayed craters
Material ejected from craters is still visible
e.g., Copernicus (a rayed crater)

Mercury
Innermost planet
Second smallest planet
No atmosphere
Cratered highlands
Vast, smooth terrains
Very dense
Revolves quickly
Rotates slowly
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