The full Moon rolls low across the south tonight. It lines up opposite the Sun, so sunlight fully illuminates the lunar hemisphere that faces our way. The Moon will just barely dip into the hazy edge of Earth's shadow early in the wee hours of the morning, but you'll need really sharp eyes to notice any difference.
Full Moon is the best time to fully study the patterns of light and dark areas on the lunar surface. The light areas are known as highlands -- they're jumbled areas of mountains and craters. The dark areas are known as seas -- they're vast plains of volcanic rock.
One of the dark areas in the Moon's northern hemisphere is the Sea of Tranquillity. It's probably the most famous lunar feature of all, because it's where astronauts first landed on the Moon, in July 1969.
The rocks and soil they picked up showed that the Sea of Tranquillity formed about 3.7 billion years ago. A mountain-sized boulder slammed into the lunar surface, and molten lava bubbled to the surface.
Over time, the surface has been pulverized by the impacts of countless tiny bits of rock, creating a powdery, sticky soil. It's mixed with rock that was blasted out by other large impacts, creating a jumbled mix of materials from around the lunar surface.
July's full Moon, by the way, is known as the Hay Moon or Thunder Moon. Since this is the month that humans first landed on the Moon, it's appropriate to add one more nickname: the Apollo Moon.
Script by Damond Benningfield, Copyright 2009
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