Science / Geology / Dune: A mound or ridge of wind-blown sand. Typically found in deserts and inland from a beach. Many dunes are moved by the wind.
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Transverse Dune

Science / Geology / Transverse Dune: A dune that has its axis transverse to the prevailing winds or to a current. The upwind or upcurrent side has a gentle slope, and the downwind side lies at the angle of repose. MORE

Seif Dune

Science / Geology / Seif Dune: A large sand dune that forms parallel to the direction of a strong wind that blows in a consistent direction throughout the year. Also called a longitudinal dune. MORE

Longitudinal Dune

Science / Geology / Longitudinal Dune: A long, narrow sand dune that has its long dimension oriented parallel to the direction of the wind. MORE

Space Opera

Entertainment / Literature / Space Opera: A subgenre of 'soft' science fiction especially popular between 1930-1960, often used in a derogatory sense. These space operas are novels or short stories set in the distant future after humanity has MORE