静しずかの海うみしずかのうみMeanings1expression, nounSea of Tranquility; Mare TranquillitatisastronomyAstronomical proper noun referring to the lunar mare where Apollo 11 landed.アポロ11号ごうは静しずかの海うみに着ちゃく陸りくした。Apollo 11 landed on the Sea of Tranquility.
