Mare Tranquillitatis

American  

[mahr-ey trang-kwil-i-tah-tis] / ˈmɑr eɪ træŋˌkwɪl ɪˈtɑ tɪs /

noun

Astronomy.

1. Also called Sea of Tranquility.  a dark plain in the first quadrant of the face of the moon: about 110,000 square miles (285,000 square kilometers).

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Example Sentences

Lorenzo Bruzzone and Leonardo Carrer at the University of Trento in Italy found the cave by using radar to penetrate the opening of a pit on a rocky plain called the Mare Tranquillitatis.

From BBC

When Neil Armstrong said: “Houston, Tranquillity Base here. The Eagle has landed,” on the 1969 Apollo 11 moon mission, “Tranquillity” was a reference to the Mare Tranquillitatis, or Sea of Tranquillity, which Riccioli had named.

From New York Times

The Cinder Lake Crater Field, as the artificial crater field was called, was designed to mimic Mare Tranquillitatis, the future landing site of Apollo 11.

From The Guardian

A 1742 map showing the Mare Tranquillitatis, created by German mathematician, astronomer, and cartographer Johann Gabriel Doppelmayr, will be one of those featured in the library tweets.

From BBC

The legacy of achievement: Buzz Aldrin salutes the US flag on Mare Tranquillitatis during Apollo 11 in 1969.

From Forbes