Description: A mare, from the Latin for "sea", is one of a series of dark flat areas on the Moon made of basalt. These are thought to be the result of ancient volcanic eruptions that left behind a relatively smooth landscape compared to the light, older, jagged lunar highlands. Their name comes from their similar appearance to flat, watery seas. We now know that these areas are very dry with no surface water.

The Mare Tranquillitatis (Sea of Tranquility) was the site of the landing of Apollo 11, the first crewed mission to touch down on the Moon.

Related Terms:

• Apollo
• Moon

Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

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