They are call Maria ( Latin for "seas" ).
The feature covering much of the moon's surface is the lunar mare, which are large dark plains formed by ancient volcanic activity. These mare areas are less cratered compared to the highlands and are thought to be composed of basalt rock.
The moons surface has mountainous highlands and large circular plains. The circular plains are called Maria. The mountain has heights up to 25000 feet.
The Lunar plains are referred to as Maria (Latin for seas .) because ancient observers thought them to be water like Earth's own oceans .
crators
it has no moon
the trench like areas on the moons surface are called craters
The four large moons on Jupiter, or Galilean moons for the astronomer who discovered them, are called Io, Europa, Ganymede, and Callisto.
Maria is a bunch of Basaltic material (which is igneous rock) that came together on the moon. It formed when the moon cooled. People used to think that the dark spots (maria) on the moon were oceans.
Natural satellites of planets are called moons, if they are large enough.
they are called meteors, comets, moons or planets.
Maria are large, dark, basaltic plains on the Moon's surface that were formed by ancient volcanic activity. They are made up of solidified lava flows and are relatively flat compared to the rugged highlands that make up the rest of the lunar surface.
there are 63 moons and 4 of them are big