i think when the moon cooled down.
The dark spots on the moon are called lunar maria, which are large plains formed by ancient volcanic activity. The lighter areas are called highlands, which are rugged and densely cratered regions of the moon's surface.
craters
The dark spots on the Moon, known as lunar maria, are made up of basalt rock formed from ancient volcanic activity. Basalt is a dark-colored, fine-grained volcanic rock that is rich in iron and magnesium minerals.
Dark spots on the moon during a lunar eclipse are caused by the Earth blocking direct sunlight from reaching the moon. These dark spots are the shadow of the Earth falling on the moon's surface, which gives the moon its reddish appearance during a total lunar eclipse.
The moon is a sphere about one- seventh of the earth's size. It has dark spots and bright spots and craters.
The dark spots on the moon are called "maria," which is Latin for seas. They are actually large plains formed by ancient volcanic activity and appear darker than the surrounding lunar surface due to their basaltic composition.
The dark spots on the moon referred to as maria (singular: mare) are large, flat areas that were formed by ancient volcanic activity. They appear dark because they are composed of basaltic rock, which is rich in iron and magnesium minerals. These maria contrast with the lighter, mountainous regions on the moon's surface.
They were created by meteors hitting the moon and making craters.
Reforming
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.
They thought they were lunar "seas" like the oceans on earth. They are actually vast plains. But even today, they are still called "seas".Many early astronomers thought the dark spots on the moon were "seas". That is how all the lunar maria got their name, such as "Mare Tranquillitatis" which translates into "The Sea of Tranquility".
They are called maria. They were formed when asteroid and comet impacts on the moon exposed the mantle of molten rock. The lava flooded into and over the craters and hardened in vast fields forming the dark spots we see when we look up at the moon.