September 28, 2022
The dark regions we see on the Moon were once thought to be seas by ancient astronomers. They are referred to as maria, which is Latin for seas. The dark material is solidified lava that once erupted to the surface of the Moon, filling large craters and impact basins.
The full moon as it will appear on October 9, 2022. The dark areas are ancient impact basins filled with lunar basalt. Image credit: NASA SVS