The Moon, that large object that we can see in the sky both at daytime and nighttime, is a natural satellite of the Earth. Its surface, with such areas of different shapes and various shadows, pop up immediately, and it has inspired practically all cultures, including artists, priests, warriors, and lovers. The Moon is, comparatively, the biggest natural satellite in the Solar System (if we measure its size in respect of the planet that orbits). In the Solar System, the only satellites which are larger than the Moon, in absolute terms, are Ganymede, Calisto and Europa in Jupiter, Titan in Saturn, and Triton in Neptune.
The Moon’s surface is covered in craters but, how were they created? Since its formation, different sizes of rocks have attacked the Moon, as the Earth and the rest of the planets have[1]. When these rocks collide with the surface at high speed, they melt the rock, turning it into some kind of lava; once the molten rock cools down, it leaves a region darker, quite flatter than its surroundings. These areas are called maria, whereas the neighboring space, lighter in color, is called plateau or ground.
During these collisions, large amounts of gases were released, but the Moon was not able to hold them back due to its low mass, and therefore, it doesn’t have an atmosphere.
Due to these impacts on the solid rock of the Moon, broken stones called regolith accumulated there. In the case of the Earth, the regolith exists mainly in tropical regions, but its origin is different from the Moon’s. Here, 1% of this material comes from meteorites, and it is thought that comes from the bombardment and accumulation of meteorites of different sizes. This regolith may vary its thickness between 2 to 20 meters, so every time a mission land on the Moon, it leaves a record of that event. Even though the Moon is covered in this dust, most of its surface (under this layer) has basalt, a volcanic rock, or, in this case, from a lunar core rock that resurfaced after meteors impacts.
The Moon, unlike stars like the Sun, but like the planets, doesn’t emit light itself but reflects the light that comes from the Sun, which happens due to the lack of mass to produce energy in its core.
- ↑ We can see some craters on Earth. However, vulcanism, water (rain, rivers, glaciations), and wind have been in charge of erasing the majority of the craters, especially the smaller and older ones.
