The Moon is two steps away from our Earth. Don’t misunderstand: we mean two steps in an astronomical sense. Compared to the 149 million kilometers separating the Earth from the Sun, the distance of 384,000 kilometers between the Moon and the Earth is certainly small.

Small celestial bodies orbiting large planets are called satellites. The Moon is the Earth’s only satellite. It is a celestial body fifty times smaller than the Earth. It is a sphere that is mountainous, airless, and waterless, covered with very large volcanic craters.
The first humans to step onto the Moon found themselves among volcanic craters and particles of soil resembling fine dust—that is, literally in a desert; they were left in a terrifying silence. Had they not been equipped with special suits and tools, they would have been scorched by the heat, frozen by the cold, and unable to speak to each other. They would not have been able to speak because there is no air to transmit sound. They would have been scorched on the side of the Moon illuminated by the Sun because the temperature there exceeds 100 degrees Celsius. In the shadowed parts of the Moon, the side not illuminated by the Sun, they would have frozen solid because there was no way for them to escape the cold far below minus 100 degrees.

When you look at the Moon at night, you always see it as if it were standing still. In fact, it is traveling at a terrifying speed of 3600 km per hour (1 km per second). Where does it go? While the Earth orbits the Sun at a furious speed, the Moon follows it, and in the process of orbiting the Earth, it also rotates around its own axis in 29 days and always shows the same face to the Earth. Just like a ship circling an island always shows the same side of itself to the island.

It is possible to examine the Moon, our Earth’s only satellite, with very powerful telescopes and take photographs of it. Indeed, the map of the face of the Moon visible from Earth was drawn before any human set foot on this satellite. Maps of the Moon’s far side were also created thanks to artificial satellites launched into space.

The Moon completes its orbit around our Earth in 29 days, and simultaneously completes its orbit around the Sun along with our Earth in one year. Its speed per second is about 20 kilometers.

The Phases of the Moon

Why do we sometimes not see the Moon at all, or only see a part of it?

Like the Earth, only half of the Moon is illuminated by the Sun. As the Moon orbits the Earth, it shows us all or part of its illuminated side. Sometimes it turns its dark side towards us. These changes are the phases in which the Moon is seen from the Earth.

These phases are: New Moon, First Quarter, Full Moon, and Last Quarter.

Due to the low gravity, objects on the Moon seem to have almost no weight.
Because the Moon is much smaller than the Earth, it pulls objects toward itself with less force. A person who weighs 60 kilos on Earth weighs 10 kilos on the Moon (meaning the weight of objects decreases by 6 times on the Moon). Because the gravitational force is less, a very fat person will be able to hop and jump on the Moon like a gazelle. Even the frailest person can easily lift loads they couldn’t even budge on Earth.