The moon is mankind's closest satellite on our journey through outer space, as well as the only celestial body that we have visited. Nevertheless, despite its relative proximity to us and seeming simplicity, our companion continues to hide many interesting secrets, and some of them are worth knowing about them.
Despite the fact that, in fact, the Moon is just a dead piece of rock with extremely low geological activity, crustal movements occur there too. They are called moonquakes (by analogy with earthquakes).
There are four types of moonquakes: the first three - deep moonquakes, vibrations from meteorite impacts, and thermal moonquakes caused by solar activity - are relatively safe. But moonquakes of the fourth type can be quite unpleasant. Typically they are up to 5.5 on the Richter scale - enough to make small objects start to shake. Such tremors last about ten minutes. According to NASA, such moonquakes make our moon "ring like a bell."
The most frightening thing about these moonquakes is that we have no idea what exactly is causing them. Earthquakes on Earth are usually caused by tectonic plate movements, but there are simply no tectonic plates on the Moon. Some researchers think that they may have some connection with the tidal activity of the Earth, which, as it were, "pulls" the moon over itself. However, the theory is not supported by anything - tidal forces are associated with full moons, and moonquakes are usually observed at other times.
Double planet
Most people are convinced that the moon is a satellite. However, many argue that the Moon should be classified as a planet. On the one hand, it is too large for a real satellite - its diameter is equal to a quarter of the Earth's diameter, so the Moon can be called the largest satellite in the solar system, given this ratio. Pluto, however, also has a satellite called Charon, whose diameter is half the diameter of Pluto itself. Only here Pluto is no longer considered a real planet, so we will not take Charon into account.
Promotional video:
Due to its large size, the Moon is not actually in low-Earth orbit. The Earth and the Moon revolve around each other and around a point in the center between them. This point is called the barycenter, and the illusion that the Moon is orbiting the Earth is caused by the fact that the center of gravity is currently inside the earth's crust. It is this fact that does not allow us to classify the Earth with the Moon as a double planet, but in the future the situation may change.
Lunar debris
Everyone knows that there was a man on the moon. But not everyone knows that Man (we will specially write this word with a capital letter) used the Moon as a standard picnic spot - astronauts who visited the Moon left a lot of garbage there. It is believed that about 181,437 kg of artificial materials rest on the lunar surface.
Of course, not only the astronauts are to blame - they deliberately did not throw sandwich wrappers and banana peels on the moon. Most of this debris came from various experiments, space probes and lunar rovers, some of which are still functioning today.
Moon grave
Eugene "Jean" Shoemaker, a renowned astronomer and geologist, is something of a legend in his circles: he developed methods for the scientific study of cosmic impact, and also invented the techniques that the Apollo astronauts used to study the moon.
Shoemaker wanted to become an astronaut himself, but could not get the job due to minor health problems. This remained the biggest disappointment throughout his life, but Shoemaker nevertheless continued to dream that someday he could visit the moon himself. When he died, NASA fulfilled his most cherished wish and sent his ashes to the moon with the Lunar Prospector station in 1998. His ashes remain there, scattered among the moon dust.
Lunar anomalies
Some images taken by various satellites show very strange things on the lunar surface. It seems that there are artificial structures on the moon, the size of which ranges from very tiny, usually in the shape of a parallelepiped, to "obelisks" at least 1.5 km high.
Lovers of the paranormal even "found" a large castle among these objects, "hanging" high above the surface of the moon. All this seems to indicate an advanced civilization that previously lived on the moon and supposedly built complex structures.
NASA has never refuted these strange theories, despite the fact that all of the images are most likely faked by adherents of the "conspiracy theory".
Moon dust
One of the most amazing and at the same time most dangerous things on the moon is moon dust. As everyone knows, sand penetrates everywhere and on Earth, but dust on the moon is an extremely dangerous substance: it is fine, like flour, but very coarse. Thanks to its texture and low gravity, it penetrates absolutely anywhere.
NASA had numerous problems related to moon dust: it tore apart astronauts' boots almost completely, penetrated into ships and spacesuits, and became the cause of "moon hay fever" in hapless astronauts if they inhaled it. It is believed that with prolonged contact with moon dust, even the most durable object can break.
By the way, this devilish substance smells like burnt gunpowder.
Low gravity difficulties
Although the moon's gravity is only one-sixth that of Earth's gravity, moving across its surface is a feat. Buzz Aldrin said that it would be extremely easy to establish settlements on the Moon: the legs of astronauts in bulky spacesuits were buried in the moon dust by almost 15 cm.
Despite the low gravity, human inertia on the moon is high, so it's easy to move quickly or change direction there. If astronauts wanted to move faster, they had to pose as clumsy kangaroos, which was also a problem, since the moon is full of craters and other dangerous objects.
The origin of the moon
Where did the moon come from? There is no simple and accurate answer, but, nevertheless, science allows you to make several assumptions.
There are five main theories about the origin of the moon. The fission theory claims that the Moon was once part of our planet and separated from it at a very early stage in the history of the Earth - in fact, the Moon could just be located on the site of the modern Pacific Ocean. The capture theory says that the Moon simply "wandered" through the Universe until it was captured by Earth's gravity. Other theories say that our satellite either formed from asteroid debris or was left from the collision of the Earth with an unknown planet the size of Mars.
The most reliable theory of the origin of the Moon at the moment is called The Theory of the Rings: a protoplanet (a planet that is just forming) called Theia collided with the Earth, and the resulting cloud of debris eventually gathered together and turned into the Moon.
Moon and sleep
The influence of the Moon and Earth on each other cannot be denied. However, the moon's influence on humans is a source of ongoing debate. Many believe that the full moon is the cause of strange behavior in humans, but science cannot provide conclusive evidence for or against this theory. But science agrees that the moon can disrupt the human sleep cycle.
According to an experiment conducted at the University of Basel in Switzerland, the phases of the moon affect a person's sleep cycles in a very specific way. People sleep worst of all, as a rule, on the full moon. These results can fully explain the so-called "lunar madness": according to the experiment and the assurances of many people, it is on the full moon that they most often have nightmares.
Moon shadows
When Neil Armstrong and Buzz Aldrin first set foot on the moon, they made an amazing discovery: the shadows on the moon are much darker than the earth's shadows due to the lack of atmosphere. All moon shadows are absolutely black. As soon as the astronauts stepped into the shadows, they could no longer see their own legs, despite the solar disk glowing brightly in the sky.
Of course, astronauts were able to adapt to this, but such a contrast between dark and light areas of the surface still remained a problem. The astronauts noticed that some shadows - notably their own - have halos. They later learned that the eerie phenomenon is due to the opposition effect, in which some dark shadow areas develop a bright halo, provided that the observer looks at the shadows from a certain angle.
The shadows of the moon have become the scourge of many Apollo missions. Some astronauts found it impossible to complete maintenance tasks on the spacecraft because they could not see what their hands were doing. Others thought they had accidentally landed in a cave - this effect was created by the shadows cast by the slopes.
Lunar magnetism
One of the most interesting mysteries of the Moon is that the Moon has no magnetic field. Surprisingly, the stones that astronauts first brought from the moon to Earth in the 1960s had magnetic properties. Maybe the stones are of alien origin? How can they be magnetic if there is no magnetic field on the moon?
Over the years, science has established that the moon once had a magnetic field, but so far no one can say why it disappeared. There are two main theories: one states that the magnetic field disappeared due to the natural motions of the iron core of the moon, and the second states that this may be due to a series of collisions of the moon with meteorites.