About the world around us: why is the Moon visible during the day? Cosmic wonders: why is the Moon visible during the day? There is no moon in the sky today.

Why is the Moon visible during the day? Two years ago, UK sociologists, conducting a national survey, found that this particular question turned out to be the most difficult among the dozen questions most often asked by children to their parents. Many adults were at a loss for an answer that would suit the little ones.

In our view, the Earth’s satellite is a “night star” that illuminates the sky precisely at night. Why can it sometimes be seen in bright sunshine? It is not easy to explain this phenomenon even to an adult, so we will try to make our answer as understandable as possible to representatives of any age category. The behavior of the Moon is another fascinating phenomenon of the Universe.

What is tellurium needed for?

In order for a child to visually imagine the relative positions of space objects, it is best to use a special device - tellurium.

Tellurium is a device that clearly demonstrates not only the annual motion of our planet around the Sun, but also rotation around its own axis. In more advanced models of the device, there is also a third planet - the Moon, which moves not only around its axis, but also around the Earth.

In general, the movement of the planets included in the “Sun – Earth – Moon” system comes down to the following scheme: The Earth and the Moon, being satellites, move along the same trajectory passing around the Sun, located in the center of this system. The lunar disk, in turn, moving together with the Earth around the Sun, also rotates around its companion, the Earth.

What can replace tellurium?

It is unlikely that tellurium is present in the household of every family, so an imitation of the system of planets of interest to us can be made from improvised objects. The role of the Sun can be played by a large flashlight; for the Earth, a large rubber ball is suitable; for its satellite, a ball whose diameter is five times smaller.

Rotation of cosmic bodies in the Sun - Earth - Moon system:

First, let the baby rotate the ball - “Moon” around the ball - “Earth”. This will help him understand that the lunar disk invariably faces its companion with only one side.

Now start rotating the ball simulating the Earth around the flashlight representing the Sun, not forgetting to rotate the “Earth” around its own axis.

Explain to your child that a complete revolution of the Earth around the Sun is a very slow process, taking 365 days or a year. The night star, rotating around the Earth, does this much faster: one revolution around our planet takes it a little more than 27 days.

Why does the “queen of the night” come out during the day?

Most people are convinced that the moon can only be observed in the night sky (you can read about why you can’t look at the Moon). This is a completely erroneous opinion, since the queen of the night can be noticeable during the day, only this happens on certain days of the cycle. This does not apply to rare astronomical phenomena. Why is the Moon visible during the day?

And why do we rarely notice it?

In the daytime, in a brightly sunny sky, the month is less noticeable, because it cannot compare with the brightness of the daylight, since it only reflects sunlight and does not emit its own light. At this time of day, usually not the full disk is noticeable, but only a small part of it, resembling a narrow crescent.

Most often, the “dark” star becomes noticeable before sunrise or sunset, and this is the time when we simply do not look at the sky.

In the tropics and subtropics, at the very beginning of its cycle, the Moon appears in the morning sky just above the horizon, not far from the rising Sun. With the onset of noon, the disk appears at its zenith and continues to be visible throughout the day, until sunset.

What are "lunar phases"?

The moon is a very unusual luminary that is constantly changing. Sometimes it disappears from the sky, and after that it appears in the form of a thin crescent called a month. At some moments, it hangs in the sky all night and looks like a bright yellow bun. Why is this happening?

Such changes are explained by different degrees of illumination of the earth's satellite by the rays of the Sun, and different states of the disk are explained by phases. Some people mistakenly believe that the shadow cast by the Earth is the cause of the changes. In fact, this is a phenomenon of a completely different order, called a lunar eclipse (you can get an explanation of why the Moon is red).

Sometimes children ask why the Moon became like a sickle? It's all about its spherical surface. When the sphere is illuminated from the side, the crescent shape is simply inevitable. If the daylight is hidden behind the skyline, the part of the lunar sphere illuminated by its rays will always indicate exactly where it is located.

What phases of disk illumination exist?

The period during which the luminary temporarily disappears from the sky is called the new moon. This is explained by the fact that, being at a point that visually coincides with the location of the Sun, it is turned towards the daylight with its brightly lit side.

The appearance of a silvery narrow crescent in the night sky marks the onset of the next phase - the new month. This happens about a day after the new moon.

A week later, when the earth's satellite moves away from the Sun so much that it is at an equal distance from both the Earth and the Sun, the next phase begins - the first quarter. At this moment, one of its halves is brightly illuminated.

The full moon looks very beautiful - the state when the disk is completely illuminated. After this, a gradual decrease begins.

The next phase of the cycle, occurring in its third quarter, is called the waning moon.

The gradual decrease in the illuminated surface of the disk marks the onset of the final quarter of the lunar cycle. At this stage, only half is illuminated again.

The phase of the old Moon again shows us a narrow crescent.

What causes the “sickle-disc” change?

This phenomenon occurs due to the movement of the earth's satellite in orbit and the constant change in the relative positions of the planets.

As a result, there is a constant movement of the terminator (the boundary separating the dark and illuminated parts of the night disk), leading to a change in the configuration of the illuminated part of the Earth's satellite. That is why every night an attentive astronomer will notice changes on the surface of the Moon.

How to distinguish an old star from a growing one?

For residents of the northern hemisphere of the Earth, there is a very simple rule that allows you to instantly determine the difference.

If the crescent that is formed resembles the letter “c,” we have in front of us an aging Moon. If the sickle is turned in the opposite direction and, being equipped with an imaginary dash, resembles the letter “r”, it is young, that is, “growing”.

The young Moon can be observed in the evening hours, and the old Moon in the morning.

This method is completely unsuitable for the inhabitants of lands located near the equator, since the lunar crescent in those parts invariably lies on its side.

Interesting Facts:

Each month, as a rule, there is one full moon, but due to the fact that the phase changes occur a little more than the number of months in a year, sometimes there is an additional full moon. This unique and very rare phenomenon, occurring every 2.7 years, is called a “blue moon.”

The name does not indicate a change in the color of the night star. It is a translation of an English idiomatic expression, which is akin to the Russian “after the rain on Thursday” and indicates the rarity and low probability of this phenomenon. The next blue moon (extra full moon) will be visible on July 31, 2015.

Five years ago, analysts from one of the leading banks in Australia published the results of their own research, according to which the dynamics of global financial market indices depends on the change in the phases of the moon.

British police intelligence officers said the level of violence is also directly related to the phases.

As many have already noticed, the Moon always faces the same side towards the Earth. The question arises: is the rotation of these celestial bodies around their axes synchronous relative to each other?

Moon Facts:

Although the Moon rotates around its axis, it always faces the same side to the Earth, that is, the Moon’s revolution around the Earth and its rotation around its own axis are synchronized. This synchronization is caused by the friction of the tides that the Earth produced in the Moon's shell.

Another mystery: does the Moon rotate on its axis at all? The answer to this question lies in resolving the semantic problem: who is at the forefront - an observer located on Earth (in this case, the Moon does not rotate around its axis), or an observer located in extraterrestrial space (then the only satellite of our planet rotates around its axis).

Let's carry out this simple experiment: draw two circles of the same radius, touching each other. Now imagine them as disks and mentally roll one disk along the edge of the other. In this case, the rims of the discs must be in continuous contact. So, how many times do you think the rolling disk will turn around its axis, making a full revolution around the static disk. Most will say once. To test this assumption, let's take two coins of the same size and repeat the experiment in practice. And what's the result? A rolling coin has time to turn around its axis twice before it makes one revolution around a stationary coin! Surprised?

On the other hand, does a rolling coin rotate? The answer to this question, as in the case of the Earth and the Moon, depends on the observer's frame of reference. Relative to the initial point of contact with the static coin, the moving coin makes one revolution. Relative to an outside observer, during one revolution around a stationary coin, a rolling coin turns twice.

Following the publication of this coin problem in Scientific American in 1867, the editors were literally inundated with letters from indignant readers who held the opposite opinion. They almost immediately drew a parallel between the paradoxes with coins and celestial bodies (Earth and Moon). Those who held the point of view that a moving coin, in one revolution around a stationary coin, manages to turn around its own axis once, were inclined to think about the inability of the Moon to rotate around its own axis. The activity of readers regarding this problem increased so much that in April 1868 it was announced that the debate on this topic was ending in the pages of the Scientific American magazine. It was decided to continue the debate in the magazine The Wheel, specially dedicated to this “great” problem. At least one issue came out. In addition to illustrations, it contained various drawings and diagrams of intricate devices created by readers in order to convince editors that they were wrong.

Various effects generated by the rotation of celestial bodies can be detected using devices like the Foucault pendulum. If it is placed on the Moon, it will turn out that the Moon, rotating around the Earth, rotates around its own axis.

Can these physical considerations serve as an argument confirming the rotation of the Moon around its axis, regardless of the observer’s frame of reference? Oddly enough, from the point of view of general relativity, probably not. In general, we can assume that the Moon does not rotate at all, it is the Universe that revolves around it, creating gravitational fields like the Moon rotating in motionless space. Of course, it is more convenient to take the Universe as a stationary frame of reference. However, if you think objectively, regarding the theory of relativity, the question of whether this or that object really rotates or is at rest is generally meaningless. Only relative motion can be “real.”
To illustrate, imagine that the Earth and Moon are connected by a rod. The rod is fixed on both sides rigidly in one place. This is a situation of mutual synchronization - one side of the Moon is visible from the Earth, and one side of the Earth is visible from the Moon. But this is not the case here; this is how Pluto and Charon rotate. But we have a situation where one end is rigidly fixed to the Moon, and the other moves along the surface of the Earth. Thus, one side of the Moon is visible from the Earth, and different sides of the Earth are visible from the Moon.

Instead of a barbell, the force of gravity acts. And its “rigid attachment” causes tidal phenomena in the body, which gradually either slow down or speed up the rotation (depending on whether the satellite is rotating too fast or too slow).

Some other bodies in the Solar System are also already in such synchronization.

Thanks to photography, we can still see more than half of the surface of the Moon, not 50% - one side, but 59%. There is a phenomenon of libration - the apparent oscillatory movements of the Moon. They are caused by orbital irregularities (not ideal circles), tilts of the rotation axis, and tidal forces.

The Moon is tidally locked into the Earth. Tidal locking is a situation when the period of revolution of a satellite (Moon) around its axis coincides with the period of its revolution around the central body (Earth). In this case, the satellite always faces the central body with the same side, since it rotates around its axis in the same time that it takes for it to orbit around its partner. Tidal locking occurs during mutual motion and is characteristic of many large natural satellites of the planets of the Solar System, and is also used to stabilize some artificial satellites. When observing a synchronous satellite from the central body, only one side of the satellite is always visible. When observed from this side of the satellite, the central body “hangs” motionless in the sky. From the opposite side of the satellite, the central body is never visible.

Facts about the moon

There are lunar trees on Earth

Hundreds of tree seeds were carried to the Moon during the 1971 Apollo 14 mission. Former USFS employee Stuart Roosa took the seeds as personal cargo as part of a NASA/USFS project.

Upon returning to Earth, these seeds were germinated and the resulting lunar seedlings were planted throughout the United States as part of the country's bicentennial celebrations in 1977.

There's no dark side

Place your fist on the table, fingers down. You see the back of it. Someone on the other side of the table will see your knuckles. This is roughly how we see the Moon. Because it is tidally locked to our planet, we will always see it from the same perspective.
The concept of the “dark side” of the moon comes from popular culture—think Pink Floyd's 1973 album Dark Side of the Moon and the 1990 thriller of the same name—and actually means the far side, the night side. The one we never see and which is opposite to the side closest to us.

Over a period of time, we see more than half of the Moon, thanks to libration

The Moon moves along its orbital path and moves away from the Earth (at a rate of about one inch per year), accompanying our planet around the Sun.
If you were to zoom in on the Moon as it speeds up and slows down during this journey, you would also see that it wobbles from north to south and west to east in a motion known as libration. As a result of this movement, we see part of the sphere that is usually hidden (about nine percent).

However, we will never see another 41%.

Helium-3 from the Moon could solve Earth's energy problems

The solar wind is electrically charged and occasionally collides with the Moon and is absorbed by rocks on the lunar surface. One of the most valuable gases found in this wind and absorbed by the rocks is helium-3, a rare isotope of helium-4 (commonly used for balloons).

Helium-3 is perfect for meeting the needs of thermonuclear fusion reactors with subsequent energy generation.

One hundred tons of helium-3 could satisfy the Earth's energy needs for a year, according to Extreme Tech's calculations. The surface of the Moon contains about five million tons of helium-3, while on Earth there is only 15 tons.

The idea is this: we fly to the Moon, extract helium-3 in a mine, put it in tanks and send it to Earth. True, this may not happen very soon.

Is there any truth to the myths about the madness of the full moon?

Not really. The idea that the brain, one of the most watery organs of the human body, is influenced by the moon has its roots in legends going back several millennia to the time of Aristotle.

Since the Moon's gravitational pull controls the tides of Earth's oceans, and humans are 60% water (and 73% brain), Aristotle and the Roman scientist Pliny the Elder believed that the Moon must have a similar effect on ourselves.

This idea gave rise to the term "lunar madness", "Transylvanian effect" (which became widespread in Europe during the Middle Ages) and "lunar madness". 20th century films that linked the full moon with psychiatric disorders, car accidents, murders and other incidents added particular fuel to the fire.

In 2007, the government of the British seaside town of Brighton ordered additional police patrols during full moons (and on paydays too).

And yet science says there is no statistical connection between people's behavior and the full moon, according to several studies, one of which was conducted by American psychologists John Rotton and Ivan Kelly. It is unlikely that the Moon affects our psyche; rather, it simply adds light, in which it is convenient to commit crimes.

Missing moon rocks

In the 1970s, Richard Nixon's administration distributed rocks recovered from the lunar surface during the Apollo 11 and Apollo 17 missions to leaders of 270 countries.

Unfortunately, more than a hundred of these stones have gone missing and are believed to have ended up on the black market. While working for NASA in 1998, Joseph Gutheinz even conducted a covert operation called "Lunar Eclipse" to stop the illegal sale of these stones.

What was all the fuss about? A pea-sized piece of moon rock was valued at $5 million on the black market.

The Moon belongs to Dennis Hope

At least that's what he thinks.

In 1980, exploiting a loophole in the 1967 UN Space Property Treaty that said “no country” could lay claim to the solar system, Nevada resident Dennis Hope wrote to the UN and declared a right to private property. They didn't answer him.

But why wait? Hope opened a lunar embassy and began selling one-acre lots for $19.99 each. For the UN, the solar system is almost the same as the world's oceans: outside the economic zone and belonging to every inhabitant of the Earth. Hope claimed to have sold extraterrestrial properties to celebrities and three former US presidents.

It is unclear whether Dennis Hope really does not understand the wording of the treaty or whether he is trying to force the legislature to make a legal assessment of its actions so that the development of celestial resources can begin under more transparent legal conditions.

Guest article.

People are accustomed to dividing the day into two parts: day and night. This opposition is one of the main motives of many folk tales, myths and legends. At the same time, during the day the main place in the sky is occupied by the Sun, and at night - by the Moon. The order of things is well known to everyone, isn’t it?

But the Moon can be seen not only at night. Each of us has noticed a pale crescent moon in the daytime sky at least once in our lives. How to explain this? Why is the Moon visible at the same time as the Sun? What is this: a strange coincidence, an illusion, or a completely ordinary astronomical phenomenon? Let's try to figure it out.

Moon and brightness of celestial bodies

We see stars, planets and other space objects because they emit or reflect visible light. The brightest celestial bodies are stars. Satellites and planets are much paler because they do not emit, but reflect the light that reaches them from an external source. The brightness level of a cosmic body is called magnitude. Another name for this property is shine.

The Moon reflects the light of the Sun, so it is visible better at night than during the day. During the daytime, the brightness of the sky increases due to sunlight scattered in the atmosphere. Because of this, both the stars and the lunar disk disappear from the sky.

Nevertheless, when our satellite is in the full moon phase, its apparent brightness reaches -13 m. And this is quite enough to break through the radiance of the atmosphere. But because the Sun is still 447,000 times brighter than the Moon, we often see only a pale spot in a clear blue sky. And because of the clouds, it is most often almost impossible to see.

Month or disk?

The entire Moon does not always appear in the sky. Sometimes we see a round lunar disk, and sometimes we see a month. On some days, the Moon disappears completely: it is not visible either day or night.

What is this connected with? It's very simple: the Moon, like all other cosmic bodies, never stays in one place. She is constantly on the move. And it rotates not only around its own axis, but also around the Earth.

It takes approximately 29 days to orbit around our planet. Throughout this space journey, the position of the Moon relative to the Sun and Earth is constantly changing. It is because of this that we see either the full Moon or the crescent moon in the sky.

The lunar cycle consists of several phases:

new moon. At this time, our satellite cannot be seen not only during the day, but also in the dark. This is due to the fact that it appears at a point that visually coincides with the location of the Sun, and completely disappears in its rays;
new month. A narrow crescent moon appears in the sky. You can notice it the next day after the new moon;
first quarter. The phase of the cycle during which the Moon is at an angle of 90° relative to the Sun. Half of the lunar disk can be seen in the sky at this time;
full moon. The phase during which one of the Moon's hemispheres can be seen in its entirety. Magnitude values are maximum;
last quarter. The Moon begins to approach the Sun, the visible surface area decreases;
old month. We again see the narrow lunar crescent, only turned in the other direction. In a few days, the Moon will be opposite the Sun and will again disappear from observers for a day.

During the day, the Earth's satellite is best seen during the period when it is in the full moon phase. Therefore, if you notice the Moon and you have a telescope or astronomical binoculars, you can try to take a closer look at the lunar surface. It is possible that you will be able to see some large craters. And even take pictures of them if you have the right equipment with you. For example, a digital camera with good resolution or a special video camera.

Why doesn't the moon rotate and we only see one side? June 18th, 2018

As many have already noticed, the Moon always faces the same side towards the Earth. The question arises: is the rotation of these celestial bodies around their axes synchronous relative to each other?

Can these physical considerations serve as an argument confirming the rotation of the Moon around its axis, regardless of the observer’s frame of reference? Oddly enough, from the point of view of general relativity, probably not. In general, we can assume that the Moon does not rotate at all, it is the Universe that revolves around it, creating gravitational fields like the Moon rotating in motionless space. Of course, it is more convenient to take the Universe as a stationary frame of reference. However, if you think objectively, regarding the theory of relativity, the question of whether this or that object really rotates or is at rest is generally meaningless. Only relative motion can be “real.”
To illustrate, imagine that the Earth and Moon are connected by a rod. The rod is fixed on both sides rigidly in one place. This is a situation of mutual synchronization - both one side of the Moon is visible from the Earth, and one side of the Earth is visible from the Moon. But this is not the case here; this is how Pluto and Charon rotate. But we have a situation where one end is rigidly fixed to the Moon, and the other moves along the surface of the Earth. Thus, one side of the Moon is visible from the Earth, and different sides of the Earth are visible from the Moon.

Instead of a barbell, the force of gravity acts. And its “rigid fastening” causes tidal phenomena in the body, which gradually either slow down or speed up the rotation (depending on whether the satellite is rotating too fast or too slow).

Some other bodies in the Solar System are also already in such synchronization.

Facts about the moon

There are lunar trees on Earth

Hundreds of tree seeds were carried to the Moon during the 1971 Apollo 14 mission. Former USFS employee Stuart Roosa took the seeds as personal cargo as part of a NASA/USFS project.

Upon returning to Earth, these seeds were germinated and the resulting lunar seedlings were planted throughout the United States as part of the country's bicentennial celebrations in 1977.

There's no dark side

Over a period of time, we see more than half of the Moon, thanks to libration

However, we will never see another 41%.

Helium-3 from the Moon could solve Earth's energy problems

Helium-3 is perfect for meeting the needs of thermonuclear fusion reactors with subsequent energy generation.

The idea is this: we fly to the Moon, extract helium-3 in a mine, put it in tanks and send it to Earth. True, this may not happen very soon.

Is there any truth to the myths about the madness of the full moon?

Not really. The idea that the brain, one of the most watery organs of the human body, is influenced by the moon has its roots in legends going back several millennia to the time of Aristotle.

In 2007, the government of the British seaside town of Brighton ordered additional police patrols during full moons (and on paydays too).

Missing moon rocks

In the 1970s, Richard Nixon's administration distributed rocks recovered from the lunar surface during the Apollo 11 and Apollo 17 missions to leaders of 270 countries.

What was all the fuss about? A pea-sized piece of moon rock was valued at $5 million on the black market.

The Moon belongs to Dennis Hope

At least that's what he thinks.

Sources: