Consistent changes in the visible moon in the sky
The moon goes through the following phases of illumination:
- new moon- a state when the Moon is not visible. New Moon is the phase of the Moon at which its ecliptic longitude is the same as that of the Sun. Thus, at this time the Moon is between the Earth and the Sun approximately on the same straight line with them. If they are exactly on the same line, a solar eclipse occurs. During the new moon, the Moon is not visible in the night sky, since at this time it is very close to the Sun on the celestial sphere (no further than 5°) and at the same time is turned to us on the night side. But sometimes it can be seen against the background of the solar disk (solar eclipse). In addition, some time (usually about two days) after or before the new moon, with a very clear atmosphere, you can still notice the disk of the Moon, illuminated by weak light reflected from the Earth (ash light of the Moon). The interval between new moons is on average 29.530589 days (synodic month). At the new moon the Jewish New Year and Chinese (Japanese, Korean, Vietnamese) New Year of the 60-year cycle.
- new moon- the first appearance of the Moon in the sky after the new moon in the form of a narrow crescent.
- first quarter- the state when half of the Moon is illuminated.
- waxing moon
- full moon- a state when the entire Moon is illuminated. Full Moon is the phase of the Moon at which the difference between the ecliptic longitudes of the Sun and Moon is 180°. This means that the plane drawn through the Sun, Earth and Moon is perpendicular to the plane of the ecliptic. If all three objects are in the same line, a lunar eclipse occurs. The moon at full moon looks like a regular luminous disk. In astronomy, the moment of the full moon is calculated with an accuracy of several minutes; In everyday life, a full moon is usually called a period of several days during which the Moon is visually almost indistinguishable from the full one. During a full moon, the so-called opposition effect can occur for several hours, during which the brightness of the disk increases noticeably, despite its unchanged size. The effect is explained by the complete disappearance (for an earthly observer) of shadows on the surface of the Moon at the moment of opposition. The maximum brightness of the Moon during a full moon is -12.7m.
- waning moon
- last quarter- the state when half of the moon is illuminated again.
- old moon
To distinguish the first quarter from the last, an observer located in the northern hemisphere can use the following mnemonic rules. If the lunar crescent in the sky looks like the letter “C (d)”, then this is the “Aging” or “Descending” moon, that is, this is the last quarter (dernier in French). If it is turned in the opposite direction, then, by mentally placing a stick on it, you can get the letter “P (p)” - the moon “Waxing”, that is, this is the first quarter (premier in French).
The waxing month is usually observed in the evening, and the aging month in the morning.
It should be noted that near the equator the month is always visible “lying on its side”, and this method is not suitable for determining the phase. In the Southern Hemisphere, the orientation of the crescent in the corresponding phases is the opposite: the waxing month (from new moon to full moon) looks like the letter “C” (Crescendo,<), а убывающий (от полнолуния до новолуния) похож на букву «Р» без палочки (Diminuendo, >). Interesting Facts Typically, each calendar month has one full moon, but since the phases of the moon change a little faster than 12 times a year, sometimes a second full moon in a month occurs, called a blue moon.
Our planet is beautiful and amazing; there is no such planet in the entire universe. In its firmament you can observe different luminaries. During the day, the sun shines brightly on the Earth, warming all living things with its rays, and at night we see how Moon shines through the windows of our houses. The moon has always been mysterious; in ancient times, people watched with fear and trepidation as it changed its face. Eclipses caused them even greater horror, when the entire Earth was plunged into complete darkness for a short time.
The moon itself cannot emit light, it reflects the light of the Sun. Why do people think that the moon is changing? The Moon is a satellite of our planet and revolves around it. We can always see the Moon only from one side, as if it were tied to the Earth with a rope. We can only see the illuminated part of the Moon. Approximately four weeks, The Moon makes its procession around the Earth. What we observe as a change in the appearance of the Moon or phase is actually a change in the illumination of the Moon as seen from the Earth. In four weeks, a complete cycle of changes in the appearance of the Moon is completed. At the beginning of the cycle, the Moon is new and it is in the same direction from us as the Sun.
The side of the Moon, which is turned towards the Earth, is dark and completely lost in the rays of the Sun; in this phase the Moon is not visible in the sky. This lunar phase is called - new moon.
The next phase has a name - the first quarter, and the Moon passes the fourth part of its path, then we see the half-illuminated disk of the Moon.
The third phase of the moon is called full moon, The Moon is on the opposite side of the Sun and we see the entire disk of the Moon illuminated by the sun's rays. The final phase is the last quarter, and the Moon's disk is also half illuminated.
To correctly determine what phase the Moon is in, you need to know one interesting rule. If its sickle looks like the bow of the letter “P”, then the Moon is growing. When its arch looks in the opposite direction and resembles the letter “C”, then the Moon is aging. This is very easy to remember and you can always determine whether the young Moon has just begun its journey or the old Moon is completing its cycle.
Sometimes you can observe amazing phenomena in the sky called eclipses.
Scientists call a solar eclipse the phenomenon when the disk of the Moon completely covers the Sun. It is very interesting to observe such a phenomenon, but you need to take a piece of dark glass with you, through which the eclipse will be visible in all its glory.
Another interesting sight in science is called lunar eclipse. This happens when the shadow of the Earth covers the disk of the Moon and instead of the luminous lunar disk one can see dark circle. If the orbits of the Earth and the Moon coincided, we could observe an eclipse of the Sun at new moon and an eclipse of the Moon at full moon at each revolution. This does not happen because the plane on which the Moon's orbit is located is tilted by five degrees.
Moon phases
On a clear, cold autumn night you go outside. The Moon had just risen, a huge round orange Moon. A few days later, you notice that the moon is no longer as round. A few more days pass - the Moon has turned into a horned moon. After two weeks, the Moon disappears altogether.
Why does the Moon change shape?
What happened? Why does the Sun always turn its round sparkling face towards us, and the Moon has phases? The moon passes them regularly every month, sometimes increasing and sometimes decreasing, like balloon, which is then inflated and then deflated.
In reality, of course, the Moon always remains a ball, invariably hard and rocky. What actually changes is the amount of the illuminated surface of the Moon that we can see.
The Moon makes one revolution around its axis in almost the same time that it makes one revolution around the Earth (in 27/3 days), so the Moon almost always faces the Sun with only one side. But it is wrong to think that eternal night reigns on one side of the moon. Although slowly, the change of day and night still occurs.
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Why do the Moon and Sun change color? Description, photo and video
Why does the moon glow?
What we call moonlight is actually sunlight reflected by the gray, rocky lunar surface. The Moon moves with the Earth around the Sun and is illuminated by the Sun. As the Moon moves, we see either a larger or smaller part of the illuminated surface of the Moon, that is, the position of the Moon in relation to the Earth is changing all the time.
What we call the "phases" of the Moon are the angles at which we see the illuminated part of the Moon. When we see it completely, this position is called the full moon. When, after a few days, the Moon becomes “defective,” we already see part of its illuminated half (the first quarter after the full moon).
As you know, the Moon does not emit light, but only reflects it. And therefore, only that side of it that is illuminated by the Sun is always visible in the sky. This side is called the day side. Moving across the sky from the west to the east, the Moon over the course of the month catches up and overtakes the Sun. There is a change in the relative positions of the Moon, Earth and Sun. In this case, the sun's rays change the angle of incidence on the lunar surface and therefore the part of the Moon visible from the Earth changes. The movement of the Moon across the sky is usually divided into phases directly related to its modification: new moon, new moon, first quarter, full moon and last quarter.
Moon observations
The Moon is a celestial body of spherical shape. That is why, when it is partially illuminated by sunlight from the side, the appearance of a “sickle” appears. By the way, by the illuminated side of the Moon you can always determine in which direction the Sun is located, even if it is hidden behind the horizon.
The duration of the complete change of all lunar phases is usually called a synodic month and ranges from 29.25 to 29.83 Earth solar days. The length of the synodic month varies due to the elliptical shape of the lunar orbit.
During the new moon, the Moon's disk is completely invisible in the night sky, since at this time it is located as close as possible to the Sun and at the same time faces the Earth with its night side.
Next comes the new moon phase. During this period of time, the Moon becomes visible in the night sky for the first time in the synodic month in the form of a narrow crescent and can be observed at dusk a few minutes before its setting.
Next comes the first quarter. This is the phase in which exactly half of its visible part is illuminated, as in the last quarter. The only difference is that in the first quarter the proportion of the illuminated part at this moment increases.
The full moon is the phase in which the lunar disk is clearly and completely visible. During the full moon, for several hours you can observe the so-called opposition effect, in which the brightness of the lunar disk noticeably increases, while its size remains the same. This phenomenon is explained quite simply: for an earthly observer, at this moment all shadows on the surface of the Moon disappear.
There are also phases of the waxing, waning and old moon. All of them are characterized by a very narrow crescent of the Moon with a grayish-ash color typical for these phases.
From all of the above we can conclude that, in fact, nothing obscures the Moon. The angle of its illumination by the sun's rays simply changes.
Some people answer this question without thinking: the Moon is covered by the Earth’s shadow. This is the wrong answer, because the Earth's shadow is always directed in the direction opposite to the Sun, and Moon, moving along its orbit, circles the Earth on all sides.
“Astronomers carefully study the movement of the Moon and describe it formula, containing in general about 700 components, and calculations are carried out with an accuracy of 15 decimal places"(I.A. Klimishin “Astronomy of our days”, M. “Science”, third edition, p. 95).
Such precision is necessary for astronautics.
In this article, without delving into details, we will consider only the simplest question: why the appearance of the Moon changes, or, in other words, why the lunar phases and conditions of their visibility change.
The figure shows that wherever the Moon is in orbit, half of it is illuminated by the Sun, here it is day on the Moon, and the other half is dark, night. An observer on Earth can only see the side of the Moon that faces Earth. From it, only the part illuminated by the Sun is visible. The outer circle of the picture shows what the Moon looks like from the point of view of an observer standing on Earth. In position (1) facing the earthly observer most of the night side of the Moon and a small fraction of the day side, it is this that looks like a narrow crescent. With each passing day, the Moon advances in its orbit, as indicated by the arrow, and the corresponding observer on Earth is able to see an increasing proportion of the day side of the Moon. In positions (2) and (3) it is clear that the Moon is gradually “growing”.
In position (4), the Moon is opposite the Sun, and the entire day side of the Moon faces the Earth. This phase is called the full moon. Why did the Moon not fall into the shadow of the Earth, directed in the direction opposite to the Sun? Because the plane of the lunar orbit is inclined to the plane of the Earth's orbit at an angle of 5 degrees 9 minutes, and the Earth's shadow usually passes by the Moon. The moon enters the earth's shadow only during lunar eclipses, the conditions for the occurrence of which must be considered specifically.
After the full moon, the daily fraction of the Moon visible from the Earth gradually decreases - phases (5), (6), (7). The latter is again a narrow crescent, but from the point of view of an observer standing on Earth in position (7), its horns are directed in the direction opposite to the growing crescent and resemble the letter “C”.
Then comes the new moon phase (8). The Moon is above the daytime side of the Earth, faces the Earth at night and is lost in the bright daytime sky. At this time the nights are dark and moonless.
To make it easier to understand when which phases are visible, the drawing is made in such a way that we are looking at the Earth and the Moon’s orbit “from above,” from the Earth’s north pole, which is placed in the center of the drawing. The sun's rays illuminate the daytime half of the Earth. The arrow shows the direction of the Earth's daily rotation and, accordingly, the change of day to evening, night and morning. Approximately 28 Earth days (lunar month) will pass in the time it takes the Moon to make a full revolution around the Earth. The phase change occurs gradually and continuously. Between the described phases, 3-4 days pass.
The duration of the lunar month differs from the duration of the solar month, therefore the same lunar phases occur on different dates of our solar calendar.
Due to the movement of the Moon in its orbit, its rising, culmination and setting occur almost 50 minutes later than in the previous day, so the visibility of the Moon shifts to an increasingly later time.
In position (1), the young crescent rose before dark and before it sets behind the western horizon, it can be seen in the early evening after sunset. In position (2), the Moon rises at sunset and is visible throughout the evening. In position (3), the visibility time shifts to the first half of the night. In a full moon (4) the moon shines all night. After the full moon, the visibility of the Moon first changes to the second half of the night (5), then to the morning (6) and to twilight before sunrise (7). During a new moon, the Moon is not visible at all.
Sun and Earth on the Moon's sky
The Earth's disk is 15 times larger than the lunar disk, visible from the Earth, in addition, the Earth shines much brighter than our Moon, since it reflects 40% of sunlight (oceans, ice, clouds), and the Moon only 12% (basalts, dusty areas ). As the Moon moves through its orbit, an observer on the Moon sees the changing phases of the Earth, but the boundary between the light and dark regions of the Earth is not clear, but blurred due to clouds and light scattered in the atmosphere. From the Moon you can see clouds floating above the Earth, notice the daily rotation of the Earth, because lunar day it makes thirty revolutions around its axis.
Let's see what happens in the sky of the Moon during its day.
In the east, the sky began to brighten, but this is not dawn; the corona of the Sun is slowly rising from the horizon. When the Sun rises in the black sky with a crown, the Earth looks like half: part day and part night. The sun rises very slowly, because the day lasts 15 of our days. While the Sun reaches its highest position, the light part of the Earth decreases, turning into a thin crescent, complemented by a light blurred border to the circumference.
At lunar noon, the Earth faces the Moon on its night side, its dark disk surrounded by an orange-red halo. The fact is that sunlight passes through the Earth’s atmosphere, and the size of the particles of the Earth’s atmosphere is such that they scatter short-wave, blue, light from the solar spectrum, and long-wave, red-orange light passes through the atmosphere freely. This phase can be called new earth by analogy with the new moon. In the afternoon, the Sun slowly descends to the west, and the crescent of the Earth gradually grows and turns into a half by sunset.
Night time is coming. At lunar midnight, the Earth faces the Moon with its day side, the full disk of the Earth illuminates the lunar landscape with bluish-greenish light. This is how the blue Earth's atmosphere and green areas of the Earth change the reflected sunlight.
By the next sunrise, the Earth will again take the form of a half-disk.
RMR_astra writes:
In the black starry sky of the Moon, the Sun rises and sets, and the Earth, swaying slightly, stands in one place.
I'm not kidding. The earth may rise. It all depends on where the observer is on the surface of the Moon. And these sunrises and sunsets are connected with....
Right. With libration (swaying) of the Moon in latitude and longitude.
And the day lasts longer than a day
A lunar day lasts 14 earthly days, and the night lasts the same amount; a lunar day is equal to a lunar month. Why are the days so long? Why does the Moon rotate so slowly on its axis?
It once spun faster, but was slowed down by the Earth. The Earth causes a tidal wave in the Moon's body. The Moon rotated around its axis, and the tidal wave, which is always directed towards the Earth, rolled along the surface of the Moon in the direction opposite to its rotation.
Now the Moon rotates so that the tidal hump does not roll, but always “looks” at the Earth. Therefore, the shape of the Moon slightly resembles an egg, and therefore the Moon always faces the Earth with its more convex side.
Only about half of the Moon is visible from Earth, and Earthlings first saw what the opposite side looked like when the Soviet Luna 3 station transmitted an image of it to Earth.
How little we know even about the Moon. I stick to lunar calendar when working in the country, visiting the hairdresser. Resolve the question, dear RMR_astra.
If the Moon is always turned towards us in the same way, why then in the lunar calendar in different months Are there 28, 29 or 30 lunar days?
It is convenient to divide your question into two questions: is the side of the Moon facing us really equal to half of its surface, and how accurately does the lunar calendar describe its movement.
We have already noted that the movement of the Moon is very complex, therefore, as before, we will take into account only the main factors. The orbit of the moon is not a circle, but an ellipse, so it becomes possible to look beyond left side of the lunar disk, then beyond the right, so from the Earth not 0.5, but 0.6 shares of the lunar surface are accessible.
The period of the daily rotation of the Moon coincides with its complete revolution around the Earth relative to the stars (27.3 Earth days), and the phases of the Moon are determined by the complete revolution of the Moon around the Earth relative to the Sun. This period is slightly longer, since during one revolution the Moon, together with the Earth, manages to move along the Earth’s orbit (29.5 Earth days). Since these inaccuracies are not noticeable to the naked eye, as a first approximation it is assumed that half of the Moon is visible from the Earth.
The lunar calendar is based on a period of changing phases, contains 12 lunar months, and the length of the year is 355 days, that is, 10 days less than the solar calendar, which corresponds to agricultural seasons. Over time, the lunar and solar calendars diverged so much that, in order to bring them together, some countries added a 13th month to the lunar calendar (not every year), while others preferred to add days to some months. These calendar changes have virtually no effect on the correctness of determining the lunar phases and on the validity of the statement that the Moon faces the Earth with one side.
It should also be noted that the illumination of the earth's surface by the Sun is almost 1,000,000 times greater than by the full Moon.
I am not interested in predictions of either the lunar or astrological calendar, but in connection with your question, I read it on the Internet.
A scientific prediction differs from a pseudoscientific one in that in the first case it answers the questions “Why?”, “How?”, “What is the mechanism of influence?” etc. For example, BY STUDYING the movements of the Moon and the Earth, it is possible to predict when a solar eclipse will occur, in which areas it will be observed, how long it will last, what fraction of the Sun will be covered by the Moon.
In the second case, the listed questions do not even arise for either the authors or the users of their predictions. Because of misunderstanding, they say: “There must be something in this.”
But you are a thinking person, try to understand what the connection is between the Moon and your hair. If you explain it to me, I will be grateful to you.
Good afternoon, dear RMR_astra.
Thanks to you, I understood why a variety of information from the Internet is not absorbed. She is impersonal. And when the ray of knowledge is directed at you personally, it hits the target. Now the difference between the words “about half” and “exactly half” is clear.
Before your question, the lunar calendar was not in doubt at all. I know well gardeners who always adhere to the lunar calendar, and their fruits ripen faster than their neighbors. But this, of course, can be explained the best care and constant care. They even talk to plants and treat them as if they were alive.
The connection between the Moon and hair. If there really is no scientific explanation, then it is the concept of FAITH. Some patients recover after taking a placebo pacifier, so why not believe in the power of the waxing moon?
