The crescent moon is convex to the right in the evening. Movement and phases of the moon

Moon - natural satellite Earth. This is the closest celestial body to the Earth; it shines with reflected sunlight. The Moon moves around the Earth approximately in an elliptical orbit in the same direction as the Earth rotates around its axis. Therefore, we see the Moon moving among the stars towards the rotation of the sky. The direction of the Moon's movement is always the same - from west to east. For an observer on Earth, the Moon moves 13.2° per day.

The Moon completes its orbit around the Earth in 27.3 days ( sidereal month). And in the same time it makes one revolution around its axis, so the same hemisphere of the Moon always faces the Earth.

The movement of the Moon around the Earth is very complex, and its study is one of the most difficult problems of celestial mechanics. The apparent movement of the Moon is accompanied by a continuous change in its appearance - a change of phases. This happens because the Moon occupies various provisions relative to the Sun and Earth illuminating it. Lunar phase called the part of the lunar disk visible in sunlight.

Let's look at the phases of the moon, starting with the new moon. This phase occurs when the Moon passes between the Sun and the Earth and faces us with its dark side. The Moon is not visible at all from Earth.

After one or two days, a narrow bright crescent of the “young” Moon appears in the western sky and continues to grow. Sometimes it is noticeable against the sky (due to the dim grayish glow - the so-called ashen light Moon) and the rest of the lunar disk. The phenomenon of ashen light is explained by the fact that the lunar crescent is illuminated directly by the Sun, and the rest of the lunar surface is illuminated by scattered sunlight reflected by the Earth. After 7 days, the entire right half of the lunar disk will be visible - the first quarter phase. In this phase, the Moon rises during the day and is visible in the evening southern region sky and sets at night. Then the phase increases, and 14-15 days after the new moon, the Moon comes into opposition with the Sun. Her phase becomes complete, comes full moon. Sun rays illuminate the entire lunar hemisphere facing the Earth. The Full Moon rises at sunset, sets at sunrise, and is visible in the southern sky in the middle of the night.

After the full moon, the Moon gradually approaches the Sun from the west and is illuminated by it from the left. After about a week, the phase begins third, or last quarter. In this case, the Moon rises around midnight, by sunrise it is in the southern sky and sets during the day. With further approach of the Earth's satellite to the Sun, the waning phases of the Moon become crescent-shaped. The moon is visible only in the morning, shortly before sunrise, and sets during the daylight hours, before sunset. This time the narrow crescent of the Moon is convexly facing the east. Then the new moon comes again, and the Moon ceases to be visible in the sky.

About 29.5 days pass from one new moon to the next. This period of changing lunar phases is called synodic month. The synodic (or lunar) month is longer than the sidereal (or sidereal) month, since both the Moon and the Earth move in a forward direction through space.

02:32 am - Night problems

According to practical astronomy, lungs. For those who have forgotten physics, just use common sense.

1. As is known, in mid-latitudes there are mnemonic rules for determining the phase of the moon, for example, in Russian these are the Growing Moon and the Aging Moon (with the convexity of the sickle to the right and left, respectively).

Do these rules work in the middle latitudes of the southern hemisphere, or are some others needed there?

2. Many people saw on a tropical night (more precisely, near the equator) the crescent moon convex downward (“boat”). Which moon does it correspond to - growing or aging? Is there a sickle with a convex upwards (“bridge”)?

3. How can you tell if you see a sickle close to the equator whether it is growing or aging?

Comments:

2. There is no bridge, but I didn’t know the explanation for this fact until I read (and realized) that the moon’s orbit is approximately equatorial. Those. when viewed from the equator, the shaded part, the complement to the crescent, will always be “on top.”

3. It seems somehow tricky in the way the internal contour of the sickle is arranged (which is part of an ellipse, not a circle), I’ll think about it some more, perhaps.

if we were transported to the southern hemisphere, then we turned upside down relative to the current state and the moon
This means that everything will be the other way around. about left and right.

3. It is visible in the morning or in the evening.

By the way, we live on the 40th parallel, that is, still quite far from the equator, and the moon is already close to the boat. But there is no bridge, I can testify :)

As an illustration - from my photographs:

Moon in the evening over El Hierra - the westernmost island of the Canary archipelago, March 2010.

And this is the dark Moon covering the Sun - partial solar eclipse in Warsaw on January 4, 2011.

Early morning moon over a mountain shelter on the outskirts of Szklarska Poreba in the Polish Sudetes, January 2011.

A partial solar eclipse, it’s better to say (as is customary).

I thought about whether to specify in the questions that the sickle does not mean from an eclipse, but I decided not to complicate it.

Thanks for the photo.

2. There is no bridge, because the sun is below (below the horizon).

1. No, of course. The rule needs to be inverted.
2. It can be during the day if the Sun and Moon are visible at the same time.
3. Stretch your spatial imagination, imagine what it would look like in mid-latitudes northern hemisphere and use rule 1 :)

2. Apparently, it will still not be visible to the naked eye.

Of course, digital photography is not proof. But I have seen the day Moon with the naked eye many times.

I've seen it many times too.

This is not quite the same, because the feast of the sickle-“bridge” Sun will be (1) strictly above the Moon (closer to the zenith) (2) close to each other (a sickle, not a “half-loaf”, as in your photo).

With this combination, I don’t really believe what will be visible.

If we allow not only sickles, but also any “loaves”, then at the equator a situation is quite possible when the Sun has just set in the west, and the Moon is in the east, say, about 45 degrees above the horizon. Then we will see the “loaf”, bitten off from the bottom by about a third of the disk.

in mid-latitudes I saw the Moon quite often during the day - usually in the summer in the late afternoon or early morning. I haven't been in the tropics long enough to collect statistics and say whether it is visible there or not.

Basically, since it gets dark very quickly in the tropics, and the Moon is only visible when the Sun is low on the horizon, the interval when the Moon is visible is very short.

See response to Nick Sakwa nearby.

It seems to me that the bridge should be visible in the mountainous area. If the Sun is at the horizon and the light only breaks through a small valley between two mountains, then the Moon will already be visible (probably). Or, for example, if you are in a deep crater, surrounded on all sides high mountains-- the Moon can be seen above as a bridge.

1) The “growing - old” rule does not work in southern latitudes, it’s the other way around there.
2) The boat can be either growing or aging. The bridge, contrary to what previous speakers have said, does happen. It occurs in the first quarter phase of the afternoon, when the Sun has not yet set and is leaning towards the west, and the Moon has already risen in the east. It's hard to see - the Sun is blocking the young Moon. But you can see it if you try. In the last quarter - symmetrically. The aging Moon has not yet set and is leaning towards the west, and the Sun has already risen in the east.
3) The phase of the Moon is always convex to the Sun, since it is the Sun that illuminates it. If the Moon is east of the Sun (including one that has already set), it is growing, if it is to the west (including one that has not yet risen), it is aging. And if at midnight, it means around the full moon. It does not depend on the hemisphere.

I propose a super task at the end.
First solution 1, 2, 3.
1. For simplicity, let the observer be at the north/south pole, and the orbit of the moon and the equator of the Earth lie in the ecliptic plane. Then the Moon's journey from new moon to full moon and further to new moon looks like the Moon moving away from the Sun and then approaching the Sun on the other side, all in the plane of the horizon.
It is known about the Aging Moon that its crescent is turned like the letter C.
But it is obvious that the crescent of the Moon is convexly turned towards the Sun.
So, with north pole The path of the luminaries in the horizon plane can be depicted as follows:

after the new moon______________________before the new moon
) ☼___________________________________☼ (

Then with south pole everything will be upside down, the sickle will be in the other direction.

2. Let us again assume for simplicity that the orbit of the Moon and the Earth’s equator are in the ecliptic plane. Then, in the sky of the equator, the Moon will rise every day in the east, pass through the zenith and set in the west. If it is a sickle, it is convexly facing the Sun. If the Moon rises before the Sun, it will be a boat at sunrise and a bridge at sunset; if after the Sun, vice versa. From the figure for question 1 it is clear that after the new moon, if viewed from the north pole, the Moon is to the left of the Sun, so that with the visible movement of the luminaries from east to west, the Sun overtakes the Moon: it runs away from the Moon in the days after the new moon, and catches up with the Moon on the other side in the days before the next new moon. This means that after the new moon, for an observer at the equator, the Sun will rise, then the sickle-bridge; At sunset the Sun will set, then the crescent boat.

Here are all 4 variants of the sickle in the equatorial sky:
boat:
after sunset (=in the west) - in the days after the new moon (=waxing moon)
before sunrise (=in the east) - in the days before the new moon (=aging Moon)
bridge - in the two remaining combinations:
after sunrise (=in the east) - in the days after the new moon (=waxing moon)
before sunset (=in the west) - in the days before the new moon (=aging
The last two combinations are not night, but daytime. This means that only the boat is visible at night, namely after sunset - on the days of the Moon's growth, before sunrise - on the days of the Moon's aging. The bridge is visible only after sunrise or before sunset.

3. The answer happened in the previous paragraph.

Super task.
Sometimes the lunisolar tides reinforce each other with the greatest precision (and earthquakes occur more often during this period). How to determine these periods by observing the inclination of the crescent in the northern hemisphere? Hint: Now abandon the assumption that the Earth's equator and the Moon's orbit lie in the ecliptic plane.

The sun has just set. Against the background of the reddish dawn, a narrow shiny sickle emerges brightly, its hump turned towards the setting Sun. It doesn't take long to admire them. Soon it will follow the Sun below the horizon. At the same time they say: “A new moon is born.”

Photo: V.Ladinsky. A new moon was born.

The next day, at sunset, you will notice that the crescent has become wider, it is visible higher above the horizon and does not set so early. Every day the Moon seems to grow and at the same time moves away from the Sun further and further to the left (to the east). A week later, the Moon appears in the south in the evening in the form of a semicircle with a convexity to the right. Then they say: “The moon has reached its phase first quarter».

The best time of year to observe the young Moon in the Northern Hemisphere of the Earth is spring, when the crescent of the new Moon rises high above the horizon. In the first quarter phase, the Moon rises highest above the horizon in late winter - early spring.

In the following days, the Moon continues to grow, becomes larger than a semicircle and moves even further to the east, until after another week it becomes a full circle, i.e. will come full moon. While the Sun will go below the western horizon on the western side, the full Moon will begin to rise on the opposite, eastern side. By morning, both luminaries seem to change places: the appearance of the Sun in the east finds the full Moon setting in the west.

The full Moon moves highest above the horizon in the first half of winter, and during short periods summer nights it can be found around midnight low in the southern sky.

Photo: V.Ladinsky. Sunrise full moon July 21, 2005.

Then, day after day, the Moon rises later and later. It becomes more and more truncated, or damaged, but on the right side. A week after the full moon, you will not find the Moon in the sky in the evening. Only around midnight it appears in the east from behind the horizon and again in the form of a half circle, but now with its hump directed to the left. This last(or, as it is sometimes called, the third) quarter. In the morning, the semicircle of the Moon, with its hump facing to the rising sun, can be seen in the southern sky. A few days later, the narrow crescent of the Moon appears over the horizon in the east just before sunrise. And a week later, after the last quarter, the Moon completely ceases to be visible - it comes new moon; then it will appear again on the left side of the Sun: in the evening in the west and with its hump again to the right.

Most favorable time year for observations of the Moon in phases between the last quarter and the new moon is early autumn.

This is how the appearance of the Moon in the sky changes every four weeks, or more precisely, 29.5 days. This lunar, or synodic, month. It served as the basis for compiling a calendar in ancient times. Such moon calendar preserved among some eastern peoples to the present day.

The change in lunar phases can be summarized in the following table:

During the new moon, the Moon is between the Earth and the Sun and faces the Earth with its unlit side. In the first quarter, i.e. After a quarter of the Moon's revolution, half of its illuminated side faces the Earth. During a full moon, the Moon is on the opposite side to the Sun, and the entire illuminated side of the Moon faces the Earth, and we see it in a full circle. In the last quarter, we again see half of the illuminated side of the Moon from Earth. Now it is clear why the convex side of the crescent moon always faces the sun.

For several days after (or before) the new moon, you can observe, in addition to the bright crescent, the part of the Moon not illuminated by the Sun, but faintly visible. This phenomenon is called ashen light. This is the night surface of the Moon, illuminated only by solar rays reflected from the Earth.

Thus, the change in the phases of the Moon is explained by the fact that the Moon revolves around the Earth. The time it takes for the Moon to orbit around our planet is called sidereal month and is 27.3 days, which is less than 29.5 days, during which the phases of the Moon change. The reason for this phenomenon is the movement of the Earth itself. As it revolves around the Sun, the Earth carries with it its satellite, the Moon.

On a new moon, when the Moon is between the Earth and the Sun, it can block it from us, then a solar eclipse will occur. During a full moon, the Moon, being on the other side of the Earth, can fall into the shadow cast by our planet, then a lunar eclipse will occur. Eclipses do not occur every month because the Moon revolves around the Earth in a plane that does not coincide with the plane (the ecliptic plane) in which the Earth revolves around the Sun. The plane of the Moon's orbit is inclined to the plane of the ecliptic at an angle of 5° 9". Therefore, eclipses occur only when at the moment of the new moon (full moon) the Moon is near the ecliptic, otherwise its shadow falls “above” or “below” the Earth (or the earth’s shadow “ above" or "below" the Moon).

Phase is the ratio of the area of ​​the illuminated part of the disk celestial body to the area of ​​the entire disk. In the new moon phase Ф = 0.0, in the first and last quarter phase = 0.5, in the full moon phase = 1.0.

The mental line drawn through the tops of the horns of the crescent moon is called the line of horns. It is often said that the line of horns points to, or below, the point of south. Perpendicular to the line of the horns indicates the direction to the Sun.

If the horns of the lunar month are directed to the left, then the Moon is growing, if to the right, then it is aging. However, this rule is reversed when observing the Moon from the southern hemisphere of the Earth, as shown in the figure:

Tasks and questions:

1. The moon is at new moon. In what phase will the Earth be visible from the Moon? The earth will be in the “full earth” phase, because... the phases of the Moon when observed from the Earth and the phases of the Earth for a lunar observer change the other way around and are in antiphase.

2. Is the Earth visible from the Moon in “New Earth”? Yes, it is visible in the form of a crescent due to the fact that the Earth's atmosphere refracts sunlight.

3. On December 25 of such and such a year, the Moon was in the first quarter phase. In what phase will it be visible in a year? To solve this problem, let’s take the synodic month of the Moon, equal to approximately 29.5 days. Multiply 29.5 by 12 months and get 354 days. Subtract the resulting value from 365 (the number of days in a year) and get 11 days. Considering that the first quarter occurs after 7 - 8 days, then by adding the resulting value (11) to 7 (or 8), we obtain the age of the Moon in a year equal to 18 or 19 days. Thus, a year later the Moon will be in a phase between the full moon and the last quarter.

4. What time will the Moon culminate in the first quarter? The first quarter moon will culminate over the point south at approximately 6 p.m. local time.

Moon phases in 2012 Time indicated is Universal (MSK - 4 hours)

New moon	Full moon	Last quarter
	January 1, 2012 06:15:49	January 9, 2012 07:31:17	January 16, 2012 09:09:09
January 23, 2012 07:40:29	January 31, 2012 04:10:53	February 7, 2012 21:55:01	February 14, 2012 17:05:02
February 21, 2012 22:35:52	March 1, 2012 01:22:44	March 8, 2012 09:40:38	March 15, 2012 01:26:16
March 22, 2012 14:38:18	March 30, 2012 19:41:59	April 6, 2012 19:19:45	April 13, 2012 10:50:45
April 21, 2012 07:18:00	April 29, 2012 09:57:00	May 6, 2012 03:35:00	May 12, 2012 21:47:00
May 20, 2012 23:48:14	May 28, 2012 20:17:09	June 4, 2012 11:12:40	June 11, 2012 10:42:28
June 19, 2012 15:03:14	June 27, 2012 03:31:34	July 3, 2012 18:52:53	July 11, 2012 01:49:05
July 19, 2012 04:25:10	July 26, 2012 08:57:20	August 2, 2012 03:28:32	August 9, 2012 18:56:13
August 17, 2012 15:55:38	August 24, 2012 13:54:39	August 31, 2012 13:59:12	September 8, 2012 13:16:11
September 16, 2012 02:11:46	September 22, 2012 19:41:55	September 30, 2012 03:19:40	October 8, 2012 07:34:29
October 15, 2012 12:03:37	October 2012 03:33:07	October 29, 2012 19:50:39	November 7, 2012 00:36:54
November 13, 2012 22:09:08	November 20, 2012 14:32:33	November 28, 2012 14:47:10	December 6, 2012 15:32:39
December 13, 2012 08:42:41	December 20, 2012 05:20:11	December 28, 2012 10:22:21

In mid-latitudes, the Sun always rises in the eastern part of the sky, gradually rises above the horizon, reaches its highest position in the sky at noon, then begins to descend towards the horizon and sets in the western part of the sky. In the Northern Hemisphere, this movement occurs from left to right, and in the Southern Hemisphere, from right to left. An observer in the Northern Hemisphere of the Earth will see the Sun in the south, and one located in Southern Hemisphere- in the north. The daily path of the Sun in the sky is symmetrical relative to the north-south direction.

2. Can the Sun be observed at its zenith in Belarus? Why?

The sun is observed at its zenith in a belt limited by the following interval geographical latitude: $-23°27" \le φ \le 23°27".$ Belarus is located further north, so the Sun cannot be observed at its zenith in our country.

3. Why does the Moon always face the Earth with the same side?

The Moon completes its orbit around the Earth in 27.3 days. (sidereal month). And in the same time it makes one revolution around its axis, so the same hemisphere of the Moon always faces the Earth.

4. What is the difference between the sidereal and synodic months? What causes their different durations?

A synodic month is the period of time between two successive phases of the same name (for example, new moons), and it lasts 29.5 days.

A sidereal month is the period of the Moon's orbit around the Earth relative to the stars, and it lasts 27.3 days.

Various durations These months are due to the fact that the Earth does not rest in one place, but moves in its orbit. Therefore, in order for the previous configuration to be repeated and the synodic month to end, the Moon has to travel a greater distance in its orbit than to complete the sidereal month.

5. What is meant by the lunar phase? Describe the phases of the moon.

The lunar phase is the part of the lunar disk visible in sunlight.

Let's look at the phases of the moon, starting with new moon. This phase occurs when the Moon passes between the Sun and the Earth and faces us with its dark side. The Moon is not visible at all from Earth. After one or two days, a narrow bright crescent appears in the western sky and continues to grow. "young" Moon. In 7 days the entire right half of the lunar disk will be visible - the first quarter phase. Then the phase increases, and 14-15 days after the new moon, the Moon comes into opposition with the Sun. Its phase becomes complete, comes full moon. The sun's rays illuminate the entire lunar hemisphere facing the Earth. After the full moon, the Moon gradually approaches the Sun from the west and is illuminated by it from the left. In about a week it comes last quarter phase. Then the new moon comes again...

6. The crescent of the Moon is convex to the right and close to the horizon. Which side of the horizon is it on?

The moon is observed in the western part of the horizon.

7. Why do solar and lunar eclipses occur?

As they move along their orbits, the Earth and Moon from time to time line up with the Sun. If the Moon is close to the plane of the Earth's orbit, an eclipse occurs. When the Moon comes between the Earth and the Sun, a solar eclipse occurs, and when the Earth comes between the Sun and the Moon, a lunar eclipse occurs.

8. Describe total, partial and annular solar eclipses.

Passing between the Sun and the Earth, the small Moon cannot completely obscure the Earth. The solar disk will be entirely closed only to observers located inside the cone of the lunar shadow, the maximum diameter of which on the Earth's surface does not exceed 270 km. Only from here, from this relatively narrow area earth's surface where the shadow of the Moon falls will be visible total solar eclipse. In the same place where the penumbra of the Moon falls, inside the so-called lunar penumbra cone, it will be visible partial solar eclipse. If at the time of the eclipse the Moon, moving along its elliptical orbit, is located at a considerable distance from the Earth, then the visible disk of the Moon will be too small to completely cover the Sun. Then a shining rim of the solar disk will be observed around the dark disk of the Moon. This - annular eclipse.