Moon phase, weather, shape of the moon

From the new moon to the full moon and then to the new moon, it is a cycle of moon phase change. The average period is 29.53 days, which is called Wang Shuoyue, that is, the movement period of the moon's appearance relative to the solar horizon. It is the source of calendar months and weeks. The months in the China lunar calendar are based on the new moon. The new moon every month is the first day of the first lunar month, which looks like the fifteenth and sixteenth. Now we celebrate the Spring Festival, Dragon Boat Festival, Double Ninth Festival and Mid-Autumn Festival, all of which are determined according to the lunar calendar.

Compared with stars, the moon's movement period is about 27.3 days, which is called sidereal moon, that is, during this time, it runs 360 degrees in space. The reason why the moon is longer than the sidereal moon is that when the moon revolves around the earth, the earth revolves around the sun. A Wang Shuo moon revolves around (360+360 * 29.53/365.24) = 389.11degree (revolution only revolves around 360 degrees). So a sidereal month is about 29.53 * 360/389.11= 27.32 days.

There is an included angle of 5 degrees between the orbital plane of the moon around the earth (ecliptic plane) and the orbital plane of the earth around the sun (ecliptic plane), so at the new moon or full moon, the moon, the earth and the sun are often not a straight line. When there is a straight line between the earth and the sun in a month, a solar eclipse (at new moon) or a lunar eclipse (at full moon) can be observed. It is precisely because of this 5-degree tilt that there are new moons and full moons every month, but there is no eclipse every month.

crescent

The longitude difference between the sun and the moon is 0 degrees. At this time, the moon is located between the earth and the sun, with its dark side facing the earth and appearing almost at the same time as the sun, so it can't be seen on the ground. This is the new moon, also known as the "new moon", which is the first day of the lunar calendar.

first quarter moon

The moon keeps spinning forward. On the eighth day of the seventh lunar month, the longitude difference is 90, the sun sets and the moon is already overhead. It didn't fall until midnight. At this time, half of the moon illuminated by the sun is just for you to see, which is called "winding".

Full moon; The baby is one month old.

On the fifteenth and sixteenth day of the lunar calendar, the moon turns to the other side of the earth with a longitude difference of 180. At this time, the earth is between the sun and the moon, and the half moon illuminated by the sun is just facing the earth. At this time, we see the full moon, or "looking". Because the moon is just opposite to the sun, the sun sets in the west and the moon rises in the east. When the moon sets, the sun rises in the east, and you can see the bright moon all night.

last quarter

After the full moon, the moon rises later every day, and the bright part of the moon gets smaller every day. By the 23rd day of the lunar calendar, the longitude difference is 270. The full moon is half lost, and then half a moon only appears in the eastern sky in the middle of the night, which is the "lower chord".

Near the end of the month, the moon will rotate between the earth and the sun again, and the waning moon will rise in the east shortly before sunrise. On the first day of next month, there will be a new moon and a new cycle will begin.

The phase of the moon is calculated by the difference between the sun and the moon (the following degrees are the difference between the sun and the moon), and * * * is divided into eight types:

New moon (the first day of the lunar calendar, the new moon): 0 degrees;

Emei month (usually around the second day of February-around the seventh day of July): 0-90 degrees;

First quarter moon (around the eighth day of the lunar calendar): 90 degrees;

Full moon (around the ninth day of the ninth lunar month-around the fourteenth lunar month): 90 degrees-180 degrees;

Full moon (full moon, 15th or 16th lunar month): 180 degrees;

Full moon (around the 16th lunar month-around the 23rd lunar month): 180 -270 degrees;

First quarter moon (around the 23rd lunar month): 270 degrees;

The waning moon (around the 24th day of the lunar calendar-the end of the month): 270 degrees-360 degrees;

In addition, the last day of the lunar month is called the dark day, that is, the moon is not seen;

There are mainly four kinds of moon phases: new moon (the first day of the lunar calendar), first quarter moon (around the eighth day of the lunar calendar), full moon (around the fifteenth day of the lunar calendar) and last quarter moon (around the 23rd day of the lunar calendar), all of which have definite occurrence times and are calculated by precise orbit calculation.

A formula (easy to remember): up to the west and down to the east-meaning: the first quarter moon appears in the first half of the lunar calendar, and the moon faces west and is located in the western half of the sky; The last quarter moon appears in the second half of the lunar calendar. The moon faces east and is located in the eastern half of the sky.

The phase of the moon is related to the tide of the ocean, because the tide is directly related to the gravity of the moon, for example, a full moon will cause a spring tide.

Tidal changes have a direct impact on people's lives, such as military affairs, tourism, ocean navigation, marine fisheries, mariculture, marine engineering, scientific experiments and various coastal production activities.