If you watch the Moon for at least a few days, you will find that it is not always visible to us as a circle. The full disk of the moon first begins to decrease, until they cease to be visible at all. Then the Moon begins to grow until it becomes again a full disk. The entire cycle takes about 29.5 days.
The lunar cycle consists of 4 phases. The phase of the moon is the ratio of the area of the illuminated side of the visible disk of the moon the whole of its area. The transitions between these phases occur in the following order:
- New moon - when the moon disk is not visible at all;
- First quarter - see the right half of the lunar disk,
- Full moon - when the moon fully visible disk
- The last quarter is visible to the left half of the lunar disk.
What linked the changing phases of the moon?
The moon itself does not light, it reflects the incident sunlight. And still the Moon revolves around the Earth. The phases of the moon reflect the movement of the moon around the Earth, which is accompanied by a change in the appearance of our satellite.
1 - the moon, 3 - first quarter, a 5 - full moon 7 - the last quarter.
In new moon, the Moon passes between the Sun and Earth. The Earth turned dark, not lit by the Sun side of the moon (1). However, at this time, the disk of the moon is lit special, ashy light. This phenomenon is caused by sunlight reflected by the Earth to the moon. That is, the rays of ashen moonlight pass the following way: the Sun --> Earth --> Moon --> the eye of the observer on Earth.
Two days after the new moon in the evening sky in the West shortly after sunset, you receive the thin Crescent of a new moon (2).
Within seven days after the new moon waxing Moon is visible in the form of a semicircle in the West or South-West shortly after sunset (3). The moon is 90° East of the Sun and is visible in the evenings and in the first half of the night.
Through 14 days after the new moon comes the full moon (5). The moon is in opposition with the Sun, and the Earth turned all the illuminated hemisphere of the moon. At full moon the Moon is visible all night, the Moon rises at sunset, sets - during sunrise.
A week after the full moon, old Moon appears before us in the phase of its last quarter, in the form of a semicircle (7). At this time, to the Earth-facing half lit and half dark hemisphere of the moon. The moon is visible in the East before sunrise, in the second half of the night.
Thus, the changing phases of the moon can be explained by two reasons: first, the Moon is dark, opaque ball illuminated by the Sun, and, secondly, the Moon goes around the Earth.
Did you know that...
In different phases of the moon its rise (i.e. the beginning of a lunar day) is observed at different times of the day.
- In the first phase the Moon rises simultaneously with the rising of the Sun or immediately after.
- In the second phase the Moon rises at noon or shortly after.
- In the third phase the Moon rises simultaneously with the sunset or shortly after.
- In the fourth phase of the Moon rises at midnight or shortly after.
By the way...
You can simulate the phases of the moon at home. In the evening, turn off the overhead light, turn nastalique the lamp and grab the ball. Stretch your arms out with the ball in front of him. You are the Earth, the ball is the Moon, and the lamp is the Sun.
Stand face to the lamp. It covers the half of the ball, which is on the other side of you. You see only the dark half of the ball. This new moon.
Then stand sideways to the lamp. Now the lamp illuminates only half of your moon is a quarter.
The situation of the full moon occurs when you are standing with his back to the lamp. The ball is in the opposite side from the lamp, and you turned all the lit side of the ball.
(Incidentally, in the latter case, you can completely obscure the ball, and then the lamp also will not cover! Is this possible? Yes! This phenomenon is called a lunar Eclipse. During a lunar Eclipse the Sun, Earth and Moon are aligned, and the Earth is between the Moon and the Sun and obscure the moon. Similarly, when the Moon is between the sun and the Earth on one line, the new moon is a solar Eclipse. Eclipses are rare because the Moon around the Earth and the Earth around the Sun rotate in different planes.).
By the way...
How to distinguish the rising moon from the waning? Very easy! If the month is similar to the letter "With", he means Withtrausi, so this last quarter. And if it is turned in the opposite direction, putting him mentally left stick, get the letter "P"which will tell us what month now - Rastushi, i.e. this is the first quarter!
Growing month is usually observed at night, and aging in the morning.