What are the phases of the Moon?

We explain what they are and what are the phases of the Moon, their causes and impact in different cultures from Antiquity to today.

1. What are the phases of the Moon?

Lunar phase or phases of the moon are apparent changes of the visible portion of the moon , depending on how is illuminated by its position on the Earth and the Sun..

It is not about real changes in the nature of our only satellite, but about its relative position and its illumination, thus allowing us to observe more or less of its surface with the naked eye. To each position, thus, we give the name of a phase. Following these moon phases, the human being has created the lunar calendar.

The phases of the Moon make up, in its entirety, a 28-day cycle that we know as a lunar cycle or lunar cycle, which goes from the total illumination of the Moon to its total concealment. It has nothing to do with lunar eclipses , although the latter can reproduce certain phases artificially.

The explanation of this lunar cycle has to do with the orbit of the Moon around our planet, which culminates in its entirety every four weeks. This is known as sidereal month.

At the same time, and since the Moon lacks its own brightness, the illuminated portion of the Moon varies depending on how exposed it is to the Sun, although the face that the Moon offers us is always the same.

1. What are the phases of the moon?

The lunar cycle consists of eight phases, which are repeated from the first to the last.

• New moon or black moon . In the initial stage of the cycle it is that of the Moon the part illuminated by the Sun, it is not visible from Earth. In these cases the Moon can only be observed during solar eclipses . From this phase, the moon “grows” in apparent brightness.
• Crescent moon . The first appearance of the Moon in the traditional sky, two days after the previous phase, is like a small scythe of light, from its right side in the northern hemisphere and its left side in the southern hemisphere. This moon can be seen at times of day.
• Crescent . Four days after the previous phase, the Moon appears with half of its circumference illuminated and the other half in shadows (again, half illuminated will be right in the northern hemisphere and left in the southern hemisphere). This phase can be seen at noon or midnight.
• Crescent gibbous moon . The darkened half of the previous phase gradually lights up, as it acquires a convex shape on both sides.
• Full moon . The entire lunar circle is in this enlightened phase, so we can see it in its fullness. This total appearance marks the middle of the lunar month (14 days, 18 hours, 21 minutes and 36 seconds).
• Waning gibbous moon . After the full moon has passed, the “decrease” of the lunar brightness begins, again showing a concave appearance as it darkens.
• Waning quarter . A phase similar to the crescent room, in which the Moon is illuminated in its middle, only in the opposite direction. The moon can be seen in the sky during the morning hours.
• Waning moon . Also known as “waning crescent” or “old moon”, it is similar to the crescent moon, but in the opposite direction. It can be seen only at dawn, in the form of a small scythe of light.

3. Importance of the phases of the moon

The phases of the Moon are part of the astronomical phenomena that humanity has observed since ancient times, and on the basis of which it has set numerous calendars.

The lunar calendars were widely used by ancient cultures such as the Egyptian or the Babylonian. They inspired numerous myths and legends , which offered explanations about the appearance and disappearance of the Moon. Also its apparent coincidence with the feminine menstrual cycle motivated the moon to be assimilated with the feminine in numerous cultures.

Thus, according to popular culture, the lunar phases could influence growth, whether of crops, human hair and even the development of pregnancy and childbirth.