I have been writing here about each of the full moons and what they mean in different cultures.  There must be an interest in the topic because they are consistently in the top posts for the site. In looking at my lunar calendar for the upcoming month, it occurred to me that there are probably some readers who don’t really know what the difference is between a full moon and a new moon.

We have a new moon coming up on October 18th.

newmoonTo astronomers, the phrase “new moon” means the lunar phase that occurs when the Moon, in its monthly orbital motion around Earth, lies between the Earth and the Sun. Therefore, it is said that it is “in conjunction” with the Sun as seen from Earth.

The dark (unilluminated) portion of the Moon faces almost directly towards us on  Earth, so the Moon is not visible to the naked eye.

If you search online, you may find photos that address the original meaning of the phrase new moon. That would be when first visible crescent of the Moon is seen.

That is a rather imprecise event because it takes place over the western horizon in a brief period between sunset and moonset. Therefore the exact time/date of this appearance would be based on your geographical location.

So, to be astronomical, this “dark moon” occurs when the Moon is invisible from the Earth. That moment when it is in conjunction does not depend on location.

Culturally, the first crescent marks the beginning of the month in lunar calendars such as the Muslim calendar, and in lunisolar calendars such as the Hebrew calendar, Hindu calendars, and Buddhist calendar. In the Chinese calendar, the beginning of the month is marked by the dark moon.

In the Hindu (Indian) calender, it is believed that new moons can create negative changes in the mental plane. The goddess Kali is worshiped on new moon night to relax these fluctuations.

Some Chinese Buddhists keep a vegetarian diet on the new moon and full moon each month.

The new moon signifies the start of every Jewish month, and is considered an important date and minor holiday in the Hebrew calendar.

The new moon is also an important event in the neopagan, nature-based religion, Wicca.  Each full moon, and in some cases a new moon, is marked with a ritual called an Esbat.

In astrology, the casting of an astrological chart or horoscope is actually a representation of celestial entities – the position of the Sun, Moon, and planets – at the moment of the event (such as a birth).

The proper English name for Earth’s natural satellite is, simply, the Moon (capitalized). Moon is a Germanic word, related to the Latin mensis (month).  In English, the word moon exclusively meant Earth’s moon until 1665. Then,  the word was extended to refer to the recently discovered natural satellites of other planets, which were given distinct names in order to avoid confusion.


lunar libration