For How Long Does A Full Moon Last

For How Long Does A Full Moon Last

A Full moon is recognizable by its almost perfect spherical shape. It occurs in the middle of the lunar cycle. Technically speaking, the Full moon only lasts for about a second or so. This distinction cannot be seen with the naked eye though. Without the aid of a telescope, it is hard for humans to distinguish between a moon that is 100% illuminated and a moon that is 99.9% illuminated. So while the Moon may only be 100% full for about one minute, it looks �full� for about three days.

The lunar cycles consider the moon to be a Waxing Gibbous when it is 95% illuminated. This changes to a Full moon when it is 100% illuminated, and back to a Waning Gibbous when it fades to 95% illumination once again. The time between these phases of Waxing Gibbous and Waning Gibbous can vary, but it is usually around 4 days total.

So what exactly is a Full moon if it can�t be seen without the aid of a telescope? A Full moon occurs when the Moon is on the exact opposite side of the Earth from the Sun. When the Moon is in opposition from the Sun, it appears fully illuminated. One half of the Moon is always illuminated, but only parts of that half can be seen from the Earth, depending on where the Moon is. Similarly, one half of the Earth is always illuminated by the Sun, but there are periods of darkness on one hemisphere while the other hemisphere experiences daylight.

Most people think of a Full moon as at least lighting up the sky for a full night. This is not precise however. The Moon viewed from Earth is constantly becoming larger or smaller, but these minor alterations are only noticeable with the help of equipment. Its absolute maximum size, and therefore a Full moon, happens when it stops expanding and is about to begin retracting. In this instance, the tangent slope is equal to zero. By this technical definition, only about half of these real Full moons are visible at all. The other half occur during the day and are therefore below the horizon. Many almanacs list the Full moon by its exact time as well as date. However, some calendars just list the day. These reports can potentially be off by a day depending on the time zone and location that they were intended for.

It is tradition to name each Full moon. For example, the Full moon that typically occurs in January is called the Old Moon in the English language. The early Spring moon, typically in April, is known as the Egg Moon, and so on. Of course, names differ depending on cultures. A Blue moon is attributed to an extra full moon in the season, so the fourth Full moon of a season is a Blue moon since there are usually only three. There are 12.37 Full moons in a year, so a Blue moon must occur on average every 2.7 years.

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