Besides the sun, the moon is the most conspicuous celestial body visible from earth. It orbits the earth at a distance of about 384,000 kilometers and sometimes comes a little closer to the blue planet, sometimes it is further away. This is due to the elliptical shape of the orbit, which is generally the rule for celestial bodies in a gravitational field. Perfect circular orbits, on the other hand, are rare. All orbit forms are based on the so-called conservation of angular momentum, a conserved quantity of physics.

The ideal shape of the orbital ellipse of the earth companion is influenced to a greater or lesser extent by perturbation effects. These are, for example, the flattening of the earth, the distance-dependent gravitational effects of the sun and planets and an inhomogeneous mass distribution in the earth’s interior. Deep below the Earth’s crust, Earth’s mass is unevenly distributed, so some regions of our planet’s gravitational pull are slightly stronger than others.

With a diameter of 3,476 kilometers, the moon is the fifth largest of the 205 moons that all the planets in our solar system have. Only three of the four large moons of Jupiter and Titan, a moon of Saturn, are larger. The earth companion has significantly less mass than our blue planet and exerts only a sixth of the earth’s gravitational pull. If a human weighing 60 kilograms stood on the moon, he would feel as if he weighed 10 kilograms and could therefore jump much higher and further.

The same side of the moon is always seen from the surface of the earth. This is because the celestial body rotates on itself exactly once while orbiting our planet once. The Soviet moon probe Lunik III transmitted the first images of the back in 1959, but people first saw the side facing away from Earth with their own eyes when the crew of Apollo 8 orbited the Earth companion at Christmas 1968.

The moon can sometimes be seen as a crescent, sometimes only half and sometimes as a luminous, complete disc. “The moon is called a full moon when its side facing the earth faces the sun and is therefore fully illuminated,” explains Dr. Manfred Gaida, astronomer and research associate at the German Aerospace Center space travel (DLR) in Bonn-Oberkassel. “Most of the time, the moon is spatially slightly above or below the plane in which the earth orbits the sun.” Full moon is only possible at night, since the moon and sun have to be on opposite sides of the globe. Therefore, the full moon rises on the horizon just as the sun sets on the other side.

In many cultures, each full moon of the year has a different name. This was also the case in Central Europe for a long time, which is why different names have survived to this day.

The list includes the old German names and the names that the North American Algonquin tribe gave to the full moon.

The so-called phases of the moon have determined people’s lives for many centuries. For example, they formed the basis for agricultural activities and for dividing the year into months. Special powers are also attributed to the full moon. For example, Christmas trees felled during the full moon should keep their needles for a very long time.

The full moon is one of the four phases of the moon. The sun and the companions of the earth stand in opposition to each other. Seen from the surface of the earth, they are therefore in opposite directions. In exactly this constellation, the side of the satellite that is facing us is completely illuminated by the sun and reaches its maximum brightness. an in winter When the sky is clear, the frequently occurring, high full moon can even illuminate the earth so brightly that colors can be perceived with the human eye. The brightness is up to 0.25 lux and thus about 250 times that of a starry new moon night.

During its orbit around the earth, we can see different amounts of our heavenly companion. Depending on the constellation, there is a full or new moon. Occasionally, phenomena such as the super moon can also be observed. So-called lunar calendars provide an overview of the phases of the moon.

Some people are only interested in knowing when to see a full, brightly lit disk of the moon in the sky just out of curiosity. Others, on the other hand, base everyday tasks such as cutting their hair or certain gardening tasks on the phases of the moon. Many people also believe that they sleep less well when the moon is full.

According to the lunar calendar, the dates for the year 2023 are on the following days:

The times correspond to the applicable Central European Time or Central European Summertime.

As a rule, the phenomenon occurs only once a month. “The full moon phase repeats itself approximately every 29.5 days,” explains Dr. Manfred Gaida from DLR. The period from one full moon to the next is called the synodic period of the Earth’s satellite. “This orbital period plays a role in all calendars that are not purely solar calendars. An example is the Gregorian calendarin which the course of the moon is relevant for determining the annual date of Easter.”

The satellite circles our planet on an elliptical orbit and after around 29.5 days (more precisely: 29 days, 12 hours and 43 minutes) it returns to its starting position in relation to the sun. Astronomers also refer to the variable period of time for this orbit as the lunation or synodic period.

The duration of the lunation is usually measured from one new moon to the next. It can differ by more than three hours compared to the previous lunar cycle, over a decade there are also differences of more than 13 hours. The average value for a lunation is 29.53 days and is also called a synodic month. The full moon also returns approximately every 29.53 days.

The phases of the moon occur regardless of the distance of the satellite in its orbit from the earth. “Because the moon moves around the earth in a slightly elliptical orbit, the distance between the earth and the moon varies. To be more precise, between the centers of both celestial bodies,” explains Dr. Manfred Gaida from DLR. “This means that the moon is sometimes closer and sometimes further away from us over the course of a so-called anomalistic month of 27.5 days.” The minimum is 356,400 kilometers and the maximum is 406,700 kilometers. “If the full moon phase falls in the period in which the distance is minimal, we have been talking about a super moon for some time, since the apparent size and brightness of the earth’s satellite then reach maximum values,” the expert describes the phenomenon.

However, the difference in the values ​​of a super moon to those of a far moon can hardly be seen with the naked eye. “As far as the proportions are concerned, it’s like looking at a one and a two euro coin in a row on a white wall 2.70 meters away and trying to tell the difference,” says Dr. Manfred Gaida a vivid example. The difference is hardly noticeable to observers with the naked eye. Only photos reveal the fluctuations in the full moon diameter.