In its orbit around the Earth, the Moon is especially close to us several times a year. This promises a particularly large and bright moonlight in the night sky. But while this effect is rarely seen with the naked eye, Super Moon amazes many viewers. In fact, it is more due to a different effect.
He is referred to again and again: Super Moon. This satellite is said to appear unusually large in the sky at certain times of the year. If you – assuming good weather – go out and look at the moon, you will be really surprised. The full moon orbits majestically on the horizon.
Especially when the moon is close to us
In fact, “Super Moon” is not a historical or astronomical term or a scientific term in general. On the contrary, it was first written by an astrologer, Richard Knoll, in 1979 about a super moon that must have caused earthquakes and volcanic eruptions – that is, the full moon or the moon whenever the satellite is closest to the new age.
But while Knoll’s considerations are not based on scientific principles, they cannot be completely ruled out. This is because the wave forces of the Moon and Sun not only lead to emission and flow, but also to the motions of the Earth’s crust. If the Sun, Earth and Moon are almost in a straight line, the wave forces of the Sun and Moon are added and particularly strong spring waves occur. Floods, often referred to as spring waves, are 20 percent higher than normal floods. In fact, based on an analysis of more than 10,000 earthquakes, a team led by geologist Satoshi Aid showed in 2016 that strong earthquakes are growing parallel to the spring waves.
The Moon does not move in a circular orbit, but because it is in a clear elliptical orbit around the Earth, not all spring waves are the same. The distance between the Earth’s satellite and our planet varies from 356 400 to 406 700 kilometers. Therefore, it is clear that the effects of the waves are stronger when the Moon is closer to the Earth during the spring waves. However, this influence is very small: on average, spring waves are two percent stronger when the Moon is closer to the Earth. Accordingly, the connection between Super Moon and earthquakes has not yet been proven.
Large and bright
Nevertheless, the concept of Supermoon has been used more and more in recent years – although different from what Knoll originally intended: today the term does not refer to the effects of a nearby moon due to earthquakes or volcanic eruptions. Instead, only the full moon and the corresponding magnitude and brightness of the Earth’s satellite in the night sky are indicated. This is because when the Moon is closer to the Earth, the apparent diameter of the Moon is up to 14 percent larger than the Moon farthest from the Earth – called the Mini Moon. With the large moon occupying a large area in the night sky, the brightness of the Earth’s satellite also increases. The moon is 30 percent brighter near the earth than it is far away.
However, these are extreme values. The Moon’s orbit is not adjusted in any way, but will vary due to the Sun’s gravitational pull and larger planets. The distance between the Moon and the Earth at Perigee, the closest point to Earth in each orbit, varies from 356,400 to 370,400 kilometers. Theoretically possible extreme values therefore rarely occur. This begs the question of whether a full moon is considered a supermoon. Knoll has changed his definition over and over again for decades – now he uses the arbitrarily selected distance of less than 368,630 kilometers as a limit with a full moon.
Only the nearby full moon is a supermoon
That means there are two to four super moons every year. On April 27, 2021, the satellite will be 357,378 kilometers from Earth. On the next lunar eclipse on May 26, the Moon will be 357 309 kilometers closer to Earth – so a month later there will be the next super moon.
Another criterion that is often used is that the exact time of the moon and the time closest to the earth fall overnight. But this definition depends on the location of the observer: there is a full moon in the mornings of April 27, 2021 in Germany, but it does not occur close to Earth until the evening – i.e. the next night. Accordingly, it will be a super moon in the United States, but not in Germany. With the moon on May 26th, this is the other way around.
A useful observation?
Whether or not a particular moon is “super” is debatable. The phenomenon of “Super Moon” has no special scientific significance. But wouldn’t it still be worth seeing if the Earth’s satellite is particularly close to us? After all, the differences in apparent size and brightness are quite substantial. In fact, in the night sky, the naked eye cannot see because there are no objects to compare the differences between an ordinary moon and a super moon. A super moon high in the sky does not look very different to the viewer than any other moon.
Nevertheless, triggered by reports of a supermoon, many go outside in the evening and marvel at its magnitude when they see the Earth’s satellite near the horizon after its rise. However, the sheer size of the moon on the horizon is based on a completely different phenomenon: an optical illusion leaves it The moon is large near the horizon They appear to be high in the sky. So this has nothing to do with Super Moon.