The closest giant full moon (supermoon) this year will be seen in the skies of the Kingdom and the Arab world on Wednesday.
It will coincide with a total eclipse for the first time in two and a half years, but the eclipse will not be seen in the Arab world because it will occur during the day.
Majed Abu Zahra, president of the Astronomical Society in Jeddah, said that a moon is described as a supermoon — whether a new moon or a full moon — when the distance between the center of the moon and the center of the earth is within 362,146 km. The scientific term for this moon is “perigee syzygy,” meaning that the moon reaches the nearest point to Earth.
The giant moon will reach the moment of completion at 2:14 p.m. Saudi time. It will be at a distance of 357,461 km after 9 hours and 24 minutes of its arrival at the perigee point. This synchronization will make its apparent size greater by about 14 percent and its illumination will be about 30 percent greater than the smallest full moon.
Abu Zahra said that the supermoon will rise after sunset from the southeastern horizon and will be orange due to the components of the atmosphere around the Earth, which will scatter the white light reflected from the moon. The colors of the blue spectrum will disperse and the colors of the red spectrum will remain. After the moon rises and moves further from the horizon, it will appear in its usual silver-white color.
He said that the supermoon is more “attractive” than the perigee. At the same time, he said, it gives the wrong impression that the supermoon will be much larger. In reality the supermoon does not appear to be larger than the normal full moon to the naked eye. Experienced observers, however, can spot the difference.
Abu Zahra explained that the supermoon will not have an effect on the globe except for on the tides. Every month on the day of a full moon, the Earth, the moon, and the sun are aligned, causing a wide tide. The high tide rises and falls more significantly on a supermoon night. And given that the full moon will be near the perigee, the tide will result in a phenomenon called a perihelion high tide.
“Given the limited influence of the supermoon, it will not affect the internal energy balance of our planet because the tides occur daily, so an increase in geological activity or unusual weather conditions is not expected,” he said.