On December 4th, something grandiose happens in the sky: a total solar eclipse. The “black sun” cannot be observed everywhere, however.
Munich – A cruise to the Antarctic * is a dream for many travel enthusiasts. Now there is a spectacular occasion to fulfill this wish: the total solar eclipse on December 4th, 2021. The “black sun” can only be marveled at on the southernmost and coldest continent on earth. At the beginning of December, the area around the South Pole can certainly be approached by cruise ships. Land-based observation from Orcadas Station is even possible from the South Orkney Islands. However, the sun is only eclipsed there for 50 seconds.
Total solar eclipse: The “black sun” can even stop wars
What goes on in such eclipses has long remained a mystery. The two Chinese astronomers Hi and Ho are said to have been beheaded for not predicting a solar eclipse. Wars were also stopped by blacking out the sun. The Medes’ army held on May 28, 585 BC. silent for six minutes. The battle-hardened warriors were stopped by fear of the enemy Lydians, but by a sudden darkness. Both sides believed that gods would be angry and made peace. The source is the Greek historian Herodotus,
Total solar eclipse: It follows a meticulous plan
Today we can calculate such a spectacle meticulously. On December 4th at 05:29:16 UT ( U niversal T ime, German universal time) the partial phase of eclipse begins in the southern Atlantic. The moon’s shadow on Earth wanders and sweeps over western Antarctica. It is getting dark and even cooler, only the solar corona shines in the sky. This totality can be admired for the longest on the southern edge of the Weddell Sea: 1 minute 54 seconds. The central eclipse ends at 08:03:47 UT at the Ross Shelf ice.
Total solar eclipse: how can the moon’s shadow slip through under the earth?
How did this scenario come about? At first, experts notice an astronomical paradox. The shadow path is moving in the “wrong” direction – east to west. Usually it wanders from west to east across the globe. The opposite direction comes about because the time of the eclipse is close to the summer solstice in the southern hemisphere. This creates an extremely bizarre earth-sun-moon constellation. The umbra cone slips through under the South Pole. It extends under the South Pole and meets the earth on the far side from the sun.
Total solar eclipse: only a “cosmic coincidence” makes it possible at all
Aside from the wrong direction, December 4th is the same scenario as any other solar eclipse. The sun, earth and moon must be in a line for the moon to cover the sun. But that only works when there is a new moon. And only because the cosmos happened to set it up like this: the sun is 400 times larger than the moon and 400 times further away. Therefore the two celestial bodies appear almost exactly the same size. Only in this way is it possible for the lunar disk to completely cover the solar disk during a total solar eclipse, like two coins placed on top of one another.
Total Solar Eclipse: How Many Are There Each Year?
If the lunar orbit * were exactly in the plane of the earth’s orbit, a solar eclipse would take place every month at a new moon. But the lunar orbit is inclined in relation to the plane of the earth’s orbit. So the moon is sometimes closer to the earth and sometimes further away. Therefore, the moon’s shadow mostly misses the earth. In order for the moon to fully hit the sun, it also has to cross the apparent path of the sun in the sky when there is a new moon. The double combination allows a maximum of five solar eclipses anywhere on earth per year.
Total solar eclipse: when can you experience a “black sun” in Germany?
Depending on the degree of coverage of sunlight by the moon, there is a total or partial solar eclipse. In a third of the cases, the moon does not “hit” exactly and therefore only covers part of the sun. Such a scarce sun can be seen on December 4th at the southern tips of the continents South America, Africa and Australia as well as New Zealand’s South Island. In Germany there is the next chance to observe a partial solar eclipse on October 25, 2022. A total solar eclipse will not take place again until August 12, 2026 over Europe and not until September 3, 2081 over Germany. For the best view you only need then to travel to the Lake Constance area. * Merkur.de is an offer from IPPEN.MEDIA
