On the eve of the partial eclipse of the Sun, on Tuesday, October 25, there is great excitement among amateur astronomers and lovers of this discipline.
In order to observe this wonderful celestial phenomenon, it is necessary to be in a specific place on the planet, and on that specific date when at least three astronomical conditions for the occurrence of an eclipse have been met. And with that, of course, that you are lucky with the clouds.
Every eclipse or eclipse occurs when the Moon is between the Earth and the Sun, so that it partially or “completely” obscures the image of our star, and its shadow falls somewhere on the surface of the planet.
Depending on whether you happened to be right there, in the moon’s shadow or in a much wider, surrounding penumbra, called the umbra and penumbra, you will see the Sun’s disk obscured completely or only partially, as will be the case on Tuesday, October 25.
Unfortunately, most of us will not see the arrival of the umbra just above us and the total eclipse, because it is expected in the year when today’s newborns will be preparing for retirement, that is, on September 3, 2081.
Why is it so? Why don’t solar eclipses happen more often? Once a month, for example, every new moon?
Let’s think about the changes of the moon, about how during a conditionally speaking period of 29 days, the Earth’s satellite changes its shape and names – new, first quarter, full and last quarter. No matter what we call them, the moons would not occur in that way if the Moon did not revolve around the Earth and occupy different positions in relation to the Sun, and therefore be illuminated in various ways. And when it is young, invisible, the Moon is actually unlit for us because it stands between the Sun and the Earth, and its dark side is facing us.
But? But, if once a month, at every new moon, the Moon is between the Sun and the Earth, why doesn’t it block the star for the observers and they don’t see the eclipse?
The answer lies in the position of the Moon’s orbit around the Earth. Perhaps you did not know, but it is not in the same plane as the Earth orbits the Sun. For reasons still insufficiently explained, the Moon’s orbit is tilted at an angle slightly greater than 5 degrees relative to the plane of the Earth’s orbit around the Sun. That is why the shadow cast by the Moon “misses” the planet almost always, except when it is found in those places where the plane of the Moon intersects the plane of the Earth’s orbit. Then all three bodies – the Sun, the Moon and the Earth – will be aligned in a line. And then there are eclipses – solar and, on the other hand, lunar (when the Earth hides the Sun).
During the year, 2 to 5 solar eclipses can occur. However, not all of them are total because everything can happen for a total eclipse, but the Moon at that time can be in its elliptical orbit too far to completely cover the Sun even when it completely “enters” its image. That is why there are several types of eclipses. By the way, they can also be seen in different locations on Earth.
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