We might think that all travelers used Polaris, better known as polar Starto find your way along a path that has existed since humans walked the Earth. However, this is not true. Once upon a time, the North Star was another one called Tuban. In fact, it gave way to the North Star for only a few thousand years, but in the future it will return to take its place.
We know that the position of the stars in the sky changes from an observer’s point of view as the hours and days of the year pass. This does not happen with the North Star, since it would be like a point placed on the axis around which the Earth rotates. This is always visible in same position. That’s why she guides travelers so well. In any case, the changes are not about this, but about something much more radical. The North Star will be different because its position relative to the geographic north pole will change.
This is due to a peculiar bulge formed at the Earth’s equator, which changes the rotation of our planet. This will be especially noticeable in North hemisphere, because in the south they do not have such a bright fixed star. In fact, travelers have traditionally used an entire constellation for orientation: the Southern Cross.
Why will the North Star change?
This change in Polaris is due to a phenomenon known as axial precession. As the Earth rotates, a number of forces arise that cause a kind of bulge at the equator. This especially changes due to gravitational attraction of the Moon and the Sun. Especially for the first one. This causes the axis around which the Earth rotates to move in such a way that it slowly draws a cone-shaped motion. A full revolution occurs in cycles 25,776 yearscausing a change in the plane of the celestial equator.
In short, if the axis around which the Earth rotates shifts, the alignment of the stars relative to geographic poles varies. Polaris is known as such because it is closest to the North Pole. Currently this is Polaris as it is located less than 1 degree. However, in the past it was the Thuban binary system, and in the future it will be again.
The guiding star of the Egyptians
Thuban is a binary system consisting of a star with 2.8 times the mass of our Sun, and another slightly smaller star with a mass of 2.6 times the Sun. Its name comes from the language of the Egyptians, who dubbed it snake head
It was placed in the position of the North Star. from 3942 to 1793 BC Later, due to axial precession, it was replaced by the North Star.
Since this movement is slow but steady, there will come a time when Polaris will lose its title again. We won’t see it, but it will happen. In any case, be that as it may, a bright star will always stand motionless in the sky, which will guide lost travelers. No matter how technology develops, this will always be a great comfort.
Source: Hiper Textual
