2024-07-06 09:20:28
The North Star is currently known as Polaris, but in the past it was a binary system called Thuban, which will regain its place in a few thousand years.
We might think that all travelers have used Polaris, better known as North Starto orientate ourselves on the road since humans walked on Earth. However, this is not true. Long, long ago, the North Star was another, called ThubanIn fact, it gave way to Polaris only for a few thousand years, but it will take its place again in the future.
We know that the position of the stars in the sky changes from the observer’s point of view as the hours and days of the year pass. This does not happen with the North Star, which would be like a point placed on the axis around which the Earth rotates. It is always seen in the same position. That’s why it’s so good at guiding travelers. But the change isn’t about that, 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 kind of bulge formed in the Earth’s equator, which alters the rotation of our planet. It will be especially noticeable in the North Hemispheresince in the south there is no fixed star as bright. In fact, travellers there have traditionally used an entire constellation to orient themselves: the Southern Cross.
Why will the North Star change?
This shift of the North Star is due to a phenomenon known as axial precession. During the rotation of the Earth, a series of forces are generated, which cause a kind of bulge at the equator. This is especially altered by the gravitational attraction of the Moon and the Sun. Especially the first one. This causes the movement of the axis on which the Earth rotates, in such a way that it slowly draws a cone-shaped movement. The complete turn occurs in cycles of 25,776 yearscausing a variation in the plane of the celestial equator.
In short, if the axis on which the Earth rotates shifts, the placement of the stars with respect to the geographic poles varies. The North Star is known as such because it is the closest to the North Pole. Currently it is Polaris, since it is located at 1000 meters above the Earth’s surface. less than 1ºHowever, in the past it was the Thuban binary system and in the future it will be so again.
The North Star is now called Polaris. Credit: Morigan 221 (Wikimedia Commons)
The guiding star of the Egyptians
Thuban is a binary system composed of a star with a mass of 2.8 times that of our Sun and another slightly smaller star, with 2.6 solar masses. Its name comes from the language of the Egyptians, who baptized it as head of the snake
It was placed in the position of the North Star from 3942 to 1793 BC. Later, axial precession caused it to be superseded by Polaris.
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. Either way, there will always be a bright star with a stationary position in the sky to guide lost travelers. No matter how much technology advances, this will always be a great comfort.
By: HIPERTEXTUAL