Polaris is not a fixed star.

Polaris circulates every 25,800 years. For example, the current Polaris is called Gouchenyi, but it will become Vega in 14000. Judging from the time of the universe, Polaris will not only change, but also become very fast.

Polaris, also known as Beichen and Zixing, refers to the star closest to the North Celestial Pole. At present, it refers to "Gou Chen Yi".

Polaris is located at the northern end of the earth's axis, which is five times as long as the extension line connecting Tian Xuan and Shu Tian in the Big Dipper. Because the earth rotates, and Polaris happens to be on the axis of celestial rotation, it is still relative to other stars. Polaris is about 434 light years away from the earth and has a diameter of about 52 million kilometers.

"Gouchenyi" is actually composed of three celestial bodies: Polaris Aa, Polaris B and Polaris Ab. It was once named Vega, and its name comes from the story of linen clothing woven by Nazis (matriarchal tribal leaders) in the late Paleolithic period, but now it is called the North Star because it is closest to the north celestial pole.

The main star Polaris A is a huge, bright and ancient yellow Supergiant star. Polaris A is six times the mass of the sun, and if it is placed with the sun, its brightness is 2000 times that of the sun.

Polaris is a bright star in the northern part of the sky, close to the north celestial pole and almost opposite the earth axis. Seen from the northern hemisphere of the earth, its position is almost unchanged, so it can be used to identify the direction. Because of the rotation of the earth, Polaris is just on the axis of celestial rotation, so it is relative to other stars.

However, due to precession, Polaris is not a star whose position will never change, and it will be Vega by the year 14000. Every 25,800 years, Polaris will cycle.

For example, in the era of Magellan's voyage to the West, Chen Yi was about 8 degrees away from the North Pole, but in 2 1 century, Chen Yi was closer to the North Pole, with an angle difference of only 40'. Astronomers calculated according to the swing of the earth's axis and the gravity of stars that by 2 100, GouChen Yi will reach the nearest position directly above the North Pole, only 28 feet away from the North Pole.

Polaris is the brightest star in Ursa minor, also known as Alpha Star in Ursa minor. It is a yellow giant with a spectral type of F, about 434 light years away from the Earth, and its mass is about four times that of the sun. It is a bright star far away from the earth, at the tip of the bear's tail in the constellation diagram.

Gou Chenyi is also a star of underworld nature. Connect a straight line between Tian Xuan and Shu Tian at the front end of the Big Dipper, and then extend the distance five times to Shu Tian. You will meet a bright second-class star, which is Gou Chenyi. This is the easiest way to find Gou Chenyi.

Polaris (Gouchenyi) is also a three-in-one system. The distant companion star (Polaris) can be clearly observed with a small telescope, while the nearby companion star (Polaris) is too close to Polaris (the apparent distance is only 0.2 ",the actual distance is 18.5) and too dark to be seen.

It was not until early August 2005 that Hubble captured its image: Polaris was very close to the North Pole of the Earth in the sky. Therefore, it always seems to be in the northern sky. It is because of its important position that it is famous.

"Extended reading"-the immortal secret of Polaris;

Because the earth rotates around the earth axis, and Polaris is very close to the north extension line of the earth axis, Polaris is almost motionless in the sky at night, with its head tilted to the north, so it can indicate the north.

Although the tilt direction of the earth's axis will change because the earth revolves around the sun all year round, the distance between Polaris and the earth is much larger than the radius of the earth's revolution, so the change of the earth's axis caused by the earth's revolution can be ignored.

So all the year round, we see that the position of Polaris in the sky seems to be motionless in the north. In fact, we just can't observe the subtle changes with the naked eye, and we feel that the earth axis always points to Polaris.