We all know that each planet in our solar system is revolving around the Sun, but at the same time, all the planets and celestial bodies are rotating on its own axis which is known as the Planetary axis of rotation.
Every planet in our solar system has an imaginary axis of rotation which is tilted at some degree from its orbital plane. Some planets have a very large angle between their orbital plane & rotational axis, and some are less tilted.
For example, our Earth’s axis of rotation is tilted at 23.5 degree from its orbital plane. And this is the main reason why seasons exist on Earth.
Venus and Uranus have the largest axial tilt in our solar system which is 177′ & 98′ respectively. It means the North pole on Uranus is nearly on its equator.
Axial Precession of Earth
We’ve discussed that the earth’s rotation axis is tilted at 23.5′ to its orbital plane and it is fixed but it is wobbling in the direction of the Earth’s axis of rotation with a period of 26,000 years. And that cyclic or wobbling motion is known as the Axial Precession of the Earth.
Why Polaris is not permenant North Star?
Currently, Earth’s rotational axis is tilted at 23.5′ and the north pole is pointing exactly in the direction of Polaris that’s why from the earth we can say that Polaris is the permanent north star, But the earth’s rotational axis is wobbling and because of that Polaris will not be always the north star. This cyclic motion of the earth’s rotational axis takes 26000 years to complete one cycle and that is a very slow motion to justify the movement of Polaris.
Around 13000-15000 years later Vega will be our north star.