What keeps the North star stuck at exactly North?

To begin with, being ‘stuck’ in the night sky is not exclusive to the North star: none of the stars in the night sky actually move enough for our time measurements to comprehend. 

They will move over the course of millions of years, meaning we won’t see them move across the sky in our lifetimes. The only reason that the stars appear to move across the night sky, just like the way the sun and moon ‘move’ across the sky, is because of the Earth spinning on its own axis.

This rotation occurs one whole time a day, so a lot of the stars in the sky will appear to move throughout the night in an arc. But it is, in fact, the Earth that is moving.

The reason that the North star appears to stay stuck in one place in the sky compared to the other stars which ‘move’, is because it is aligned the most with our North pole on Earth.

 Since the Earth spins on an axis, anything aligned with that axis will not appear to move to us. You can compare this to a spinning plate at the circus: imagine a pristine white plate with a red dot sticker on the outer rim and blue dot sticker in the center of the plate.

What keeps the North star stuck at exactly North

When the plate spins on the spike, the red dot sticker will spin with the rim, but the blue dot sticker will appear to stay in place since it is directly above the point where the spike interacts with the plate. This is because the spike touching the plate acts as its point of axis.

Now imagine that the North star is that same blue dot, and the Earth is that spinning plate. Although the North star is not stuck to Earth like a dot sticker, the same principle applies. Because the star is aligned with the North of Earth and therefore the axis it spins on, the North star does not appear to move like the other stars in the night sky.

But all this talk about the ‘North star’ is a little misled. Because the North star is not actually a single star, as the name would have us all believe. When we look at it with a naked eye, or even most telescopes, the North star seems to be a single celestial entity. But research has since shown that the North star is actually five stars.

This star system is called Polaris, again suggesting a correlation with the Earth’s polar axis. It just so happens that three of the stars in the system Polaris are clustered close together and then the subsequent two stars are further away. So, why can we still see five stars as one star in the sky? So big and bright that we assume it is one star?

 Well, the Polaris system’s first three stars are so close that two of them actually orbit the main star. This main star in the system is a supergiant and is the brightest of the five, so it is likely the main reason we can see the ‘North star’ from Earth.

The other two stars that are further away from the main three stars just happen to be aligned with the main system in a way that sees them fall into the same axis line. This means we could draw a crude, floating line from Earth’s North pole and see all five stars intersect with the line of axis in some way.

If these stars were viewed from another angle in a whole other galaxy, it is unlikely that the outer two stars of the Polaris system would be aligned with the main three.

Interestingly, Earth’s axis is not actually completely fixed. This is because the Earth is not entirely a sphere shape, it has a bulge around the equator. This means that the Earth’s axis is also not completely aligned with Polaris.

The bulge around the equator also means that the sun’s gravitational effects are not as even as they would be if the Earth was completely spherical. This effect is actually causing the Earth to twist slowly on its own axis, so the system Polaris is very slowly becoming more and more misaligned with the Earth’s axis and North pole.

This also means that over a long period of time (in none of our lifetimes), the title of ‘North star’ is likely to be handed off to another star in our night sky. This is because the Earth will tilt on its axis thanks to the unsymmetrical gravitational pull from the sun, as a result of the Earth not being perfectly spherical.

So, to answer the question directly: nothing keeps the North star ‘stuck’ at North. The North star is made up of five stars that just happen to be aligned with the North axis of Earth. Although the system Polaris (what we call the North star) is technically moving, it is not moving fast enough for it to become misaligned from our North pole any time soon.

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