Polaris appears nearly fixed because it is located very close to the north celestial pole, which is the direction Earth’s rotational axis points. With so many stars in the sky, its likely one will be close to the north pole axis.
On a globe, Earth rotates once per day. Because Polaris is almost lined up with Earth’s axis of rotation, it appears to stay nearly still while the other stars appear to circle around it. That is exactly what we would expect if Earth is rotating.
It is also not perfectly motionless. Polaris is not exactly at the north celestial pole. It makes a very small circle in the sky, but the movement is subtle because it is so close to the axis point.
Polaris also changes position depending on where you are on Earth. Near the North Pole, Polaris is almost overhead. Near the equator, it is close to the horizon. In the Southern Hemisphere, you cannot see Polaris at all as it disappears below the horizon. This is exactly what you would expect from a sphered earth.
https://www.youtube.com/watch?v=LTfSu60TnMY
If the argument is, “Why doesn’t Polaris move if we are flying through space?” this is because most of that movement is shared movement. Polaris is in the Milky Way galaxy with us, so we are not moving past each other, mostly we are moving together.
Our movement around the Sun is also tiny compared with the distance to Polaris. Polaris is hundreds of light-years away, so the change in viewing angle from one side of Earth’s orbit to the other is extremely small. It is not something you would notice just by looking up at the night sky.
What does fit a spherical Earth is how Polaris changes when you travel north or south. The farther north you go, the higher Polaris appears in the sky. The farther south you go, the lower it appears, until eventually it disappears below the horizon in the Southern Hemisphere. It doesn’t get small and fade away but dips down.
Examples:
- Rochester, MN is around 44° north latitude, so Polaris appears about 44° above the northern horizon.
- If you traveled due east or west while staying around 44° north, Polaris would still appear about 44° high.
- If you traveled north to 60° latitude, Polaris would appear about 60° high.
- If you traveled south to 20° latitude, Polaris would appear about 20° high.
- At the equator, Polaris is near the horizon.
- South of the equator, Polaris drops below the horizon and is no longer visible.
But if you travel east or west at the same latitude, Polaris stays at about the same height above the horizon. That makes sense on a globe because your latitude has not changed.
So the real observation is not “Polaris never moves.” The better observation is: Polaris stays nearly fixed in the sky because it is close to the direction of Earth’s rotational axis, and its height changes with latitude. That is exactly what we would expect on a spherical Earth.
Watching the stars appear to “move” across the sky, the stars around it, is exactly what we would expect to see if Earth is spinning.
Polaris appears nearly fixed because it is close to the direction of Earth’s rotational axis. The other stars appear to circle around that point because earth is rotating.
Could the stars be moving around us?
Sure, you can take that position, but you can’t flip/flop when I later present other evidence.
Here is a video showing the effect. This is also something you could test yourself. On a clear night, set up your phone facing north and time-lapse. Watch how the stars form circular trails around Polaris. If Earth is spinning, that is exactly what you should expect to see. This is hard to see in a city however due to light pollution.
https://www.youtube.com/watch?v=t8GfpNo-sSQ
Conclusion: Polaris appears to move very little because it is close to the north celestial pole. The way the stars appear to rotate around Polaris, and the way their angles change as a person travels north or south, is consistent with living on a rotating sphere.
A very cool experiment you can do is measure the angle between the ground and Polaris in this video. That is the latitude that this video was recorded at! Very cool. You can also do the same at home.
Here is an idea for you, without looking up the latitude, measure the angle and see if it matches.
“Reality is stranger than fiction”
-Mark Twain