Polaris just happens to be the star in that spot now, and it's not exactly perfect, it does move a very slight amount. You're right that the Earth's axis wobbles. 5000 years ago Thuban was the North Star.
The wobble in the Earth's axis exists, but it is very slow.
Ah, I had thought you were talking about the precession.
Yeah, the earth is tilted 23.5 degrees from the plane of its orbit around the sun. That's why summer in the Northern hemisphere is winter I'm the Southern hemisphere, and vice versa.
Regarding Polaris appearing in the same location, the average distance between the Earth and the Sun is 94 Million miles. So the diameter of the Earth's orbit is 2x that, so on average 188 Million miles. The distance to Polaris is 434 light-years, or 2.551x10^15 miles. So you create an isosceles triangle with the base being the diameter of the Earth's orbit and the height being the distance to Polaris and calculate the angles of the corners of the triangle. tan^-1 (2.551x10^15 miles / 94,000,000 miles) = 89.999997889 degrees.
You end up with a triangle that has 2 corners (at either side of Earth's orbit) that are 89.999997889 degrees and one corner (at Polaris) that's 0.000004223 degrees. Since the angles at each end of Earth's orbit are nearly 90 degrees, Polaris appears to not move in the sky, although it does a very small amount that's almost imperceptible.
Polaris just happens to be the star in that spot now, and it's not exactly perfect, it does move a very slight amount. You're right that the Earth's axis wobbles. 5000 years ago Thuban was the North Star.
The wobble in the Earth's axis exists, but it is very slow.
Ah, I had thought you were talking about the precession.
Yeah, the earth is tilted 23.5 degrees from the plane of its orbit around the sun. That's why summer in the Northern hemisphere is winter I'm the Southern hemisphere, and vice versa.
Regarding Polaris appearing in the same location, the average distance between the Earth and the Sun is 94 Million miles. So the diameter of the Earth's orbit is 2x that, so on average 188 Million miles. The distance to Polaris is 434 light-years, or 2.551x10^15 miles. So you create an isosceles triangle with the base being the diameter of the Earth's orbit and the height being the distance to Polaris and calculate the angles of the corners of the triangle. tan^-1 (2.551x10^15 miles / 94,000,000 miles) = 89.999997889 degrees.
You end up with a triangle that has 2 corners (at either side of Earth's orbit) that are 89.999997889 degrees and one corner (at Polaris) that's 0.000004223 degrees. Since the angles at each end of Earth's orbit are nearly 90 degrees, Polaris appears to not move in the sky, although it does a very small amount that's almost imperceptible.
BeerMan FTW! 👍🍻