I just learned about precession of the equinox, i.e. the Earth's axis tilts one degree every 72 years.
And it takes 72 years/degree x 360 degrees = 25,920 (years in one cycle)
There are many theories to this, i.e.
- Sun's gravity is affecting the tilt of Earth's axis
- Sun itself is revolving around another star, and it takes 25,920 years, hence the slow tilt of Earth's axis
I googled whether the Sun revolves around something else, and according to NASA.gov, Sun revolves around center of Milky Way it it takes 230 million years.
Now, I am confused between precession of the equinox and Sun revolving around another star.
Does precession of the equinox have anything to do with the Sun revolving around another star? Or is it simply the Sun's gravity acting on the Earth?
What is the explanation according to modern science? I understand there were astronomers in the past who deduced that the Sun revolved around another star and it took 25,920 years.