Ever since I wrote a post on Polaris, I have been wondering, is there a south pole? Sadly, there isn’t, not really.
There are two candidates for a south pole star. By 14 000 CE Canopus will, because of the wobble in the earth’s axis, be as close as it will ever get to being the South Pole, about 10° from magnetic south. The other, Sigma Octanis in the Octant, is the closest star at present. The Southern Cross points to where a south pole would be, and like Ursa Minor is a circumpolar constellation, so it’s always above the horizon.
Vega is the fifth brightest star in the sky, a brilliant blue-white star two and a half times larger than the sun. It takes turns with Polaris and Thuban as the pole star, and will be the nearest star to the celestial north pole again in 14 000 AD.
The North Star is not a particularly bright star; it doesn’t make the top 20. It’s no. 45, actually. What’s even more disturbing is that it hasn’t always been the pole star, and it will eventually move out of position again. The Earth’s orbit has a wobble in it, and thus the north pole rolls around a little over the course of the millennia.
Imagine the poles as the ends of the dowel sticking out of a round top, and you can imagine the north end wobbling around as the top rolls. This is a bit of a blow to myths about the north star, because they tend to stress the constancy and centrality of Polaris. Continue reading