The earth has wobbled on and off the Canopus-Vega axis forty times in the last million years. On the axis is seen as the Golden Age and off the axis is seen as the Iron Age in Vedic thought. For the 12882 years when we are heading towards this axis we ascend and for the 12882 years when we head away from this axis we descend.

The precession cycle matches the annual path of ascent and descent of the seasons in reverse. The Great Year ascends through the northern winter and autumn signs, while the northern earth season is descending, and descends througn the summer and spring signs, while the annual northern cycle is ascending. This matches the cycle of life, with equinoxes at apex and nadir, and follows one season after the cycle of light, with solstices at apex and nadir.

Regarding the astrophysics of this material, I earlier posted comments at Precessional Cosmology suggesting a scientific experiment to model the twelve signs as ripples caused by regular drops of water on the four cardinal points of a round bucket of wet sand. I still haven't managed to do this experiment, but suggest it would be interesting to help visualise the claims.