: : : :Yes - this is precession, the period is 25,776 yrs.

: Can anyone tell me when this occurred last? : And if we should worry if it happend 25.775 years ago?

: : Gerwin

::::::::::::::::: Not to worry at all my friend. It's not something that happens suddenly.

Imagine a toy top spinning on its little point. Remember how the top goes thru a gentle rocking or wobble motion as it's spinning? The Earth does exactly the same thing as it spins. The wobble takes the aforementioned number of years to complete the cycle of one complete wobble. In other words, it's doing it right now as we speak.

I don't feel anything terribly catastrophic happenning. But....in roughly half that time, Vega will become the north star (again) and at the end of that wobble cycle we'll be right back where we are now with Polaris as the north star.

As far as I know, this hasn't caused any problems with any creatures I can think of. Well, maybe some celestial navigation ones, but it looks like we got over it.

:-)