Thursday, 20 September 2012

Pole star.

The correct term is circumpolar stars.

There isn't just the one.
If we are talking history

I like the idea of a fixed pole star.
I  believe in it
Because we have Polaris

2000 years ago, there was no pole star...

Now I actually think about the stars and their orbit around the sun and other suns
I feel my head start to spin.

Fact is...

There is no pole (even though we draw it, talk about it, use it).

The pole exists in relation to the sun.

Whilst a pole star is a position occupied by a star relative to earth.

The earth spins daily

Rotates yearly

And North (another imaginary feature of this planet) would point- if it existed-  another circle in the sky 26,000 years wide.


Even magnetic north refuses to stay fixed
Moving about 40 miles a year....
Flips periodically upside down to the south
Between times seems to fracture..

But back to the stars
Stars closest to the tip of the pole appear to rotate least...
That much I find easy to understand.

Fact is
There was no pole star between 1550 BC and AD 800.

Does it matter?

Here is the path of the 'north' in the sky
And approximate years:

In 2750 BC the pole star was Thuban.