[neilep (OP)]

Dearest Polarity experts ?

The Sun is well big, a million Earths could fit inside it making it nice and cosy (cozy- USA translation service)..sheesh !! )  during those harsh winter climes. Of course, there are much larger stars, Stephenson2-18 for instance but none of them compare to Sheepys ego .....................of course !! (I am an 'arrogant-free-sheepy')

Anyway, digressing like I do I want to get to the main topic in that why does the Sun's polarity change ? why every 11 years ? and why does Earths change so irregularly like every 300000 years etc and we are well overdue !! What's the universal standard Solar Polarity Change Interval nowadays ?

Your thoughts would be most gratefully received.


Zank ewe


Neil
xxxxxx



Oh Sun, ewe change your mind every 11 years
Flipping your head between both ears
Making your spots so very dull
As ewe flip between your North/South pole.

[evan_au]

A magnetic field is generated by the movement of conductive fluids inside the Earth and the Sun.
- In the case of the Earth, this is liquid iron/nickel alloy in the outer core
- For the Sun, it is Hydrogen/Helium plasma in the core
- Laboratory studies have used liquid sodium, and produced magnetic field reversals on timescales that are feasible in a laboratory experiment (ie much less than years)
- As you could imagine, there is a very different viscosity and inertia (and temperature) between these different fluids
- So it is not surprising that magnetic field reversals happen on very different timescales in these different environments.

Fluid flow is often a chaotic process, as we see with the Earth's magnetic field, and laboratory studies.
- The Sun's magnetic field is not exactly a model of regularity, since sunspots virtually disappeared for 70 years during the Maunder minimum (ironically, this started not long after Galileo brought them to the attention of European scientists - the Chinese had been studying them for centuries).

See: https://en.wikipedia.org/wiki/Maunder_Minimum

[neilep (OP)]

Thank ewe evan for the  very interesting post and links.

Why does the polarity reverse anyway ?

A magnetic field is generated by the movement of conductive fluids inside the Earth and the Sun.
- In the case of the Earth, this is liquid iron/nickel alloy in the outer core
- For the Sun, it is Hydrogen/Helium plasma in the core
- Laboratory studies have used liquid sodium, and produced magnetic field reversals on timescales that are feasible in a laboratory experiment (ie much less than years)
- As you could imagine, there is a very different viscosity and inertia (and temperature) between these different fluids
- So it is not surprising that magnetic field reversals happen on very different timescales in these different environments.

Fluid flow is often a chaotic process, as we see with the Earth's magnetic field, and laboratory studies.
- The Sun's magnetic field is not exactly a model of regularity, since sunspots virtually disappeared for 70 years during the Maunder minimum (ironically, this started not long after Galileo brought them to the attention of European scientists - the Chines had been studying them for centuries).

See: https://en.wikipedia.org/wiki/Maunder_Minimum