[Axenolith]

If the earths core, the physical mass of it itself, stopped and reversed the kinetic energy converted to heat would probably re-liquify the planet…

[tired&retired]

Earth’s inner core may be reversing its rotation

https://www.sciencenews.org/article/earth-inner-core-reverse-rotation#:~:text=While%20the%20inner%20core%20appeared,every%2035%20years%20or%20so.

[tired&retired]

One would think the sun shifting its polarity would have a similar massive disaster, but it does it gradually.