Originally Posted by rtomes

Because of the time element of building up a displacement from a
velocity, it turns out that distant objects such as nearby stars and
the galactic plane generally and the galactic centre have significant
effects on the solar displacement also. As it happens, there is a
lopsidedness of matter in the southern sky, which means that a long
term average heat flow will be biased in the direction of the sun's
south pole (not in the direction of the stars or galaxy).
Over very long periods, the sun moves up and down through the galactic
plane. This would cause major heat flow variations in the sun with
reversals about every 30 million years. It is possible that this is
another link in the chain of events leading to the major extinction
events.