74.4/4 = 18.6 years is the Lunar nodal cycle
74.4/7 = 10.62 years is the avg. Solar cycle.
Fossil records suggest that the Solar cycle has been stable for at least the last 290 million years. For example, the cycle length during the early Permian is estimated to be 10.62 years. https://en.wikipedia.org/wiki/Solar_cycle
Arctic Melt to Arctic Melt and other climate features and records set 74 years apart.
This is why I say the Baseline should be 7 Solar Cycles.
It is a harmonic dance out there.
Weaving in and out of the galactic dust plane gives the 100,000 year ice age.
