## Saturday, May 7, 2016

### There is a natural 208 year de Vries-like cycle in the Lunar Tidal Forces acting upon the Earth

1. The Defacto 13 year Lunar tidal cycle

There is a defacto 13 year lunar tidal cycle created by the difference
between 31 perigee/syzygy cycle and the 18 year Saros cycle, such that:

13 years = 31 – 18 years

Now the reason for the 18.03 sidereal year Saros cycle is:

223 Synodic months______= 18.02931 sidereal years
239 anomalistic months___ = 18.02990 sidereal years
242 Draconic months______= 18.02941 sidereal years
[with closest alignment between Synodic and Draconic cycles,
though the anomalistic cycle is not far off]

while the reason for the 31 year cycle is:

383.5 Synodic months______= 31.005568 sidereal years
411.0 anomalistic months___ = 31.005401 sidereal years
416.0 Draconic months_____= 30.992708 sidereal years
[with closest alignment between Synodic and anomalistic cycles]

hence, the defacto 13 year cycle possibly comes about because:

160.5 Synodic months______= 12.976254 sidereal years
172.0 anomalistic months___= 12.9754963 sidereal years
174.0 Draconic months_____= 12.9632963 sidereal years
[with closest alignment between Synodic and anomalistic cycles]

2. The 208 year de Vries Cycle
Now
16 x 13 years = 208 years
Thus, this would indicate that a possible reason for the ~ 208 de Vries cycle is:
16 x 160.5 = 2568.0 Synodic cycles________= 207.6200718 sidereal years
16 x 172.0 = 2752.0 anomalistic cycles_____= 207.6079414 sidereal years

16 x 174.0 = 2784.0 Draconic cycles_______= 207.4127406 sidereal years

or with a drift of 3.0 Draconic cycles in roughly 208 years you get:
2787.0 Draconic cycles___= 207.6362457 sidereal years
[with closest alignment between Synodic and anomalistic cycles]

Finally, if you allow for a slight drift of 4.5 Synodic cycles and 5.0 anomalistic and
Draconic cycles you get:

2572.5 Synodic cycles___= 207.98389 sidereal yrs_____= 207.99196 tropical yrs
2757.0 anomalistic cycles_= 207.98514 sidereal yrs____= 207.99321 tropical yrs
2792.0 Draconic cycles___= 208.00875 sidereal yrs____= 208.01682 tropical yrs

Of course, the drift required to realign the sidereal/tropical reference frame
with the seasonal year of 4.5 synodic = 5.0 anomalistic = 5.0 Draconic cycles
over 208 tropical years is not arbitrary since this is equivalent to:

132.887 days in 75970.375 days = 0.0017492 of a full cycle in 208 tropical years.

which for the Earth’s orbit is 0.6297133 degrees in 208.0 tropical years
or 10.90 ~ 11 arc second per tropical year!

This is just the (pro-grade) rate of precession of the perihelion of the Earth’s orbit

11.45 arc seconds per year – theoretical
11.62 arc seconds per year – observed epoch 2000.

CONCLUSION
Hence, If we look at times where the perigee of the lunar orbit points at the
Sun, they will realign with the seasons in (almost) precisely 208.0 tropical
years or one de Vries Cycle, if you measure the alignment in a reference
frame that is fixed with the Earth’s orbit (i.e. a frame that is tracking the
perihelion precession of the Earth’s orbit).