Precession
How It Works introduced two counter-rotating motions as the foundation of the model. This page traces how their interaction produces the complete precession picture: the 333,888-year Holistic-Year, perihelion precession, and the observed rate of the equinoxes.
The Two Fundamental Motions
| Motion | Direction | Period | What Moves |
|---|---|---|---|
| Axial Precession | Clockwise | ~25,684 years | Earth around EARTH-WOBBLE-CENTER |
| Inclination Precession | Counter-clockwise | ~111,296 years | PERIHELION-OF-EARTH around Sun |
These two motions, running in opposite directions, create all the precession phenomena we observe.
The Holistic-Year
When axial and inclination precession interact, they create a complete cycle called the Holistic-Year:
- Duration: 333,888 years
- Ratio: 13 axial cycles = 3 inclination cycles
- Pattern: Based on the Fibonacci sequence (3, 5, 8, 13…)
All Precession Cycles Derived
From the Holistic-Year of 333,888 years, all other cycles can be calculated:
| Cycle | Formula | Duration |
|---|---|---|
| Holistic-Year | 333,888 ÷ 1 | 333,888 years |
| Inclination Precession | 333,888 ÷ 3 | 111,296 years |
| Ecliptic Precession | 333,888 ÷ 5 | 66,778 years |
| Obliquity Cycle | 333,888 ÷ 8 | 41,736 years |
| Axial Precession | 333,888 ÷ 13 | ~25,684 years |
| Perihelion Precession | 333,888 ÷ 16 | 20,868 years |
The numbers 1, 3, 5, 8, 13 are all Fibonacci numbers. This suggests a balanced, stable system. These same Fibonacci numbers also govern the relationships between planetary eccentricities and inclinations — see Fibonacci Laws for an accessible overview, or Fibonacci Laws Derivation for the full technical treatment.
Axial Precession
Earth’s axis slowly traces a circle in the sky over ~25,684 years. This is why the North Star changes over time:
- Today: Polaris
- ~2900 BC: Thuban
- ~13,700 AD: Vega
In the model, this is caused by Earth orbiting the EARTH-WOBBLE-CENTER in a clockwise direction.
Inclination Precession
The PERIHELION-OF-EARTH orbits the Sun counter-clockwise in ~111,296 years. This motion:
- Changes Earth’s orbital inclination
- Shifts when perihelion occurs in the calendar
- Creates the ~100,000-year climate cycles seen in ice cores
Perihelion Precession
Every 20,868 years, axial and inclination precession align:
- The last calculated alignment was in 1246 AD
- December solstice aligned exactly with perihelion
- This marks the start/end of a complete perihelion precession cycle
Connection to Climate
The 333,888-year Holistic-Year cycle appears in historic temperature records. The ~100,000-year patterns visible in ice cores correspond to the three inclination precession cycles (3 × 111,296 years = 333,888 years).
Earth’s climate is also affected by solar cycles, volcanic activity, and other factors. The precession cycles represent the primary orbital driver.
Comparison with Standard Formulas
The longitude of perihelion describes where in Earth’s orbit the closest approach to the Sun occurs. The model’s predictions closely match the polynomial formulas from Meeus (1998) for thousands of years around the present.
Comparison with Meeus shows close agreement near the current epoch: the model predicts 85.77° at 1000 AD versus Meeus’s 85.8° (±0.03°), and 111.46° at 2500 AD versus 111.55° (±0.09°). Beyond ~3,000 AD, the two predictions diverge — the model completes 360° in a mean period of 20,868 years (with a varying rate within each cycle), while Meeus’s polynomial extrapolation deviates increasingly.
Calculate Precession at Any Year
To calculate axial precession, inclination precession, and other cycle durations for any year, see the Formulas page which provides the complete formulas.
Key Takeaways
- Two motions create all precession: axial (clockwise) and inclination (counter-clockwise)
- Fibonacci ratios connect all cycle durations
- 333,888 years is the complete Holistic-Year cycle
- 20,868 years is the perihelion precession cycle (when the two motions meet)
- All values match scientific observations
Continue to Obliquity & Inclination to learn how axial tilt and orbital inclination interact to create the obliquity cycle.