Illustrating
Roger Elliott's
1/2 Right Angle Rule
Summary
On the right are three rows of images. Each image represents a planet, Mercury, Earth and Jupiter in the top row, Venus, Mars and Uranus in the second row, and Saturn, the Moon and Neptune in the third.
The background in each square represents the 'fixed' background in which the sun and planets are rotating and orbiting. The central sphere represents the planet spinning on it's axis, while the surrounding ring represents the planet's orbit.
The display illustrates two first order relationships between the planet's orbits and their spins. The rotation of the planet shows it's position relative to the background after exactly one earth year's rotation.
The circles show each planet's rotation advanced exactly 1 earth orbital period against the background.
You can see Earth (top center) has gained 1/4 rotation. Not surprizing, that's why we have leap years every 4 years.
Jupiter and Mercury have both also executed 1/4 extra rotation in the period.
The ring represents the orbital motion of the earth, relative to that planet's orbital motion. The spin of each planet and the length of it's year are both synchronized with the length of earth's year.
Venus and Uranus meanwhile have executed an extra 1/2 rotation while Mars has 0 additional rotation.
Saturn has gained a 5/8 of a rotation, the Moon 3/8 and Neptune 1/8 or 45 deg. They attain a 90 deg rotation relative to one another
| Mercury |
| Orbital Period (year) 87.9694 Rotation Period (day) 58.6462 6.228 rotations per Earth orbital period (circle) 0.241 Earth orbital periods per Mercury's orbital period (ring) |
| Earth |
| Orbital Period (year) 365.25636050 Rotation Period (day) 0.997269663 366.256 rotations per Earth orbital period (circle) 1.000 Earth orbital periods per Earth's orbital period (ring) |
| Jupiter |
| Orbital Period (year) 4330.595 Rotation Period (day) 0.41353831 883.247 rotations per Earth orbital period (circle) 11.856 Earth orbital periods per Jupiter's orbital period (ring) |
| Venus |
| Orbital Period (year) 224.695 Rotation Period (day) 243.0187 1.503 rotations per Earth orbital period (circle) 0.615 Earth orbital periods per Venus's orbital period (ring) |
| Mars |
| Orbital Period (year) 686.980 Rotation Period (day) 1.025956019 356.016 rotations per Earth orbital period (circle) 1.881 Earth orbital periods per Mars's orbital period (ring) |
| Uranus |
| Orbital Period (year) 30717.682 Rotation Period (day) 0.71833 508.480 rotations per Earth orbital period (circle) 84.099 Earth orbital periods per Uranus's orbital period (ring) |
| Saturn |
| Orbital Period (year) 10727.16 Rotation Period (day) 0.44401 822.631 rotations per Earth orbital period (circle) 29.369 Earth orbital periods per Saturn's orbital period (ring) |
| Moon |
| Orbital Period (year) Rotation Period (day) 27.321660879 13.369 rotations per Earth orbital period (circle) 0.000 Earth orbital periods per Moon's orbital period (ring) |
| Neptune |
| Orbital Period (year) 60215.912 Rotation Period (day) 0.671252 544.142 rotations per Earth orbital period (circle) 164.859 Earth orbital periods per Neptune's orbital period (ring) |