Much study has gone into investigating the local aspects of fine-tuning in the solar system and Earth that has proven necessary to allow life on our planet to survive and flourish. Intelligent design is reasonably inferred as the best explanation, especially when noting the overlap of conditions leading to both survivability of life on Earth and “discoverability” of fundamental aspects of the universe by inquiring humans. The recently updated book, The Privileged Planet, by Gonzalez and Richards, presents scientific evidence highlighting many such design-rich characteristics.
Fine-tuning for survivability is essential for our existence and fine-tuning that facilitates discovery enhances our lives by advancing and satisfying our knowledge and curiosity. Yet another aspect of design becomes apparent within our solar system when we observe the planets dynamically, as objects tracing out paths through space and time.
No Absolute Motionlessness
All natural objects move through space. There is no absolute motionlessness in our universe, whether we refer to subatomic particles or to massive conglomerations of particles, such as planets, stars, and galaxies. Our perception of whether an object is at rest or in motion is relative to our own motion. And even if an object appears at rest, such as a chair in your room, its constituent atoms unceasingly vibrate and jostle in relation to one another.
We are usually only aware of a statistical average of atomic motions of a substance, the amplitude (average kinetic energy) of which is related to the object’s temperature. Quantum effects also come into play here, refusing to cancel all particle motion, even as an object’s temperature plummets towards absolute zero.
The primary macroscopic objects of our universe, and especially the planets of our own solar system, exhibit motions that are more easily observable and traceable over time than the motions of individual particle. The passages of the sun, moon, and planets across the expanse of the heavens have drawn our attention and stirred our wonder ever since humans first walked the Earth.
A Deeper Level of Design
From a geocentric model to the heliocentric model of the solar system, and from perfectly circular orbits to delicately balanced ellipses, human understanding of the motions of planets has gradually advanced over the centuries. And yet, for most of us, a deeper level of design lies hidden within the grand scheme of the planetary dance over time.
By carefully examining the orbital paths of the planets visible to the naked eye, Kepler began to elucidate the geometric design in our solar system. His well-known first law of planetary motion states that each planet traces out an elliptical path around our sun, with the sun located at one of the ellipse’s two focal points. Amazingly, Newton was able to mathematically derive this as a result of his newly proposed law of gravity and his law of motion, relating the acceleration of an object to an external force. Kepler’s other two laws of planetary motion, more mathematical in nature, were also successfully proven by later application of Newton’s laws.
No Mathematical Necessity
Further studies of the orbital motions of the planets reveal additional geometric patterns that have, as far as I know, no mathematical necessity dictated by the laws of physics. Given this, an interesting field of study would be to determine if the apparent contingency of the planets’ orbits is in fact required for long-term stability of their orbits and maintenance of habitability conditions on Earth.
My favorite example of geometric design in the solar system arises from the mean orbits of our innermost two planets, Mercury and Venus (pictured at the top). Their mean orbital radii are 0.387 AU and 0.723 AU, respectively, where 1.0 AU (astronomical unit) is the average distance of the Earth from the sun. We might ask why Mercury and Venus have these particular orbital radii (actually, these are the semimajor axes of their slightly elliptical orbital paths). Although their distances from the sun may seem arbitrary, we find that they fit a special geometric pattern.1
We can see the pattern by drawing any three identical circles adjacent to each other so that each circle just touches the other two. Next, draw another circle that passes through the centers of the three touching circles. Call this the mean orbit of Mercury around the Sun, lying in the center of the drawing. Finally, draw a larger circle that just encloses the first three circles. Call this the average orbit of Venus around the Sun.
Using a bit of trigonometry, one can calculate that the ratio of the radius of the larger circle to the radius of the smaller circle is 1.866. Now, here’s the fun part — using NASA data for the average orbital radius of Venus and Mercury, we find that their orbital radii form a ratio of 1.868, matching our simple circle construction to 99.9 percent accuracy!
Another example of geometric design hidden in our planetary orbits relates to the average orbital radii of Earth and Mars. These can be matched to the geometry of two nested pentagons. Inscribe a circle within the inner pentagon so that the circle is tangent to each of the five faces of the figure. Call this the mean radius of Earth’s orbit. Then circumscribe a larger circle so that it touches the five corners of the larger pentagon. Call this the mean radius of Mars’s orbit. Using trigonometry, we find the ratio of these radii to be 1.52786, which matches the actual ratio of these two planets’ mean orbital radii to 99.8 percent.
Earth’s Two Nearest-Neighbor Planets
More design appears when we map the motion of the planets relative to one another. Accounting for the greater strength of the Sun’s gravitational force, the closer a planet is to the Sun, the faster it orbits. As a result, each planet will constantly overtake and “lap” any planet orbiting further from the Sun than itself. Let’s consider Earth’s two nearest-neighbor planets — Venus on the Sunward side, and Mars on the outer side of Earth’s orbit. Based on their relative orbital velocities and mean orbital radii, we find an interesting three-four resonance. It takes Earth the same amount of time to lap Mars three times as it does for Venus to lap Earth four times (accurate to 99.8 percent). Both events take on average 6.40 Earth-years.
A fascinating geometric number is the Golden Ratio (approximately 1.618), which is also the limiting ratio of consecutive terms in the Fibonacci series of numbers (0,1,1,2,3,5,8,13,21…). Returning to the example of Venus “lapping” Earth in its orbit, we find that Venus orbits to a position between the Earth and the Sun (an “inferior conjunction”) every 584 days, or 219 days more than one Earth year. The ratio of 219/365=0.6, so every time this alignment occurs, Earth and Venus are three fifths of a circle further around the Sun. Five such alignments bring us back to the starting point after 5×584 days = 2920 days, or 8.0 Earth-years (which turns out to be 13.0 Venus-years). The relevant numbers in this analysis are 5, 8, and 13, found in sequence in the Fibonacci series. Moreover, the ratio of the orbital periods of Earth to Venus matches the value of the Golden Ratio (99.5 percent).
If Venus Rotated “Normally”
Another curiosity with Venus is that it is the only planet in the solar system that rotates backwards, albeit very slowly. Venus takes 243 Earth-days to rotate once on its own axis, slightly longer than its orbital period or year of 225 days. The rotation period of 243 days is two-thirds of an Earth year, a ratio that does not seem to be explainable by gravitational interactions between Earth and Venus. The design plot thickens here, when we combine Venus’s rotation period with its synodic period of 584 days, discussed in the previous paragraph. Every time Earth and Venus “kiss” in an inferior conjunction, the same face of Venus is turned towards the Earth (perhaps she feels it’s her good side). This unexpected alignment only occurs because of Venus’s unique retrograde rotation — the alignment wouldn’t occur if Venus rotated “normally” at the same rate.
Additional geometric designs are apparent in the orbits of the planets, moons, and asteroids of the solar system.1 One or two such patterns might be adequately ascribed to coincidence, even when not predicted by gravitational interactions between the orbiting bodies. But when multiple “coincidences” appear, a thoughtful observer has reason to suspect that a conductor has orchestrated the celestial harmonies, perhaps out of sheer delight in creating a masterpiece.
Geometric design in the solar system as evidence of intelligent design was the conclusion reached by the scientist whose work most fundamentally explained the force constraining the motions of objects in the solar system, Sir Isaac Newton:
This most beautiful System of the Sun, Planets and Comets, could only proceed from the counsel and dominion of an intelligent and powerful being.
Notes
- John Martineau, A Little Book of Coincidence in the Solar System (New York: Bloomsbury, 2001).