The Remarkable Design of the Solar System’s Turbulent Youth, Part 3

The Remarkable Design of the Solar System’s Turbulent Youth, Part 3

More and more research shows that it’s one thing for the solar system to support unicellular life; it’s quite another matter to reach the ability to host advanced life. Supporting human civilization presents even more daunting requirements. The major events that took place between about 30 million to a billion years after the solar system’s birth present a picture of exquisite fine-tuning necessary for humanity’s existence.

In part 1 of this series I described the solar system’s birthing experience. Part 2 outlined the 50 million years of fine-tuning following the solar system’s birth, particularly (1) the configuration of the solar system’s gas giant planets and (2) the collision event that formed the Moon and helped prepare Earth to support humanity. In parts 3 and 4, I will describe other fine-tuned events that took place during the next 800 million years of the solar system’s history.

Hostile Conditions

During the first 700 million years of solar system history the Sun was especially unstable—making the solar system hostile to life. Not only was the Sun’s x-ray and ultraviolet radiation output orders of magnitude greater than it is now, but it was also highly variable.1 (See figure 1.) Also during this epoch, the Sun lost between 15–20 percent of its mass.2 This mass loss translates into the Sun dimming by a factor of two because the luminosity of a star increases in proportion to the fourth power of its mass.

Additionally, huge belts of planetesimals (small bodies in the process of planetary formation), comets, and asteroids delivered frequent colliders to Earth and the other inner solar system planets. At this time, too, the solar system’s gas giant planets had not yet evolved to attain their present orbits. The closer proximity of Jupiter, Saturn, Uranus, and Neptune’s orbits disturbed Earth’s orbit significantly.

Thousands of years ago, Moses recorded in Genesis 1 that, previous to the six creation days (Genesis 1:2), Earth was “formless and void.” The Hebrew phrase tohu wabohu connotes a seething, uninhabitable, and empty chaos.3 It looks like scientists’ recently acquired knowledge of the early solar system’s hostility toward life yields yet one more piece of evidence for the Bible’s predictive power.

Taming the Gas Giants

The youthful solar system’s enormous population of planetesimals, asteroids, and comets was most predominant at the orbital distances of Jupiter, Saturn, Uranus, and Neptune. These asteroids and comets interacted gravitationally with the gas giants in a way that caused the planets (1) to gradually drift outward away from the Sun, and (2) to develop orbits free of mean motion resonances. Both effects benefitted Earth in that Earth’s orbit suffered less-frequent and less-dramatic gravitational disturbances from the gas giant planets.

The best formation models for the gas giants indicate that these planets formed on quasi-circular, quasi-coplanar orbits that, if unchanged, would have resulted in mean motion resonances damaging to advanced life on Earth. A team of four planetary scientists found a possible way to prevent this destructive scenario. Their research suggests that Jupiter and Saturn approaching, attaining, and leaving a 1:2 orbital resonance would prevent such a permanent mean motion scenario.4 In a 1:2 resonance Jupiter makes exactly two orbits of the Sun for every single orbit of Saturn.

According to the team’s research, the 1:2 orbital resonance event arose because Saturn was closer than Jupiter to the densest portion of the cloud of planetesimals, asteroids, and comets. This configuration, plus the fact that Saturn’s mass = 0.299 of Jupiter’s mass, caused Saturn to migrate outward from the Sun at a faster rate than Jupiter. Therefore, Jupiter’s orbit evolved from making less than two orbits about the Sun for every single Saturn orbit, to briefly attaining exactly two orbits for every single one of Saturn’s, and finally to making slightly more than two orbits for every single Saturn orbit.

The planetary science team proved that a carefully crafted and timed 1:2 orbital resonance event between Jupiter and Saturn produced “all the important characteristics of the giant planets’ orbits, namely their final semi-major axes [distances from the Sun], eccentricities, and mutual inclinations.”5 In a separate research paper the same team showed that such a 1:2 orbital resonance event also produced both the orbital distribution and the total mass of the 4,000+ Trojan asteroids that now share Jupiter’s orbit approximately.6 The solar system’s Trojan asteroids orbit the Sun near Jupiter’s two Lagrangian points of stability (see figure 2), located 60 degrees ahead and behind Jupiter in its orbit. 

Figure 2: Jupiter’s Lagrange Points

Joseph-Louis Lagrange, a French mathematician, discovered that Newtonian mechanics allows for five special points in the vicinity of two orbiting masses where a third, smaller mass or several much smaller masses can orbit at a fixed point from the larger masses. Of the five points only two, the L4 and L5, are stable over long time periods. At both L4 and L5 along Jupiter’s orbit a total of 4,078 asteroids have been discovered.

In a third research paper, the team demonstrated that the 1:2 orbital resonance event also yielded the long-sought answer to the cause of the Late Heavy Bombardment (LHB).7 Next week, I’ll describe the LHB and how it, like the events discussed above, prepared the solar system and Earth for the arrival of human beings.

Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | Part 6
  1. Sylvaine Turck-Chièze, Laurent Piau, and Sébastien Couvidat, “The Solar Energetic Balance Revisited by Young Solar Analogs, Helioseismology, and Neutrinos,” Astrophysical Journal Letters 731 (April 20, 2011): id L29.
  2. Turck-Chièze, Piau, and Couvidat, “Solar Energetic Balance,” id L29; Joyce Ann Guzik and Katie Mussack, “Exploring Mass Loss, Low-Z Accretion, and Convective Overshoot in Solar Models to Mitigate the Solar Abundance Problem,”Astrophysical Journal 713 (April 20, 2010): 1108–19.
  3. Fazale Rana and Hugh Ross, Origins of Life (Colorado Springs: NavPress, 2004), 37–40.
  4. K. Tsiganis et al., “Origin of the Orbital Architecture of the Giant Planets of the Solar System,” Nature 435 (May 26, 2005): 459–61.
  5. Ibid., 459.
  6. A. Morbidelli et al., “Chaotic Capture of Jupiter’s Trojan Asteroids in the Early Solar System,” Nature 435 (May 26, 2005): 462–65.
  7. R. Gomes et al., “Origin of the Cataclysmic Late Heavy Bombardment Period of the Terrestrial Planets,” Nature 435 (May 26, 2005): 466–69.