Reasons to Believe

Research Rules Out Rogue Planets

A high-sensitivity search for very distant planets in the solar system reveals a lack of rogue planets and other features common in other planetary systems. This remarkable circumstance allows our solar system to manifest a benign environment for enduring advanced life and suggests the involvement of an intentional Designer.

A rogue planet on a collision course with Earth is something science-fiction stories have in common with doomsday theories (such as the 2012 Mayan calendar prophecies). Astronomy, however, has revealed nothing to lend credence to these fantastical scenarios. Researchers had used powerful telescopes to rule out the existence of any planet the size of Mars or greater within 7 billion miles of Earth and any planet the size of Jupiter or greater within 100 billion miles.1 (For comparison, Neptune orbits the Sun at a mean distance of 2.8 billion miles.)

While these findings may provide reassurance for those developing investment strategies for their grandchildren, it is quite another matter when attempting to use very distant planets to understand the stability of advanced life over the past several million years. Some astronomers have hypothesized that an extremely distant planet in the solar system may be responsible for causing the mass extinction events noted in the fossil record (such events took place at regular intervals throughout a 27-million-year period).2 To address these considerations, astronomer Kevin Luhman analyzed the database from the Wide-Field Infrared Survey Explorer satellite to search for possible thermal emission signals from gas giant planets and brown dwarfs that may be lurking in the outer limits of the solar system.3 (Brown dwarfs are bodies ranging in size from 12–75 Jupiter masses.)

Luhman determined that no planet the size of Saturn or greater exists within 2.6 trillion miles (0.44 light-years) of the Sun and no planet the size of Jupiter or greater exists within 7.6 trillion miles (1.30 light-years).4 Such a stringent limit on distant solar system bodies effectively rules out the possibility that a distant planet could be responsible for the mass extinction events noted in the fossil record.

This limit also implies that, over the past several million years, advanced animals on Earth have been relatively undisturbed by events in the extreme outer realms of the solar system. One can only hope this limit will also put an end to speculations that a hypothesized Planet X will bring about the end of civilization or usher in the apocalyptic events prophesied in Scripture.

A Unique Planetary System

Such a lack of large planets and brown dwarfs may be an exceptional feature for planetary systems. In spite of the fact that planets orbiting at great distances from their stars are extremely difficult to detect, astronomers have found a substantial number.5 Researchers have also discovered several free-floating planets and brown dwarfs (bodies unattached to any star).6 

Large planets cannot form at great distances from their stars because the circumstellar disks from which they form do not extend far enough. However, the nearly ubiquitous high-eccentricity orbits observed for exoplanets located more than a 100 million miles from their host stars (Earth’s distance from the Sun = 92.8 million miles; see the exoplanet catalog) implies that many planets will be ejected from their planetary systems. Given the expected large population of ejected planets, there exists a high likelihood that many stars will capture these free-floating bodies into very wide orbits.7

Our solar system’s lack of planets with high-eccentricity orbits, lack of wide orbit planets, and lack of any large body within a light-year of the Sun all suggests that our planetary neighborhood is special. At RTB, we propose that the uniqueness of our solar system indicates that it was designed intentionally, in order to make possible the existence of enduring advanced life on Earth. We can thank God that the closest we’ll be to a rogue planet is the pages of a sci-fi novel.

Subjects: Solar System Design

Dr. Hugh Ross

Reasons to Believe emerged from my passion to research, develop, and proclaim the most powerful new reasons to believe in Christ as Creator, Lord, and Savior and to use those new reasons to reach people for Christ. Read more about Dr. Hugh Ross.

References:

  1. Lorenzo Iorio, “Constraints on Planet X/Nemesis from Solar System’s Inner Dynamics,Monthly Notices of the Royal Astronomical Society 400 (November 2009): 346–53.
  2. Daniel P. Whitmire and Albert A. Jackson IV, “Are Periodic Mass Extinctions Driven by a Distant Solar Companion?Nature 308 (April 19, 1984): 713–15; Marc Davis, Piet Hut, and Richard A. Muller, “Extinction of Species by Periodic Comet Showers,” Nature 308 (April 19, 1984): 715–17.
  3. K. L. Luhman, “A Search for a Distant Companion to the Sun with the Wide-Field Infrared Survey Explorer,” Astrophysical Journal 781 (January 20, 2014): id. 4.
  4. Ibid.: p. 1.
  5. Adam L. Kraus et al., “Three Wide Planetary-Mass Companions to FW Tau, ROXs 12, and ROXs 42B,” Astrophysical Journal 781 (January 20, 2014): id. 20; Brendan P. Bowler et al., “A Disk Around the Planetary-Mass Companion GSC 06214-00210 b: Clues About the Formation of Gas Giants on Wide Orbits,” Astrophysical Journal 743 (December 20, 2011): id. 148; M. J. Ireland et al., “Two Wide Planetary-Mass Companions to Solar-Type Stars in Upper Scorpius,” Astrophysical Journal 726 (January 10, 2011): id. 113; P. Delorme et al., “Direct-Imaging Discovery of a 12–14 Jupiter-Mass Object Orbiting a Young Binary System of Very Low-Mass Stars,” Astronomy & Astrophysics 553 (May 2013): id. L5; A. Vigan et al., “Results of the NaCo Large Program: Probing the Occurrence of Exoplanets and Brown Dwarfs at Wide Orbit,” Proceedings of the International Astronomical Union 8, Symposium S299, Exploring the Formation and Evolution of Planetary Systems (June 2013): 17–20.
  6. Kraus et al., “Three Wide Planetary-Mass Companions”: id. 20; Sascha P. Quanz et al., “Search for Very Low-Mass Brown Dwarfs and Free-Floating Planetary-Mass Objects in Taurus,” Astrophysical Journal 708 (January 1, 2010): 770–84; Michael C. Liu et al., “The Extremely Red, Young L Dwarf PSO J318.5338–22.8603: A Free-Floating Planetary-Mass Analog to Directly Imaged Young Gas-Giant Planets,” Astrophysical Journal Letters 777 (November 10, 2013): id. L20.
  7. Hagai B. Perets and M. B. N. Kouwenhoven, “On the Origin of Planets at Very Wide Orbits from the Recapture of Free Floating Planets,” Astrophysical Journal 750 (May 1, 2012): id. 83.