Early Solar System Catastrophism

The two moons of Mars have always presented planetary scientists with something of a mystery. These tiny moons, Phobos and Deimos, whizz around Mars at no great height at all: Phobos whips around the red planet in less than 8 hours, at a height of only 3,700 miles – the closest of any moon to its parent planet. I say ‘parent’ advisedly because a new theory of the origin of these peculiar little moons suggests that they emerged from a major impact between mars and a dwarf planet. It has generally been assumed that they were captured asteroids, but the relative circularity of their orbits argued against such a capture. Work on the possibility of a catastrophic origin was carried out last year by two separate teams of researchers, after decades of battling intense scepticism within the scientific community (1). An important finding of the modelling at that time was that the resultant debris would circulate around the red planet at a relatively low altitude, which is in keeping with the orbits of the two extant moons.
More recently, further computer modelling of various impact scenarios carried out by one of those teams has narrowed down the range of masses of an impactor to about the size of Pluto. The resultant debris field was initially far more extensive than the two moons left today:

“The results show that [an impacting object with roughly the mass of Pluto] would throw around a thousandth of Mars’s mass into orbit, and the edge of the disc would reach beyond the 24,000-kilometre orbit of Deimos, the outer moon. Over time, the material nearer to Mars would coalesce into large bodies, but the planet’s gravity would eventually drag them back down. But the outer part of the disk would spin fast enough to keep it out of gravity’s clutches, and the material would form into the Phobos and Deimos we see today.
“The idea is that Phobos and Deimos are the only two survivors of a once much larger population of satellites,”says [Julien] Salmon [of the Southwest Research Institute], who presented the work at the Lunar and Planetary Science Conference in The Woodlands, Texas, last month. Such a large object hitting Mars in its past could also explain some other features we see today, like the planet’s relatively fast rotation and the large differences in average surface height between its northern and southern hemisphere, says Salmon. “It makes sense to think about a big impact for Mars.”” (2)
I don’t think anyone’s going to be too surprised that during the early period of the solar system, planets like Mars could have been struck by substantial ‘dwarf planets’ during that turbulence.  For me, potentially the most interesting aspect of this would be the timing of such an event.  If it occurred very early on, where the Mars was in a primordial, molten state, then this is no real news. However, Mars appears to have been killed at some point, and the most likely time period for such an event would have been during the late, heavy bombardment, a long period of on-going catastrophe between 3.9 and ~3.6 billion years ago.

mars-attacked2

No one knows what caused this late period of immense destruction. It’s become increasingly clear that the solar system’s early history was exceptionally violent, perhaps even exceptionally so compared with other star systems. Dr Batygin, the dynamicist who worked with Dr Mike Brown on the Planet Nine paper in January (3), has published a new paper with other collaborators, and puts it like this:
“A wealth of new evidence from computer simulations as well as observations of planets throughout the galaxy is revealing new details of our solar system’s dynamic and violent history.
The solar system’s configuration of small inner rocky worlds and large outer giants is anomalous in comparison with most other planetary systems, which have different architectures.
The best explanation for the solar system’s oddity is that the giant planets went through an extended sequence of orbital migrations and dynamical instabilities billions of years ago.
These tumultuous events could have sent entire planets tumbling into the sun or out to interstellar space and may have been crucial for the origins and earliest evolution of life on Earth.” (4)
These statements turn the common conception that the solar system was once a ‘normal’, straightforward youngster on its head. On the contrary, astrophysicists look at our solar system’s current configuration, which on the face of it seems so calm and well-structured, and see a past filled with widespread violence on a cosmic scale, major planetary migrations and complex reconfigurations before today’s relative calm was achieved.
This is not news to catastrophists, like me. I consider it highly likely that a usurper planet, yet to be discovered in our outer solar system, played a major role in this, and that much of what Zecharia Sitchin wrote on the subject (5) has some truth to it. I think things went something like this: Up until 3.9 billion years ago, Nibiru/Marduk was a substantial companion object of the Sun well beyond the protoplanetary disk, safely out of the way (although perhaps, as researcher Barry Warmkessel has suggested, an intrinsically important element in the whole planet formation process (6)).  At the 3.9 Gyr point, something (a passing star?) caused Nibiru/Marduk to shift gears, and cruise through the planetary zone, causing the Celestial Battle Sitchin speaks about.  That catastrophe created a chaotic environment, both for the inner planets, but also for this object itself. Things evidently eventually settled down into a steady state, but it seems that the late, heavy bombardment’s longevity, of ~300 million years, offers us an opportunity to see an extended aftermath. It may have been during this period of repeated intrusions of Nibiru/Marduk through the planetary zone that the kind of impact that Mars suffered occurred. Hence, why the timing of this is so crucial.
Where I part with Sitchin is that after 3.6 Gyr, the usurper clearly stopped causing this chaos and destruction. Therefore, it seems likely to me that its orbit shifted once again, perhaps by one of these catastrophic incursions, and it migrated out to a much safer distance, leaving the planetary zone of the solar system in relative peace from that point onwards. This is not Sitchin’s view, of course, but I think it makes more sense of the facts as we know them.

A Captured Exoplanet?

My contention that Nibiru/Marduk was an original partner of the Sun (albeit initially in a very loosely bound, distant orbit) is based purely upon probability. It’s difficult, but not impossible, to capture objects moving through interstellar space, and it just seems more likely to me that the Dark Star companion to the Sun was already on the scene at the beginning. But that is not the only possibility by any stretch of the imagination, as has been pointed out by my French researcher friend François Berguerand in correspondence we have recently shared on the subject.
In 2012, researchers from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and Peking University in China simulated young star clusters containing free-floating planets and realised that it would not be as uncommon as one might imagination for stars to effectively swap planets between them (7). Planets which are ejected by one star might be picked up by another within the tightly-knit cluster (which might contain thousands of young stars). These clusters spread out over time and, with as a result of this process, the likelihood of this ‘planet-snatching’ process taking place declines.

redorbit5-2
So, it’s entirely possible that Nibiru/Marduk might have originated from a sister star within the Sun’s birth cluster, and was effectively snatched away from her by our Sun. That would be in keeping with Sitchin’s original hypothesis about the incursion of a rogue fiery planet travelling through interstellar space which becomes captured by the Sun into a highly elliptical orbit. Whether the timing of such an event is realistic as late as the Late, Heavy Bombardment, some 700 million years after the birth of the Sun, is a moot point, because the initial birth cluster would have been well on the way towards dissipation by that point. Birth clusters seem to retain their definition for about 100 million years.
As discussed in the first article in this blog, such a scenario might be applied to the Planet Nine object which has captured the imagination of the astronomical community this year. A team of astrophysicists – Drs Mustill (of the Lund Observatory in Sweden), Raymond and Davies – consider it perfectly plausible that the Sun might have captured the purported Planet Nine body from a sister star early on in the life of the birth cluster, and have conducted computer simulations to demonstrate how this might have occurred, under certain conditions:
“Any capture scenario must satisfy three conditions: the encounter must be more distant than ~150 au to avoid perturbing the Kuiper belt; the other star must have a wide-orbit planet (a>~100au); the planet must be captured onto an appropriate orbit to sculpt the orbital distribution of wide-orbit Solar System bodies.” (8)
Even so, the odds of such a capture are low, they say (9), but certainly not impossible. Much of this speculation hangs upon the prevalence of interstellar free-floating worlds and Dark Stars, which remains an unknown quantity presently. The more of these objects there are in existence, the more likely it becomes that these wilder possibilities might have taken place.

The LHB and Mars

The Late, Heavy Bombardment features in other theories about the nature of early Mars, and what might have happened to it. We have delved into the mysteries of Martian water in previous blogs, and the probable existence of a sizeable northern ocean on the red planet at some point in the past. The chaotic tilt and orbital variance of Mars might play a significant role in terms of periodic melting of substantial bodies of underground ice (10). Furthermore, it is quite possible that liquid water existed on the Martian surface far more recently than is generally accepted, creating further riddles for scientists to ponder (11).

ancient_Mars2
New work looking at the topography of likely ancient ocean shorelines has potentially added more detail to this debate but remains contentious (12). Perhaps the early Martian surface was partially covered by a thin layer of ice, which was then bombarded by asteroids to evaporate away into and beyond the thin atmosphere of Mars. Or perhaps, a shallow ocean existed in aqueous form which succumbed to sublimation over a longer period of time, driving much of the early water of Mars away into space. Whatever the case, it seems likely that many mysteries of the solar system are tied up with the Late, Heavy Bombardment, whose origins remain unclear. I suggest that Zecharia Sitchin’s ideas on this front were very much ahead of their time!

Written by

18-28th January 2016
References:
1) Ken Croswell “Are Mars’s moons homegrown—or snatched from the asteroid belt?” 19th May 2015 http://www.sciencemag.org/news/2015/05/are-marss-moons-homegrown-or-snatched-asteroid-belt
2) New Scientist “Mars moons may have formed after collision with Pluto-like world” 8 April 2016, https://www.newscientist.com/article/2083503-mars-moons-may-have-formed-after-collision-with-pluto-like-world/
3) K. Batygin & M. Brown “Evidence for a Distant Giant Planet in the Solar System” 20th January 2016, The Astronomical Journal, Volume 151, Number 2, http://iopscience.iop.org/article/10.3847/0004-6256/151/2/22
4) Konstantin Batygin, et al “Born of Chaos” 19th April 2016 http://www.nature.com/scientificamerican/journal/v314/n5/full/scientificamerican0516-28.html
5) Zecharia Sitchin “The Twelfth Planet” Avon, 1976
6) Correspondence from Barry Warmkessel on the Google Dark Star Planet X Forum, 15th April 2016 https://groups.google.com/forum/#!topic/dark-star-planet-x/26b8AvkWXZQ
7) Ian O’Neill “Thieving Stars Snatch Orphan Planets” 30th April 2012 http://news.discovery.com/space/thieving-stars-snatch-orphan-planets-120430.htm
8) Alexander Mustill et al “Is there an exoplanet in the Solar System?” 23rd March 2016 http://arxiv.org/abs/1603.07247
9) Shannon Hall “Planet Nine might be an exoplanet stolen by the Sun” 4th April 2016 https://www.newscientist.com/article/2082970-planet-nine-might-be-an-exoplanet-stolen-by-the-sun/ with thanks to Lee
10) Andy Lloyd “The Implications of Mars’ Chaotic Tilt” 22nd March 2016 http://www.andylloyd.org/darkstarblog24.htm
11) Andy Lloyd “A Martian Riddle” 22nd September 2014, http://www.andylloyd.org/darkstarblog18.htm
12) Elizabeth Howell “Did Asteroid Impacts Incubate Mars’ Ancient Oceans?” 25th April 2016 http://www.space.com/32686-did-asteroid-impacts-melt-up-mars-ancient-oceans.html with thanks to Lee

Leave a Reply