Kuiper Belt Mystery: What Left Our Outermost Solar System in Chaos?


A group of astronomers from the Max Planck Institute for Radio Astronomy in Bonn, Germany and Queen's University in Belfast, Ireland have released a study concluding that the chaos in our outer solar system may have been caused a close fly-by of a star during our solar system's formation.

The study, published August 9, 2018 the peer-reviewed Astrophysical Journal, sought to answer two troubling questions about our outer solar system. The first relates to the less-than-expected total mass of the Kuiper Belt (objects beyond the orbit of Neptune). The second is the eccentric orbits of bodies in those outer realms of our solar system. While the primary planets of the inner solar system orbit the sun in nearly circular orbits and on a common plane, trans-Neptunian objects have wildly irregular orbits and do not conform to that common plane.

Using observations from other solar systems and computer modeling, the team determined that among the best explanations for these two facts was a stellar object passing near our still forming solar system at a distance as close as three times the orbit of Neptune. The simulations show that such an event would have pulled large amounts of matter away the outer edges of our solar system and left that part of the solar system in a chaotic state still present today. The culprit star would have been 0.5-1 solar masses.

In the statement released by the team about their study, co-author Pedro Lacerda says the following.

Team lead  Suzanne Pfalzner (Max Planck) said "Our group has been looking for years at what fly-bys can do to other planetary systems, never considering that we actually might live right in such a system. The beauty of this model lies in its simplicity."

Co-author Pedro Lacerda (Queens University) added, “It is important to keep exploring all the possible avenues for explaining the structure of the outer solar system. The data are increasing but still too sparse, so theories have a lot of wiggle room to develop. There is a certain danger that one theory crystallizes as truth, not because it explains the data better but because of other pressures. Our paper shows that a lot of what we currently know can be explained by something as simple as a stellar fly-by.”

Articles on some alternative websites claimed this is evidence o Nibiru. In his landmark 1976 book The 12th Planet, author and researcher Zecharia Sitchin put forward the idea that ancient Sumerian writings point to a large planetary body periodically entering the inner solar system, presumedly, through the Kuiper Belt and creating chaos out there and closer to home.

More recently, a Cal-Tech team led by Mike Brown has been urgently in search of what they dub Planet Nine in the outer solar system. That team believes the erratic orbit of some objects in the Kuiper Belt are caused by a large planetary body similar to the one proposed by Sitchin, though with a different orbit. 

I reached out Mr. Brown to ask if this finding at all impacts his team's research. Here was his reply.


What we all can agree on, is that our outer solar system is chaotic and there must be an explanation for it. By the Max Planck team's own admission, their hypothesis, while borne out by simulations, is not definitive nor conclusive.

Whether it's an ancient fly-by, Planet Nine, Nibiru or something else, the search for answers about the Kuiper Belt has all the intrigue of a detective novel. The evidence lies strewn around our sun. The question remains, "Who dunnit?"

Ray Davis
6 Sense Media