The far reaches of our solar system are populated by intriguing objects with bizarre orbits that seem to defy the rules to which all the major planets have adhered.
One such example is the dwarf planet Sedna, one of the peculiar residents of the Kuiper Belt lying beyond the orbit of Neptune. As the Inquisitr previously reported, Sedna has the longest orbital period in the entire solar system and it takes 11,400 Earth years to circle the sun.
Together with a handful of small icy worlds in the Kuiper Belt, Sedna is part of what astronomers call “detached objects,” which follow strange orbital paths around the sun.
Also known as trans-Neptunian objects (TNOs), these tiny bodies have “eccentric, inclined orbits” that some astronomers suspect could be the result of a wild celestial encounter, Phys.org reports.
Another puzzling thing about the outer solar system is that the combined mass of all the TNOs beyond Neptune is extremely low compared to how much material there should actually be present there.
All these inexplicable things have made scientists wonder if perhaps “something out of the ordinary happened to our solar system during its early years” that flung the TNOs into their tilted orbits and catapulted thousands of similar frozen worlds out of the Kuiper Belt and into the deep corners of space.
According to a new study, the culprit may have been a “rogue” nearby star that buzzed our solar system too close during its early years and ended up creating chaos and throwing the planets into disarray.
This could also explain why Neptune is so much more massive than Uranus, despite being farther away from the sun.
Conducted by scientists from the Max Planck Institute for Radio Astronomy in Bonn, Germany, and from Queen’s University in Kingston, Canada, the research argues that our solar system may have been visited by a mysterious celestial object that “changed its configuration,” notes Phys.org.
While some astronomers theorized that the unusual orbits of the TNOs might have something to do with the elusive Planet Nine (or Planet X) — the missing super-Earth presumed to be hiding out in the Kuiper Belt, although it hasn’t yet been spotted, NASA explains — the study authors point to “external forces” that “restructured the outer solar system after its formation.”
Their explanation is that a massive star could have wandered by the solar system billions of years ago, disrupting the order of things at the far ends of the system.
“The study presented here shows that a close fly-by of a neighboring star can simultaneously lead to the observed lower mass density outside 30 AU and excite the TNOs onto eccentric, inclined orbits,” the authors wrote in their paper, submitted to the Cornell University Library and posted on the preprint server arXiv.
The 30 AU the scientists are referring to represent 30 astronomical units, where 1 AU equals the average distance between the Earth and the sun, calculated at 93 million miles (or 150 million kilometers).
While the idea in itself isn’t a new one, the team ran computer simulations that disproved the previous objections to this controversial theory.
The main critique that can be brought to the “rogue star” hypothesis is that such an event would have had to take place some 10 million years after the birth of the Milky Way. Yet at that time the objects in the outer solar system were still in the process of formation, meaning that they wouldn’t have been affected by a stellar interloper.
However, the study authors suggest that the outer region of the system could have been more developed than previously believed, which would have made it vulnerable to the gravitational pull of a passing star.
The scientists base their claim on the results of other studies looking into different solar systems than our own and which uncovered that the farther reaches of a solar system can mature faster than the inner regions.
Their computer simulations back up the claim and have revealed that, in such a scenario, our solar system would end up looking pretty much like it does today, “with odd characteristics at its outer edges.”
“Our simulations suggest that many additional [TNOs] at high inclinations still await discovery, perhaps including bodies like the postulated planet X,” the authors concluded in their paper.