The outer reaches of our solar system are populated with more than 2,300 celestial bodies floating around in a distant realm known as the Kuiper Belt, which lies just beyond Neptune's orbit.
Some of these bodies — which are called trans-Neptunian objects (TNOs), notes Space.com — have very peculiar orbits that set them apart from everything else in the solar system.
As the Inquisitr last month, these objects have a tilted orbit that makes them wobble out of the plane of the solar system and engage in long, elliptical trips around the sun. For some years now, researchers have speculated that something is pulling these objects away from the plane where the system's major planets are orbiting, giving them a downward inclination of 30 degrees.
Until now, the culprit was believed to be the elusive Planet Nine — a mysterious ice giant 10 times more massive than Earth and which is presumably lurking in the Kuiper Belt.
But a new study offers a different explanation for the strange orbits of these "detached objects" in the far reaches of the solar system.
Ann-Marie Madigan, an assistant professor in the Department of Astrophysical and Planetary Sciences at the University of Colorado Boulder (CU Boulder), says that the Kupier Belt is a lot more dynamic than we imagine.
"The picture we draw of the outer solar system in textbooks may have to change. There's a lot more stuff out there than we once thought, which is really cool."In a new study presented on June 4 at the 232nd meeting of the American Astronomical Society in Denver, Colorado, Madigan and her colleagues argue that it was these objects' collective gravity, and not some enigmatic unseen planet, that nudged them into their detached orbits. What Is Sedna?
According to CU Boulder, the team looked at one of these objects in particular — a dwarf planet called Sedna, which orbits the sun at a distance of nearly eight billion miles and is distant enough so as not to be affected by Neptune's gravity, the Inquisitr previously reported — and tried to understand why its orbit looks the way it does.
Just like other "detached objects," Sedna has a circular orbit that moves it away from the system's major planets, propelling it into a journey of more than 11,000 years around the sun. That's how long it takes for this icy minor planet, slightly smaller than Pluto, to complete a full orbit.
The explanation may come from "bumper car-like interactions" going on in the Kuiper Belt and which cause these "detached objects" to slam into each other and collide with space debris.
"The picture we have in our head is a lot of little moons floating around the solar system, interacting with comets," Madigan told reporters yesterday during a news conference, notes Space.com.
After calculating the orbits of the "detached objects" in the Kuiper Belt, Sedna included, the CU Boulder team discovered that these small bumps and jostles in outer space make for a more plausible explanation for the orbital oddity that the existence of Planet Nine.
"They are what's causing this detachment, and not an unseen ninth planet," study lead author Jacob Fleisig, an undergraduate astrophysicist at the university, said during the conference.
Not Planet Nine
Fleisig ran a computer model for the orbits of these strange distant objects and uncovered that they move a lot like hands on a clock. His research shows that the bigger objects, such as Sedna, move slowly around the sun — the equivalent of the hour hand, while smaller objects in the Kuiper Belt, such as asteroids, move "relatively fast and in tandem," like the minute hand.
As Fleisig explains, this causes the smaller objects to amass together and generate a sufficient amount of collective gravity to impact the course of the bigger objects.
"You see a pileup of the orbits of smaller objects to one side of the sun. These orbits crash into the bigger body, and what happens is those interactions will change its orbit from an oval shape to a more circular shape."These findings are supported by a 2012 study, which revealed that bigger "detached objects" tend to wander farther away from the sun, notes CU Boulder. This is what happened in Sedna's case, says the team, who puts the extreme orbits of these objects solely down to the power of collective gravity. Although their theory does breathe fresh air into these objects' mystery, after scientists looking for Planet Nine over the past couple of years have consistently come up empty-handed, it does, however, fail to explain why these "detached objects" are all titled in the same way, on the same 30-degree downward angle.
"Planet Nine explains this really well, and we do not," admits Madigan.
Where Do Dinosaurs Fit Into All Of This?
Well, as it turns out, the new theory that axes Planet Nine might also be tied to the dinosaur extinction. If these gravity bumps are strong enough to push big objects like Sedna away from the sun, then, theoretically, they could also hurl comets and asteroids toward the inner solar system, targeting the unsuspecting rocky planets.
If this is true, then Earth makes no exception and could also be subjected to the repeating cycle of cosmic bombarding triggered by the small gravitational interactions in the Kuiper Belt.
According to the team, the dinosaur-killing asteroid that hammered our planet 65 million years ago, wiping out nearly 75 percent of life on Earth, could have been sent on its collision path by the periodic comet showers that turned up in Fleisig's computer model.
"While we're not able to say that this pattern killed the dinosaurs," Fleisig said, "it's tantalizing."