Stories
Slash Boxes
Comments

SoylentNews is people

posted by takyon on Tuesday January 22 2019, @08:47AM   Printer-friendly
from the planet-doubt dept.

The strange orbits of some objects in the farthest reaches of our solar system, hypothesised by some astronomers to be shaped by an unknown ninth planet, can instead be explained by the combined gravitational force of small objects orbiting the Sun beyond Neptune, say researchers.

The alternative explanation to the so-called 'Planet Nine' hypothesis, put forward by researchers at the University of Cambridge and the American University of Beirut, proposes a disc made up of small icy bodies with a combined mass as much as ten times that of Earth. When combined with a simplified model of the solar system, the gravitational forces of the hypothesised disc can account for the unusual orbital architecture exhibited by some objects at the outer reaches of the solar system.

[...] "The Planet Nine hypothesis is a fascinating one, but if the hypothesised ninth planet exists, it has so far avoided detection," said co-author Antranik Sefilian, a PhD student in Cambridge's Department of Applied Mathematics and Theoretical Physics. "We wanted to see whether there could be another, less dramatic and perhaps more natural, cause for the unusual orbits we see in some TNOs. We thought, rather than allowing for a ninth planet, and then worry about its formation and unusual orbit, why not simply account for the gravity of small objects constituting a disc beyond the orbit of Neptune and see what it does for us?"

[...] Earlier attempts to estimate the total mass of objects beyond Neptune have only added up to around one-tenth the mass of Earth. However, in order for the TNOs to have the observed orbits and for there to be no Planet Nine, the model put forward by Sefilian and Touma requires the combined mass of the Kuiper Belt to be between a few to ten times the mass of Earth. [...] "It's also possible that both things could be true -- there could be a massive disc and a ninth planet. With the discovery of each new TNO, we gather more evidence that might help explain their behaviour."

Shepherding in a Self-Gravitating Disk of Trans-Neptunian Objects

Related: CU Boulder Researchers Say Collective Gravity, Not Planet Nine, Explains Orbits of Detached Objects


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 2) by bob_super on Tuesday January 22 2019, @05:14PM

    by bob_super (1357) on Tuesday January 22 2019, @05:14PM (#790143)

    That would not be the first time we found a planet after noticing its influence on other things. It just gets harder the farther we go.

    Last time I checked my gravity equations, a bunch of distributed mass versus a single massive object was equivalent. But if we're talking about a disc centered around the sun, then the center of mass wouldn't be where a planet would be. That disc has to be pretty darn clumpy.

    Starting Score:    1  point
    Karma-Bonus Modifier   +1  

    Total Score:   2