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Weird Orbits of Distant Objects Can Be Explained Without Invoking a 'Planet Nine' (space.com)
schwit1 shares a report from Space.com: The weirdly clustered orbits of some far-flung bodies in our solar system can be explained without invoking a big, undiscovered "Planet Nine," a new study suggests. The shepherding gravitational pull could come from many fellow trans-Neptunian objects (TNOs) rather than a single massive world, according to the research. "If you remove Planet Nine from the model, and instead allow for lots of small objects scattered across a wide area, collective attractions between those objects could just as easily account for the eccentric orbits we see in some TNOs," study lead author Antranik Sefilian, a doctoral student in the Department of Applied Mathematics and Theoretical Physics at Cambridge University in England, said in a statement.
The duo's modeling work suggests that the strength-in-numbers explanation does indeed work -- if the mass of the Kuiper Belt, the ring of bodies beyond Neptune, is a few to 10 times that of Earth. This is a pretty big "if," given that most estimates peg the Kuiper Belt's mass at less than 10 percent that of Earth (and one recent study put the figure at 0.02 Earth masses). But other solar systems are known to harbor massive disks of material in their outer reaches, Sefilian and Touma noted. And our failure to spot one around our own sun doesn't mean it doesn't exist, they stressed. The new study has been accepted for publication in the Astronomical Journal.
The duo's modeling work suggests that the strength-in-numbers explanation does indeed work -- if the mass of the Kuiper Belt, the ring of bodies beyond Neptune, is a few to 10 times that of Earth. This is a pretty big "if," given that most estimates peg the Kuiper Belt's mass at less than 10 percent that of Earth (and one recent study put the figure at 0.02 Earth masses). But other solar systems are known to harbor massive disks of material in their outer reaches, Sefilian and Touma noted. And our failure to spot one around our own sun doesn't mean it doesn't exist, they stressed. The new study has been accepted for publication in the Astronomical Journal.
Not exactly. The whole mass of the Kuiper Belt (containing millions of objects) has to be about 10 mass of the Earth in this model to explain the special orbits of some known Kuiper Belt objects. But no single object has to be exceptionally large. A million objects each 10 km in diameter would have the same mass than one planet of 1000 km diameter of the same density.
The news in 2018 was all "There's a Planet X, there's a Planet X". Fast forward to January 21 2019. Two Cambridge PhD's claim "it may be a ring of smaller" objects. Now the news is all "There is no Planet X, there is not Planet X." Nobody has been able to observe either a 9th Planet or a ring of smaller objects yet. So basically, nobody knows whether there is a 9th Planet out there or not. Everybody's speculating. (Btw, Nibiru sounds like a Linux distro =)
No, the news used to be that a Planet X about 10 times the mass of Earth could explain the strange orbits of some of these Trans Neptunian Objects. Now the news is that a ring of smaller objects could also explain the strange orbits of these same TNOs. It just gives scientists something else to look for. That is how science works, people come up with educated guesses (hypotheses) to explain a phenomenon and then try to confirm or disprove them through observation and experiment. This is just science working properly, so no need to get your underwear all tied up into a knot over it.
Not so. The proposed planet nine to explain the unlikely clustering of TNOs would have a period in the 10,000-20,000 year range https://en.wikipedia.org/wiki/...
By Kepler's Law (T^2 proportional to R^3), that would put it's semi-major axis at between 464 to 737 AU, and its apogee could be almost twice that.(semimajor axis is the average of apogee and perigee)
Assuming it basically looks like Pluto scaled up 11-23x (to the estimated 2-4x the Earth's diameter) Would mean it's angular diameter would be between (11x)*40AU/737AU = 0.6x and (23x)*40/464 = 2.0x the size, for an angular area between 0.36x and 4.0x Pluto, and a corresponding effective brightness between 0.6*(40/737)^2= 0.2% and 4.0*(40/464)^2=3% as bright as Pluto. Assuming a circular orbit - it might be far smaller and dimmer at apogee.
Easy to overlook. Especially since it would move only 0.02 to 0.04 degrees per year. Or potentially much less it it's near apogee.
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