Divining Planet 9 (Twice Baked)

{Updated analysis is found at the bottom of the blog.}

I've taken another look at the Planet 9 debate and there are some helpful on-line articles. This one puts things in laymen's terms very nicely:


There is a growing consensus that the hypothetical Planet 9 is in a 3:2 resonance relationship with Sedna. That means that Planet 9 orbits the Sun twice for every three orbits that Sedna makes. If I understand correctly (assuming counter-clockwise rotation), then the two bodies will line up on the same side of the Sun when Sedna is its closest to the sun (perihelion) and Planet 9 is its furthest from the Sun (aphelion). Coincidentally, Sedna is now reaching its closest approach to the Sun. However, Planet 9 is not necessarily in the same direction as Sedna. It only lines up with Sedna once every three orbits of Sedna.

According to the above linked article, French scientists do not think that this is one of those alignments. Instead, the two bodies will next line up on the following perihelion of Sedna (around 11,000 years from now). The above article includes a chart that shows the three basic regions where Planet X should/could be right now based on its expected resonance relationship with Sedna. This makes very good intuitive sense to me. However, the most probable region (according to the French) does not appear to match the one being searched by Mike Brown using the Suburu Telescope, which instead seems to assume that the two bodies are roughly aligned at this time on the same side of the Sun.


From a mythological perspective, there is at least some suggestion that there is still some life left in the "old devil" Sin/Nannar/Apophis. In other words, the brown dwarf occasionally flares up and reveals itself (even if it can't do any direct damage). Intuitively, this would most likely happen when it is at perihelion. But, if it can never be at perihelion when Sedna is also at perihelion (due to resonance), then we will have to wait a very long time to witness this! Depending on where "Planet 9" currently is at in its resonance cycle with Sedna, the last time it reached perihelion was either ~850 BC, ~6,550 BC or ~9,400 BC. All of these dates are within human memory.

There are of course other known unknowns. Particularly, what gravitational effects did Scholz's Star have when it passed through our outer solar system 70,000 years ago?


1st Update:

Another way to figure out the general location of "Planet 9" is to chart variation is solar output. When "Planet 9" approaches its perihelion we would expect increased activity from the Sun in response. I made a quick google search and did not come up with much. However, the article below does suggest that there was in fact increased solar activity at the end of the Last Ice Age, and probably even during the Younger Dryas Period.

"A History of Solar Activity over Millennia"


Paul LaViolette and Robert Schoch have explored cosmic sources for solar disruption during the Younger Dryas. However, it may be that the major source is right here within the solar system itself. If the perihelion of our sun's "failed twin" is close enough to effect our sun, then we would expect increased radiation and also "Carrington Events" during that portion of its orbit. (Increased solar radiation might also at least partially explain gigantism, and again without needing an extra-solar system cause.) It also means that the Younger Dryas mini-Ice Age was not the result of reduced solar output, but other factors (such as impact events).

If I'm reading the chart correctly (in the Universe Today article, above), then if "Planet 9" is where the French scientists are looking, then the last time it was at perihelion was at the end of the Ice Age. Hmmm.

Another curiosity is that the proposed orbit of hypothetical Planet 9 is 1.5 times (3:2 resonance) that of Sedna or 17,113 years. If you multiply the hypothetical orbit of Planet 9 by 1.5 you get 25,668 years and this is the approximate length of a precessional cycle. Double Hmmm. In other words, there is reason to expect that Planet 9 is associated with the phenomenon of precession itself.

2nd Update:

Surely the astrophysicists have also considered other possible resonance relationships. A 2:1 resonance is actually even more interesting to me. In that case, "Planet 9" should be in the same general direction as Sedna right now, but further out than for a 3:2 resonance scenario. Unfortunately, that may also mean that it is beyond recognition range using the current technology, because of the more elongated orbit (22,816 years vice 17,112 years). I suppose 3:1 and other resonance relationships could also be considered, but I don't have a feel for whether these are workable or not. Obviously, a 2:1 (or 3:1) resonance would place a greater loading on the Sun (and produce a greater "wobble") in comparison to 3:2.

For the 2:1 resonance, the last perihelion of "Planet 9" was 11,408 years ago, i.e., also at the end of the last Ice Age.

Join the "Citizen Scientist" search for Planet 9 at NASA:


3rd Update:

An interesting (and unexplained) aspect of precession is that it is not uniform and is currently accelerating. According to Walter Crutenden, "the companion star must have just turned the corner at their aphelion point and is now beginning to approach Earth [from its furthest separation].


Crutenden concedes that the same change in the rate of precession could also be associated with the binary reaching their perihelion. However, he is of course justified in assuming the opposite, as we would have detected the mystery body by now if it were now at its closest approach.

The additional "strain" of this turning event could conceivable be effecting (increasing) solar activity, as well:


4th Update:

A brown dwarf with an orbit the same length as the precessional cycle could be in a 9:4 resonance with Sedna. However, I don't know if resonance is a straightforward calculation in this case due to the currently unknown number of other ETNO's that would be in resonance with the hypothetical "Planet 9" as well. In any event, this would certainly complicate the search due to the more elliptical/longer orbit and larger number of regions where the body could be potentially located.

And as mentioned above, we don't know if the orbit of a large outer planet/small sun had been disturbed by the passing of Scholz's Star. This could, of course, still be effecting precession to this day (if not outright destabilizing the system).