Andy Lloyd's

Dark Star Blog



Blog 52   (July 2017)

(Currently being written)

  News, links, videos and comment   relating to the Dark Star Theory 



Planet Nine:  Are They Digging in the Wrong Place?

Last month, scientists working on the Outer Solar System Origins Survey (OSSOS) published a large dataset of new Kuiper Belt Objects, including several new extended scattered disk objects discovered way beyond the main belt (1).  These four new distant objects seemed to have a more random set of properties, when compared to the rather more neat array of objects which had previously been constituted the Planet Nine cluster.  This led to scepticism among the OSSOS scientific team that there was any real evidence for Planet Nine.  Instead, they argued, the perceived patterns of these distant objects might be a function of observational bias (2). 

Whilst reporting on these new discoveries and their potential implications, I predicted that the debate was about to hot up, bringing forth a new series of Planet X-related articles and papers (3).  Indeed, leading outer solar system scientists were publishing related materials in quick succession (4,5), each finding new correlations and patterns which might indicate the presence of an unseen perturbing influence.

Now, Caltech's Konstantin Batygin has published an article analysing the impact of the discovery of these new extended scattered disk objects on the potential for a Planet Nine body.  The short conclusion he draws is that although the objects are, on the face of it, randomly distributed, their property set is largely consistent with Caltech's original thesis (6).  They are either anti-aligned to the purported Planet Nine body (as the original cluster is thought to be), or aligned with it in a meta-stable array. 

The one object which is completely off-kilter, 2015 GT50, turns out to have a resonance relationship with a set of values for the unseen Planet Nine object, as described in the original 2016 Caltech paper (7).  At least, that's what Dr Batygin argues.  Others may sense a circular argument here, whereby a cluster of objects points to a set of parameters for the mystery perturber, whose theoretical orbital characteristics can then be used to explain a data point that fits neither the anti-aligned nor the aligned cluster :

"A more cursory inspection (sic) of the above plot however, brings to light the existence of a string of specific orbital radii that correspond to resonances with Planet Nine, where the simulated objects circulate through the full 0-360 degree range of orbital orientations. Remarkably, the outlier (2015 GT50) falls *exactly* on one such orbit (i.e. note on the plot above that the gray point falls on a vertical blue line).  This is kind of staggering. Without changing the Planet Nine parameters at all (to make this plot I’ve adopted the same a=700AU e=0.6 m=10Mearth P9 configuration as in the original Batygin & Brown 2016 AJ paper), the model manages to fit all the data, including the supposed outlier" (6)

Dr Batygin goes on to say that the cluster effect is just one of five lines of enquiry pointing towards the existence of a super-Earth Planet X body.  Even if the cluster argument is weakened by the new OSSOS dataset of objects (he doesn't agree that it is), there is still compelling evidence for Caltech's 'Planet Nine' object, he argues, including the mystery of the retrograde Kuiper Belt Objects Niku and Drac (8).  The mechanism put forward last October for Planet Nine to generate these anomalies (9) can be successfully applied to two new objects within the OSSOS dataset (10), Batygin argues.

It's good to see these arguments being thrown about so quickly, and within a public domain.  Journal publications will no doubt follow, but such is the heat generated by the Planet Nine debate that there is little patience to wait for these publications, and more formal conference discussion that follows.  Or else, science's battlefields are modernising on competing blogs.  To some extent, I welcome this, because it provides welcome clarity and speed to this debate, wrapped up in an informed, but relatively understandable, format.  It is clear that the Caltech team seem unperturbed by the new OSSOS data, and ensuing scepticism about Planet Nine.  But none of this counter-argument is peer-reviewed, yet.

There's one last issue I would like to point out here, above and beyond the existence of Planet Nine debate.  Let's say the extended cluster does indeed point towards a Planet X body.  The original cluster was very one-sided, and the Caltech team interpreted that as being the dynamically stable 'anti-aligned' orientation to Planet Nine.  in other words, the bulk of Planet Nine's eccentric orbit lies in the opposite hemisphere of the solar system than the bulk of the extended TNO orbits within the cluster.  In the opposite orbital diagram, the original (and now enhanced) cluster is seen in purple.

Now we have two data points (seen in green in the diagram) which fall into the 'meta-stable' aligned cluster, as noted by Dr Batygin (6).  Given the discussion about observational bias, it seems perfectly possible to me that as more discoveries are made, the population of this side of the fence will grow.  Perhaps, in time, this side of the fence will be the dominant sector.  In which case, it may be that the Caltech team have misinterpreted the initial data set as anti-aligned, when they are actually the meta-stable aligned grouping.  I argued this early last year, citing evidence that Planet X is located in the opposite part of the sky to Caltech's preferred location in Orion (11).

Of course, it's too early to say based upon just two new objects, but if that's the case, then, in the immortal words of Indiana Jones, "They're digging in the wrong place!"


Written by Andy Lloyd,  3rd July 2017


1)   Cory Shankman et al "OSSOS VI. Striking Biases in the detection of large semimajor axis Trans-Neptunian Objects", 19th June 2017, accepted for publication by the The Astronomical Journal,

2)   Josh Sokol "New haul of distant worlds casts doubt on Planet Nine", 21st June 2017

3)  Andy Lloyd "New Arguments about Planet Nine Cluster" 23rd June 2017

4)  Volk, K. & Malhotra, R. "The curiously warped mean plane of the Kuiper belt", Astronomical Journal, (in press) (2017)

5)   C. de la Fuente Marcos & R. de la Fuente Marcos "Evidence for a possible bimodal distribution of the nodal distances of the extreme trans-Neptunian objects: avoiding a trans-Plutonian planet or just plain bias?" 21 Jun 2017, Accepted for publication in Monthly Notices of the Royal Astronomical Society: Letters,

6)  Konstantin Batygin "The Search for Planet Nine: Status Update (Part 1)" 30th June 2017

7)  K. Batygin & M. Brown "Evidence for a Distant Giant Planet in the Solar System" 20th January 2016, The Astronomical Journal, Volume 151, Number 2,

8Andy Lloyd "Niku, Drac and L91 Perturbed by Planet Nine...or Something Else?" 18th October 2016

9)  Konstantin Batygin & Michael Brown "Generation of Highly Inclined Trans-Neptunian Objects by Planet Nine" 17th October 2016

10)  Konstantin Batygin "The Search for Planet Nine: Status Update (Part 2)" 2nd July 2017

11)  Andy Lloyd "Planet Nine Constellations Predicted by Sitchin, and IRAS" 26th January 2016



The aligned and anti-aligned clusters

Image credit: Konstantin Batygin

Relative stabilities of the growing P9 ETNO clusters

Image credit: Konstantin Batygin









Weighing up the Options for X

Also covered last month was another paper about Planet X, this time proposing that there could be a terrestrial-sized object (Mars-sized up to maybe about two times that of Earth), lying much closer to the outer Kuiper Belt (1).  This version of Planet X is much closer than Caltech's Planet Nine (2).  Astrophysicists from the University of Arizona have examined the average mean plane of Kuiper Belt Objects (KBOs), and discovered that the outermost populations of these objects have a mean plane that varies significantly from the ecliptic (3,4).  They conclude that an unseen gravitational influence must be perturbing these more distant KBOs.  Their calculations provide a best-fit with a not-too-distant terrestrial Planet X. 

This conclusion is in keeping with a previous Planet X proposal made 15 years ago by astronomers Brunini and Melita who suggested an embedded Mars-sized object at around 60AU could explain the Kuiper Gap (or sometimes 'Kuiper Cliff'), where the distribution of KBOs drops off significantly at around 50AU (5). They concluded that a Planet X body would need to have quite an eccentric, inclined orbit to account from the anomalies, and to have remained undetected for so long.

I wrote to one of the UA scientists, Dr Renu Malhotra, to ask whether there was any correlation between their recent 2017 findings about Planet X, and a paper that they had written in 2016 about a possible resonance relationship between the orbits of various KBOs, and Planet Nine (6,7).  In her reply, she indicated that these were largely unrelated issues, and explained the thinking behind each piece of research:

"Our paper from last year was on possible orbital resonances of distant KBOs with an unseen planet (so-called Planet Nine) of about 10 times Earth's mass orbiting at several hundred astronomical units distance from the Sun."

"The new paper is about the mid-plane of the Kuiper belt and its measured warp at distances of 50-80 au. We think that this warp is unrelated to the so-called Planet Nine -- that hypothetical planet would be too weak to influence the Kuiper belt's mid-plane at 50-80 au.

"In the resonance work last year, the useful sample of KBOs was limited to just the 4 most distant KBOs (whose mean distance from the Sun exceeds ~200 au and whose perihelion distance exceeds ~40 au); this was because we wished to probe the effects of a very distant planet, some 10-20 times more distant than Neptune. We used the resonance work to compute the possible planet mass range and the possible planet sky location.

"In the new paper, we are probing a closer range of heliocentric distances, so the KBO working sample is much larger - known KBOs whose mean distance from the Sun is between 30 and 150 au (a data sample size of ~600). We find that the KBOs whose mean distance from the Sun is between 50 and 150 au (a sample of more than 150 objects) have a mid-plane that does not follow expectations (it deviates greatly from the solar system's invariable plane).

"Our inventory of the outer solar system remains highly incomplete, but as we discover more KBOs we can use their orbital distribution to probe the structure of the solar system at larger distances, in a kind of bootstrapping way! But we have to be very cognizant of observational biases and small number statistics." (8)

So, we have two quite different scenarios, which are presumably not mutually exclusive.  The first is the Planet Nine Super-Earth, located perhaps 700AU away in an inclined orbit which is well away from the Kuiper Belt.  This body may be occasionally drawing up Kuiper Belt Objects into the anomalous extended scattered disk cluster (1), creating resonance patterns with the distant shepherding body.  The second scenario is that of a much closer, Mars+ sized object whose orbit largely lies within that of the ETNO cluster, but which is capable of distorting the outer sections of the main Kuiper Belt. 

If Brown and Batygin are correct about Planet Nine's perturbing influence, drawing up objects from the outer solar system into anomalous distant orbits, then it seems unlikely to me that Volk and Malhotra's Planet X object would be able to achieve this same effect - because it is effectively too close to the Kuiper Belt to draw objects away from it in this manner.  Perhaps it is capable of shunting them outwards?  Or perhaps these extended scattered disk objects originate elsewhere. 

It has been suggested that the retrograde KBOs, like Niku & Drac, may have been inner Oort Cloud objects originally, occasionally nudged towards the planets in much the same way as long-period comets are perturbed from their more distant locations towards the Sun (9).  But if the extended scattered disk objects, which cause astrophysicists and dynamicists so many sleepless nights, have also originated from a more distant location, then how did they pick up the claimed-for relationships between them, like their similar arguments of perihelion, and other contentious patterns of behaviour (10)?  Does something still need to shepherd them into their related organised orbits (which some argue can be attributed to mere observational bias)?  It's not clear to me how a Planet X object embedded within the Kuiper Belt could achieve this.  One would expect, instead, that its influence would create a more homogenous arrangement, in the same way that Neptune shepherds the main belt of objects beyond it.

Back in 2005, I argued that a substantial PX body whose inclined and eccentric orbit creates a broad range of orbital values (perihelion ~80AU to aphelion ~2000AU) might explain why there is such a striking absence of objects between the Kuiper Belt and inner Oort Cloud (11).  This seemed a highly unlikely solution at the time, because one could well argue that such an object would be dynamically unstable over long periods of time, and have a provenance which is difficult to explain.  Now, everything seems wide open, with lots of different ideas as to the nature of the alleged perturbing body, and different ideas as to how it might have got there in the first place.  It still seems to me that a very eccentric orbit, allowing PX to periodically gently perturb the outer zone of the Kuiper Belt, as well as the inner aspect of the Oort Cloud, is the best bet to help explain these varied issues.


Written by Andy Lloyd,  6th July 2017


1)  Andy Lloyd "Warping of outer solar system indicates presence of Planet X" 30th June 2017

2) K. Batygin & M. Brown "Evidence for a Distant Giant Planet in the Solar System" 20th January 2016, The Astronomical Journal, Volume 151, Number 2,

3)  K. Volk & Renu Malhotra "The curiously warped mean plane of the Kuiper belt", Astronomical Journal, (in press) (2017)

4)  Daniel Stolte, University of Arizona Press Release "UA Scientists and the Curious Case of the Warped Kuiper Belt" 20th June 2017,

5)  A. Brunini & M. Melita “The Existence of a Planet beyond 50AU and the Orbital Distribution of the Classical Edgeworth-Kuiper Belt Objects” Icarus, 2002, 1, 160, pp32-43,

6)  Andy Lloyd "Planets IX, X, XI etc, etc" 23rd June 2016

7) Renu Malhotra, et al "Corralling a distant planet with extreme resonant Kuiper belt objects" 2nd June 2016, The Astrophysical Journal Letters, 824, L22

8)  Correspondence from Renu Malhotra, 4th July 2017

9)  Andy Lloyd "Going the Wrong Way Round" 14th August 2016

10)  Konstantin Batygin "The Search for Planet Nine: Status Update (Part 2)" 2nd July 2017

11)  Andy Lloyd "Dark Star: The Planet X Evidence"  2005, Timeless Voyager Press


Image credit: Heather Roper/LPL


























Dark Star Blogs

 2013:  01   02   03   04   05   06   07   08   09  

2014:  10   11   12   13   14   15   16   17   18   19   20   21

2015:  22   23   24   25   26   27   28   29   30   31   32   33

2016:  34   35   36   37   38   39   40   41   42   43   44   45

2017:  46   47   48   49   50   51   52   53   54

You can keep informed of updates by following me on Twitter:


Or like my Facebook Page: