Why Haumea and Eris

The Kuiper Belt contains thousands of trans-Neptunian objects, yet only five have been officially recognised by the International Astronomical Union as dwarf planets: Pluto, Eris, Haumea, Makemake and Ceres (the last of these in the main Asteroid Belt). Among them, jabbah-project's choice falls on Haumea and Eris, for precise reasons concerning their mass, physical structure and orbital dynamics.

The zodiacal sequence, in jabbah-project's view, is completed by two bodies that embody the two axes along which the Kuiper Belt expresses its extremes. Eris represents the extreme of mass and distance: the heaviest body, among the most remote, the one that literally redefined the boundaries of the Solar System. Haumea represents the extreme of physical singularity: shape, rotation, rings and collisional dynamics that have no equal. Together they mark out the space of what, beyond Pluto, is truly remarkable.

On an astrological-interpretive level, this selection has an internal coherence: rather than adding arbitrarily chosen bodies, the sequence integrates the two objects that, by measurable data, mark the physical and dynamic boundaries of the known Solar System. The choice is not quantitative but qualitative: not "the biggest" in absolute terms, but those that best represent the idea of threshold, of limit, and of exception.

Finally, a consideration tied to the parallel and opposite planets in jabbah-project's scheme: Haumea's opposite is Pluto and its parallel is Venus; Eris is opposite Neptune and parallel to Mercury. Now, within the "twelve planets" scheme, one can see that it is above all the parallel planets that have comparable masses: giant Jupiter is parallel to Neptune (both "gas giants"), Mars is parallel to Pluto (both rocky and only slightly smaller than Earth), Saturn is parallel to Uranus (also both "gas giants"), and so on. We can say that Haumea and Eris fall within this "rule" as well (said, so to speak, in a great many scare quotes).

A brief digression on the names these bodies carry is worthwhile, but with an indispensable premise. This is extremely slippery ground, on which many have exercised themselves and many more will, and it must be taken for what it is: only an intellectual divertissement, nothing more. jabbah-project's selection rests on the astronomical data set out above — mass, distance, shape, density, orbital dynamics — not on the names. That naming conventions produce suggestive resonances is a happy coincidence, not an argument. That said, the coincidence exists, and it is curious.

The name Eris, in Greek convention, refers to a figure associated with discord and conflict. It is hard not to notice how this fits the body's actual historical role: it was precisely its discovery that generated the scientific "discord" which led to redefining the concept of planet and demoting Pluto. But note well: here the suggestion works after the fact, because the name was chosen afterward, precisely because of that controversy. There is nothing predictive about it, only a play of mirrors between event and naming.

The name Haumea, by contrast, belongs to the Hawaiian tradition and is associated with a figure linked to generation and fertility. The choice was not astronomically arbitrary: the body's two moons bear names connected to the same tradition, and Haumea's entire "collisional family" — those fragments originating from an ancient impact — lends itself to the image of a scattered progeny. Even here, though, the link between name and physical characteristics is a narrative construction built by the discoverers, not an intrinsic property of the object.

Were one to push the game as far as the Haumea–Pluto polarity discussed further on, one might observe that a name tied to generation and one tied to the dominion of the underground and the invisible make for an elegant opposition. Even more, we may recall that the Italian astrologer Lisa Morpurgo hypothesised a "Planet X", right after Pluto, as a "Great Feminine Principle", opposite to the "Great Masculine Principle" represented by Pluto. But let us repeat, because it is the point that matters: it is, precisely, a game. The soundness of the selection lies in the numbers, not in the labels. A critical reader has every right to ignore this parenthesis without the main argument suffering in the least.

Haumea's shape deserves one last consideration. Its extremely fast rotation, completing a full turn in under four hours, deforms the body into an elongated ellipsoid — what astronomers call a Jacobi ellipsoid. Visually, this geometry is often compared to a rugby ball or a slightly flattened egg. It should be made clear that this is an analogy of shape: the elongation arises from the centrifugal force of the rotation, not from a shelled internal structure. It remains an objective fact, however, that Haumea is the only dwarf planet not to be spherical, and that its outline spontaneously evokes this image.

On this basis, jabbah-project proposes a symbolic key of interpretation — it is important to stress that this is an interpretation specific to the project, not an established fact of astrological tradition, which on these recently discovered bodies is still taking shape. Haumea's "ovoid" form suggests a generative nature, comparable to a feminine principle, placed in mirrored opposition to Pluto.

This polarity, far from being purely decorative, finds confirmation in measurable physical contrasts. Pluto rotates slowly, in about six and a half days, and is substantially spherical; Haumea rotates in under four hours and deforms. Pluto's surface is dominated by nitrogen and methane ices, dark and reddened in some regions; Haumea's is covered in crystalline water ice, particularly bright and reflective. These are two bodies which, while belonging to the same outer region of the Solar System, express almost opposite characteristics: slowness and speed, sphere and ellipsoid, dark surface and luminous surface. The interpretive axis that jabbah-project builds between the two is thus founded not on an arbitrary attribution, but on a contrast that the astronomical data render tangible.

The main reason is that Chiron does not belong to the Kuiper Belt. It is a centaur — a body that orbits in the intermediate region between Jupiter and Neptune, roughly 8 to 19 astronomical units from the Sun. The Kuiper Belt begins beyond Neptune's orbit, around 30 AU. Already on this level Chiron is out of scope: if jabbah-project's criterion is to complete the sequence with trans-Neptunian objects marking the outer boundaries of the Solar System, Chiron remains structurally inside, in a completely different orbital zone. Including it would mean contradicting the very principle of the selection.

There is then a question of scale that places it on an entirely different order of magnitude. Chiron has an estimated diameter of around 210 km. To give a sense of the gap: Eris and Haumea exceed 2,000 km — ten times as much in diameter, and hundreds of times as much in volume and mass. Chiron is not remotely a dwarf planet. It does not possess sufficient mass for its own gravity to make it spherical, which is precisely the physical requirement the International Astronomical Union uses to define a dwarf planet. While Eris, Haumea, Makemake and Pluto all fall within this official category, Chiron has never been classified as one and could not be. It is a small, irregular body, comparable in size to a medium-sized asteroid.

Its physical nature is, moreover, unstable and ambiguous. Chiron shows cometary activity: it displays a coma and brightness variations typical of comets, to the point of holding a double designation, both as an asteroid (2060 Chiron) and as a comet (95P/Chiron). Centaurs like it have chaotic, dynamically transient orbits, perturbed by the giant planets, and on astronomical timescales are destined either to be ejected from the Solar System or to plunge inward, turning into comets. In other words, Chiron is not a "stable" body marking a boundary of the Solar System: it is a transient object, probably of Kuiper-Belt origin but now captured in an unstable zone. It does not represent a threshold; it represents a temporary transition.

The internal coherence of the selection is therefore clear-cut. The criteria that led to Eris and Haumea — membership in the trans-Neptunian region, dwarf-planet status, notable mass or physical singularity, an outer-boundary role — exclude Chiron on every single parameter: inner orbital position, the dimensions of a small body, lack of dwarf-planet status, cometary nature, and transient orbit. Adding it would mean abandoning the physical principle of the sequence in favour of a criterion of pure astrological popularity — something the project has explicitly chosen not to do.

One last clarification, which matters to us. Nothing said here is meant to assert that jabbah-project's choice is "better" than that of anyone who has decided to adopt Chiron within their own zodiacal scheme. Toward that work goes our utmost respect. The reasons set out here explain only why this project, given its own selection criteria, does not include it: these are internal, declared criteria, valid for the coherence of this system, not a judgement on others. A project starting from different premises — for instance, giving weight to the symbolic role of "bridge" between the classical and the outer planets, often attributed to Chiron precisely because of its intermediate orbit — will legitimately arrive at different conclusions, and will do well to do so. The presumption of holding one's own key to be the only valid one is a mistake, and a sin of pride, which we have seen committed many times: let us try not to fall into it again.