Indo-Aryan v. Indo-Iranian Religion (Speculative)

The Vedic religion of South Asia, which ultimately gave rise to modern Hinduism, can be understood as a mash-up of the proto-Indo-European pantheon, which also influenced Nordic/Germanic and Greco-Roman polytheism, with an indigenous Harappan religious substrate that had a somewhat more animistic and a somewhat less anthropomorphic character. It is a process not unlike the process seen in Europe.

In contrast, the Indo-Iranian religion of present day Iran, which appears to have emerged contemporaneously with the Vedic religion from Indo-European contributors very similar to their Indo-European counterparts, was the progenitor of Zoroastrianism, which marks a dramatic departure from proto-Indo-European polytheism, replacing it with what is typically simplified to being described as dualism rather than a polytheistic pantheon.

The open question is, what made Indo-Iranian religion depart so markedly from other Indo-European religious landscapes.

We have a fairly rich trove of written sources, both Jewish and non-Jewish, that sheds light on how Jewish monotheism emerged from Eastern Mediterranean Semitic polytheism to henotheism (in which there are multiple gods but one is pre-eminent and the center of worship) to true monotheism, with some influence from a brief and failed flirtation in Egypt with a monotheistic or henotheistic religion that was heralded by a pharaoh, then abandoned not longer after that by another one.

But in West Asia, we have pretty much only the Avesta, the core and original Zoroastrian scripture, itself to guide us.

One possibility is that the Indo-Iranians had Zoroaster who just happened to be a truly remarkable individual that no other contemporaneous culture had, to make the leap in a way that secured large numbers of followers somehow. Maybe Zoroaster charmed and won over the most powerful kings and princes of West Asia who imposed his religion upon their people. Maybe Zoroastrianism secured a mass grass roots following somehow and was co-opted by West Asia's leaders.

Alternatively, perhaps Zoroastrianism is the legacy of a pre-existing religious tradition and worldview of West Asia that had a powerful influence on the conquering Indo-Iranians, which would certainly not be unprecedented. The Hittites, for example, heavily borrowed from and adopted the Hattic religion of their predecessors, keeping the Hattic language alive as a liturgical language long after it had ceased to be a living liturgical language. The linguistically Semitic Akkadians did something similar with the Sumerian religion. The fact that the language of the Avesta is written in an Indo-Iranian dialect that is a close sister to Sanskrit, somewhat disfavors this hypothesis, but it could be that the fact that Sumerian and Hattic were written languages, while the pre-Indo-European languages of South Asia and West Asia were not, could also explain this fact.

In any of these scenarios, however, there is another point. What about West Asia in the Bronze Age caused Zoroastrianism to fill a spiritual need better filled by dualism than polytheism, that was absent from contemporaneous polytheistic cultures which came under Indo-European rule?

Religions tend to imagine the world of the divine that is parallel to the leadership structure of their own societies in their formative eras. 

Animistic religions are associated with hunter-gather societies with weak political structures of fragmentary local bands. Polytheistic religions tended to emerge in chiefdomships where a chief ruled in concern with subordinate but independently powerful other leaders in a sort of council. Egypt's flirtation with monotheism and Jewish monotheism emerged in solitary monarchies with a single clear king or queen. Chinese conceptions of the spiritual world mirrored the vast bureaucracies of its own quick emerging empire.

Was the political situation in West Asia such that the dualism of Zoroastrianism better mirrored its political reality than the chiefdom style of rule of other polytheistic early Bronze Age societies?

Perhaps, for example, the Eastern Iranian region to which the Avesta refers was ruled by a strong unified monarchy, rather than a mere chiefdomship, of the conquering Indo-Iranians, but faced a strong insurgency, perhaps from the pre-Indo-Iranian king who was deposed or from an arguably more legitimate heir to the throne who was passed over and was seeking to regain the rule of his dynasty, at the time that Zoroaster formulates Zoroastrianism.

The fact that West Asia was an early place of metallurgy mastery and the Copper Age first and then the Bronze Age is suggestive of the possibility that its political culture may indeed have in some way differed materially from that of its Bronze Age peers, so this isn't an implausible hypothesis.

Cosmic Daybreak

The dating of the start of star formation at z = 15 by extrapolating from James Webb Space Telescope observations, rather than merely relying on theory, is a big deal that provides a benchmark for cosmologists trying to fit their models of star and galaxy formation to observational data. 

This corresponds to 270 million years after the Big Bang (2% of the current 13.8 billion year age of the universe) in standard ΛCDM cosmology, also called more idiomatically "Cosmic Dawn", although the authors use the alternative term "Cosmic Daybreak" is used to make clear that the authors think that this result prefers "wave dark matter" with an ultralight dark matter particle to the ΛCDM cosmology is which context the ordinary meaning of "Cosmic Dawn" is defined.

The reference to the String Axiverse in abstract of this paper is gratuitous and detracts from the paper, but doesn't impact the ultimate conclusions of the paper with respect to a generic ultra-light boson as a dark matter particle.

Luminous young galaxies have been uncovered with relative ease by JWST, extending to z = 14.5, so it is puzzling that deeper spectroscopy of fainter candidates now finds only interlopers. This redshift `ìmpasse" is underscored by the measured stellar ages of these high-z galaxies, which we show converge to zero by z = 15, with a marked absence of earlier star-formation. 

Taken literally, such a late transition from the Dark Ages to luminous galaxies is unlike the gradual Cosmic Dawn of standard LCDM, but does confirm a key prediction of Wave Dark Matter, ψDM, as a Bose-Einstein condensate. The de Broglie wave pressure resists gravity until a substantial Jeans mass of 4 × 10^9 M⊙ is overcome at z = 15, corresponding to a light boson mψ = 2.2 +0.4 −0.3 × 10^−22 eV, and similar to independent estimates from lensing anomalies and dwarf galaxies. 

Furthermore, the substantial luminosities of the highest redshift galaxies appear to converge to the initial Jeans scale of ψDM, whereas LCDM predictions extend to lower luminosities and larger ages than observed. These contrasting predictions can be definitively tested as JWST observations accumulate, with diametric implications for Dark Matter as heavy particles beyond the Standard Model, or ultra-light bosons motivated by the String Axiverse.

Jiashuo Zhang, et al., "JWST evidence for a sharp "Cosmic Daybreak" at z = 15" arXiv:2609.28257 (September 23, 2026).

More Thoughts On Red River

The first twelve episode cours of the anime Red River a.k.a. Anatolia story, based upon the long hit manga series of the same name finished yesterday, and has prompted me to research the actual history of the period depicted in this historical fiction piece (another twelve episodes are contracted for the fourth quarter of this year).

One of the points highlighted by the series that often gets overlooked in academic research is that: (1) the Hittites, the Mittani kingdom, a Mesopotamian regime, and the Egyptian 18th dynasty, were all contemporaneous, and (2) that these kingdoms meaningfully interacted with each other, exchanging correspondence, diplomats, and brides with each other, and engaging in military conflicts with the intermediate Hittite empire.

At least two royal Egyptian brides were from the Mittani Kingdom in roughly the 14th century BCE when Red River is set.

This is especially notable because, while the everyday commoners in the Mittani Kingdom were Hurrian language speakers (a language associated with the highlands of the Zargos Mountains and to a lesser extent the eastern Anatolian highlands where the possibly related Hattic language was spoken), the Mittani elites in the 1300s BCE spoke a Sanskrit derived Indo-Aryan language (that gave rise, most famously, to the Hindi language of northern India) and worshiped Indo-Aryan gods in their pantheon that became part of the Hindu religion rather than the Avestan language and religion that was starting to emerge in what is now Iran at around this time. (A cultural affiliation that neither the anime or the manga make much of.)

The Indo-Aryan linguistic and religious link to western Iran and connection the Anatolia and Egypt, disappears, however, when the Mittani kingdom falls, for historical reasons that like its brief appearance in the Mittani kingdom have since been lost and are currently unknown.

The Mittani kingdom featured in Red River as a major military adversary of the Hitties, therefore, provides a concrete human, person to person bridge between the culture of South Asian Indo-Europeans and late Bronze Age ancient Egypt: two cultural worlds usually thought of as unrelated and independent of each other despite being contemporaneous.

Actual history is unclear over whether the famous ancient Egyptian Queen Nefertiti was one of those Mittani brides or not, as the manga and anime assert, because it is a legitimate historical possibility and makes for a good story. But the historicity of the Mittani kingdom providing two royal brides to Egypt in the historical era in which Red River is set is not seriously questioned, nor is the Red River story point that at least one of those marriages was driven to a significant extent by a Mittani expectation of receiving large amounts of gold from Egypt in exchange (although, historically, the Egypt failed to deliver the gold).

Is There Really No Cusp-Core Problem?

I'm highly skeptical of a study that purports to contradict decades of previous observational data whose results had a broad consensus in the field of galaxy dynamics (and which was the main motivator for dark matter particle models such as self-interacting dark matter, warm dark matter, and axion-like particle/fuzzy/ultralight dark matter), with a small "curated" sample. 

I also question comparing  this small curated sample mostly to cold dark matter simulations which themselves are often devised to fit the data rather than having a rigorous physics basis. 

This comes across as cherry picking rather than as the robust observational constraint that the paper claims to be seeking to develop, particularly where there doesn't seem to be a lot of attention given to the uncertainties in their observational data points. 

There seem to be a lot of observation points outside the CDM range in Figure 4 below, and Figure 5 represents only comparisons with simulations, which again, aren't very rigorous reproductions of pure physics and have a strong phenomenological matching component.

Also, while this paper purports to quantify how much energy from stellar feedback is necessary to produce the observed results (which is a worthwhile and important thing to do), its analysis of whether that amount is actually plausible and has a strong physics justification is lacking.

But I'm blogging this paper anyway. That's because I don't want to ignore papers just because they might disagree with my preconceived notions. It is better to engaged and struggle with scholarship that you doubt, and to change your mind if it is sufficiently convincing. 

The images below are the ones described in the arXiv comment from the authors as containing the "main results."

Two of the most prominent small-scale challenges to the cold dark matter (CDM) paradigm are the cusp-core and diversity-of-rotation-curves problems. The former concerns the shallow inner DM density profiles inferred for many galaxies compared with the cusps predicted by collisionless CDM, while the latter concerns the wider range of inner DM densities and rotation curve shapes inferred observationally than hydrodynamical simulations traditionally reproduce. Robust observational constraints on DM core sizes and halo densities are therefore essential for testing both the nature of DM and the impact of galaxy formation processes. 

We analyse the inner DM distribution of a curated sample of 48 gas-rich galaxies and 8 Milky Way gas-poor satellites, spanning 6 orders of magnitude in M∗. We find substantial scatter in DM core sizes and degrees of coreness, with both cuspy and cored haloes occurring over a broad M∗ range. The cores are energetically consistent with stellar feedback, requiring modest supernova energy coupling efficiencies of order 0.1−1%. Comparisons with the NIHAO, FIRE-2, and EDGE simulations reveal broad agreement in the inner DM densities and logarithmic slopes of observed and simulated galaxies. 

The main residual differences concern the steep slopes of some massive simulated galaxies and differences in SHMRs. Using a rotation-curve diversity diagnostic from previous work, we find that extreme discrepancies with simulations are absent from our curated sample and largely attributable to uncertain kinematics or baryonic mass distributions. Within the scope of our analysis, we find no evidence of a systematic inner-density tension between our galaxy sample and current ΛCDM hydrodynamical simulations. Together with the modest energetic requirements for core formation, this substantially alleviates the cusp-core and diversity-of-rotation-curves problems.

Pavel E. Mancera Piña, Justin I. Read, Jorge Sarrato-Alós, Claudia Muni, "Dark matter haloes from dwarf to massive galaxies: no systematic inner-density tension with ΛCDM hydrodynamical simulations" arXiv:2609.25220 (September 21, 2026) (Accepted for publication in A&A).