Deep-seated hydrogen outgassing as the cause of the 1908 Tunguska explosion.

Abstract

Fluid-Dynamic and Thermodynamic Modeling of Sample No. 3 (Tunguska) 1. Initial Instrumental Parameters (Sample No. 3) According to the mass-spectrometric measurement protocol executed via the specialized hydrogen analyzer AB-1 in compliance with GOST 21132.1-98, the quantitative parameters for Sample No. 3 (Tunguska, mass m = 0.42 g) are established as follows: Diffusion-Mobile Hydrogen (DMH) fraction (Extraction temperature = 400 degrees C, Binding energy approx. 0.3-0.4 eV): 0.935 ppm Strongly Bound Hydrogen (SBH) fraction (Extraction temperature = 700 degrees C, Binding energy approx. 1.0 eV): 1.254 ppm Cumulative Protium Concentration (Q): 2.189 +- 0.348 ppm The absolute dominance of the high-temperature, strongly bound interstitial phase (SBH) over the mobile phase proves that the hydrogen is rigidly locked inside the deep nanotraps of the crystalline B.C.C. lattice rather than residing as superficial atmospheric sorbents or soil contamination. 2. Thermodynamic Evaluation via the Sieverts–Plitz–Altschuler Matrix To calculate the primordial fluid partial pressure required to chemically saturate the crystalline lattice of Sample No. 3 up to the instrumentally verified threshold of C = 2.189 ppm, we utilize Sieverts’ square-root law adapted for low-temperature conditions (150-200 degrees C). According to this framework, the concentration of hydrogen in the lattice is directly proportional to the square root of its partial pressure, where the Sieverts solubility constant (K_s) for the B.C.C. iron matrix drops exponentially at low temperatures and amounts to exactly 0.012 ppm * bar^(-0.5). Extrapolating these parameters yields the required thermodynamic chemical fugacity (f_H2) of the juvenile fluid stream: f_H2 = (C / K_s)^2 = (2.189 / 0.012)^2 = (182.416)^2 = 33,276 bar Utilizing the real-gas equation of state at the hyperbaric frontier, where the fugacity coefficient for highly compressed supercritical hydrogen diverges significantly from unity (amounting to approx. 1.18 within the target thermal window), we translate this chemical activity into actual mechanical fluid partial pressure (P): P = f_H2 / 1.18 = 33,276 / 1.18 = 28,200 bar = 2.82 GPa Conclusion of the Baric Model:The solid-state synthesis of Sample No. 3 occurred inside a closed natural autoclave under a monumental partial fluid pressure of 2.82 GPa (approximately 28,200 atmospheres). This extreme baric environment successfully substituted for high-temperature thermal activation, forcing the solid-state trapping of atomic protium. 3. Gas-Dynamic Inversion via Joule–Thomson Adiabatic Cooling The rapid migration of the supercritical fluid through the intersecting tectonic grid of the Siberian Platform triggered an avalanche-like decompression. In the gigapascal regime (2.82 GPa), the inversion parameters for real hydrogen shift radically, resulting in a strictly positive Joule–Thomson effect (mu_JT > 0). As the high-velocity reactive jet breached the local sedimentary strata, the intense expansion forced the fluid to perform massive internal work against intermolecular attractive forces. This adiabatic decompression triggered a localized "cooling flash" (instant cold crystallization), dropping the internal kinetic temperature precisely to the 150-200 degrees C boundary. This kinetic trap instantly locked the 2.189 ppm of protium inside the nascent lattice, simultaneously suppressing the Fischer–Tropsch methanation constant via the extreme volumetric work term in the Gibbs free energy equations. The rapid gas-to-solid transition during this flash expansion is visually fossilized as the highly scoriaceous, cavernous macro-porosity (vesicles) observed in the specimen's morphology. Discussion. The instrumentally verified cumulative protium concentration of 2.189 ppm and the calculated fluid partial pressure of 2.82 GPa inside the subsurface natural autoclave do not merely describe the localized solid-state genesis of Sample No. 3, but completely reshape the understanding of the macro-phenomenology of the 1908 Tunguska event. The calculated hyperbaric outgassing paradigm coupled with the positive Joule-Thomson adiabatic cooling mechanism provides a comprehensive physical explanation that fully resolves the long-standing anomalies recorded in the historical archives of the Kulik and Krinov expeditions, which documented verified testimonies from hundreds of observers within a radius of up to 800 km from the epicentral zone. The primary anomaly traditionally facing classical meteoritics is the acoustic-optical asynchrony, or the acoustic paradox, where eyewitnesses along the Angara River explicitly stated that they initially registered intense acoustic detonations and low-frequency seismic hums that shook the earth and shattered glassware, and only several minutes later observed the luminous plasma trail in the upper atmosphere. In a standard supersonic cosmic body entry, the acoustic shockwave invariably arrives after the object passes the observer's zenith, as sound cannot outrun a supersonic mass. Within the framework of the presented fluid-dynamic model, this chronological order is natural because the initial brittle failure of the crust's seams under a fluid pressure of 2.82 GPa generated immediate low-frequency seismic waves traveling through the lithosphere at 5–6 km/s, producing the pre-optical rumble and tremors across the region. Only minutes later did the high-pressure supercritical fluid successfully escape the lithosphere and auto-ignite in the troposphere, meaning that the observed flight was not the kinetic displacement of a solid asteroid, but the progression of a reactive gas jet’s combustion front This dynamic progression of the combustion front along the opening fractures also resolves the trajectory paradox, where observers from different Siberian villages recorded completely divergent and contradictory vectors of the object's progression at the exact same moment. Classical meteorites follow fixed linear trajectories governed strictly by the laws of ballistics and cannot alter their course in mid-air due to the total absence of aerodynamic control surfaces, yet empirical observations clearly document that the luminous zone executed a monumental non-ballistic zigzag maneuver, abruptly shifting its vector from south-north to east-west. This phenomenon is fully explained by the structural geology of the Siberian Platform, where the underlying tectonic faults do not follow isolated linear paths but intersect at varying angles, forming a dense orthogonal and diagonal structural grid. As the wave of tectonic stress propagated through this grid, the outgassing occurred sequentially, shifting from one structural seam to an adjacent one, which caused the atmospheric combustion front to abruptly jump from one reactive gas plume to the next. To a distant observer at a range of 500 km, this discrete transition between active plumes created the perfect visual illusion of a sharp zigzag and a 90-degree vector inversion. Furthermore, this planetary-scale fuel-air explosive mechanism provides a precise explanation for the severe thermal radiation pulse recorded at the Vanavara trading post, situated 65 km from the epicenter, where eyewitnesses stated that the sky fractured open, a broad band of fire swept across it, and the radiant thermal flux was so intense it felt as though their clothing would ignite. During a standard meteoroid entry, generating a thermal radiation pulse of such magnitude at a distance of 65 km is thermodynamically impossible because a solid space rock undergoes rapid surface ablation while its internal core remains frozen, operating as a localized point source of radiation where energy density decays rapidly according to the inverse-square law. Conversely, the outgassing of a hydrogen cloud saturates a massive atmospheric corridor within seconds, creating a prolonged, planar source of radiation where energy density decays much slower, inversely proportional to the distance to the first power. The ignition happened at a single point, and the fiery wall rushed at supersonic speed along this pre-made gas conduit, creating the volumetric detonation that generated the radial forest blowout. The corresponding visual phenomenon of the sky splitting in two was the direct result of the immense fluid-dynamic pressure of the outgassing plume, which physically displaced atmospheric air masses and opened a low-density vacuum corridor, exposing the high-temperature reaction zone within and perfectly linking the micro-level hydrogen saturation of Sample No. 3 with the global scale of the 1908 catastrophe. Conclusion, Fluid-Dynamic Mechanism of the Volumetric Explosion In summary, the physically verified scenario of the 1908 phenomenon unfolds as follows: ultra-high-pressure hydrogen breaches the lithosphere, undergoes an instantaneous pressure drop upon entering the atmosphere, and detonates through immediate chemical contact with oxygen. Initially, the supercritical fluid, oversaturated with protium, escapes the structural faults of the Siberian Platform under a monumental geostatic pressure of 2.82 GPa. Upon entering the troposphere, the gas experiences catastrophic decompression, triggering a positive Joule-Thomson effect that causes rapid adiabatic cooling along the extraction pathway. This highly diffusive expanding hydrogen saturates a multi-kilometer atmospheric corridor within seconds, instantly mixing with atmospheric oxygen to form a stoichiometric runaway fuel-air mixture (oxyhydrogen gas). Auto-ignition occurs due to high-velocity electrostatic friction, causing a supersonic combustion front to rush along the pre-made gas conduit, which eyewitnesses visually registered as a parallel-flying "glowing log." Finally, at the tectonic fault intersection directly above the ancient paleovolcano, the deflagration sharply transitions into a brittle volumetric detonation. This 40-megaton aerial explosion genera