Lumenis IO — The Magnetic Death of Mars: A 4.5-Billion-Year Reconstruction of Planetary Decay
Year: 2025
Type: article
Abstract: This dataset and accompanying manuscript present a physically constrained reconstruction of Mars’s long-term geological, magnetic, and atmospheric evolution spanning approximately 4.5 billion years. The work addresses a central problem in planetary science: how Mars transitioned from an early state capable of supporting surface liquid water to its present cold, arid condition with a tenuous atmosphere and no global magnetic field. The reconstruction is based on a coupled numerical simulation that evolves Mars as an integrated planetary system. Rather than modeling internal dynamics, magnetic field behavior, and atmospheric loss as separate or sequential processes, all components are evolved simultaneously within a single causal framework. This allows key transitions—such as magnetic field collapse and atmospheric erosion—to emerge naturally from the underlying physics rather than being imposed as assumptions. Mars is represented as a differentiated terrestrial planet consisting of a metallic core, silicate mantle, and solid crust. Internal thermal evolution is governed by conductive and convective heat transport and by radiogenic heat production consistent with early Solar System abundances. As internal heat is lost over time, convective efficiency within the core diminishes, leading to progressive core crystallization and a reduction in the energy available to sustain a global magnetic field. Magnetic field generation arises self-consistently from thermally driven core convection. The model does not prescribe a magnetic field history. Instead, field strength evolves continuously in response to internal heat flow, and complete magnetic field shutdown occurs once convective thresholds are no longer met. The timing of this collapse is constrained by observational evidence indicating that Mars’s global magnetic field ceased early in its history. Atmospheric evolution is treated as a balance between sources and loss mechanisms. Early Mars is initialized with a dense, water-bearing atmosphere consistent with geological evidence for past surface liquid water. Atmospheric loss proceeds through thermal escape and non-thermal processes, with solar forcing treated as time dependent to reflect elevated activity during the early Sun. While magnetic shielding is present, atmospheric erosion remains moderate. Following magnetic field collapse, direct interaction with the solar wind substantially increases atmospheric escape rates. Hydrogen loss plays a central role in the irreversible depletion of water. As hydrogen escapes preferentially to space, water is progressively lost through photodissociation, permanently reducing the planet’s hydrological inventory. Declining atmospheric mass weakens greenhouse warming, leading to surface cooling that further accelerates atmospheric collapse. These feedbacks are resolved explicitly within the coupled system. Present-day observational constraints—including surface pressure, mean surface temperature, and the absence of a global magnetic field—are imposed as terminal conditions. Only evolutionary trajectories that converge to these values within defined tolerance bounds are retained. This constraint-based approach ensures that reconstructed histories remain empirically grounded and physically plausible. The results identify a clear causal sequence linking Mars’s small planetary size to rapid internal cooling, early magnetic field collapse, enhanced atmospheric erosion, and long-term water loss. The findings support the interpretation that Mars’s habitability window was intrinsically limited by its internal thermal evolution rather than by isolated external events. Beyond Mars, this reconstruction has broader implications for comparative planetology and exoplanet studies. It highlights the importance of planetary mass and internal heat retention in sustaining long-lived magnetic protection and atmospheric stability, suggesting that long-term habitability depends not only on stellar irradiation but also on deep interior dynamics. This Zenodo release provides the full scientific description, simulation configuration, and derived results to support transparency, reproducibility, and reuse in planetary science research.
Author: Lumenis IO PTY LTD
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
SDG: Climate action
Open Access status: green
OpenAlex ID: W7104290652
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