Reduced Variations in Earth’s and Mars’ Orbital Inclination and Earth’s Obliquity from 58 to 48 Myr ago due to Solar System Chaos
Reduced Variations in Earth’s and Mars’ Orbital Inclination and Earth’s Obliquity from 58 to 48 Myr ago due to Solar System Chaos
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DOI：
10.3847/1538-3881/ac80f8
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发表时间：
2022-07
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通讯作者：
R. Zeebe
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作者：
R. Zeebe
太阳系的动力学演化是混沌的，内行星的李雅普诺夫时间只有1.5亿年。由于混沌，基于目前的天文观测，根本不可能准确预测太阳系超过15000万年的轨道演化。我们最近开发了一种方法来克服这个问题，通过使用地质记录来限制过去的天文解。我们得到的最佳天文解（称为ZB 18 a）显示出与地质记录的异常一致性，直到158 Ma（百万年前），以及大约50 Ma的特征共振跃迁。在这里，我们表明，ZB 18 a和整合地球和火星的自旋矢量的基础上ZB 18 a产量减少地球和火星的轨道倾角和地球的倾斜度（轴向倾斜）的变化，从2058年至2048年马-后者是与古气候记录一致。温度的变化对地球和火星的气候历史具有重要意义。我们提供了一个详细的分析太阳系的频率（g和s模式），并表明，在地球和火星的轨道倾角和48 Ma左右的变轨的变化的变化与共振过渡，并造成的变化的贡献叠加的s模式，加上g-s模式的相互作用在太阳系内部。g-s模式相互作用和共振跃迁（与地质数据一致）是混沌的明确表现。因此，太阳系中的动态混乱不仅影响其轨道特性，而且通过偏心率和倾角与轴向倾斜之间的联系影响行星气候的长期演变。
The dynamical evolution of the solar system is chaotic with a Lyapunov time of only ∼5 Myr for the inner planets. Due to the chaos it is fundamentally impossible to accurately predict the solar system’s orbital evolution beyond ∼50 Myr based on present astronomical observations. We have recently developed a method to overcome the problem by using the geologic record to constrain astronomical solutions in the past. Our resulting optimal astronomical solution (called ZB18a) shows exceptional agreement with the geologic record to ∼58 Ma (Myr ago) and a characteristic resonance transition around 50 Ma. Here we show that ZB18a and integration of Earth’s and Mars’ spin vector based on ZB18a yield reduced variations in Earth’s and Mars’ orbital inclination and Earth’s obliquity (axial tilt) from ∼58 to ∼48 Ma—the latter being consistent with paleoclimate records. The changes in the obliquities have important implications for the climate histories of Earth and Mars. We provide a detailed analysis of solar system frequencies (g and s modes) and show that the shifts in the variation in Earth’s and Mars’ orbital inclination and obliquity around 48 Ma are associated with the resonance transition and caused by changes in the contributions to the superposition of s modes, plus g–s mode interactions in the inner solar system. The g–s mode interactions and the resonance transition (consistent with geologic data) are unequivocal manifestations of chaos. Dynamical chaos in the solar system hence not only affects its orbital properties but also the long-term evolution of planetary climate through eccentricity and the link between inclination and axial tilt.