The planets’ gravitational interaction causes rhythmic changes in Earth’s orbital parameters (also called Milanković cycles), which have powerful applications in geology and astrochronology. For instance, the primary astronomical eccentricity cycle due to the secular frequency term (g ₂−g ₅) (∼405 kyr in the recent past) utilized in deep-time analyses is dominated by the orbits of Venus and Jupiter, i.e., long eccentricity cycle. The widely accepted and long-held view is that (g ₂−g ₅) was practically stable in the past and may hence be used as a “metronome” to reconstruct accurate geologic ages and chronologies. However, using state-of-the-art integrations of the solar system, we show here that (g ₂−g ₅) can become unstable over long timescales, without major changes in, or destabilization of, planetary orbits. The (g ₂−g ₅) disruption is due to the secular resonance σ ₁₂ = (g ₁ − g ₂) + (s ₁ − s ₂), a major contributor to solar system chaos. We demonstrate that entering/exiting the σ ₁₂ resonance is a common phenomenon on long timescales, occurring in ∼40% of our solutions. During σ ₁₂-resonance episodes, (g ₂−g ₅) is very weak or absent and Earth’s orbital eccentricity and climate-forcing spectrum are unrecognizable compared to the recent past. Our results have fundamental implications for geology and astrochronology, as well as climate forcing, because the paradigm that the long eccentricity cycle is stable, dominates Earth's orbital eccentricity spectrum, and has a period of ∼405 kyr requires revision.

中文翻译：

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太阳系长期共振扰乱了地球轨道偏心率 (g 2 − g 5) 的主导周期：对天文年代学的影响

行星的引力相互作用导致地球轨道参数发生有节奏的变化（也称为米兰科维奇周期），这在地质学和天文年代学中具有强大的应用。例如，由于长期频率项（G ₂ −G ₅ )（近年约405 kyr）用于深时分析的主要是金星和木星的轨道，即长偏心率周期。广泛接受和长期持有的观点是（G ₂ −G ₅）在过去实际上是稳定的，因此可以用作“节拍器”来重建准确的地质年龄和年表。然而，利用最先进的太阳系集成，我们在这里表明（G ₂ −G ₅）在很长一段时间内可能会变得不稳定，而行星轨道不会发生重大变化或不稳定。这 （G ₂ −G ₅）破坏是由于长期的共鸣σ ₁₂ = (G ₁ −G ₂）+（s ₁ −s ₂），太阳系混沌的主要贡献者。我们证明进入/退出σ ₁₂共振是长时间尺度上的常见现象，出现在我们约 40% 的解决方案中。期间σ ₁₂ - 共振片段，（G ₂ −G ₅）非常弱或不存在，与最近相比，地球的轨道偏心率和气候强迫谱无法识别。我们的结果对地质学和天文年代学以及气候强迫具有根本意义，因为长偏心率周期是稳定的、主导地球轨道偏心率谱且周期为~405 kyr的范式需要修正。