阿尔伯塔大学的研究人员揭示了地球自转长度变化的深层机制。1该研究由博士生Huifeng Zhang和教授Mathieu Dumberry完成，于2026年9月23日发表在《自然》杂志上。1科学家发现，地球内核旋转速度的微小波动会产生引力矩，与地幔相互作用，导致地球自转周期出现毫秒级的变化。1
地球自转的这种变异源于其内部复杂的物理过程。1地球的液态外核和地幔以相反方向旋转，以维持整体角动量恒定。1由于地球内核并非完全球形，其运动能与地幔中不均匀的质量分布产生的引力相互作用。1地幔与核心边界处存在的摩擦力和电磁阻力与这些引力矩形成平衡，进而影响地球的自转速率。1研究表明，地球内核可能在约10年的时间尺度上经历粘性变形，这一过程使得地球深部比此前预想的更具动态特征。1
Researchers from the University of Alberta have identified a mechanism that could explain why Earth's rotation length varies by milliseconds over years.1 According to their study published in Nature on September 23, 2026, subtle fluctuations in the rotation speed of Earth's inner core generate gravitational torques that interact with the mantle, causing measurable changes in the planet's rotational period.1
The research reveals that Earth's deepest layers are far more dynamic than previously understood.1 The liquid outer core and mantle rotate in opposite directions to maintain constant total angular momentum, while the inner core—which is not perfectly spherical—can gravitationally interact with uneven mass distributions in the mantle.1 This interaction occurs at the core-mantle boundary, where friction and electromagnetic resistance balance the gravitational torques.1 The findings suggest that the inner core may undergo viscous deformation on timescales of approximately ten years.1 Doctoral student Huifeng Zhang and Professor Mathieu Dumberry from the University of Alberta led the investigation into how these internal processes drive Earth's rotational variations over multiyear cycles.1
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