Core Viewpoint - The recent research challenges the fundamental role of the solid inner core in the generation of Earth's magnetic field, suggesting that the dynamo action in early Earth models is invariant and not dependent on the presence of a solid inner core [4][6]. Group 1: Research Findings - The study published in Nature by Lin Yufeng and colleagues reveals that the dynamo action in an early Earth model exhibits characteristics independent of fluid viscosity, indicating that viscosity can be considered negligible in simulations [5]. - The magnetic field strength and morphology generated by models using early Earth geometries align closely with ancient geomagnetic data and show significant similarity to the present Earth's magnetic field [5]. Group 2: Historical Context - Earth's magnetic field has likely existed for at least 3.5 billion years, initially sustained by the long-term cooling of the core and currently driven by the growth of the solid inner core [1]. - Existing numerical models of the Earth's dynamo have successfully simulated a terrestrial magnetic field that closely resembles real dynamic mechanisms, although the understanding of the dynamo mechanism in a fully liquid outer core remains limited [2].