Revisiting Expanding Earth in the Age of AI: How ChatGPT Helped Reframe a Dismissed Theory Retired faculty member of Zuyd University of Applied Sciences, Social Work, Sittard, and Life Sciences, Heerlen, Netherlands Email: RMMLoeffen@gmail.com Creative Commons CC BY 4.0 April 3, 2025 1. Introduction — Revisiting the Forgotten with AI For over a century, mainstream geology has maintained that Earth’s size has remained constant, and that plate tectonics alone explains the drift of continents. Theories suggesting otherwise— such as Expanding Earth (EE) and Expansion Tectonics (ET)—have been pushed to the scientific margins, often labeled unscientific or obsolete. And yet, some of the patterns these theories sought to explain have not disappeared. From fossil distributions to paleogeographic reconstructions and deep-sea volcanic formations, there remain unresolved questions about Earth’s structural evolution. This article tells the story of how artificial intelligence, in the form of ChatGPT, became a creative and critical partner in revisiting these long-dismissed ideas. It also introduces a new conceptual framework: the Cosmic Influx Theory (CIT)—a gravitational and cosmological model developed independently and refined through dialogue with AI. CIT provides a potential physical mechanism for planetary mass growth, offering a modern way to revisit EE and ET not as relics of the past, but as testable ideas for the future. Rather than being about proving or disproving one theory, this paper explores the power of collaborative thinking—human and machine—to challenge assumptions, connect forgotten data, and spark new lines of inquiry. This article was written in close collaboration with ChatGPT, building on our ongoing cooperation in developing the Wikiversity page Cosmic Influx Theory: https://en.wikiversity.org/wiki/Cosmic_Influx_Theory