My dissertation explores the relationship of the earth sciences with and against broader currents of decolonization and postcolonial worldmaking in the post-World War II period. In particular, it focuses on the mundane and tedious data practices that made it possible for scientists from the Third World to access and produce knowledge about geophysical processes. While existing scholarship in the history of the earth sciences has shown how this period witnessed a boom in novel conceptions of the planet, its outsize focus on actors from the global North risks taking for granted questions surrounding access to data and scientific infrastructure that animated much of the Third World. I propose, instead, a down-to-earth history of the planet, with an eye to the humble, quotidian and often frustrating work—such as applying for visas, financing conference travel, and stocking libraries full of journals and books—that undergirded the production of knowledge about the earth.