Renn's research projects focus on long-term developments of knowledge while taking into account processes of globalization. His research projects have dealt with the historical development of mechanics from antiquity until the 20th century. In this context Renn also investigates the origins of mechanics in China, the transformation of ancient knowledge, and the exchange of knowledge between Europe and China in the early modern period. A main focus of Renn's research is the history of modern physics, investigating the origin and development of general theory of relativity, and of quantum theory in particular. Renn has written about the Anthropocene in relation to the history of knowledge and science.
Digitalization and open access
Since the emergence of the World Wide Web, Renn has advocated for free access to historical sources. In 1992 he launched an initiative with Peter Damerow and Paolo Galluzzi to create a freely accessible “Galileo-Einstein Electronic Archive” online. With support from the European Community, he later founded the ECHO-Initiative to promote the study of historical sources online. Renn is one of the initiators of the Berlin Declaration on Open Access to Knowledge in the Sciences and Humanities and launched the publishing platform Edition Open Access together with other colleagues from the Max Planck Society.
Exhibitions
Renn has organized several exhibitions in the area of the history of science, technology, and culture. He has co-organized several exhibitions, including:
2005: Albert Einstein - Chief Engineer of the Universe in the course of the World Year of Physics 2005, Kronprinzenpalais
1992: Visiting scholar at the Forschungsschwerpunkt "Wissenschaftsgeschichte und Wissenschaftstheorie" der Gesellschaft für wissenschaftliche Neuvorhaben der Max Planck Society Berlin
Wissensgeschichte der Architektur. Vol. 1: ; vol. 2: ; vol. 3: . Studies 3, 4, 5: Max Planck Research Library in the History and Development of Knowledge. Berlin, Edition Open Access, 2014.
"Einstein’s Copernican Revolution," in , edited by Michel Janssen und Christoph Lehner, 38–71. New York: Cambridge University Press, 2014.
in Rechtsgeschichte/Legal History 2014 :52–60.
"Beyond Editions: Historical Sources in the Digital Age," in , edited by Michael Stolz, and Yen-Chun Chen, 9–28. editio / Beihefte 38. Berlin: De Gruyter, 2014
"Learning from Kushim about the Origin of Writing and Farming," in , edited by Katrin Klingan, Ashkan Sepahvand, Christoph Rosol und Bernd M. Scherer, 241–259. Cambridge: MIT Press, 2015.
"Schrödinger and the Genesis of Wave Mechanics," in , edited by Wolfgang L. Reiter und Jakob Yngvason, 9-36. Zurich: European Mathematical Society, 2013.
"The Emergence of Statistical Mechanics," in , edited by Jed Z. Buchwald und Robert Fox, 765–788. Oxford: Oxford University Press, 2013.
"The Transformation of Ancient Mechanics into a Mechanistic World View," in , edited by Georg Toepfer und Hartmut Böhme, 243–267. , Berlin: De Gruyter, 2010.