Collaborator
George Ellis
The South African cosmologist who co-wrote Hawking's rigorous technical masterwork on the structure of spacetime, and later a leading voice on the philosophy of science.
Last updated 23 May 2026 · How we research
George Ellis, born in 1939, is a distinguished South African cosmologist and, with Hawking, the co-author of one of the most important technical books in the field. The two were contemporaries in the relativity community that grew up around Dennis Sciama and Roger Penrose.
His own work
Ellis is a major figure in cosmology and the study of general relativity, with deep contributions to our understanding of the large-scale structure of the universe. In later decades he became equally well known for his thoughtful writing on the philosophy of cosmology and on the relationship between science, ethics and religion, and he was awarded the Templeton Prize in 2004. He was also a committed opponent of apartheid in his native South Africa.
His connection to Hawking
In 1973 Ellis and Hawking published The Large Scale Structure of Space-Time, a rigorous, mathematically demanding book that set out the geometric tools of general relativity and the proofs of the singularity theorems in full technical detail. It stands in deliberate contrast to Hawking's later popular work: where A Brief History of Time was written for everyone, this earlier book was written for specialists, and it remains a respected reference decades later. It represents the serious scientific bedrock beneath the public fame, and Ellis was Hawking's partner in laying it down.