Ranking scientific achievement is a very dodgy pursuit and physics is no exception. There is a path dependence that makes it almost impossible to compare indiv

Ranking scientific achievement is a very dodgy pursuit and physics is no exception. There is a path dependence that makes it almost impossible to compare individuals that worked in different eras. This is hinted at by the famous "standing on shoulders of giants" quote of Newton and is further complemented by something I believe Lev Landau has expressed using the phrase "all the brides are taken" (he felt there weren't big enough problems for him to have a chance to measure against the "greats)" There is one and only Universe, the understanding of which by humans is a single historical trajectory. There is no possibility to control for any variable and repeat the experiment. Would the absence of the specific "Newton" individual delay the process of understanding the physical works? by how much? A few years, decades, centuries? Taking into account that ideas and possibilities tend to "float" in the environment of a particular era but also the presence of non-linear loops such as: influential scientists that get recognized early on can stall further development during their own lifetime! Making the best of a risky task would require that we only compare apples with apples, individuals of a particular era and operating in the same information environment. So in this instance, ranking Oppenheimer against individuals of his generation only. Having said all that, imho there is really nobody like Einstein. Ever since the 18th century most physics is in a sense "programmatic". There is a defined mental framework that people apply repeatedly to an ever growing range of accessible or relevant domains. Einstein's journey created an entire new paradigm (the fabric on which physics plays out is itself physics) and one we still have not fully understood. The most exciting possibility is that somebody might be able to piece together that growing observational hints from cosmology and the various puzzles of black holes to take that paradigm to the next stage.