By 1938 radioactivity, nuclear fission, nuclear fusion, and quantum phenomena had been observed in the laboratory. Quantum mechanics and theories of special and

By 1938 radioactivity, nuclear fission, nuclear fusion, and quantum phenomena had been observed in the laboratory. Quantum mechanics and theories of special and general relativity were already well-developed. I think that the 20th century would have seen technologies mushroom from these new scientific observations even without WW II. Of course scientific discovery continued after 1950. The difference is that newly discovered physical [1] phenomena -- though very impressive in their own ways -- don't have the same obvious technological applications as ionizing radiation, nuclear phenomena, and quantum mechanical phenomena. The discovery of gamma ray bursts, continental drift, the cosmic microwave background, and exoplanets were all very scientifically exciting. But they don't have obvious technological applications the way that nuclear fission or the photoelectric effect did. It may be possible that we ran low on interesting physical phenomena amenable to incorporation in new inventions much sooner than we ran low of interesting physical phenomena in general. [1] I almost forgot biology. I would say that the progress of biological knowledge and applied biotechnology has been impressive in recent decades, even if it hasn't matched the hype around the time of the original Human Genome Project. I also think that biotechnology has yet to reach its peak rate of development.