In swapping Eternity for Infinity, time travel is expressly rejected in favour of space travel. One change is made—and not one that would be made today to bring about a brighter future! They give the people of the primitive era of 1932 a hint about atomics, which of course will lead to mankind going to the stars at the earliest possible opportunity. It’s hardly possible to read this in 2010 with the same optimism as readers did in 1955, or even as I did in 1975, even given the recent discovery of lots more extrasolar planets.Really? Why?
We have seen no evidence that indicates that nuclear power is unexpectedly dangerous. We don't see three-eyed mutants walking around Hiroshima; we don't see nuclear explosions at reactors (cf. “Blowups Happen” by Robert Heinlein); we've seen only one major meltdown at Chernobyl (as well as a minor meltdown at Three-Mile Island); we didn't see cancer epidemics as a result of the bomb testing in the 1950s; we're no longer faced with an insane great power armed with thousands of nukes (we might be faced with an insane medium power armed with dozens, but that won't produce an On the Beach scenario). Even radioactivity looks less dangerous than we thought.
The only two unexpected anti-nuke phenomena are: 1) the anti-technology movement; and 2) the fact that large capital expenditures are unprofitable in an inflationary environment. Even anti-technology movement was predicted (“Trends” by Isaac Asimov); the only unexpected feature was the identity of the idiots involved.