Was wondering about that but then came across this passage in the paper: “ The last date on which a transient was observed within a nuclear testing window in this dataset was March 17, 1956, despite there being an additional 38 above-ground nuclear tests in the subsequent 13 months of the study period.” I would expect to see artifacts of the tests themselves continue under that hypothesis. Of course this raises a whole bunch of other questions…

The bomb casing from a successful nuclear detonation would be entirely atomized and instantly vaporized. The exponential runaway of an atomic chain reaction produces so much radiation (read: light, heat, X-rays, and even gamma rays) in the first nanoseconds that literally every chemical bond is ripped apart, plus so many fast-moving neutrons that many nuclei (even not of the initial fissile material) are either fissioned themselves or altered to radioactive isotopes. Because so much EMR is produced so fast, there literally isn't even time for matter to be physically accelerated away before being absolutely soaked in EM. It's possible that some other matter in the vicinity might be intact and blasted away, but anything within the fireball radius of ~100m is absolute toast.

These things are i think around 400,000km out in space so no.

Try reading the article. You might enjoy it and it will answer your question.

> Weren't Nazis sending rockets into space by 1945? Soviets and Americans, probably as well.

No to all, without reservation. The German V-2 didn't go into orbit, and the US and USSR weren't active in large missile activity at all, until long post-war.