A cidade no fim do mundo by Edmond Hamilton. Publicado pela primeira vez na revista Histórias surpreendentes (Julho 1950), e depois impresso como um livro no 1951, e reimpresso em várias ocasiões desde então. Na verdade, acabei de descobrir que você poderia obter uma versão em e-book para o Kindle, via site da Amazon, como parte de um pacote que inclui outras histórias do 15 do mesmo autor, convenientemente reunidas em um grande "Megapack", tudo por meros centavos do 55 (dinheiro dos EUA).
Eu possuo uma das reimpressões em brochura, com a arte da capa mostrada abaixo (que pode tocar uma campainha para você?), Mas eu não tenho minha cópia em mãos para me deixar citar passagens, então vou resolver por citar algum material de uma longa revisão sobre Goodreads para demonstrar que você está pensando na mesma história que li alguns anos atrás.
Você disse:
The premise was a scientist working on a "Superbomb" (described as a
Hydrogen bomb) in a rural American town/city. An atomic war breaks out
and the city is hit.
The bomb doesn't destroy the town; instead the town is catapulted
millions of years into the future where the Sun is a growing red giant
star and humanity is long gone.
A resenha publicada por um cara chamado "Sandy" no livro Página Goodreads diz, em parte:
The novel strains the reader's credulity in its opening pages, but if
you can get past them alright, and buy into the central premise,
you'll be home free. In "City at World's End," the reader is
introduced to the small city of Middletown, in Anywhere, U.S.A.; a
burg of some 50,000 souls going about their business on a beautiful
June morning. What the citizens of Middletown don't know, however, is
that its local industrial laboratory is actually the secret working
site of a group of atomic physicists, which makes the otherwise
undistinguished locale a prime target in a potential war. And before
the citizenry is even aware of it, a so-called "super atomic" is
exploded right over their heads, knocking one and all off their feet.
And that's all! As the populace dusts itself off, it is noticed that
the air is now very much colder, and that the sun has changed to a
gloomy-looking red ball in the heavens. The moon is now enormous, the
stars are visible in the daytime sky, and the lab scientists, by
analyzing those changed star patterns, soon come to realize the
impossible truth: The city of Middletown has somehow been blown, via a
rift in the time-space continuum, millions of years into Earth's
future!
Você disse:
Aliens find the town and help the folk out somehow.
Sandy em Goodreads diz:
In the book's next section, men from outer space, representing the
League of Stars, arrive near New Middletown in response to its radioed
pleas for assistance; these Earthmen of the future and their alien
shipmates help get New Middletown going but then insist on evacuating
the 20th century community to another, more livable world, much
against the wishes of the old-fashioned folk. Thus, in "City at
World's End"'s next section, it is up to Kenniston, as the city's
representative, to go to the galaxy's capital world near Vega and
plead his neighbors' case before the Board of Governors. And before he
knows it, he has also become embroiled in a plot involving the
futuristic scientist Jon Arnol, who claims to have invented an "energy
bomb" that can revive a dying planet....
Coloque esses pontos de semelhança com sua lembrança de que a história remonta aos primeiros 1950s, e eu não acho que haja espaço para dúvidas!