One of my favourite episodes of Deep Space Nine, "Little Green Men", involved Quark, Nog, and Rom accidentally traveling back in time to 1947 Earth, crash-landing in Roswell, and being captured by the US military. There's a wonderful conversation between the three about nuclear weapons and ultra-cynic Quark of all people being surprised and horrified by the concept.

ROM: I'm working as fast as I can, brother, but there must be some kind of interference disrupting our translators.

QUARK: What kind of interference?

ROM: I'm not sure. Could be solar flares, or maybe ionic interference. Or I suppose it could be beta radiation, but that's only produced by nuclear fission.

QUARK: Don't be an idiot. Nuclear fission doesn't happen within planetary atmospheres.

NOG: It does here. In the twentieth century humans used crude nuclear reactors as weapons. They called them atom bombs. They used to blow them up all the time.

QUARK: They irradiated their own planet?!

ROM: If Nog says so, they did. He knows all about Earth history.

QUARK: You'd better fix those translators fast. The sooner we start talking to these savages, the better off we'll be.