"Here's the only tricky thing," Peggy says, "When we arrived here for the first time, it was as if someone had been here before. Someone had been living here and whether it was the people who set this up for us or simply another group of unfortunate people, it wasn't empty. "There's another alternative, of course," she points out.

"We're not in a place that has any ships or anything of the like," she says, which is just as likely as any of the other possibilities, isn't it? "If all the evidence around us suggests we're in the 19th century, wouldn't it stand to reason there would be no starships or space travel, because it hadn't existed at that point?"