Cesium is the most reactive of all metals. It burns in air and reacts violently in water. For which reason, it is best stored in interstellar vacuum.
The Precursors, that most mysterious of (presumably) extinct alien races, built cesium castles as large as moons in the emptiest reaches of intergalactic space. We'd been prospecting for hard vacuum when we found one. One minute the readings were down to a single atom per cubic mile, and the next they were off the meters. We went in to look.
The castle was so spacious as to have an average density equivalent to that of a light fog. We drifted through rooms as large as cities using tiny puffs of steam for propellant. Wherever we went, walls burned behind us. It didn't matter. There was a lot more where they came from.
At last, sated with wonders, godlike architecture, and miles-long statues that looked like they'd been forged by Michelangelo's more talented brother, we gathered in the exploration ship's conference room to decide what to do.
"It's a hundred percent cesium," the Ship's Chemist said. "No impurities at all. I can't imagine how they refined it, much less how they shaped it."
"The art is magnificent," the Ship's Xenologist observed. "But where could we display it? It's all volatile as hell and the best of it is so large and delicate that if we put it in orbit around a planet, tidal forces would tear it apart."
"I'm skunked," the Captain said. "I have no ideas whatsoever. It's magnificent. But what practical use is it?"
I cleared my throat.
"In nineteenth century Egypt," I said, "mummies from looted tombs were burned by the coal-tender load to power steam locomotives. Dry as they were, they made excellent fuel, far better than coal."
"Mummies?" the Ship's Biologist asked, appalled. "You mean, like real mummies?"
I nodded. "A century later this was considered a terrible cultural crime, of course. But by then the entrepreneurs who had opened the graves and sold the mummies in lots of thousands, had retired rich, died old, and left prosperous dynasties behind them."
"So you're proposing … that we …" The Ship's Physicist could not quite finish the thought.
"Break it and sell it as starship fuel, that's right. There's got to be a billion quads worth of power out there. Enough to make every one of us richer than Croesus."
The vote was quick and unanimous.
There's a good reason why I was included in the science vessel's crew. Sometimes you need the kind of perspective that only a Ship's Historian can provide.
© 2002 by Michael Swanwick and SCIFI.COM.