… it occurred to me that if the U-Bahn system could somehow be hooked up to massive, earth-anchored magnets, and made, therefore, to produce a magnetic field of its own, that you could transform all of Berlin into a geomagnetic harddrive.
As a sail traps the wind, a planetary harddrive would use geomagnetism.
Provided constant motion on behalf of the trains, I thought, and given absolutely gigantic magnets of the right polarity and location, Berlin could start producing its own magnetic field â€“ which meant that any city with a subway could be transformed into a harddrive. Harddrive London. Harddrive Beijing. Harddrive Moscow.
Of course, it’s obvious even to me that you’d have to do quite a lot more than just bury some magnets underground in order to transform a city into a harddrive â€“ you’d need a shovel, for instance, and perhaps some strong anti-manic drugs; but my point is that if Christopher Wren could build a tower that simultaneously memorialized the Great Fire of London even as it acted as a scientific device, then perhaps you could turn urban infrastructure itself into a kind of working scientific apparatus.
You could turn all of Berlin into a geomagnetic harddrive….
(Thanks to Matt Jones)