Imagine it is the year 2100. The population of the Earth, doubling every 30 years or so, has reached nearly 50 billion souls. The price of a comfortable single-family house on one acre in New Jersey, doubling every 10 years or so, has reached 250 million dollars. While your back was turned, however, nanotechnology was invented and Utility Fog has become possible. Utility Fog is a kind of universal substance, programmable matter, that can simulate everything from air to solid rock. A kind of 3D TV screen, but instead of making any desired picture visible, it makes any desired shape tangible.

So we go off somewhere, rope off a square mile, dig down a few hundred feet for foundations, and erect a block of Utility Fog a mile high. It doesn't have to be a cube, of course, it can be any shape you like, and indeed can change shape from minute to minute. As for the objects inside, nanotechnology will take care of that: it can build anything from the simplest structures to the most complicated.

In a cubic mile of Fog there are over 125 billion cubic feet. That's 10 by 10 by 10 foot rooms for 125 million people. Not that you would be stuck in a 10 by 10 foot room. First off, it's not a fixed location, it's 1,000 cubic feet of ‘personal space’ wherever you go. Secondly, it's like a Star Trek ‘holodeck’, it can seem to be any place, filled with any people and objects you choose – a vast country estate, the deck of a wooden sailing ship in the mid-Atlantic (complete with driving rain and pitching decks), or everybody’s favourite, the London of Sherlock Holmes.

And that's just your bedroom… Read More (by John Storrs Hall, author of the book Nanofuture: What's Next For Nanotechnology.)