One thing about running is that you get time to think, you can take a small inkling of an idea that you have, and turn it over in your head until it’s grown into something more, something usable in a story.

Over the weekend I was discussing personal force fields with a friend of mine, the sort to keep the rain off rather than the sort to deflect lasers – I live in Manchester after all – and I pointed out that the theory is already sound, using ultrasound.

In very basic terms, ultrasound uses sound waves to produce a thin “wall” of air at a fixed height away from the generator. You can move your hand underneath it and meet no resistance, but the wall of sound will push back. And it’s totally invisible.

Tests and experiments have shown that small objects can even be pushed along, and I recommend looking up videos on acoustic levitation and seeing water droplets being suspended in mid-air. Researchers in Tokyo took this one step further a few years ago, and rather than suspending small objects, created touchable holograms. Sensors detected where the hand was, and when it came into contact with a holographic object, ultrasound was used to create pressure on the hand, and give the impression of touch.

So when out running this morning I was thinking more about this, and what other uses it could be put too. I’m not a scientist, I’m a writer, so I don’t know if what I came up with is actually feasible or if there’s something pretty important I’ve overlooked, but it’s by coming up with these ideas, and writing them into books, that we hope that the real scientists will read them and act on them.

What I was thinking about was how artificial gravity works on spaceships. There’s lots of idea out there, based mostly on rotational or linear movement. But I was thinking, what if we’re going about this the wrong way? What if, instead of trying to create gravity, we instead created the impression of it? What if the ceilings of spaceships were lined with ultrasound generators and sensors, and as someone walked along, ultrasound was used to push them down to the floor? There’d be no need for massive flywheels or huge power supplies either.

We wouldn’t be creating gravity, we’d be mimicking it. Muscles and bones would still have to work against a force, so deterioration of muscular and skeletal structure shouldn’t be a problem, and having an “up” and “down” would help with the mental effects of long-term free-fall. Obviously this wouldn’t work when you got close enough to a planet where its gravity would take over, but it’d certainly work for space itself where it was only pushing against nothing.

It would take a very fast computer to monitor all crew and passengers, and to shift the ultrasound along with them, and there would most likely be a fair amount of heat generated behind the ceilings, but we’ve all seen in films that spaceships have lots of air ducts, perhaps this is the reason why?