> like shining a bright flashlight into the dark night sky. Tho once you shut
> off the flashlight, the beam winks out. But the beam really has travelled
> at 186,000 miles a second upwards into space and is still going.
Here is the crux of the problem... technically this idea is totally
feasible, except for the one minor problem that makes it totally
impossible: how do you shut the lid of the box fast enough to prevent the
light from escaping. Answer? You can't. No shutter mechanism in the world
can act fast enough. A shame, isn't it?