Science fiction needs to reinvent itself if it still wants to hold people in thrall to the magic of extrapolation. Because over a period of time — and especially during the last 50 years or so — hard science has been catching up and delivering even on some of SF's most far-out and fantastic ideas. Faster-than-light speeds, teleportation, thought transference, artificial intelligence, time travel and synthetic life, for instance, which were once considered the exclusive province of fantasy, are being approached by serious scientists seemingly determined to bring the Enterprise down to Earth. The latest in their list of achievements now appears to be invisibility. According to the scientific journal, Optic Letters, researchers at the University of Illinois in the United States have demonstrated by means of a computer simulation how it might be possible to make an object appear to vanish from sight. The trick apparently is to coat it with multiple concentric layers of a type of silicon crystal so that when light of a particular wavelength strikes the coating it bends around the object and continues on its way, like water flowing around a rock. Since seeing something requires light waves to actually strike the object and reflect off it in order to impinge on our eyes, this process would, effectively, render it invisible. Of course there are still several problems to be solved regarding such "optical cloaking", as it's being called. For one thing, the simulation has been successful so far only with samples the size of a human hair. But the researchers feel it shouldn't be too difficult to scale up the extent to everyday sizes over the next few years. Also, they've demonstrated the effect using just red light at present, whereas true invisibility would be achieved only if it worked with all waves of light along the entire visual spectrum. However, when and if they do get light to bend around, say, a battleship or a tank — since military applications come to mind immediately — the entire meaning of stealth warfare could change drastically. So could social interaction when clothes come pre-optically cloaked too. If anyone could become invisible at will by using a Harry Potter like cape, a whole lot of issues relating to privacy would have to be addressed. That's the problem with science approaching the magical.