Scientists in the US say they are a step closer to developing materials that could render people invisible. Researchers at the University of California in Berkeley have developed a material that can bend light around 3D objects making them "disappear". The materials do not occur naturally but have been created on a nano scale, measured in billionths of a metre. The team says the principles could one day be scaled up to make invisibility cloaks large enough to hide people. Stealth operations The findings, by scientists led by Xiang Zhang, were published in the journals Nature and Science. The new system works like water flowing around a rock, the researchers said. Because light is not absorbed or reflected by the object, a person only sees the light from behind it - rendering the object invisible. The new material produces has "negative refractive" properties. It has a multi-layered "fishnet" structure which is transparent over a wide range of light wavelengths. The research, funded by the US government, could one day be used in military stealth operations - with tanks made to disappear from the enemies' sight BBC NEWS | Science/Nature | Invisibility cloak 'step closer'