The dream of invisibility goes back to at least the Greeks whose god of the underworld, Hades is supposed to have had a helmet of invisibility.
But this week scientists at the Nanyan Technological University in Singapore, unveiled a video of a goldfish and cat disappearing and reappearing behind a new ‘invisibility cloak’ they’d developed. If you haven’t seen it yet you can find a link to the video below but in the meantime here’s the Quickfire Science...
At the moment objects like tanks can only be disguised, using cameras to project the view behind the tank onto screens covering the other side. This was seen on a car in the James Bond movie, Die Another Day.
However this technology only works from one perspective – the angle the camera is facing – so if you spotted the tank from a different angle, it would distort the illusion.
But in 2006, British Researcher Sir John Pendry came up with a way of bending light around an object to create a ‘cloak’, which would make it invisible to the naked eye.
However when light waves are bent around an object they have to travel further than the light unaffected by the cloak. This means the bent light arrives slightly later than it should so the image isn’t perfect.
To correct this, the bent light waves have to appear to move faster than the unaffected light travelling in air, which is impossible with natural materials.
Cloaks like this have been built successfully with artificial ‘metamaterials’, made with carefully designed structures smaller than the wavelength of light. But they’ve only been able to hide objects from view in microwaves rather than visible light.
To disguise large objects in visible light, the team in Singapore decided to see how well they could manage with conventional materials, not worrying about whether the light was delayed.
They used prisms of glass in a hexagon or square which refract the light through one another around the object – so even if your pet moves inside the prisms it looks like it has disappeared!
This can still only be seen from a maximum of six angles but the hope is that they will be able to increase this by changing the layout of the prisms.
They have managed to hide goldfish and even a cat in a real life environment and hope it could be used for both surveillance and entertainment.
I haven't read the link above as it's taking ten minutes to load a page at the moment due to my slow net connection. What you really want for invisibility is a covering with lots of spherical pits in it acting as pinhole camera/projecters. If the covering is rigid, the equivalent of a retina in each pit would detect light and be able to pass it through to a single pixel in a single pit elsewhere through an unchanging link, and that pixel would then emit as much light of the same colours as hit the original. The more pits used, the better the illusion (or un-illusion, in that you wouldn't see it). At a distance, one centimetre might be sufficient pit resolution, and a person could probably be covered adequately with a couple of square metres, so 20,000 pits be required with perhaps a similar number of pixels each. That would require 400 million connections between pixels, although the wiring could obviously be simplified by timesharing the wires. It strikes me that this should really be quite a trivial thing to build these days. David Cooper, Fri, 14th Jun 2013
Yes the invisibility cloaks are actual and real, ( though they do not make people or objects disappear, they bend light ) and they are being used, and developed further, by Defense Research and Development Canada, one of the companies involved with the program, Hyperstealth Biotechnology Corp., the U.K. and the U.S. as far as the owner of the textiles company has commented on.
You guys make it really hard to see the invisible cat when the dropbox is denied and this is my third attempt at a comment because the first two were denied and then was unable to 'Go Back'!! Just let me see the video. Please. amber, Tue, 18th Jun 2013