Invisibility in simple terms can be defined as a state of 100 percent transparency or a state in which an object cannot be seen. Since objects can be seen by light in the visible spectrum from a source reflecting off their surfaces and hitting the viewer’s eye, the most natural form of invisibility is an object that neither reflects nor absorbs light (that is, it allows light to pass through it).
Although no natural (considering man-made material as some form of natural material) material is known to have this property, science has been working on different ways so that invisibility can be achieved by improving the camouflageapplication.
What is a camouflage?
Camouflage is a method of hiding, it allows a thing to be almost invisible by blending it with the environment. A perfect camouflagecan be regarded as perfect invisibility and an object that has achieved this is said to be invisible. Most common examples of camouflageare the animals like chamaleon that change their color with respect to the environment to try to hide their presence and hence save themselves from possible attack from another animal. Another example of camouflagecan be seen at the defence sector where the uniform of personnel in the forest area is made of green color with some leaves on it, by this an attempt is made to hide the presence of a person by environmental blending.
How to achieve invisibility ?
We will discuss a few basic methods here, on which research is going on so some day a advancement in any such method may enable us to see or rather not see a object:
Making use of real-time image displayed on a wearable display, scientists are able to create a see-through effect, if not invisibility. This is known as active camouflage.
Though stealth technology is cited as invisibility to radar, all officially disclosed applications of the technology can only reduce the size and/or clarity of the signature detected by radar.
In some science fiction stories, a hypothetical “cloaking device” is used to make objects invisible. On Thursday, October 19, 2006 a team effort of researchers from Britain and the US announced the development of a real cloak of invisibility, though it is only in its first stages. The technology behind that device is the way it reflects light, diverts it and makes light virtually pass through a object thereby making it invisible to naked eye.
In film making, people, objects, or backgrounds can be made to look invisible on camera through a process known as chroma keying.
Another method of gaining invisibility is by psychological means which a bit less scientific to be discussed here.
Research is going on these methods and many other methods and we may in near future find invisible people and objects moving all around us, like it or not it is much likely that this will happen.