Dashing the dream of ideal 'invisibility' cloaks for stress waves

Whether Harry Potter's invisibility cloak, which perfectly steers light waves around objects to make them invisible, will ever become reality remains to be seen, but perfecting a more crucial cloak is impossible, a new study ...

Invisible tags: Physicists write, read and erase using light

A team of physicists headed by Professor Sebastian Reineke of TU Dresden has developed a new method of storing information in fully transparent plastic foils. Their innovative idea has been published in Science Advances.

New technique proposed to make objects invisible

In recent years, invisibility has become an area of increasing research interest due to advances in materials engineering. This research work by the UEx, which has been published in Scientific Reports, explored the electromagnetic ...

Updating high-resolution MRI

How can you make a high-frequency MRI machine more precise? By taking an electrical engineering approach to creating a better, uniform magnetic field.

Beyond good vibrations: New insights into metamaterial magic

If invisibility cloaks and other gee-whiz apps are ever to move from science fiction to science fact, we'll need to know more about how these weird metamaterials actually work. Michigan Tech researcher Elena Semouchkina has ...

page 1 from 11

Invisibility

Invisibility is the state of an object that cannot be seen. An object in this state is said to be invisible (literally, "not visible"). The term is usually used as a fantasy/science fiction term, where objects are literally made unseeable by magical or technological means; however, its effects can also be seen in the real world, particularly in physics and perceptional psychology.

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 (whether real or fictional) is an object that neither reflects nor absorbs light (that is, it allows light to pass through it). In nature, this is known as transparency, and is seen in many naturally occurring materials (although no naturally occurring material is 100% transparent).

Visibility also depends on the eyes of the observer and/or the instruments used. Thus an object can be classified as "invisible to" a person, animal, instrument, etc. In the research of sensorial perception invisibility has been shown to happen in cycles.

Invisibility is often considered the supreme form of camouflage, as it doesn't show any kind of vital, visual, nor any of the frequencies of the electromagnetic spectrum such as radio, infrared, ultra violet, etc.

This text uses material from Wikipedia, licensed under CC BY-SA