Cloak of invisibility
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A cloak of invisibility is a theme that has occurred in fiction, and more recently, reality.
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[edit] Cloaks of invisibility in fiction
Cloaks of invisibility are relatively rare in folklore; although they do occur in some fairy tales, such as The Twelve Dancing Princesses, a commoner trope is the cap of invisibility.[1] The cap has appeared in Greek myth: Pluto was ascribed possession of a cap or helmet that made the wearer invisible.[2] A similar helmet, the Tarnhelm, is found in Norse mythology.
An invisibility cloak is used in the Harry Potter series. The cloaking device, appearing in Star Wars and Star Trek, is a similar idea.
[edit] Cloaks of invisibility in science
On October 19, 2006, a joint effort between scientists from England and the United States of America produced a cloak that prevented a copper cylinder from being detected by microwaves. The cloak was made from metamaterials. It cast a small shadow, which the designers hope to fix.
The device works only in two dimensions and only on microwaves, items are still visible to the naked eye although the research may lay ground work to address that form of invisibilty also[3][4].
David R. Smith, Augustine Scholar and professor of electrical and computer engineering at Duke University which demonstrated the first working "invisibility cloak" has been quoted as saying:
"It's not yet clear that you're going to get the invisibility that everyone thinks about with Harry Potter's cloak or the Star Trek cloaking device. To make an object literally vanish before a person's eyes, a cloak would have to simultaneously interact with all of the wavelengths, or colors, that make up light."[5] However, new studies by an American group of scientists say that the cloak would be very similar to the invisibility cloak in Harry Potter, but no shadow would be produced, because the cells would allow light to bend around them. The design calls for tiny metal needles to be fitted into a hairbrush-shaped cone at angles and lengths that would force light to pass around the cloak. This would make everything inside the cone appear to vanish because the light would no longer reflect off it.
"It looks pretty much like fiction, I do realize, but it's completely in agreement with the laws of physics," said lead researcher Vladimir Shalaev, a professor of electrical and computer engineering at Purdue.
"Ideally, if we make it real it would work exactly like Harry Potter's invisibility cloak," he said. "It's not going to be heavy because there's going to be very little metal in it."
[edit] References
- ^ Maria Tatar, The Annotated Brothers Grimm, p 332 W. W. Norton & company, London, New York, 2004 ISBN 0-393-05848-4
- ^ Edith Hamilton, Mythology, p 29, ISBN 0-451-62702-4
- ^ [1]
- ^ [2]
- ^ [3]
