Posted on 01/04/2009 2:47:09 PM PST by LibWhacker
Researchers are cloaking materials from light, sound, and even matter itself.
Two years ago a team of engineers amazed the world (Harry Potter fans in particular) by developing the technology needed to make an invisibility cloak. Now researchers are creating laboratory-engineered wonder materials that can conceal objects from almost anything that travels as a wave. That includes light and sound and—at the subatomic level—matter itself. And lest you think that cloaking applies only to the intangible world, 2008 even brought a plan for using cloaking techniques to protect shorelines from giant incoming waves.
Engineer Xiang Zhang, whose University of California at Berkeley lab is behind much of this work, says, “We can design materials that have properties that never exist in nature.”
These engineered substances, known as metamaterials, get their unusual properties from their size and shape, not their chemistry. Because of the way they are composed, they can shuffle waves—be they of light, sound, or water—away from an object. To cloak something, concentric rings of the metamaterial are placed around the object to be concealed. Tiny structures—like loops or cylinders—within the rings divert the incoming waves around the object, preventing both reflection and absorption. The waves meet up again on the other side, appearing just as they would if nothing were there.
The first invisibility cloak [subscription required], designed by engineers at Duke University and Imperial College London, worked for only a narrow band of microwaves. Xiang and his colleagues created metamaterials that can bend visible light backward—a much greater challenge because visible light waves are so small, under 700 nanometers wide. That meant the engineers had to devise cloaking components only tens of nanometers apart.
Xiang’s group also cleared another design hurdle. A competing team had devised a metamaterial to cloak visible light, but it was just one atom thick, too flimsy to deflect anything more than a single sheet of incoming light. Xiang’s new metamaterials have heft.
Last March José Sánchez-Dehesa and Daniel Torrent, physicists at the Polytechnic University of Valencia in Spain, presented a design that would allow a cloaked submarine to hide from sonar. This technology could also allow an orchestra patron sitting behind a cloaked column to hear music as clearly as one in an unobstructed spot.
In September French and British physicists presented a plan for using metamaterials to shield shorelines from the impact of massive waves. Their proposed device [subscription required] would look like a scaled-up acoustic cloak: concentric circles of posts surrounding a hidden object. When a wave hits them, the posts would redirect it around the object without ever breaking the wave. The researchers say that such a device could be used to protect isolated spots in the ocean—like drilling platforms or low-lying islands—or coastal regions vulnerable to tsunamis.
But the weirdest extension of the cloaking concept is undoubtedly the “matter” cloak described this past year by Shuang Zhang, a postdoctoral associate in Xiang’s lab. Subatomic particles like electrons travel as waves, and Shuang showed how metamaterials could be used to divert an atomic wave the same way the invisibility cloak redirects a light wave. If such a device could be scaled up to the human-size world (far from certain, alas), it might be able to steer a bullet around a bulletproof cloak.
Question for you physicists out there... Is gravity a wave? If so, this could be a cool method for propulsion in outer space... Just cloak the spaceship from gravity emanating from one half of the cosmos and the other half tugs you in the direction you want to go.
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I've got some things that work something like these in my house. We call them mirrors.
This could have some major implications for warfare...
Now we know where the aliens (of the intergalactic kind) are hiding. All those UFO sightings are only because their cloak failed.
Seriously though, I’ve always believed Gene Roddenberry was an alien or lived with one. ;^)
/johnny
Who was that directed at? Just curious.
If I need to type slower, I can.
Welcome to FreeRepublic.
/johnny
Soon to be seen er.... used at Galt’s Gulch.
Answer that question fully and get a Nobel Prize :-) There are several theories of gravity, but there are difficulties at the quantum level.
If so, this could be a cool method for propulsion in outer space... Just cloak the spaceship from gravity emanating from one half of the cosmos and the other half tugs you in the direction you want to go.
You won't get a patent on this, Wells invented this method first, see his 1901's story The First Men in the Moon (you can read it here.)
Gravity is part of the quantum world, which means that when observed or measured one way it should or will behave like a wave, and when observed or measured another way it behaves like a particle. In physics this is called Wave-Partical Duality. This is best demostrated using visible light... especially the discovery of the Photoelectric effect.
In any case, quantum physics is a strange world where things are simultaneously wave and particle, where particles exist in 2 spaces at once, where particles pop into existence out of nothingness (the fabric of space itself) and where we can never know everything about it because of the Heisenberg Uncertainty Principle.
Regarding gravity... Einstein suggested gravity was a wave, quantum physicists (such as Bohr) suggest gravity is a particle (the graviton). Neither has really been confirmed yet. As for using gravity waves as a means of propulsion... this has been discussed by some of the best minds in pysics, so you’re on to something! Well done!
“We call them mirrors. “
We got you beat... We can look right through solid walls with our devices ... We call them windows.
In fact, a person can pass right through a solid wall with another device we call a door.
....Bob
Cavorite!
LOL! That was good!
http://www.youtube.com/watch?v=mFGo6kCmf38
Hey navyguy, you had them on ships but called different things. Looking through steel walls were called portholes, and going through steel bulkheads were called hatches.
.....Bob
Beware of Romulans bearing gifts.
I remember them well... kinda wish I was back out there, haze grey and underway...
Happy New Year!
Thanks, navyguy, but it seems H.G. Wells beat me to the punch about a hundred years ago, lol! I actually read that book when I was a kid and it's undoubtedly where the old subconscious mind dredged up the idea.
I know some physicists say it's impossible. You cannot block gravity. If you could, it would violate the principle of conservation of energy; namely, you could raise up a weight with little expenditure of energy, then drop it and convert the kinetic energy to electricity as it fell. But that would be a perpetual motion machine. In fact, it would even output more energy than required to keep it running. Impossible. They say.
HOwever, this article seems to imply that it may be possible to "cloak" anything from any wave (including gravity?). So that's why I asked. :-)
BTW, thanks for the nice responses, each of you. Cheers!
I’ve seen that before, very cool! Now I wanna see one that routes bullets around it!
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