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Invisibility - The New Technology
In a report from London’s Sunday Times, researchers at UC Berkeley are
apparently close to developing a cloaking device that will render people, places
and things invisible to the human eye.
While this news may excite Star Wars fans and may, too, spark the imagination
of readers who, having read the H.G. Wells novella, The Invisible Man, wished
that they could make themselves invisible, to we, as engineers, the news actually
doesn’t come as great a surprise. Given our present technological abilities
and understanding the nature of light, the development of methods to bend light
and render objects invisible to the human eye was not only inevitable, it has
already been done using various, albeit primitive, techniques.
Most people, when they think of something becoming “invisible”, assume
that something will be done directly to the object that will render it invisible.
But that can never be the case. The only thing you can do to an object that will
make it invisible is to eliminate the object. For example, if you want to make
an apple disappear by using a method that will alter the visible structure of
the apple, then the only logical end result will be the elimination of the apple.
You can’t say you turned the apple into an invisible vapor or random molecules
and still claim that these molecules or vapor is an apple. The apple is gone!
It’s the same thing when we convert water into steam. The water isn’t
just invisible - it no longer exists!
So when we talk about invisibility, what we really mean is a method to render
observers incapable of seeing an object or person. Invisibility can come from
camouflage, smoke and mirrors or, in the case of UC Berkeley, through bending
of light.
Man has attempted to make himself invisible since the dawn of time. If our
primitive ancestors weren’t trying to hide from animals that would eat
them, they were trying to sneak up on other animals they wanted to eat.
It wasn’t until World War I, however, that militarists and scientists seriously
became involved with the development of methods that would render people and
objects invisible. Around 1910, American artist Abbott Handerson Thayer (1849-1921),
sometimes referred to as “the father of camouflage,” devised a
way for individuals to design their own camouflage, using cutout silhouettes.
Thayer
believed that war paint used by aboriginal people served more for the purpose
of camouflage than any type of warlike statement.
When the War came along, German U-boats were sinking allied ships at an alarming
rate. While various colors of paints were used to disguise ships, for u-boats,
none worked well because of a constantly changing background. If you painted
a ship black to conceal it at night, it would stick out like a sore thumb during
the day. That’s when a British artist and naval commander, Norman Wilkinson
proposed using techniques similar to those Thayer had proposed in a scheme that
became known as “dazzle camouflage” or Razzle Dazzle as the Americans
came to call it a year later when they adopted the technique.
The American navy had enlisted its best to make ships invisible, including
Thomas Edison who developed several concepts that all proved to fail during
testing.
Razzle Dazzle camouflage recognized that the trick to camouflage is not so
much in making the object you wish to conceal invisible as it is to make your
opponent
incapable of recognizing or noticing the object. Dazzle camouflage, with its
bright colors and eccentric patterns did not attempt to conceal a ship, but
made it difficult for an observer to determine the size of the ship and the
direction
it was moving. In theory, by confusing the observer, he would not be able to
properly target the vessel for a torpedo strike.
Razzle Dazzle camouflage was used throughout World Wars I and II. Once radar
and other modern targeting methods were developed, dazzle camouflage became
obsolete. But the search for the perfect camouflage continues on.
The announcement that the U.S. had developed a stealth aircraft that was “invisible” to
radar got techies excited throughout the country. The F-117 Nighthawk, B-2
bomber and their more modern equivalents are all made from composite and plastic
materials
that either deflects or absorbs radar waves, preventing them from returning
to receivers. While effective against high power radar over the horizon, low
power
radar is reported to be very effective in identifying these stealth type aircraft.
If the new technology being developed at UC Berkeley performs as advertised,
it is important to note that radar will not be affected by the technology.
The Berkeley invention is reported to bend light around an object so that observers
will see the light from behind the object and not the object.
Perhaps the best way to explain this technology is to start by saying that
technically, everything we see with our eyes, no longer exists. As you learned
in high school,
when you view stars at night, you are actually viewing the light from those
stars, which is millions of years old. When you look at your face in the mirror,
you
are also seeing the light that was reflected to and from the mirror. While
the distance is so close that the light traveling is almost instantaneous -
it isn’t
instantaneous. What you see is from the past. That’s just the condition
and limit of human sight. All that we see is light. And light, like all matter
in the universe, travels at a constant speed in a straight line unless it is
interrupted by an outside force or agency. If I can intercept the light coming
from a distant star and redirect that light so that it turns, we on Earth would
never see that star. To us, the star would be invisible.
If I can develop a coating or material that redirects light, I can bring
light from the back of an object that has this coating, direct it around the
object
and then allow it to continue its travel upon its original path. Doing so,
would make the object I directed light around invisible to onlookers. Because
light
is all that we actually see, removing matter from the path of light, removes
our ability to see that matter within the light.
Besides giving future illusionists the ability to perform incredible tricks,
like making huge objects disappear before our eyes, this new technology
will provide obvious benefits upon the battlefield or upon the sea. Even giant
vessels like an aircraft carrier could be rendered invisible to human sight.
But again,
the vessel would be detectable with other sensing equipment. The most logical
outcome in warfare is that the technology will require future combatants
to rely more on instrumentation and sensors than on their own eyesight.
When you think about it, this technology can usher in many applications.
It may also serve as a precursor to development of what could be called,
illusion
anatomy.
While directing a light around an object, we can project images within
that light around an object. So theoretically, you could see the image
of one
person seemingly
emanating from the body of someone else or the vision of a friendly ship
emanating from what is actually an enemy ship.
Humans have progressed a long way since the first hunter found that applying
mud to his body kept some animals from detecting his presence. It will
be very interesting to see just how this new technology is deployed
both for
defensive
and peaceful purpose.
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