Ever wanted to be invisible?
Well science is getting closer to making that fantasy, a reality.
So invisibility cloaks seem like the realm of fantasy.
But science is working on it.
We see things when light bounces off an object and reaches our eyes.
To make something invisible to our eyes, researchers have to find ways to bend light or other forms
of electromagnetic radiation around an object.
Previous versions of an invisibility cloak were less of a cloak and looked more like
a medical device.
One involved a series of lenses that bend light around an object, you could find out
more about there here in Amy’s video.
But scalability proved to be an issue.
It couldn’t cover large or irregularly shaped objects, like a human body for example.
It was really limited to simple objects like a cylinder and only at specific viewing angles.
If you were to walk around the object, it would be visible.
But in the two years since, other researchers have come up with their own versions of an
invisibility cloak.
A team of researchers at UC Berkeley came with a metamaterial that’s super thin according
to a paper published in the journal Science.
The thin cloak is only 80 nanometers thick, made up of tiny gold antennas that make you
think you’re looking at a flat surface instead of a three dimensional object.
t’s because this metamaterial changes the way light is scattered.
When we look at someone, our brains work to interpret the way light is scattered by their
face and body.
But the cloak, disrupts the way light scatters.
So instead of seeing the person in front of us, we would see a flat surface.
Pretty clever huh?
. One of the authors of the study told The Washington Post that “Each antenna is designed
to react with the light and scatter it back.”
And it’s so thin that it actually acts like a cloak by wrapping around the object it’s
hiding.
The benefit of this material is that it can cloak irregularly shaped objects, like the
human body.
But don’t get too excited, so far the material can only cover an object about one square
millimeter or about the size of a grain of sand.
So that’s very tiny.
And only at a very specific wavelength of light.
So, while we’re inching closer to a true invisibility cloak, we’ve got some major
hurdles to jump over first.
Since we’re playing with light waves and bending them and scattering them at will,
things start to get a little strange.
It does a weird timey-wimey thing.
In reflecting and scattering light, it actually delays light, it delays the reflection.
So there’s a lag effect, where the image appears slower than that thing it’s reflecting.
Like time is moving at two different rates.
So if you’re walking by a cloaked, invisible box, a bird flying by would pass at normal
speed, but if it flew inside the box, it would be a few seconds slower.
And most of the cloaks so far, have to stay still.
As soon as you move, the illusion is broken.
You’ve heard of the doppler effect, it’s where the pitch of sound changes as a object
moves past you, and that’s because of how the sound waves are emitted when an object
is moving fast, it changes the space between the waves, thus changing the pitch.
And according to a study published in the journal Physical Review A, a similar thing
causes a fast moving cloaked object to appear visible.
Basically the frequency of the light waves changes as the object moves, which causes
distortions in the image.
And as the object moves faster these changes get more noticeable.
Which, kind of defeats the purpose of the cloak in the first place.
The other issue with these kinds of invisibility cloaks, is that while it might make an object
invisible, if someone were inside of that object, they couldn’t see out.
But this paper also makes the case that these distortions, might actually enable someone
in the cloak to be able to see out.
So perhaps there’s solutions on the horizon for some of the tricky science behind invisibility
cloaks.
For now, I’m just going to go read some fantasy books until science perfects it.
Telescope push If you want an incredible behind-the-scenes
look at the James Webb Space Telescope, make sure to check out Discovery’s brand new
documentary Telescope!
The world premiere is this Saturday, February 20 at 9pm on the Discovery Channel.
We’ll be watching too!
It’s crazy to think about how technology is making fantasy a reality.
Like scientists are already working on mind control!
To learn more about that check out this episode right here.