In Search of the Blackest Thing on Earth (1)
- This is a $2 million diamond. The reason you can't see it is because it's coated
with a nano material that makes light almost disappear. Even under bright illumination,
the facets and reflections that give diamonds their beauty just disappear. The stuff that
makes this possible is the blackest substance made by humans. But is it the blackest thing on Earth?
This bird might disagree. Hey, smart people, Joe here. What does it mean for something to be black?
So this is something that we normally think of as black. like really really black but
then you see it next to something like this. We painted this with the blackest paint that
you can get. And this is really really black. But then when you see it next to these super
black bird feathers I don't know. This is an orange, and this is one of the blackest
paints in the world. It really messes with your brain. It's almost blacker than black.
For something to be black, it has to stop light from getting back to your eyes. But it turns
out there are different blacknesses of black, different materials and structures that trap or
absorb light in different ways. Some allowing as few as one photon in 100,000 to escape.
Beyond being cool and fun to play with, what's the point of stuff like this? Well,
ultra black materials have a bunch of uses, from lining the inside of telescopes to help us see
the light from distant stars, to making better solar panels, to radar-tricking camouflage.
For decades, scientists, engineers, even artists, have been racing to create the blackest black, and
they're getting some inspiration from some pretty interesting places.
These are terrifying looking. This just looks like a gallery of monsters. These
represent some of the blackest fish ever found, ever discovered?
- These guys represent some of the blackest organisms known on the planet.
- The deep ocean is full of strange life forms that we know very little about. Karen Osborne
is a scientist at the Smithsonian trying to shine a light on these mysterious creatures,
but there are a few species she could never quite get a look at.
- So I started studying these guys out of pure curiosity. I could never
get a picture of these black fish. I just got these beautiful silhouettes.
- These super black, deep-sea fishes have names like anglerfish, dragonfish, and fangtooths.
It's a pretty accurate name, actually, when you take a look at it. For these fish,
surviving means not being seen. In the inky water at the bottom of the ocean.
That may sound pretty easy, but it's actually harder than you might think.
- By the time you hit 1,000 meters, which is like 3,300 feet, there is no light whatsoever coming
from the surface. Even though there isn't a whole lot of light coming down there's a lot of light in
that habitat. So if you go down and you turn off all the lights you suddenly start to see lights
all around you. If I am startled that you're here, I spew out a whole bunch of bioluminescence so
that it lights you up so that something else can see you and go, "Ooh, that looks tasty."
- Many deep-sea animals have such sensitive eyes that they can detect just a single photon in that
dark environment. So to stay unseen, these ultra black fish have evolved an extreme way
to absorb almost every last bit of stray light that hits them. On the surface of their skin
is a super dense layer of pigment granules. When light hits that pigment, it disappears
into the pigment molecules. Our skin has pigment granules too. How densely those are packed is why
you might have lighter or darker skin. But these fish have skin pigments built like nothing else
on earth. These blue dots are pigment granules in the iris of someone with brown eyes. Now,
compare that with how dense the pigment granules are in the ultra black fish skin.
The density of pigment is crazy. Because of how these pigment packets are shaped and arranged,
any light that isn't immediately absorbed by one bit of pigment bounces sideways
into a neighboring bit of pigment, like a sticky sponge, but for light.
- [Karen] They take the same pigment that they normally use in the same type
of cells they normally use and they just exaggerate it, and they move those cells,
instead of within their skin layers, they move those cells out to the very surface.
- How much light are these absorbing?
- [Karen] So to be considered ultra black, you have to reflect less than 0.5% of the light that
hits you. So they're really not bouncing back any light. When we first tried to measure these guys,
reflectometers couldn't measure small enough to be able to get a good reading. It's like,
well, it's zero. And we're like, well, it can't be zero. Like how close to zero is it?
- Really, really close to zero.
- Really, really, really close to zero.
- Studying what makes these deep-sea fish so black could even inspire new ways for us to hide things.
- And so all you have to do to replicate this, if you wanted to make armor or camouflage clothing,
or you want to make something disappear is you just need the right size melanin granules,
the right size and shape melanin granules, which you can make bacteria produce.
- So we can, we could have biotech, recombinant,
deep-sea fish pigments that we could paint with soon? Is that what you're saying?
- You could.
- Okay. Or you could build, you could make a shirt out of
- I like that.
- Or something.
- Okay, so let's see. We can, not a fair comparison maybe, because you know, A,
it's dead, and not in its natural environment, but we're neck and neck here on blackness. This
is the best that humans can do, pretty much. Do you think there's something
even blacker waiting in the deep sea or have you reached like peak blackness
- I think we've reached peak blackness.
- These fish may be the blackest things in the ocean, but humans have made things that
are even blacker. The pigment in this paint is on a similar level with what happens in
those fish. It absorbs about 99.4% of all the light that hits it. That means
just 6 out of every 1000 photons manage to escape. So much light is absorbed by
these pigments that we start losing the ability to pick out shapes and depth.
I mean, my shirt is black, but look at this. Black, black? Black. Orange. Humans have made
even blacker things than that. But to do that, we have to leave pigments behind, and go to nanotech.
In 2014, scientists realized that tiny forests of carbon nano tubes can be used to make ultra
black materials Unlike pigments, which absorb light, these nanotubes trap light in sort of
molecular cages. So photons that get in can't get out. The blackest carbon nanotube coating,
developed by MIT engineers, traps 99.995% of light meaning that only 5 in 100,000 photons escape that
forest of light-trapping nanotubes. That's what made this diamond disappear. Unlike paints, these
nano coatings have to be laid down using elaborate processes, so their applications are more limited
and considerably more expensive. But you may be surprised to learn that evolution figured
out this way of using nanotech to make ultra black more than 100 million years before we did.
- I'm so excited to see these birds 'cause
I've only ever seen these on TV doing ridiculous dances.
- This one almost looks like it's dancing.
- It has the right outfit. - It's got the right- It's got the right look.
- The shirt.
- What we're looking at here is the blackest of black birds. These are three species of
birds of paradise. There are many more than three. They're found on archipelago in Papua, New Guinea.
- These have some of the blackest feathers I've ever seen in a living- or blackest anything I've
ever seen in a living thing. But why these birds are black is kind of weird. Unlike deep-sea fish,
these birds aren't ultra black for camouflage. They use their ultra black to get noticed.
- These guys, we think, and we've pretty good evidence to say this,
that the reason these guys are so bizarre-looking is that they have an extremely intense sexual
selection. One female bird of paradise, who sadly does not look as cool and exciting as these guys
is going to choose a mate. And his only job is to provide genetic material for the offspring.
He does not help raise them. He does not help protect them from predators,
just delivering the genetic material, and off he will go. And so if she wants the best shot
at having the best offspring, she needs to pick the healthiest male. And those two things come
together in these birds, where they're doing these fabulous dances to show off how cool they look.
- A male with brighter feathers and stronger dance moves can communicate
how healthy and strong his genes are to any female who's watching. That's the
basis of sexual selection. So this sort of evolutionary race has taken place on
this island of the pressures of mating have pushed these birds to ridiculous extremes.
- Yes, yes, like the most bizarre of all dating scenes.
- Because there's black and then there is this. This is like, you lose the shape of where the
edge of the bird is because it just, it's like a void of darkness. It's short circuiting my brain.
- Presumably it's also short circuiting the bird's brain, but we haven't asked them yet.
So that's the coolest part of the blackest black, right? We have the blackest black here,
and then we have the brightest bright in the front. And when these birds are
doing their mating displays, what they're doing is they're holding up these feathers
in a way that arranges the blackest black next to the brightest bright iridescence.
- [Joe] Okay.
- And that contrast would be startling by itself. But even more cool is that what it's
actually doing is tricking the visual system. Because looking at that blackest black makes it
impossible to really know how bright the bright is. Usually your brain is figuring that out for
you and adjusting it constantly. So scientists have looked at, deep down at the structure of
these feathers to try and understand how is this so black? And it turns out that the answer is,
that's like velvet. Velvet is black, right, but it has little fuzzy bits-
- [Joe] Mm-hmm.
- That stick up. Like velvet but better than velvet, these feathers have little
bits that stick up, and when the light goes in to the top of that feather,
then instead of bouncing straight back out, it's kind of scattered back around
in all of these little nanostructures that stick up and bounce the light back in.
- The fuzzy structures in the feathers work like a cage for light,
just like those carbon nanotubes. When light goes in, it just bounces around. Ultimately,
these feathers trap something like 99.95% of light. That's remarkably close to the blackest
black nanomaterials that humans have ever been able to create. Other animals like butterflies,
spiders, even snakes, make ultra blacks using similar pigments or structures as these fish and
birds. Nature was able to mold these incredible materials millions of years before we did,
through the forces of evolution and selection. And nature's nanotech has inspired us to create our
own. Because of ultra black materials, we've been able able to take pictures of the universe like
never before, harness energy, even make our own camouflage. Who knows what we'll think up next?
Ultimately, making something totally and completely black may only be possible at the
extremes of physics and spacetime. But nature has had some surprisingly not bright ideas of its own.
