- 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.