TRACE DOMINQUEZ: Hey guys, Trace here.
And today we're going to be doing something
a little bit different.
Some of you may recognize this set up.
We used to do a show called DNews Plus,
and it was a show where essentially we'd
come across topics and we didn't have enough time
to talk about them in our regular Seeker videos.
Or maybe I just got really excited about it,
and wanted to talk about it for a long time.
So that was what DNews Plus was for.
But a while ago we put DNews Plus on hiatus,
and since then we've become Seeker.
So welcome to Seeker Plus.
We're going to spend a little while talking about something
that we discovered that we just couldn't wait to tell you
a whole bunch of stuff about.
There's no B-roll.
There's no music.
It's just you and me and my notes and some science.
So let's kick into it.
Today we're going to talk infrared light.
Because you know, there's talk lately about infrared light
replacing Wi-Fi.
Infrared light replacing Wi-Fi, can you believe that?
I know, it's shocking.
So that got us thinking, how would that work?
And then we you started thinking, what
is infrared light all about?
You hear about it all the time.
It's used in a variety of different applications
across the things that you do on a day to day basis,
and you probably never even think about it.
Light is everywhere.
You know this, I know this.
The only reason you can see me right now
is because light is coming out of your device,
and there are lights in this room,
and the camera is picking up light.
Light is everywhere.
It's very important.
Light is just electromagnetic radiation, just little
bits of energy that it can be picked up by your eyeballs
or by the camera and are being emitted
by all sorts of different things.
That energy travels through space in waves,
things like radio waves and microwaves
and x-rays and UV light and visible light are all light.
They're all in the electromagnetic or EM spectrum.
And they're all based on wavelength.
We divide them up into different groups.
Because that's what humans love doing,
is dividing things up into groups.
But the EM spectrum is just that, it's
a spectrum of different light.
And we've just picked, these are the ones that we like the best.
Visible light isn't the best light,
it's just the light that our eyeballs have chosen to see.
"Chosen" to see.
We interpret visible light with color.
The shortest of those wavelengths of light
are violet, and the longest are red.
So knowing this gets you to how infrared was discovered.
A German dude moved to England in 1757.
His name, Sir Frederick William Herschel.
He built telescopes and eventually he
discovered Uranus.
In 1800, he directed sunlight through a prism
and it made a rainbow.
Ah, pretty.
You can do this at home if you happen to have a prism.
He measured the temperatures of each of the colors.
Probably wouldn't have thought to do that,
but this guy thought of it.
And he found that the temperatures
increased from violet to red.
Violet was cooler, red was warmer.
That's interesting, right.
But then he saw that it was even higher if he moved
a little bit further past red.
It was warmer.
So there was something there that he couldn't see.
There was no light in that rainbow,
but the thermometer was still picking something up.
Cool right?
Infrared light is what was there.
He discovered this thing called infrared.
It's on the other side of red.
It's the first time someone had found light
that we could not see.
Now the European Space Agency has named their infrared space
observatory after Herschel.
Pretty cool.
Infrared light is next to visible light
on the electromagnetic scale.
It's on the reddish side.
Infra meaning below red.
Red of course, meaning red, infrared.
OK, you got it.
So infrared light is just wavelengths of light
that are longer or have a more distance
between the peaks of the waves and then
one side of the visible light.
Ultraviolet, UV light, makes sense, right,
on the other side of violet.
Pretty cool.
Everything gives off infrared radiation.
You are, I am, your kitty cat is, everything is giving off
infrared radiation.
Unless your thing is absolute zero.
If your cat is absolute zero though,
that probably wouldn't be good for your cat.
That's where all the molecules in the thing stop moving.
It's the coldest possible temperature that we know of.
It's negative 273.15 Celsius, negative about 460 degrees
Fahrenheit.
The hotter something is, the more molecules and atoms
are going to move inside of that, right.
Boiling water, those water molecules
are just zooming around in there.
Frozen water, they're just kind of vibrating, not really moving
at all.
So the more something heats up, the more motion
it has inside of it.
And that produces infrared radiation.
But things that are cold, even though they're not moving
as much, are still moving.
So they're giving off infrared radiation.
Ice cubes give off infrared radiation.
And if something is not hot enough
to give off any light at all, it can still be giving off
infrared radiation.
And you can feel that because you
can feel infrared radiation in the same way that Herschel did.
It's heat.
One example we found on a website that we liked
was charcoal.
It doesn't have to be glowing to be hot, right.
If you put your hand near charcoal you can feel its heat.
That's infrared radiation.
This is something I learned very early on.
Some of you know this.
I am a blacksmith.
So I hit metal with a hammer, and sometimes
that metal is not glowing.
It doesn't start glowing until like the 1,300 degree range.
But if it's 900 degrees or 1,000 degrees, it's still hot,
and you don't want to touch it.
But you can feel the infrared radiation coming off
of the steel.
So infrared is everywhere.
You can't see it, but you can feel it.
And hot things emit a lot of it.
But just knowing that is kind of a fun fact
that you can tell people at a party.
But Seeker Plus, that's not what we're all about.
We're all about let's push it past that, right.
How do we use this knowledge?
What can we do with infrared light?
It gives off heat.
So we can use infrared to measure how much heat
is being emitted by something, as long
as we build a camera that can read it
or we can feel it somehow.
An obvious thing comes to mind like thermographic images
and night vision.
That is using infrared heat.
So you have this special camera that picks up
the infrared wavelengths of light,
and then it can display them for you.
And we've seen those images.
They look super trippy.
It picks up the heat off of objects.
So different parts of a body, for example,
are going to be hotter or cooler.
And the background is blue and the hot things
are white and red and yellow, you know.
It's really, really cool.
And even at night, people are giving off warmth.
So you can use those to spot things
like prey or other humans or even something someone touched
a while ago that hasn't cooled off yet enough.
Very important.
And there are also electronics that
can create images using infrared light using special lenses
and sensors to enhance what you and I just
can't see with our sad little evolved eyes here.
Infrared light is also used in astronomy,
because it can pick up things that
are too cold to emit light.
Because as things cool off and that motion stops,
sometimes they're not energized enough
to release light that we can see.
So infrared is a way to see those things still.
Also, because those wavelengths are so long,
longer than even red light, it can cut through things
that regular light would be blocked by.
So let me give you a quick aside.
The reason the sky is blue is because blue light scatters
more easily than any other type of light, right.
So the light hits the atmosphere,
it scatters all over the place.
But when the moon goes low on the horizon
and it turns orange, that's the red light
not being scattered as much.
Infrared would mean that it would
scatter even less than that.
So that means that there's a nebula in between you
and something, you might be able to see parts of it in infrared
if you know, it's a very small nebula.
But really, if it's just dust and gas and things in the way.
So there are wavelengths that can
cut through some of those things that are blocking you
from seeing them out in space.
And astronomers know this, so they
can utilize these methods to see those things.
Infrared wavelengths get absorbed, however,
in the lower atmosphere, which sucks.
So you have to go above it like into the mountains
or into an airplane or into space.
And that way the infrared light doesn't
get screwed up before it can get to your telescope.
You can also send up infrared space telescopes
like we did in 1983 with IRAS.
It's an Infrared Astronomical Satellite,
and it mapped the entire sky in infrared wavelengths,
which is pretty cool.
They found six new comets, the core of our own galaxy,
and evidence that there might be other planetary
systems around stars.
This was in 1983.
Really awesome stuff.
It's also used to study the earliest things that we
know of in our universe.
So galaxies that are far, far away
and that are moving away from us that are pretty cool,
have cooled off.
We can still see those with infrared light, right.
But there's this thing that astronomers know about,
and maybe you've heard about as well, called red shifting.
Which means things that are far away
and that are moving really fast shift toward the red spectrum.
Because the light that they emit gets longer.
It gets stretched out.
Which means it's shifting toward red, red shifting.
The best way to see that, of course, also
an infrared telescope.
Basically, infrared astronomers get to see what the rest of us
can't see with our eyes.
It's really, really cool.
Speaking also of satellites, weather images
taken by satellites are often measured in infrared,
because you can get pockets of heat.
You don't have to look at clouds.
You can see air movement and measure the different amounts
of heat coming out of that air.
You can also take the temperatures of clouds
and get hot and cold places within those clouds.
You can also see if the cloud is producing rain,
because colder clouds are raining harder, which
is pretty interesting, right.
The satellite just has to say, oh,
that one's a little colder than this one.
Must be raining harder over there.
If there are no clouds at all, the weather satellite
isn't useless, it can take measurements
of the surface temperatures.
And in different places it's going
to have different temperatures.
This is how we know that say trees maybe
reflect less heat than something like an urban area.
And these are just a couple of examples.
Infrared is, speaking of trees, used to detect forest fires.
It's used to heat saunas.
It can penetrate through paintings
and reveal what is underneath them
so we can see if a painter used the canvas more than once.
Which a lot of really old paintings,
that's what they did.
It can be used by your remote control device
when you point it at your television
and tell it to change the channel,
it flashes an infrared light across the room
that your TV picks up.
Really, really neat.
They're even using infrared in the medical field
to detect things like breast cancer,
or helping with skin disorders.
And Google shows a lot of light therapy results,
although there's not really any credible sources on that.
Some people sit under infrared light
because they say it helps them feel
better, which is interesting.
Infrared radiation sounds scary.
But it's not radiation like nuclear radiation,
it's light radiation, right.
That said, infrared, even though it's just heat
and you're just giving it off all the time.
I mean, unless you're sitting in a 98.6 degree room,
you're giving off infrared radiation into the room.
It can still be dangerous, because you can't see it.
If someone were to shine a really bright infrared light,
and I'm putting "bright" in quotes here.
So if you put bright infrared light into your eyeball,
normally bright lights cause something
called blink aversion.
You blink to protect the inside of your eye.
Infrared light you can't see it.
So you can damage your eye with that.
So one, don't do that.
But two, really interesting and also kind of strange.
The thing about not being able to see it though,
is a little disappointing, right.
Because you know it's there.
Like I want to be able to see it.
I want to see infrared light.
Wouldn't that be cool?
You could see all of these little things flitting around.
You could see temperatures, and you could see pockets of air.
That would be so cool.
But even though we can't see it, which is disappointing,
there was this one specific science experiment
which shows that we might be able to detect,
which is really cool.
One experiment shot infrared photons at an eye.
And if two photons hit the same receptor one after another,
it created a photon of visible light.
But that light was not red it was green.
Which is weird.
Science is cool.
Anyway, we can't really see infrared,
and neither can most animals.
But snakes, they can sense infrared waves
with pits in their mouth.
Vampire bats and bedbugs, they can sense infrared.
And some animals can see ultraviolet, again,
the other side of the spectrum.
But that's kind of like a whole other episode of Seeker Plus.
So that's infrared.
We had so much fun looking into this.
It's the heat that's given off by everything that we can't
see except one specific incidence, in which case
then it was kind of green which is weird
and a little mind blowing.
But we use it to predict weather and learn about the universe
and turn on our TV and see if Picasso screwed up his painting
and started over, which is great.
Because sometimes we all screw up.
Thanks so much for watching this Seeker Plus episode.
Let us know down in the comments if you like this format,
because we're trying all sorts of cool things
with this new Seeker re-branding.
And we really want to know your thoughts.
I've got all of your comments.
I keep reading them every single day.
And thank you so much for subscribing to us
and sticking around and watching this episode.
So tell us, what did you think?
And also tell us if we missed anything about infrared
that you think is really cool that we should also think
is really cool.
Because maybe we'll use that in future episodes of Seeker Plus.
Light is cool.
It's real-- well, and sometimes it's hot.
It's complicated.
Anyway, thanks for watching.
Come find me on Twitter @TraceDominquz.
Come find us at Seeker.
See you next time.