- This episode of Because Science
is sponsored by Star Wars Jedi: Fallen Order.
At this point, I guess a significant percentage
of earth's population knows what this is.
But what about this?
What is a dark saber?
And how does it work?
Let's get technical.
(electronic whirring)
(upbeat techno music)
The dark saber first appeared in Stars Wars canon
back in the Clone Wars TV show in 2010.
It may not be as flashy-looking as a light saber,
but it's definitely more mysterious,
and very cool-looking.
A singular weapon
crafted by the first Mandalorian Jedi.
It may be shaped a bit differently,
but it's supposed to function
just like a regular light saber
in that it's very hot and glowy
and it can cut through stuff with ease.
But, how can it function just like a light saber
if the dark saber's design is based on,
apparently, the absence of what makes a light saber
a light saber?
(off screen squealing)
Whoops!
First, what is a light saber?
Well, my pet explanation
that is the correct one,
is that a light saber is hot and dangerous,
just like Han Solo,
because it is a tightly-confined ring of ultra-hot plasma
kept in place by ludicrously strong
and helical magnetic fields
and powered by ..... something.
A light saber's plasm emits enough light and heat
to slice through just about anything.
Ohhh!
If a dark saber is supposed to operate in a similar way,
then it should be designed in a similar way, right?
Well, I'm not so sure.
Star Wars lore implies that a dark saber
is just a light saber that uses black plasma
instead of another color, like blue or green.
But, (guttural noises)
I don't think that's right.
If you could see the atoms and the molecules
that make up the air you're breathing right now,
you would find that everything is more or less together.
Nuclei in these atoms have their associated electrons,
and everything's chill.
But if we started adding heat to the equation,
or applied a very strong electromagnetic field,
you'd find that things get decidedly less chill,
as atoms and molecules have their electrons ripped from them
and everything is bouncing around
and gaining more and more energy.
Ho ho, not chill!
This is now plasma,
one of the four states of matter.
Gas that is partially or fully ionized.
And a plasma can have a huge temperature range,
from basically cold enough for you to touch,
like the plasma inside of a fluorescent light tube
in your office building that makes you look sick,
to hand cutting and star hot,
something you should definitely not just grab!
Ohh! This kind of heat,
if a dark saber has it,
is why it needs to be something else.
Can I get a robot hand, please?
Anything with a temperature above absolute zero
will emit radiation.
For example, you, with a human body temperature,
emit radiation in the range of about 10 micrometers,
in terms of wavelength.
This is infrared, and it's also why infrared cameras
are good at finding humans.
Like you.
And maybe me.
A star, on the other robot hand,
is hot enough to emit radiation
across the electromagnetic spectrum,
from IR up through visible radiation
and all the way to x-ray.
The relationship between an object's temperature
and the wavelength of radiation it's putting out
can be characterized
by what's called Wien's displacement law,
which sketches out a graph, as you see here.
Hotter and hotter objects,
if you look at the graph,
emit shorter and shorter wavelengths,
which is why some of the hottest stars
are blue-hot, even white-hot.
Now, if a light saber and a dark saber
are hot enough to cut and cauterize,
then they should be star-hot,
very, very, hot.
And looking at a normal light saber,
you can infer from it's color
that it must be thousands of kelvin.
And there's no room on this graph
for "black" plasma.
So, since the canon is wide open
as to how a dark saber's actually made,
I'm gonna suggest that it's exactly what it looks like,
a black hole blade, hoooo.
I know that sounds extreme,
and it would introduce a number of problems,
however, a black hole blade
would explain a few crucial aspects of dark saber design.
First of all, the look.
You probably already know
that a black hole looks the way it does
because any light that would be reflected off of it
and return to your eye,
is instead funneled down into oblivion.
Why, though?
If you wanted to leave the earth,
and I don't blame you,
the minimum velocity you would need to give yourself
is the velocity that would take you
infinitely far away from the planet
without ever falling back
down the gravity well.
If you consider your total amount of energy
before and after escape,
your kinetic energy and your gravitational potential energy,
you find that once you're infinitely far away from earth,
slowing all the way down to zero,
this side of the equation afterwards just goes to zero.
So you can solve this side,
giving you the equation for escape velocity.
If you ignore air resistance and plug in earth digies,
you get an escape velocity
of around 11 kilometers per second.
Now, notice how this relationship depends
on both the mass of the body and the radius of the body,
and therefore there's no real upper bound
on escape velocity.
In theory, an object could have an escape velocity
higher than, say, the speed of light.
And some do.
Any object with a mass and radius
sufficient to make it's escape velocity
higher than the speed of light,
is necessarily a black hole.
Not even light,
going the fastest speed there is in the universe,
can escape it.
And therefore it gets this characteristic voidness.
If a dark saber had a similar inescapability,
it might look right,
just like we see it in Star Wars.
But where is this glow coming from?
And is this what kids call a glow-up?
I have no idea.
Because black holes gobble up the information
that would let us observe them directly,
we have to rely on indirect evidence of their existence,
like their warping of space-time,
or the changing orbits
of planets and stars in their vicinity.
But black holes aren't always so passive.
As we explained in a previous episode
about turning Jupiter into a star,
using a black hole,
in the presence of this kind of gravity,
material will swirl around down the gravity well,
forming what's called an accretion disc,
that gets hotter and hotter
as that material smashes up against itself.
Accretion discs, or round black holes,
can get so hot, in fact,
that they can outshine entire galaxies.
Now imagine a dark saber with similar properties.
It would have this characteristic voidness,
but then it might also have
that glow around the edge of the blade,
in the form of a mini accretion disc,
as material, like the air that it's in,
falls down into it and creates temperatures
that should be hot enough to slice the Sarlacc,
or another Star Wars word that begins with S.
Ssssaba the Hut. No.
A black hole blade would also explain
the dark saber's final curious property.
It's attraction (bird squawking)
it's attraction (bird squawking).
In Stars Wars lore, the dark saber
has an almost magnet-like pulling effect on other objects,
most notably, other light sabers.
And this could be a black hole's doing, too.
Technically, everything in the universe
is pulling on everything else at all times,
no matter the mass and no matter the distance.
The moon is pulling on you right now,
as is Pluto.
As am I, no matter how far apart we actually are.
Most of the time, this pulling is so small
that you don't even notice.
But if you put a black hole in a sword,
you'd feel it!
A black hole on the scale of something like a sword,
would be really heavy,
like, trillions and trillions of kilograms heavy.
And so, according to the force of gravity,
if you held this much mass,
just, maybe an arm's length away,
you'd be subjected to an incredible pulling force,
so much that you would need something like
six billion of our best rockets
to pull you in the opposite direction.
Everything near a black hole blade
would be incredibly attracted to it (bird squawking)
And, as you can see,
this is where we start running into problems.
Unfortunately, a black hole dark saber
creates as many problems as it solves.
Aahh! (bird squawking)
The heaviest actual sword ever used in human combat
didn't weigh all that much,
maybe around 15 pounds or so.
But a black hole, somehow shaped into blade form,
would be a bit heavier
(cheesy muzak)
A bit heavier.
A black hole blade would obviously be so massive,
no one could ever swing it,
no-one could ever lift it.
And it wouldn't just attract other objects,
like light sabers, at arm's length.
It would,
it would rip you apart.
For example, if you took a black hole dark saber
and put it on the opposite side of the planet,
it would still pull on you with 70 pounds of force,
even a planet away.
So, you can imagine,
if you were close enough to wield this thing,
it would spaghettify (long drawn out moan).
The other big problem is shape.
A source of gravity pulls inwards in all directions
through an object center of gravity.
Not an actual point,
just the mathematical average of where all the weight is.
Now, what shape would you expect these forces
to make something?
Gravity has to make everything in the universe a sphere.
Well, why then isn't everything in the universe spherical,
a young Padowan might ask?
Well, that's because gravity is very weak,
the weakest of nature's fundamental forces.
You can beat it right now on this planet
with a simple hop.
So, it's just the case that most smaller objects
have internal forces and structures
that are stronger than gravity.
It's not until you have, like, the mass of a planet,
that gravity starts spherifying stuff.
In fact, that's one of the ways we classify planets.
If a dark saber was really made from,
or had the properties of,
a black hole,
there is very little chance
that it would maintain this shape.
It would probably immediately return to a sphere.
And then it's not a saber anymore, is it?
It's like a spheratawk.
No, that's worse than therm scissor punch.
That doesn't work.
So, where does that leave the dark saber?
Well, a black hole blade would be able to explain
the look, the glow and the cutting heat,
in my estimation.
But it would create the immediate problems
of mass, shape and spaghettifying gravity.
My idea only really half works here,
but it's the best scientific analog I could find,
and it's better than "The Force" or "kyber crystals",
because those don't really
have good explanations themselves.
It's not a perfect explanation, Sir,
but it checks out.
Kinda.
Because Science.
Whaaaaay (jibberish).
(upbeat techno music)
Thanks again to Star Wars Jedi: Fallen Order,
for sponsoring today's episode.
You play Cal Kestis,
a Jedi Padowan who narrowly escaped the purge of Order 66
following the events of Episode Three: Revenge of the Sith.
On a quest to rebuild the Jedi Order,
you must pick up the pieces of your shattered past,
to complete your training,
develop new, powerful Force abilities
and master the art of the iconic light saber,
all while staying one step ahead of the Empire
and it's deadly inquisitors.
Fallen Order is available on Xbox One, PS4 and PC
on November 15th.
Look, I'll be the first to admit
that this is certainly not a perfect explanation.
It has a lot of problems.
But then we'd be in very good company
with most Star Wars technology.
Wild blasters just shoot plasma
that, kinda like, expands like a little fart out
and does nothing.
Why does anti-gravity tech work on spaceships?
Why Ewoks?
There's a lot of problems with everything.
Yub-nub.
(electronic beeps)