- 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)
