How to build a lightsaber and power up a Death Star: The science behind Star Wars

Ever wanted to build your own Death Star and blow up a planet? Now science knows exactly how much energy you'll need to power the weapon. Thanassis Psaltis is a graduate student in Nuclear Astrophysics at McMaster University in Hamilton. He tells us about the science behind Star Wars.

There's a planet in the known universe where, like Tatooine, you can see both suns set

What if in a galaxy not so far, far away and at time not at all long ago, the fantasy technology of Star Wars was real? 

What if, here and now, you could use the force? That would probably change things for you and the boss around the office.

Or what if you could rip through foes with a lightsaber. Or had an R2D2 or a C3PO of your own to help you knock things off your to-do list?

Thanassis Psaltis, a graduate student in Nuclear Astrophysics at McMaster University in Hamilton, has studied the science of Star Wars. He spoke with the CBC's Conrad Collaco about how close modern science is to building a lightsaber or R2D2 and answered many other questions about Star Wars science in the modern world. 

You can listen to the full conversation by clicking on the image at the top of this page or read an edited and abridged transcript on the page below.

Thanassis Psaltis, McMaster University nuclear astrophysicist 
Thanassis Psaltis is an astrophysicist from McMaster University. (Athanasios Psaltis)

What made you want to look at the science behind Star Wars?

Star Wars has been a flagship of pop culture for at least four decades. Its audience spans a wide range of ages. Science fiction provides a unique opportunity to talk about real science. Star Wars is the best playground to do that since it's so popular, especially with kids. 
This lightsaber was used by Kylo Ren and was first seen in Star Wars: Episode VII The Force Awakens. (Disney)

How close are we to building a real lightsaber?

The name is a bit unfortunate because they're not made out of light and don't have a sabre shape. Light beams do not interact with each other so you couldn't have the usual fight we see in the movies. They are not laser swords as George Lucas likes to say in interviews. But as I argue in my Planetarium show we could use plasma, the fourth state of matter, to create lightsabers. Gas, liquids and solids are the other three states of matter. Plasma is an ionized gas, a very hot gas. You could imagine it as a hot soup of atoms and electrons.  

You could use plasma to build a lightsaber, however plasma is very difficult to handle. You would need very strong magnetic fields to create the sword shape. The good thing about the plasma is that it can explain the colours of the lightsaber. Different kinds of gasses, different plasma, can create different colours. We can get exactly the same colours we see in the movies.

A planet circling two suns much like Tatooine, the planet of Luke Skywalker's birth, was discovered by the Kepler Space Telescope in 2011. (Disney)

What about the planets we've come to know in Star Wars like the desert world Tatooine with its two suns. Is there a planet out there like there like where Luke Skywalker grew up? 

There is actually. The amazing fact is that when the planet was first introduced to the audience in 1977 there was no observational evidence of such planets. A couple of years ago a space telescope called Kepler, which is dedicated to look for exoplanets, planets not located in our own solar system, found a planet now called Kepler-16b, which is rotating around two suns. 

McMaster University astrophysicist Thanassis Psaltis says your Death Star would need about 2.3 percent of the Sun's energy in a year to blow up the Earth. (Disney)

That's pretty cool that a planet with two suns, the type that only existed in the imagination of George Lucas in 1977, has now been found to exist in the known universe. 

Yeah. That's amazing. In fact, George Lucas said in an interview a couple of years ago that when he was making Star Wars he wasn't restrained by any kind of science. He said 'I just made a world that was fun and had a reality to it.' But we see that four decades after the first movie there was a lot of science.

That's an interesting idea — that what we may come to discover in the future about our world through scientific investigation may only exist now in our imagination. What do you think about that?

That's what science fiction does. It provokes the mind, even for scientists like us. It's also really useful for people to appreciate and respect science.  

Of course the most powerful weapon in the Star Wars universe is the Death Star. How much energy would the Death Star require to destroy Earth? I'm asking for a friend. 

Quite a lot, actually. Tell your friend. It's easy to calculate the amount of energy to destroy the Earth with a Death Star. It's a number with almost 35 zeroes. It's equal to about 2.3 per cent of the energy the sun produces every year. The sun produces energy every second that is equal to 1 billion times the energy humans consume in one year. A mind-blowing amount of energy.

So, if we could harness a fraction of the sun's power, a Death Star might be real?

That's really, really hard to do right now.

The droid C-3PO (Anthony Daniels) appears alongside Luke Skywalker in 1977's 'Star Wars.' (AP photo)

How close are humans to creating robots like R2D2 and C3PO? 

Not really far, I would say. We have sent robots like R2D2 to other planets like the Curiosity rover, a small robot that is working around the surface of Mars right now taking samples and sending the data back to scientists at NASA. And something similar to C3PO is a droid called Asimo, which is made by Honda. It's an interesting robot that has really nice features. It doesn't say we're doomed all the time but it's pretty good.  

Now, the idea of the Force – an energy that seems to connect all living things in the galaxy and can be used for good or evil – is something philosophers have contemplated for years. Is there science behind it?

The Force is kind of something that exists in the universe, not as Star Wars and George Lucas have introduced it to us. We are all connected to the universe because we are all made of exactly the same material. Everything that makes us up contains the building blocks of matter, the atoms, and were forged billions of years ago in the very heart of the stars. We are all connected to the universe. We are a living part of it. We are made of star stuff as Carl Sagan said. 

We have four forces in the universe. The first one is the gravitational force. That makes the planets revolve around the sun and keeps our feet on the ground. We have the electromagnetic force and the weak and strong nuclear force that keep the atoms together. Scientists have tried to find one equation or theory to unify all these forces — a unified theory of everything. So far we are not there yet. The biggest theory we have so far accounts for three of the four forces excluding gravitational theory. We're still trying to find a way to get gravity into the game. 

Until we can come up with a unified theory for these forces we are left to leave the idea of using the Star Wars force to our imaginations. Maybe that's not such a bad thing.

That's not bad at all. It's great. 

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