Star Wars tech: The physics of Death Stars and lightsabers

Melissa Mathers
23 November 2015

Above: Image © LeventKonuk,

In late 2014, Star Wars lovers around the world rejoiced at the release of the official trailer for Episode VII: The Force Awakens. Science enthusiasts were also eager to see what science fiction technologies would make an appearance in the latest installment of the famous saga.

Is the idea of flying a Death Star through deep space or wielding a lightsaber strictly science fiction? Would developing Star Wars technologies actually require breaking any laws of physics? Surprisingly, the answer is often no.

Did you know? Plasma is considered the fourth state of matter—along with solid, liquid and gas.

Physics of the Impossible

In his book Physics of the Impossible, Michio Kaku explains how understanding physics and the laws that govern the universe makes it possible to predict which science fiction technologies are most likely to become reality. He classifies technologies generally considered “impossible” into three categories:

  • Technologies that theoretically follow the known laws of physics
  • Technologies that are at the threshold of scientists’ current understanding of the laws of physics
  • Technologies that violate the known laws of physics

Many of the technologies featured in Star Wars—including deflector shields, blasters, and interstellar travel at the speed of light—actually fit in the first category. They do not defy the known laws of physics and could actually become reality in the decades to come, perhaps even in your lifetime!

For example, in the book Kaku explains how a real-life lightsaber could plausibly be built using a hollow telescoping tube that fills with hot plasma when activated. Not only does hot plasma glow like a lightsaber, it would also be hot enough to melt most solids.

Did you know? Plasmas are essentially clouds of ions that have many properties of a gas but easily conduct electricity.

Gamma-ray bursts

What about a Death Star, a moon-sized weapon with laser cannons that incinerate entire planets? It might surprise you to learn that there is no physical limit on how much energy could be delivered by a beam of light, such as those emitted by a ray gun, a lightsaber, or a Death Star. In fact, extremely high-energy beams of radiation already exist in nature!

Gamma-ray bursts (GRBs) are large flashes of high-energy radiation in deep space. They produce enough energy to incinerate nearby planets and can send deadly radiation to ones further away. But don’t worry, the closest GRBs have only been observed in galaxies very far from Earth (over 8,000 light years away), and there is a very low chance of one happening closer to home. Still, there is evidence that the energy from a GRB reached Earth around the year 775.

Did you know? Gamma-ray bursts (GRBs) are beam-like explosions in space. In just a few seconds, they emit more energy than the Sun will in its entire lifetime!

Powerful lasers

Some of the most powerful lasers ever developed are capable of producing up to one petawatt (one quadrillion or 1015 watts) of power. That’s still far from the planet-destroying power GRBs. Also, the petawatt laser’s high rate of energy transfer is only possible because it releases light in short pulses that last no more than a few femtoseconds (10-15 or one quadrillionth of a second).

But don’t give up hope of being a space super-villain just yet! Many different kinds of lasers have been developed and scientists are constantly working on better ones. For example, many of the materials used in lasers crack under high energy conditions. To solve this problem, the scientists who built the petawatt laser used a strong combination of glass mixed with neodymium as their gain medium. That’s the area inside the laser where energy builds up. However, to build a laser as powerful as a GRB, researchers would first have to discover a gain medium that remains stable under conditions much more extreme than those inside the petawatt laser.


Perhaps the biggest challenge scientists would face in trying to build a ray gun or a lightsaber is developing a portable energy source. Its output would need to be equivalent to that of a commercial power plant. Currently, the only portable device that could deliver that much power is an atomic bomb. That would, of course, destroy whoever was holding the lightsaber, not to mention the ray gun and everyone else on the Death Star.

Researchers who study nanotechnology have proposed developing tiny batteries that could safely deliver high energy. This research is still in its very early stages, but it suggests the possibility that your grandchildren might someday wield a lightsaber.

* * *

Would you would rather your grandchildren not spend their time blowing up planets and battling Sith Lords? Rest assured that there are also more peaceful uses for discoveries related to lasers, efficient energy generation, and nanobatteries. How do you think these technologies could be used in the future? Does hearing about them make you want to learn more about physics and astronomy? You could help make them a reality!

Learn more!

Magazine article on calculating the speed of a Star Wars vehicle:

How Fast Is the Speeder in Star Wars VII? (2015)
Rhett Allain, Wired

Website with more information on gamma ray bursts (GRBs) and related research:

Gamma-Ray Bursts
Kavli Institute for Particle Astrophysics and Cosmology<

Melissa Mathers

Melissa is a graduate physics student at York University who studies antimatter with the ALPHA collaboration at CERN.  She completed her undergraduate physics degree at the University of Windsor in spring 2015.  She began volunteering with Let's Talk Science in her 3rd year of undergraduate studies, and has never looked back!  In her spare time, she updates her science blog,

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