It’s the iconic weapon from the Star Wars universe: the light saber, used by both Jedi knights and Sith lords — but is it physically possible to make one?

Of course, many people would love to have their own light saber, but making it happen would be quite a challenge, according to a Space.com report.

The light saber is about 4 feet in length and contains huge amounts of energy that could melt metal, indicating that they must have a compact energy supply — not only providing that energy, but also resulting in a handle that is cool to the touch.

There are some other wrinkles: light sabers can’t pass through each other, they clash like regular swords.

All of this information indicates that a laser isn’t a workable solution. For one thing, lasers continue forever rather than ending at a fixed point, no would lasers “clash” as seen in the epic sword fights of the Star Wars universe.

A second option is plasma, which is a material that is the end result of stripping away the electrons from a gas’s atoms, resulting in glowing material. It has been called the fourth state of matter, and can be found in everyday items like fluorescent lights. They also fix the problem of not burning your hand when you touch the hilt.

But while plasmas can create a huge amount of heat, the electrical characteristics of it create problems because they would need a huge amount of electric current flow. Since plasma acts like a hot gas that expands and cools like fire, it would need to be contained within something if it were to be used as a light saber.

However, there is a way to do this, as plasmas can be contained within magnetic fields. This holds some promise for the future of light sabers, and the possibility of creating a real one. But there are still problems with this, as the two magnetically contained tubes of plasma would still pass through each other, meaning duels would be impossible as it would require the saber to have a solid core, which would also need to hold up against extraordinarily hot temperatures.

So it’s possible to create something which checks a lot of the boxes of a light saber, but probably not all of them.