It was 2003 in a galaxy far far away. I was watching Star Wars for the first time in my uncle’s coffee shop. I had no idea what the story was about — to me it looked like another Power Rangers movie. But Obi-Wan’s lightsaber immediately caught my attention. It reminded me of something familiar.

I impulsively ran home, grabbed a flashlight, and rushed back. If you lived around that time, you probably remember that standard silver flashlights with the red button. Doesn’t it look like a lightsaber? I turned it on and started playing around, but the light beam kept going and hit the ceiling. I asked my uncle if there was any way to make the light stop shorter. He said, “It’s not possible. We still don’t have the technology to limit the length of light yet.”

It’s been 22 years (or 48 years since the first Star Wars: A New Hope movie). We still can’t make light stop at a fixed point. (Or can we? Maybe someone’s secretly working on it?)

What Do We Have Now?

So far, we already have industrial lasers powerful enough to cut through metal, and plasma cutters used in metalworking that reach temperatures of 20,000°C For comparison, the surface of the sun is roughly 5,500°C. So we are dealing with something almost four times hotter than the sun’s surface.. A few years ago, Hacksmith Industries built a lightsaber replica using a plasma and a laminar flow nozzle to shape it. It looked impressive, but with a backpack fuel supply and hose, it resembled more like a fancy welder than Obi-Wan Kenobi.

So What’s the Challenge?

The fundamental physics problem is that photons have no mass Specifically, they have no invariant mass. However, because they have energy, they still possess momentum and can exert “radiation pressure” on objects they hit. and travel indefinitely until they hit something. They can’t just stop at an arbitrary length in empty air. The saber also needs to be solid enough to clash against another saber, yet light passes through light. It needs to generate extreme heat to cut through materials, but the wielder holds it inches away without protection. And then there is question of power, how are you supposed to provide enough power for all this in something that fits in your hand?

Thought Experiment

What if we stopped trying to make light behave differently and instead gave it something to bounce off of?

Consider a scenario where billions of miniature reflective particles are released from a hilt, each equipped with a self-mirroring mechanism where all controlled centrally. These particles could be held in place by intricate electromagnetic fields, mimicking the structure formation around magnets by ferrofluids Ferrofluids are liquids that become strongly magnetized in the presence of a magnetic field, often forming exotic “spiky” structures.. Instead of trying to limit the length of light, we would create a tangible structure visible to light. I have no idea if this is feasible. Precisely controlling such nanoparticles, keeping them from dispersing in air currents, and making them robust enough to collide. It appears this concept does not violate fundamental physics but just our current engineering limits.