If you’ve watched Star Wars long enough—or caught a scene in shows like Rick and Morty or Robot Chicken—you’ve probably wondered: what would really happen if someone dropped a lightsaber straight down? Would it drill deep into the earth? Would it stay on forever? Let’s break down both scenarios based on Star Wars lore and some fun “science.”
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When a Lightsaber Falls and Stays On
A lightsaber is a beam of plasma contained within a magnetic field, burning at roughly 10,000°F. In theory, if one fell straight down, gravity would carry it like a blazing spear, burning its way into the ground. According to one popular theory, it wouldn’t stop until reaching the depth of the deepest hole ever dug on Earth, the Kola Superdeep Borehole — roughly 4,230 feet deep.
But even that hole had its limits. At that depth, temperatures rise to about 356°F (180°C), which is enough to cause equipment to fail. The lightsaber’s hilt, with its electronics and focusing crystal, would almost certainly melt long before it sank any deeper. So while the blade itself can burn through nearly anything, the weapon wouldn’t survive the intense temperatures deep underground.
This theory is why you sometimes see animated gags making fun of the concept, like Morty dropping a lightsaber and watching it cut its way down until it disappears.
In reality, a lightsaber doesn’t have an infinite fuel supply, and its electronics aren’t built for such temperatures.
When a Lightsaber Switches Off as It Falls
Most lightsabers have a built‑in safety feature called a pressure grip. The blade only stays active when the person using it is holding down the switch. As soon as the person lets go, it switches off instantly.
We’ve seen this in action across the saga. In The Phantom Menace, Qui‑Gon’s lightsaber deactivates when he is impaled and drops it. The same goes for Anakin when he’s disarmed on Coruscant, or when Obi‑Wan drops his blade while fighting General Grievous. The pressure grip feature prevents a fallen weapon from burning wildly and causing unintended damage.
This design makes sense for a weapon like a lightsaber. I always liked that the blade doesn’t stay on when it’s dropped, because it means a Jedi doesn’t have to worry about a fallen blade cutting into the floor or hurting someone else.
The Realistic Outcome
Thinking about this, I can imagine both ideas being true, just in different situations. If a lightsaber had its safety switch overridden and was dropped, it would burn deep into the earth until the hilt gave out. In most situations, though, a lightsaber just switches itself off the moment it leaves the user’s hand.