I remember reading somewhere(I don't really remember where, sorry) that a lightsaber isn't really hot, it just makes atoms vibrate and hence heat is produced in a material the lightsaber comes in contact with.

I am not entirely sure if this is true, but it just got me wondering if a lightsaber comes in contact with an extremely flammable substance(gasoline or gunpowder or any similar thing in the SW universe), would it ignite the substance or not?

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    Isn't that the very definition of heat? The transfer of kinetic energy from one particle to another?
    – Yorik
    Feb 5, 2016 at 16:21
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    I am imagining Luke being careless and starting forest fires all over Endor. Feb 5, 2016 at 16:41
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    I read something similar, but took it to mean that the lightsaber itself isn't giving off heat. Meaning if the lightsaber is 0.001 inches from your face, you don't feel "heat" coming from it, but as soon as it makes even the slightest contact, whamo, instant burns.
    – Geoff
    Feb 5, 2016 at 17:28
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    @Geoff If the lightsaber is .001" away from your face, has the capacity to instantly make substances really hot, and there is air between it and your skin, you're getting a burn. If you mean to say that is isn't giving off microwave, infrared, and ultraviolet radiation, all of which can give you burns, then that's kind of strange: it's clearly giving off visible light radiation, whose spectrum is between ultraviolet and infrared. On the other hand, if a Jedi can do some sci fi woowoo when making a lightsaber, then it's a useful feature for preventing constant burns on the Jedi's hands.
    – Misha R
    Feb 5, 2016 at 18:31

4 Answers 4



The lightsaber is shown many times to burn and melt objects.

Such as when Anakin loses his arm against Dooku in Attack of the Clones, you can see his skin and clothes burning.

anakin armless

Or when Darth Maul stabs Qui-Gon you see a burn mark on his clothes in The Phantom Menace

bye qui-gon

Or When Qui-Gon Melts the Trade Federation ship doors in The Phantom Menace

melty door

It may even steam in the rain, as this picture taken from screen shots of Attack of the Clones does show a fuzzier, more jagged looking lightsaber blade when Obi-Wan is in the rain on Kaminio than when he fights Dooku on Geonosis, which could be caused by steam.



And depending on the level of canon we are delving into, the game Jedi Outcast 2: Jedi Academy shows definite sparking from rain on the lightsaber.

The clone wars cartoon shows actual steam coming off of both Anakin and Assajj Ventriss' blades.

Heat is therefore produced one way or another.

This heat would transfer to a flammable material and cause ignition.

Even if the lightsaber isn't hot and "...it just makes atoms vibrate and hence heat is produced in a material the lightsaber comes in contact with" (which I have never heard) when a lightsaber blade came into contact with a flammable or combustible material it would make the atoms vibrate in that material, it would then heat up and cause ignition within itself.

It is still creating heat through one mechanism or another.


Yes, simply by heat. Heat exchange from a lightsaber is seen in The Phantom Menace, when Obi-Wan Kenobi and Qui-Gon Jinn use their lightsabers to melt through the doors in the Trade Federation ship. The metal is seen to heat up and glow red while melting.

enter image description here

enter image description here

  • +1, and I added two images of the scene. I hope you don't mind. :)
    – Wad Cheber
    Feb 5, 2016 at 17:25
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    Having worked in a glass shop, molten glass heated to white hot (much hotter than red hot) it's hot while in close proximity (an inch or two) but it quickly drops off to just warm past 3 inches. Doesn't matter whether it's metal or glass red hot is the same regardless of material. It's how much red and infrared light is radiated.
    – Escoce
    Feb 5, 2016 at 18:42
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    @corsiKa That is why he looks so intent. He is force pushing the heat away.
    – Erik
    Feb 5, 2016 at 18:49
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    That makes sense that the heat drops off pretty quickly. I didn't think about it until you mentioned your experience but a more common experience would be putting your hand over a pan to see if it has warmed up yet. I will say that his hand looks much closer to the molten metal than 3 inches away but maybe the glowing metal is making it look like his hand is closer than it really is. On a separate note, before now I thought your avatar was holding a spear. Now I know it is a tube for blowing glass... ;)
    – Erik
    Feb 5, 2016 at 18:53
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    @Escoce: Red-hot is always the same temperature but different objects will radiate different amounts of heat at the same temperature, due to varying emissivity. engineeringtoolbox.com/emissivity-coefficients-d_447.html Feb 5, 2016 at 20:53

It could (and has)

In canon, we see a lightsaber start a fire at least once. When Kylo Ren smashes up his instrument panel with his lightsaber, there are a few small fires.

enter image description here

(See in particular the upper left). Clearly, some flammable components were ignited.

This is consistent with the general nature of lightsabers. They seem to create a great deal of heat when they come into contact with objects, being capable of cauterizing wounds and melting metal. On the other hand, it’s not clear exactly how flammable an object must be to start a fire: we see lightsabers cutting through trees, but not producing anything more than localized burning, rather than setting the tree on fire immediately.

enter image description here

But in any case, a lightsaber is certainly capable of setting something on fire.


When Darth Vader was fighting Obi-wan the first time in the Kenobi series, he used his lightsaber to light a big flame and used the Force to throw Obi-wan into the fire. He said "Now you will suffer Obi-wan, your pain has just begun."

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