Do lightsaber blades/blaster bolts cast shadows?

Question

Do lightsaber blades and/or blaster bolts cast shadows? (I know it's possible to see a blade's shadow on the ground during Episode VI, but that was clearly due to technical limitations, not intentional.) I'd appreciate an answer that lines up with the canon, please.

@DarthVader Being a light-casting entity doesn't preclude you from casting a shadow. — Ghoti and Chips, May 08 '18 at 21:57
Why do people think that plasma is transparent?? Plasma is made of excited gas and it is in fact opaque to light at the frequencies that it emits. — ThePopMachine, May 10 '18 at 16:13
@GhotiandChips Obviously! Otherwise, Jedi wouldn't be able to fall to the Dark Side! ;) — Darth Vader, May 10 '18 at 21:21
@DarthVader Actually, humans really do literally glow light, which should have been another tip that emitting light does not preclude an object from casting a shadow. — Ghoti and Chips, May 10 '18 at 21:47
@GhotiandChips WHAT?!?!??!?!?!?!!?!?!?!?!?!?!?!?!?!!??!?!?!?!?!?!?!!?!!?!??!!? That is all I have to say about that. — Darth Vader, May 11 '18 at 12:15
Anything blocks light cast a shadow if it don't blocks light it's transparent, so if it's not transparent it cast a shadow. Trick is when it also emits light it's light can mask the shadow. Think about the two Tatooine suns, one cast a shadow over the other light — jean, May 11 '18 at 13:26
Although this does not answers the question for the star wars universe, light emitting objects (like a flame) have a shadow, hence if the situation is the same, then a laser sword should have a shadow. — willeM_ Van Onsem, May 12 '18 at 08:38
It would. Even glass, which we generally conceive of as transparent, doesn't transmit light perfectly, and therefore, casts a shadow. — ifly6, Jun 09 '18 at 04:14

score 90 · Answer 1 · edited May 08 '18 at 19:10

90

If we assume that lightsabers and blaster bolts are some kind of plasma, they should cast a shadow under the right circumstances. Stars are big balls of plasma and one star can block the light of another, such as in an eclipsing binary. Flames, which include a small amount of plasma, can also cast shadows, either by absorbing some of the light or refracting it due to currents of heated air.

_{Quora, Why doesn't a fire or a flame cast a shadow, while other things around it do? If there is no shadow, does it mean light can pass through it, even though flame is not transparent?}

Shadows are formed when there is something between a distant light source and a surface blocks some of the light. However, if the object blocking the light, like a lightsaber, is emitting light itself, the shadow will only be obvious if the distant light source is much brighter than the light-emitting object.

Plasma strongly absorbs light, but also strongly emits light. However, if you have a strong enough light source, you should be able to see a shadow from a lightsaber or blaster bolt.

edited May 08 '18 at 19:10

TheLethalCarrot

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answered May 08 '18 at 18:51

WaterMolecule

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Not only brightness, also color plays a big part! A red lightsaber will cat a shadow in a room with blue lights - most of the room will be blue the surroundings of the lightsaber will be violet and the shadow will be red. – Falco May 09 '18 at 06:33
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@Falco well, that’s still “brightness”, just with different values for the individual color bands. – Holger May 09 '18 at 06:41
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What does any of this have to do with the star wars universe? This is totally unrelated to the canon, and wrong as proven by the answer below. Furthermore, the OP has clearly asked for an in-universe, canon answer. – Edlothiad May 09 '18 at 07:55
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@Edlothiad Which answer below? The one with in-universe photos proving that they do cast shadows, or the ones with the assumptions and guesses? – Mr Lister May 09 '18 at 12:42
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The one with the strong canon backing, while the conclusion above may have been "They might cast some shadows", the method it used to reach there is off-topic to the question and in my opinion, to the site. – Edlothiad May 09 '18 at 12:51
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They don't cast shadows in the three movies that matter. But they should've. +1 – Mazura May 09 '18 at 17:08
@Falco That's incorrect. Just because something emits red light doesn't mean it only absorbs non-red light. Also, even if that were true, I believe red-tinted glass under a blue light should have a black shadow, since it blocks the blue light. – BlueRaja - Danny Pflughoeft May 10 '18 at 04:57
@BlueRaja you misunderstood, the plasma blocks all external light - so would cast a black shadow. But the blade is emitting red light itself, which will color everything red. Thus the shadow will be an area where the room-light is blocked, but the light from the blade itself is visible. – Falco May 10 '18 at 06:46
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@Falco the surroundings of the [red] lightsaber [in a room with blue lights] will be violet I think you mean magenta – xDaizu May 10 '18 at 07:37
The candle flame in the illustration demonstrably DOES cast a shadow. Just not much of one. Because gas, even hot gas, isn't very opaque. – Laurence May 10 '18 at 22:48
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@LaurencePayne: I think you must have misunderstood something. This answer is using that illustration in order to show that the flame casts a shadow; so there's no need to reply saying so. – ruakh May 10 '18 at 23:54

TheLethalCarrot · Accepted Answer · 2018-06-08T15:29:51.923

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From this image from Episode I would appear that they do cast shadows, though the angles don't look quite right to me.

From Season 1 Episode 14 of Star Wars: The Clone Wars, "Defenders of Peace", Ahsoka's lightsaber clearly casts a shadow. This is animated and so is not the result of a mistake on post production forgetting to remove a prop's shadow.

The above example comes from the verified Facebook page Star Wars: The Clone Wars and has the following description (emphasis mine).

When Ahsoka cuts down droids inside the Separatist base in season one episode Defenders of Peace, she is shown in silhouette and her lightsaber casts a shadow. Contrary to online debate, there's nothing wrong with this. Lightsabers do indeed cast shadows; anything that is opaque does. Try it with a fluorescent light tube.

Blaster bolts on the other hand would appear not to cast a shadow as we see when Kylo Ren halts a blaster bolt in Episode VII.

Again in Episode II there appear to be no shadows coming off of the blaster bolts.

Some out of universe reasoning here is that the bolts are added in with effects whereas the lightsaber blades are full props used in the fighting and so will cast a shadow.

edited Jun 08 '18 at 15:29

answered May 08 '18 at 16:22

TheLethalCarrot

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If there were a sufficiently bright enough source of light above the blaster bolt, it might have casted a shadow. Since this occured at night time, there simply wasn't enough light for a shadow to be created.
Out of universe, you can see the actor on the right has a shadow from a backlight.
– DarkSkyForever May 08 '18 at 16:34
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I bet that the shadow's weird angles are because they use a green screen and the lighting came from a different angle than what the in universe sun would have. – Sam Harrington May 08 '18 at 17:09
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The shadows are from them using broomstick handles for lightsabers in the prequels. – Ghoti and Chips May 08 '18 at 20:30
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@GhotiandChips whereas the lightsaber blades are full props used in the fighting and so will cast a shadow. – TheLethalCarrot May 09 '18 at 07:52
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"This is animated and so is not the result of a mistake on post production forgetting to remove a prop's shadow."
That's not necessarily the case, depending on how the scene was created (technology and production process). They might actually have created the shadows the same way you'd have done it with actual props; Have them stand before an actual light source and record the shadows cast on the wall. The animator could easily have made the light sabers not cast any shadows of course, but it's entirely possible they didn't think too hard about whether or not they should.
– Cubic May 09 '18 at 09:57
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@Cubic Of course I was just over simplifying things for ease. Though it's likely more of a conscious decision to show the shadows here than in the main series. Especially given the scene is all shadows so it would appear to be even more on purpose. – TheLethalCarrot May 09 '18 at 10:06
@DarkSkyForever Added another image for the blaster bolts in a brighter area and there still appears to be no shadow. – TheLethalCarrot May 09 '18 at 13:05

score 2 · Answer 3 · edited May 09 '18 at 14:47

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In Legends a lightsaber wasn't really the same thing as a blaster bolt. In fact, in Legends the explanations of lightsabers have changed from source to source. One interesting example I will link, at 3:35 it shows that lightsabers are far more solid than just magnetically contained plasma. This would support the shadows seen in the films and shows as more than just a result of the limitations in filming.

Blaster bolts have always been described as plasma and would likely obey the rules of our known science and not cast a shadow unless particularly outshone by another light source. I can't think of any visual examples of this.

edited May 09 '18 at 14:47

TheLethalCarrot

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answered May 09 '18 at 14:39

Roy

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Hello and welcome to SFF! This is a decent answer (would be better if it was Disney canon of course). However, it would be better if you could include the relevant parts of the video into your answer, I don't want to watch a 5 minute video to look for a 1 second clip of a shadow. Lastly, don't forget to take the [tour] – TheLethalCarrot May 09 '18 at 14:41
@TheLethalCarrot The timestamp appears to be included in the answer already. The description of what happens at that point could be a little clearer, but it looks okay to me. – F1Krazy May 09 '18 at 14:45
@F1Krazy Somehow missed the timestamp, edited the link to start at the right point now though :) – TheLethalCarrot May 09 '18 at 14:47
I don't think this shows solidity, just the strength of the forces keeping the beam intact (along with Satele's http://starwars.wikia.com/wiki/Tutaminis ability). – Matthew Read May 10 '18 at 22:56
@Mathew-Read, Its the way the blade begins to crack or at least react to the amount of force being applied that doesn't appear to be just a magnetically contained plasma. I don't think pure energy would crack like that. It's the only time I've seen anything like it and it's not really canon anymore, so take it with a grain of salt. – Roy May 11 '18 at 14:36

score 1 · Answer 4 · edited May 09 '18 at 10:30

There would be many factors involved. Mainly the intensity of secondary light source that is hitting the blaster bolt or blade, distance to surface that a potential shadow would be cast upon, the direction of travel from the light source (is it focused in one direction or being cast out in all directions), as well as the frequency of the light from the source, the blade, and/or the blaster bolt.

This link talks about how any light source that contains mass is technically able to have a shadow when certain criteria are met. All that is needed to create a shadow is to block or redirect light.

So technically the answer would be yes assuming that a lightsaber blade or blaster bolt is more than just a source of light but actually plasma or some other form of matter undergoing a reaction. But to get further into an explanation of the exact requirements to cause this shadow, one would have to make assumptions about the intensity and frequency of both a lightsaber blade and a blaster bolt. So the answer is absolutely that yes, they would in the right situation cast a shadow but attempting to determine that right situation is not scientifically possible without an actual real world example.

Hello and welcome to SFF! This seems to be merely a yes answer with not much evidence, do you have any to add? Lastly, don't forget to take the [tour]! — TheLethalCarrot, May 08 '18 at 19:07

Sam Harrington · Answer 5 · 2018-05-09T00:48:41.320

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Lightsabers are Plasma beams and have almost no mass. explained here But I have very little knowledge of how plasma and light interact.

The out of universe answer is that they used props of solid objects therefor casting a shadow.

I would guess that a lightsaber might have the capacity to cast a shadow, if the light it's casting is much less the light it's blocking.

Edit: There is a helpful explanation on plasma here

edited May 09 '18 at 00:48

answered May 08 '18 at 16:57

Sam Harrington

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Your link is to a google search. And "we have very little knowledge of how plasma and light interact." seems like a strange claim to make, plasma is very well understood. – Yakk May 08 '18 at 20:19
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"we have very little knowledge of how plasma and light interact." ??? What? It's a false statement. – Ghoti and Chips May 08 '18 at 20:31
I meant that I have little knowledge, but I miss spoke. @GhotiandChips – Sam Harrington May 09 '18 at 00:49
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You don’t need to know much about the interaction of plasma and light. There is a simple rule of thumb: if you can’t look through it, it can cast a shadow. – Holger May 09 '18 at 06:22

score -1 · Answer 6 · answered May 09 '18 at 10:25

-1

I think that neither lightsabers, nor blaster bolts cast dense shadows, but they may and probably do cast a poor shadow. Why I think so? Take for instance a laser from real life, it won't cast a dense shadow since most light will go through it. A lightsabers will probably block some of the light too, but most of it will go through.

answered May 09 '18 at 10:25

SovereignSun

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This may be a better answer if it read as an answer. Though I don't really see what it adds on to what is already here. – TheLethalCarrot May 09 '18 at 10:28
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Lasers don't cast shadows at all. You need to get way to the gamma range to get any measurable interaction between photons, visible light just isn't anywhere near energetic enough. Plasma is very different - it both absorbs and emits light readily (thanks to all those free electrons). – Luaan May 09 '18 at 12:27
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@Luaan My shop laser casts a barely seen shadow, so your statement is wrong. – SovereignSun May 09 '18 at 13:03
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Really? How did you measure that? And why do you think the laser casts the shadow? If there is any real optical effect (and not just an illusion), it probably has to do with how the laser interacts with the air in the room - most likely by changing the optical properties of the air, causing light to bend and producing areas of higher brightness and correspondingly lower brightness - not casting a shadow. Unless you consider lenses concentrating (or dispersing) light as casting shadows. – Luaan May 09 '18 at 13:52
Blaster bolts in Star Wars are ionized plasma, not lasers. – TylerH May 10 '18 at 14:46
@TylerH How do you know? – SovereignSun May 10 '18 at 14:55
@SovereignSun It is a well-established principle; see https://scifi.stackexchange.com/questions/13702/why-do-blaster-bolts-move-slower-than-the-speed-of-light for one example. – TylerH May 10 '18 at 14:59
As Luan said, a laser will at most distort light, not shield it, so it's not a shadow. Even that would require a very strong laser, best tuned to 760 nm (absorption line of oxygen), so you actually heat the air significantly. No consumer-available laser will do that. – leftaroundabout May 10 '18 at 16:57

Do lightsaber blades/blaster bolts cast shadows?

6 Answers6