Why don't lightsabres make people explode?

[Ender]

Huh, and here I figured that stripping effect was a little loophole around that, like how quantum tunneling is for "cannot go faster then C". Guess Bob Brown didn't put the same level of scientific research into it as you I usually see.

[PainRack]

Well, this is funny...looks like PainRack and I primarily disagree on the words "hot" and "heat" (admittedly, misnomers).

Well duh! Your only attempt to shrug off the electron stripping theory is to simply say that the lightsabre needs to be "hot".

Hell, your OP started off with if Lightsabres are so "hot".......

There are a lot of fatal flaws with the electron stripping theory, of which one of the most fatal is what can cause it yet still repulse another lightsabre, but Qui Gon sticking his lightsabre into a door isn't one of them.

EM energy. And if EM energy can't be restrained by forcefields (assuming you're referring to EM energy), explain why things like lasers are stopped by sufficiently strong shields.

Shields reradiate(white flashes), deflect energy weapons and radiation from stellar objects.

That wave is a particle - a quantum of energy. It isn't a medium for itself.

If you choose to use quantum physics, there's still a damn medium called the photon.

So photons don't have energy states in the same sense as matter, in which one particle can have more energy than another, allowing potential differences between one object and another.

I will like to see how this is going to be relevent to your "Pure energy" lightsabre, restrained by a forcefield that's impossible to do so.

[Metrion Cascade]

Well, this is funny...looks like PainRack and I primarily disagree on the words "hot" and "heat" (admittedly, misnomers).

Well duh! Your only attempt to shrug off the electron stripping theory is to simply say that the lightsabre needs to be "hot".

Hell, your OP started off with if Lightsabres are so "hot".......

There are a lot of fatal flaws with the electron stripping theory, of which one of the most fatal is what can cause it yet still repulse another lightsabre, but Qui Gon sticking his lightsabre into a door isn't one of them.

EM energy. And if EM energy can't be restrained by forcefields (assuming you're referring to EM energy), explain why things like lasers are stopped by sufficiently strong shields.

Shields reradiate(white flashes), deflect energy weapons and radiation from stellar objects.

So they can stop EM energy. Concession accepted.

That wave is a particle - a quantum of energy. It isn't a medium for itself.

If you choose to use quantum physics, there's still a damn medium called the photon.

Therefore there can be potential energy differences between matter and EM energy? No. Your potential difference analogy requires a common medium. The energy of a photon and molecular kinetic energy have different media. The only way your potential difference bit works is via the plasma forcefield theory (which you disagree with).

So photons don't have energy states in the same sense as matter, in which one particle can have more energy than another, allowing potential differences between one object and another.

I will like to see how this is going to be relevent to your "Pure energy" lightsabre, restrained by a forcefield that's impossible to do so.

Forcefields do stop EM energy. And I do call photons pure energy, despite the debate over light momentum and light mass.

[PainRack]

So they can stop EM energy. Concession accepted.

Concession my ass.
They absorb, then reradiate it in most cases. In deflection, the turbolaser, which is not entirely pure energy, is splintered into smaller bolts.

None of them confine a pure energy beam into a solid energy blade.

Therefore there can be potential energy differences between matter and EM energy? No. Your potential difference analogy requires a common medium. The energy of a photon and molecular kinetic energy have different media. The only way your potential difference bit works is via the plasma forcefield theory (which you disagree with).

I'm still waiting to see how this is going to prop up your "pure energy blade" theory.

Forcefields do stop EM energy. And I do call photons pure energy, despite the debate over light momentum and light mass.

Prove it. Science doesn't say so, and we have seen precious few incidents in SW to suggest that they do do that.

[Darth Wong]

Well duh! Your only attempt to shrug off the electron stripping theory is to simply say that the lightsabre needs to be "hot".

There are lots of other problems with the electron stripping "theory", starting with the fact that it's not a theory at all; it makes no attempt to explain how it works, it only argues that it heats by ionizing things: hardly unique. In fact, it explains none of the unique properties of lightsabres.

Hell, your OP started off with if Lightsabres are so "hot".......

Her OP was based on mistaken terminology.

There are a lot of fatal flaws with the electron stripping theory, of which one of the most fatal is what can cause it yet still repulse another lightsabre, but Qui Gon sticking his lightsabre into a door isn't one of them.

What about the fact that air has electrons too, and that heating it to the point of ionization will create a blinding light, not to mention creating all of the other problems associated with any other heating theory?

If you choose to use quantum physics, there's still a damn medium called the photon.

No, the photon is the carrier particle, not a medium, and it is massless so it can be considered pure energy. Mass-equivalence does not mean actual mass.

[PainRack]

There are lots of other problems with the electron stripping "theory", starting with the fact that it's not a theory at all; it makes no attempt to explain how it works, it only argues that it heats by ionizing things: hardly unique. In fact, it explains none of the unique properties of lightsabres.

Okay, so, it should be more accurately termed electron stripping mechanism.

As for your second argument, I already acknowledged that was the most fatal flaw when I said this

which one of the most fatal is what can cause it yet still repulse another lightsabre

Electron stripping doesn't answer how it can repulse another lightsabre, as well as blaster fire and etc etc etc.

What about the fact that air has electrons too, and that heating it to the point of ionization will create a blinding light, not to mention creating all of the other problems associated with any other heating theory?

Thus, air wasn't heated up significantly.

No, the photon is the carrier particle, not a medium, and it is massless so it can be considered pure energy. Mass-equivalence does not mean actual mass.

The medium is what carries the energy. If the photon is the carrier particle that carries the EM energy away, it looks like a medium to me. May not be scientifically accurate, but it sure looks that way.

[Winston Blake]

The medium is what carries the energy. If the photon is the carrier particle that carries the EM energy away, it looks like a medium to me. May not be scientifically accurate, but it sure looks that way.

AFAIK, photons don't 'carry away' EM energy, they ARE EM energy. I think you might be confusing the word 'medium' for 'mediating'. You could say "photons 'mediate' the electromagnetic force" and that "photons 'carry away' energy", but i don't think you could say "photons are the medium of electromagnetic energy". Electromagnetic waves don't require any medium. What you've said just doesn't make sense to me (possibly through my own ignorance).

Also, i've noticed the figure 100MW being mentioned a lot in this thread. I seem to remember reading something (by Mike Wong?) stating that 100MW would make a lightsaber capable of putting out similar power to a nuclear reactor. Is this unrealistic? Or have lightsabers really demonstrated 100MW?

Keep in mind i am a complete newbie, so please forgive my ignorance (if any).

[Darth Wong]

There are lots of other problems with the electron stripping "theory", starting with the fact that it's not a theory at all; it makes no attempt to explain how it works, it only argues that it heats by ionizing things: hardly unique. In fact, it explains none of the unique properties of lightsabres.

Okay, so, it should be more accurately termed electron stripping mechanism.

How does that help? There's no defined mechanism!

As for your second argument, I already acknowledged that was the most fatal flaw when I said this

which one of the most fatal is what can cause it yet still repulse another lightsabre

Electron stripping doesn't answer how it can repulse another lightsabre, as well as blaster fire and etc etc etc.

Correct. So why do you keep referring to it?

What about the fact that air has electrons too, and that heating it to the point of ionization will create a blinding light, not to mention creating all of the other problems associated with any other heating theory?

Thus, air wasn't heated up significantly.

... which does not jive with this so-called mechanism.

No, the photon is the carrier particle, not a medium, and it is massless so it can be considered pure energy. Mass-equivalence does not mean actual mass.

The medium is what carries the energy. If the photon is the carrier particle that carries the EM energy away, it looks like a medium to me. May not be scientifically accurate, but it sure looks that way.

Might not be scientifically accurate, but you think it's correct anyway? This is like saying that electrons are a medium for electrons; photons are energy, which is why there's no such thing as a photon which has dumped its energy and continues to exist!

[Darth Wong]

Also, i've noticed the figure 100MW being mentioned a lot in this thread. I seem to remember reading something (by Mike Wong?) stating that 100MW would make a lightsaber capable of putting out similar power to a nuclear reactor. Is this unrealistic? Or have lightsabers really demonstrated 100MW?

I've never derived that figure directly myself, but I assume it has something to do with melting that blast door in TPM. In any case, typical commercial nuclear power plants tend to be in the 500MW to 1000MW range, although some of the bigger units exceed 1 GW.

[PainRack]

Correct. So why do you keep referring to it?

Because I was referring to MC argument that the theory doesn't work because the lightsabre is hot?

Might not be scientifically accurate, but you think it's correct anyway? This is like saying that electrons are a medium for electrons; photons are energy, which is why there's no such thing as a photon which has dumped its energy and continues to exist!

Fine. But I still like to see how any of these facts is going to go towards sustaining a "radiant energy" blade theory.

[Graeme Dice]

One hardly needs to invent fanciful explanations for that. A modern laser dumps its energy into metal very effectively, but has little noticeable interaction with air. Air is, after all, an insulator.

While the high conductivity of metal does cause high losses in a laser beam, there is also a significant effect from focusing. It's a pretty routine test and part of the optimization procedure when setting up a high-power laser to focus it in air and try and get the plasma to give off as wide a bandwidth as possible. I didn't take a picture when we were setting up our newest laser, but it's quite an impressive effect.

[Graeme Dice]

1. Photons do have multiple energy states. They're defined by e=hf.

Photons do _not_ have multiple energy levels. From its emission to its absorption a photon will have one energy, and one energy only. That energy can be any one of an infinite band of quantized amounts, but the energy contained in any particular photon will never change.

2. There is a medium. Its called an EM wave. EM energy travels along the EM wave.

Totally and completely incorrect. There is no medium involved in the propagation of radiation through free space. An EM wave is nothing more than a collection of photons. Each photon contains a quantized amount of energy and moves at the speed of light in a particular material.

[Graeme Dice]

There are a lot of fatal flaws with the electron stripping theory, of which one of the most fatal is what can cause it yet still repulse another lightsabre, but Qui Gon sticking his lightsabre into a door isn't one of them.

If a theory fails to explain the evidence then what good is it?

If you choose to use quantum physics, there's still a damn medium called the photon.

A photon is not a medium. A photon is a packet of energy.

I will like to see how this is going to be relevent to your "Pure energy" lightsabre, restrained by a forcefield that's impossible to do so.

It's no more impossible than stripping electrons from an atom without supplying the required ionization energy.

[PainRack]

If a theory fails to explain the evidence then what good is it?

Because out of all the proposed theories, the plasma forcefield,electron stripping and one other proposed by Ted(IIRC, something about a arc circuit equivalent. I didn't understand that) fits the canonical facts as best as they can. The problem lies in the fact that all the theories are fundamentally flawed, even when we're just using something as vague as "lightsabre strips electrons".

I'm personally in favour of the plasma forcefield theory because it sounds the most plausible. We just have to explain how it has enough energy to cut through anything, while not causing the lightsabre itself to be hot.
And how such a lightsabre can operate in water.
And where the matter goes after the blade is switched off.

It's no more impossible than stripping electrons from an atom without supplying the required ionization energy.

And who said that the lightsabre doesn't supply the required energy? Other than MC that is.

[Graeme Dice]

And who said that the lightsabre doesn't supply the required energy? Other than MC that is.

If the lightsaber supplies the required energy, then it will raise the temperature of any material it comes into contact with, including the air.

[Darth Wong]

Because I was referring to MC argument that the theory doesn't work because the lightsabre is hot?

Define "hot". If you mean high temperature, the fact that the lightsabre achieves thermal equilibrium with surrounding metal at somewhere above the metal's melting temperature does, in fact, mean that it is thermodynamically hot (see zeroth law of thermodynamics). It does not, however, seem to radiate like a blackbody of equivalent temperature.

[Darth Wong]

While the high conductivity of metal does cause high losses in a laser beam, there is also a significant effect from focusing. It's a pretty routine test and part of the optimization procedure when setting up a high-power laser to focus it in air and try and get the plasma to give off as wide a bandwidth as possible. I didn't take a picture when we were setting up our newest laser, but it's quite an impressive effect.

Well, there's obviously some interaction, but it's much weaker than its interaction with metal: a characteristic also demonstrated in the lightsabre.

[PainRack]

Define "hot". If you mean high temperature, the fact that the lightsabre achieves thermal equilibrium with surrounding metal at somewhere above the metal's melting temperature does, in fact, mean that it is thermodynamically hot (see zeroth law of thermodynamics). It does not, however, seem to radiate like a blackbody of equivalent temperature.

Except that in ANH, as well as shadows of the Empire, and indeed, if not for Corran Horn in NJO, all the evidence suggests that lightsabres do not feel warm to the touch, or interact significantly with the air around them. So, we have a blade that is hot , without any heat transfer down to the hilt?

I think we have to ask why a lightsabre can work underwater, and not cause convection currents or heating of the nearby waters.

EDIT: Here's the relevent quote from ANH.

It was dense to the point of opacity and a little over a meter in length. It did not fade, but remained as briliant and intense at its far end as it did next to the disk. Strangely, Luke felt no heat from it, though he was very careful not to touch it."

Alternative quotes in Shadows of the Empire that Luke felt no heat in the hilt.

[PainRack]

If the lightsaber supplies the required energy, then it will raise the temperature of any material it comes into contact with, including the air.

So pray tell, what caused the door to melt? Force powers?

[Darth Wong]

Define "hot". If you mean high temperature, the fact that the lightsabre achieves thermal equilibrium with surrounding metal at somewhere above the metal's melting temperature does, in fact, mean that it is thermodynamically hot (see zeroth law of thermodynamics). It does not, however, seem to radiate like a blackbody of equivalent temperature.

Except that in ANH, as well as shadows of the Empire, and indeed, if not for Corran Horn in NJO, all the evidence suggests that lightsabres do not feel warm to the touch

That's an incredibly fucking stupid thing to say. A lightsabre cuts off your fucking hand and cauterizes the wound when you touch it, moron.

, or interact significantly with the air around them. So, we have a blade that is hot , without any heat transfer down to the hilt?

Are you seriously arguing that the hilt must be hot if the blade is?

I think we have to ask why a lightsabre can work underwater, and not cause convection currents or heating of the nearby waters.

That never happened in a canon film, and it makes no physical sense whatsoever.

EDIT: Here's the relevent quote from ANH.

It was dense to the point of opacity and a little over a meter in length. It did not fade, but remained as briliant and intense at its far end as it did next to the disk. Strangely, Luke felt no heat from it, though he was very careful not to touch it."

Alternative quotes in Shadows of the Empire that Luke felt no heat in the hilt.

All this means is that it does not radiate the way a blackbody would. Luke only had the blade on for a few seconds in ANH; even if the blade had an effective thermodynamic temperature of thousands of Kelvin, it wouldn't necessarily heat up the air to a noticeable degree, particularly if its real size is smaller than the visible glow width (for example, if the active region is a thin wire-like filament in the centre of the blade).

[PainRack]

That's an incredibly fucking stupid thing to say. A lightsabre cuts off your fucking hand and cauterizes the wound when you touch it, moron.

I meant that no heat was exuded from the lightsabre.

Are you seriously arguing that the hilt must be hot if the blade is?

Errr..................
Not exactly, but I'm wondering why if the blade does bring to thermal equivalence its surrondings, why the hilt, isn't warm, as per SOTE.

That never happened in a canon film, and it makes no physical sense whatsoever.

Yet, from the comics as well as the novels,(Thrawn duology for example) we do know that lightsabres do operate underwater. Unless we do a purist and claim that Obi-wan example in TPM equals to all lightsabres not being able to operate underwater.........

All this means is that it does not radiate the way a blackbody would. Luke only had the blade on for a few seconds in ANH; even if the blade had an effective thermodynamic temperature of thousands of Kelvin, it wouldn't necessarily heat up the air to a noticeable degree, particularly if its real size is smaller than the visible glow width (for example, if the active region is a thin wire-like filament in the centre of the blade).

If you switch on a bunsen burner and put your hands near the flame, you feel that the air is warm. The lightsabre dumps out more energy than a bunsen burner, yet, Luke didn't feel anything, although his hand was on the hilt. His fingers should had felt something! They were so close to the disk after all, which is where the blade starts.

[Darth Wong]

Not exactly, but I'm wondering why if the blade does bring to thermal equivalence its surrondings, why the hilt, isn't warm, as per SOTE.

Do you figure that a laser gun should get hot because the laser beam can heat things?

Yet, from the comics as well as the novels,(Thrawn duology for example) we do know that lightsabres do operate underwater. Unless we do a purist and claim that Obi-wan example in TPM equals to all lightsabres not being able to operate underwater.........

This isn't about being a "purist"; it's about not being stupid. The notion of a lightsabre having no heating effect on water is fucking stupid and makes no scientific sense whatsoever. Are you going to tell me that I'm also a "purist" because I reject the ridiculous "solar panel" literature interpretation of TIE fighter wings?

All this means is that it does not radiate the way a blackbody would. Luke only had the blade on for a few seconds in ANH; even if the blade had an effective thermodynamic temperature of thousands of Kelvin, it wouldn't necessarily heat up the air to a noticeable degree, particularly if its real size is smaller than the visible glow width (for example, if the active region is a thin wire-like filament in the centre of the blade).

If you switch on a bunsen burner and put your hands near the flame, you feel that the air is warm. The lightsabre dumps out more energy than a bunsen burner, yet, Luke didn't feel anything, although his hand was on the hilt. His fingers should had felt something! They were so close to the disk after all, which is where the blade starts.

So if you held a laser gun close to its barrel, its temperature should be related to the heat pumped out by the beam? You honestly don't see how you are engaging in an obvious leap in logic, do you?

[Winston Blake]

I have one word for you all: Cheese.
Oh yeah, and a quote:

Photoablation occurs when a laser produces photons whose energies exceed the energies of the bonds holding molecules together, Li explains, so that a photon striking one of these bonds immediately breaks it. The millions of photons emitted by a UV laser smash all the bonds in a material, obliterating it molecule by molecule with little or no heating.

UV lasers slice cheese in Wisconsin:
http://oemagazine.com/newscast/2004/011 ... ast01.html

My two cents: who cares how lightsabers work (plasma confinement, electron stripping, radiant energy, microscopic core, etc); the original question was asking why explosive vaporisation in people doesn't occur. It's gradually been answered, i'll summarise:

-lightsaber blades are enclosed in a weak 'forcefield'

-the forcefield pushes away gases but can't push away solids, so is broken by contact with a target

-this forcefield interacts with the air to make a humming sound

The problems are:

1. Corran attempts to free slaves on Belkadan is meant to be an example of air-heating i think. But we don't have a quote.

2. Tipoca City rain hitting Obi-Wan's lightsaber. Did it interact? If so, why didn't Qui-Gon's bodily fluids explode when he was stabbed?

3. Lightsabers working underwater.

My thoughts:

1. Eithe the blade or it's forcefield heats the air up over a long (how long was it in the novel?) period of time.

2. Perhaps Qui-Gon's fluids were vaporising on contact with Maul's blade, but the body fluid vapor was 'pushing away' other fluids as it escaped out the hole. This might limit the blade-viscera interaction, as opposed to blade-metal.

3. This would point to a water-repellant strength forcefield, and if Tipoca City had blade-rain interaction, we might say that the hilt has ambient pressure sensors that determine how strong to make the forcefield.

[Metrion Cascade]

And who said that the lightsabre doesn't supply the required energy? Other than MC that is.

I never said lightsabres don't have to supply the energy needed for electron stripping.

[Metrion Cascade]

Not exactly, but I'm wondering why if the blade does bring to thermal equivalence its surrondings, why the hilt, isn't warm, as per SOTE.

Do you figure that a laser gun should get hot because the laser beam can heat things?

I understand that this isn't the case, but why is that? What effect on the crystal's temperature does all that light have? Is the heat that's carried away by a high-powered laser's cooling system just the waste that doesn't make it from the electrical power supply to the beam?

And is there some other term besides "heat" we can use for what radiant energy does to matter?