What is the Speed of Dark?

GA Redfred. Interesting question and good answer. In philosophical sense, speed of dark is infinite and geometrically increasing and speed of light is very very small.

This reminds me a discussion with Jorrie -in CR4- about this issue, a long time ago. In fact, it was a kind of question: Can the darkness be faster than light (and how)???

At some point, Jorrie presented the following intellectual experiment: We transmit a long light pulse from a laser source. On its path, we have placed a sequense of diaphragms. As the light pulse is passing through the first diaphragm, the diaphragm is closed "cutting" some photons on the "tail" of the pulse. After this, as the light pulse is passing through the second diaphragm, this diaphragm is closed removing some more photons on the "tail" of the pulse. This procedure is repeated in every diaphragm of the sequence. So, the pulse -during its travel- is getting shorter and shorter: its back end is "moving" towards its front end. So, the front end is moving at c, while its back end -which is actually the "front end" of the resultant "darkness"- is moving with a mean speed greater than c.

Of course, this is rather philosophical issue and (I think that) you can not use this experiment to transmit information in a speed faster than c.

"resultant "darkness"- is moving with a mean speed greater than c"

Ahhhh! This seems to make sense this morning before my first cup of coffee, but it appears from this scenario the dark can only move as fast as the light or an outside force will allow it. I'll have to get that coffee, this deserves a little more pondering.

No sooner than I had that first sip of coffee, I thought about Zeno's paradox of Achilles and the Tortoise. It seems the dark will never have enough endurance to pass the light in this scenario and jut be content to speed up in spurts.

My take on this is that you are 'injecting' some dark at the beginning of your dark after each of your diaphragms has 'cut off' some light. Thus, while it would appear that your light pulse is getting shorter, this is only due to the additional dark injected before the original start of dark...

Has anybody seen the movie 'Pitch Black'?

In a way, you are right (and wrong). First of all, I thought of the following experiment in order to "move forward" the front end of the light pulse (in the same way that we "move forward" the front end of the darkness in the Jorrie's thought experiment).

Pulse1 (the light pulse emited from Laser1) is passing through the semitransparent mirror. Pulse2 (the light pulse emited from Laser2) is reflected on the semitransparent mirror. The two lasers are synchronized accurately so that the front end of pulse1 meets exactly the back end of pulse2. In this way, it seems like the pulse1 has been extended and its front end has moved forward instantaneously. But, in fact, we just have added a new pulse (pulse2) in front of pulse1.

The result is "equivalent" as in Jorrie's experiment. The only difference is that I add light (instead of adding darkness). The main issue is that we cannot forward the information, i.e. any information included in the front end of pulse1 is not transfered in the new front end of the total pulse. The same happens by "adding" darkness as in Jorrie's experiment. Hence, the whole concept has no importance.

However, in Jorrie's experiment, you substract some photons. In a philosophical manner, it is equivalent to the extension of the existing darkness. On the other hand, in my experiment, you cannot say that you extend the existing photons. You just add some new photons.

A simple analogy would be a freight train which is periodically loosing cars off the back. The 'back' of the train is now moving faster than the 'front'.
Or maybe it's just hogwash as the 'back' isn't consistent (it's not the same 'back' at all), thus with Jorrie's thought experiment, you need to pin a marker on the leading edge of the dark, an you soon see it's just new dark that has been added.
So it's the speed of something which is changing, and indeed things can change faster than the speed of light. (A woman can change her mind faster than that)
So what is the speed of thaught? Just askin'
Del

The fastest thing in universe is neither the light nor the thought... It's the collywobbles... Because if it happens you don't have the time either to turn on the toilet's light or even think about it... ...

Addendum; The speed of light is 670,616,629 mph. I double checked. I' m not sure where the 186,000 mph came from, just old age, I guess.

I liked your reply redfred - give me tonight to wrap my brain around it - it makes some sense - Thank you - Loupy

P.S. Maybe it's 186,000 mps - i'll check again

Yup - the speed of light is 186,000 mps instead of mph.- My bad .

Actually it is 186,282 mps.

2.99792458 e 8 meters/second exactly. In a vacuum. The only physical constant to be exact and the only physical constant that is a whole number.

299 792 458.000000000..... m/s

I'd assume dark to be the ebb and flow counter to light, moving only as fast as light in the given medium. But does "nothing" move? Perhaps it is omnipresent and only reveals itself when light vacates the give area...

Since an absolute vacuum cannot be produced, how can anyone say for sure what the speed of light (or dark) is in a vacuum?

Ha, by extrapolation...I've measured the speed of light in brick and worked back from there.
Del

The magic word for today is asymptote.

Agreed, but

we have to ass u me something.....

It is the basis from which all other physical constants are measured... the ultimate meter stick, and it may not be accurate.

Ha !, I also bet that His interpolation was based on the Ass-U-Me-Option that light travels in a PERFECTLY straight line.

Same speed as the speed of light.

Of course there's a speed of darkness. Just like there is hole propagation and hole drift velocity in semiconductors even though holes are the shift of a valence electron. So if we can measure, quantify and predict the absence of electrons, we certainly can do the same with photons.

I disagree dark is a relative term. Like full or empty. We can measure the entities that fill them. Space being the medium. It can be illuminated or dark we can measure the amount of light. We can't measure the amount of darkness. Light traveling though it illuminates it. The dark doesn't move.

But if the dark doesn't move then the light cannot enter.

This entire thing can be said to be a purely semantic argument. But if we are going to argue semantics then we should get it right. "Darker" and "Lighter" are relative terms. "Dark" and "Light" are absolute terms.

Dark can not be considered absolute it is dependant on light. Dark is absence of light(photons) moving though a space. The dark does not move the condition of that point in space just changes. I understand what you are trying to say. Example would be a sealed box in a illuminated room. No light can pass though the walls of the box. The space inside is totally dark. As we move the box around the room we can say me are moving the dark.

Dark is a condition it has no substance it does not move so light(Photons) can enter. In arguing semantics then we have to define the term light are we talking about physical light photons or it's definition as a condition?

Read Post #25....

I beleive a similar question would be " what is the speed of Air "

It is matter of definition. When (or if), we define the dark as absence of light, matter is solved. Thus the speed of dark means speed of space where light is absent. Now redfred's explanation fits.

Picture this :

A space (e.g the universe) is filled with darkness, light passes ( piercing ) thruogh it and giving illumination as it travels through. As nature will not allow vaccum, Darkness immediately ( instantaneously) fills up the gap left in the fabric of space as a result of light passing thruogh at the SAME RATE ( Equal Velocity ). Darkness can attain any velocity , depending on whats passing through it. ( Fire a bullet through air, and the trailing wind attains the same velocity as the bullet.)

Hope this answers your question. So we can all go to sleep.

I like how you with vocabulary give dark substance. Filled? Vacuum? Then compare it to things that have physical substance like air and a bullet.

Light does not pass though darkness it passes though space. Dark or darkness is the condition of the space depending on the amount of light that there to illuminate it. If when light illuminates dark space the condition in that space of being dark ceases to exist.

What is the color of Air.

Must an oxymoron be forced, or can they breed on their own.

Oxymoron's live in peace and need not breed at all. They come and go just like light and dark. We are only the parasites that enjoy when they pop up and scratch our heads when we watch them change color and shape, not to forget context.

Depends on what world you are on. Here on earth its blue due to the amount of H2O evaporated into it.

I agree with your answer up to the point where the "space of dark ceases to exist"I believe the space is made up of more than a condition. (and this is off the wall)If light travels at 186,282 mps, and I ride my Beamer until I over run my headlight, does that mean if I role backwards down hill the light will beat the dark by the same speed variation ratio? There are only 3 forms of power transmission, mechanical, electrical and fluid power, maybe if we understood these relationships better there would be a fourth. I love these discussions! I learn quite a bit from you guys! I wish I had more time to absorb it and contribute. I found this today at lunch. Thought it may be interesting.

http://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/

INTERESTING !.

I have never seen this article before. But I beleive it does support my theory in thread #25.

" I am not a scientist , I am only trying to make logical sense of Gods' Creations "

The Guest

......there is no measure of cold.....

What is -273⁰C........when I went to school it was called Absolute Zero or 0⁰K.

As I sere it, temperature is the degree or intensity of sensible heat in a body, and it is measurable whether we use degrees Kelvin, Celcius (Centigrade) or the other one that you persist in using in the USA...........and can be called hot or cold dependent on what the temperature is relevent to.

What is -273⁰C........when I went to school it was called Absolute Zero or 0⁰K.

What is the unit of measure used here? That is a THERMAL measurement.It is a measure of heat displacement not cold. Cold as it is has no known measurement. A "-" before a heat measurement does not make it a cold measurement.

I agree with your answer but not your example.

Agree: "Dark" is nothing but "Nothing", so "Nothing" can not have properties.

Disagree: "Cold" or "HOt" are both measures degree F or C or K... These terms used or only expression of relative feel of us.

- JP Reddy

So is GOOD the absence of EVIL? Black and White... Inteligence and Stupidity...Don't you need one to have the other?

I always wondered, is "Lucifer" (light-bearer) a different fella' than the "Lord of Darkness"?

And by the way, which was created first, the light or the darkness?

It only matters if somebody was watching.

Would you say that stupidity or intelligence is tangible?

Light is a wave frequency, and travels in a magnetic field the same as radio waves and xrays, radio and xrays can not be seen, therefore they are dark waves, but still travel at the same speed as light waves. Just a thought?

Regards JD.

"Light is a wave frequency, and travels in a magnetic field the same as radio waves and xrays, radio and xrays can not be seen, therefore they are dark waves, but still travel at the same speed as light waves."

Just because they are not visible waves does not make them "dark" waves. We can not see wind but we would not call wind dark,would we?

Dark is the absence of light, which is an electro magnetic wave length, so light travels at some speed governed by some natural constant, and this constant applies to all other electro magnetic wave lengths travelling through space. So this then boils down to the meaning of dark? As you pointed out, you can not see wind, but because you can not see it does not mean that some force is not acting? So the rate that something is travelling through space, be it light which can be seen, or some other wave length, is not dependent on whether it is with in the light wave length spectrum, or some other wave length which could be classified as dark. So to summarise, light does not govern the speed that electro magnetic waves travel though space, and dark could easily be a word to describe a wave length not within the necessary light wave length. But that does not imply that no other wave length is present, only that is not in the light wave spectrum.

ouch Regards JD.

Are we not now referring to something different completely? There is no absolute darkness so we are still talking about diminished light waves? (or am I just trying to keep this thread going because I'm bored?)

Wakey wakey don't get bored, diminished light wave? No, I do not think we are talking about a very dull light, I think we are talking about the absent of any wave length in the light spectrum at all, and because its not in the light spectrum it must have no existence? Its like saying that when the sun goes down at night it ceases to exist, and because it dark nothing around us exist until the sun rises again in the morning? I think the question poses something about human nature, if we do not sense it, does it exist? Look at the meaning behind the question?

Regards JD.

PS hope it don't hurt to much.

"PS hope it don't hurt to much"

You have no idea.

I feel as though we have gone as far as possible with this. You'll keep up with the empirical data and I'll continue being a pain in the @$$ as the devil's advocate.

I am not a scientist nor am I an engineer(I have no idea how to drive a train!)so I can only spout on about what I have read in the past. You likely have a greater knowledge than I in this field. But I'll keep going until I am convinced without a doubt, or I'll just walk away knowing that I'll never change your belief.

Therefor I'll be the bigger(?) man here and bow down to your superior intellect.Thank you for my daily dose of humility.

Dear All
In my oppinion, the "REDFRED"and the "Not so Smart" comments together complete this curious question.

Really, darkness is complete absense of energy and refference to anything.

The question is a semantic joke.

Light is a physical thing, a photon or a stream of photons or packets of photons. Therefore one can speak of the speed of photons or light.

On the other hand dark is, as has been pointed out a concept embracing the absence of photons and therefore the non existence of the thing called light.

You can speak of a speed of dark just as you can frame any mystical concept like, for instance, god. But you can't prove such a concept until you can show me one. You can't show me dark because it is the absence of photons or any other radiant energy. You can infer dark but by its nature you can't show me one.

Things that are non-existent don't travel except as they may be enclosed in something like a dark box hence they don't have a speed.

This last also addresses the issue of the "holes" in solid state electronics. Without the solid state media there are no holes save as the absence of an electron of the solid state media.

j.

Darkness is pure, light is pollution - but sometimes practical.

To have light, there must be some grade less light to darkness to make it physical.

Light in lighter (more light)doesn't show.

We have been taught about sunrise and sunset in reference to the sun.

The sun has been always an example of warmth, joy and growth, while darkness has been pictured as obscurity, and dark.

But the sunset could have been described as the darkrise, the same time lapse and the sunrise as darkset, also sunrise.

The understanding of dark is only referred to absence of light.

5000 years we say "don't curse the darkness, make light". Black and white Television should have been terrible, if we had no control of darkness, just by absence of that modulated lightbeam, that writes a full display or screen in tints from black (or dark grey for non trinitron tubes) to white.

Same goes for the movies but in frames.

Maybe we need to start studying upside down? Or reverse- engineer it?

it's one millisecond slower then the speed of light.

millisecond is time dimension. We are talking about the speed... L/t

I know this is going to get me in trouble but I can't resist.

The speed of light is not a philosophical issue, rather one of the motion in a dimension of time of a physical thing or stream of things, i.e. photons.

You appear to have just corrected someone who used the term "millisecond."

"millisecond is time dimension. We are talking about the speed...L/t"

Would you please explain. Is the speed of light not expressed in units of time or is there something special about light? Am I just confused by your shorthand?

j.

The speed of anything is expressed in units of speed i.e units of length divided by units of time not only in units of time. Therefore using only miliseconds ( unit of time ) is not enough to express speed.

I think this is the explanation for gsuhas's post

My dear friend

Yes, I corrected the dimensions given by guest.

I hope, you are engineer, and will remember the basic dimensions and their units.

There are only few basic units and all other units are derived units.

Second/millisecond/ nanosecond.... all are time units.(t). This is basic unit.

L is another basic unit... that is the length, whatever may be the measurement unit like meter (metre)/ centimeter/kilometer/ nanometer or foot or inch.

Speed is rate of change of location of the object (here light) per unit time. Thus it is derived unit L/t

Thus unit of speed is not milliseconds but, it will be L/t .... (milli/centi/kilo....)meter per second/millisecond/hour/month/year.

Well summed up by 'Redfred' and 'Not so smart' - GAs

Absence of light is darkness and absence of Heat is cold.

Darkness and cold can not be measured in units but I suppose can be equated to light and heat respectively by the same degree.

I am stunned that people here cannot accept the idea that one can measure and quantify something that does not have a tangible object to measure. Humanity has been doing this for centuries, but to make my point I'll limit myself to a few things measured today.

In archaeological geology and potentially global warming, we've measured the rate that glaciers have receded back up the mountains and exposed more land. Yet, all of the water of this glacier are actually moving down the mountain slope. We calculate the very useful centrifugal force on parts of a spinning object. But this is a false force that only manifests when one must view something from a non-inertial reference frame. We measure the velocity and magnitude of current that flows from the positive to the negative leads of a battery even though the electron flow actually moves from the negative to the positive terminal of the battery and that the actual drift velocity of the electrons is many orders of magnitude less than the current velocity in the opposite direction.

So saying that one cannot measure the speed of darkness because darkness does not exist is a specious argument. We already measure and use many things that do not exist.

Do we actually measure them or do we measure something tangible that is dependant on them and make comparison. We don't measure the dark we measure the amount of light.

So you have faith. You are willing to believe because of other measures of physical properties that have no merit on the subject the dark.

All Ye smart @$$£$ that question that ye knowesth noth.

Darkness is the absence of light . Thus Vacuum is the absence of Air .

Answer me this. " WHAT IS THE DENSITY OR MASS OF A VACUUM ?"

Otherwise close this thread until you find me answers.

The Guest

Are you talking about a Hoover or an Orick? Hoover is made mostly out of plastic so less dense than an Orick, more metal. HA!

I think, more accurately, a vacuum is the absence of matter. Which is theoretical.

Redfred,

If we were to agree with what you say then we would have to agree with the views of Bishop Berkeley, i.e., the ultimate solipsist, a few hundred years ago who said that "None of this exists except as it exists in the mind of god."

j.

Now you've baffled me. I do not see at all how my observation compels anyone to this philosopher's views. I've briefly scanned the Wikipedia description of Bishop Berkeley and do not see a correlation between either his early optics observations or philosophies. Let alone a causality that my idea that one can implicitly measure a non-tangible item to compel anyone to agree with this man's ideas. You also raise Bishop Berkley's name as if he's a completely discredited man. In contrast I quote the Wikipedia article^* on his optics work:

His earliest publication was on mathematics, but the first that brought him notice was his Essay Towards a New Theory of Vision, first published in 1709. In the essay, Berkeley examined visual distance, magnitude, position and problems of sight and touch. Though giving rise to much controversy at the time, its conclusions are now accepted as an established part of the theory of optics.

Hardly a discredited reputation. Now as for his philosophy:

He thus concluded that all that individuals know about an object is their perception of it.

This is the very antithesis of my argument, there are many aspects of an object that one cannot directly perceive.

However by resorting to such an esoteric reference or a straw-man attack to defend against my proposal, I get the sense that my idea deeply troubles you and a few others here.

_{* I do dislike resorting to Wikipedia as a reference but I'm feeling a little lazy tonight.}

Redfred,

All of the things you have used as examples of intangibles are in fact tangible in one or another of their aspects.

So your examples fail. Indeed I cannot think of anything that is material and real that does not manifest itself in one or another aspect of reality.

The thing least tangible, because it melts and the water runs down hill as you point out is still tangible insofar as its former mass as ice can be measured by the proper conversions and at any rate the retreat you speak of is measurable these days by any number of imaging devices from numerous sites including space let alone the use of the term "retreat" is itself simply a linguistic device as is dark.

What brought on the Berkeley quote was the fact that you spoke of measuring intangibles and connected that with something that in fact is not intangible but is rather the term we apply, as others have pointed out, to something that is non-existent except as a concept of the absence of light, therefore outside a mental concept has no existence. (This of course leaves out the concept some offer that space is indeed fully filled with one or another form of energy of which light is but one.)

I did not know that Berkeley also had an interest in material science which is a real contradiction given that his remark asserts that none of this, you nor I, your very material examples that in fact manifest themselves in material ways,...that indeed none of this exists, including the optic functions he examined, except as a thought in god's mind which god is itself a non-existent concept, a statement Berkeley would have taken violent exception too.

To a materialist, to a consistent scientist, the above statement of Berkeley's is of course without credit. It was not intended to extend to any other aspect of him.

Since, as you know, I know that you are a scientist working as such, your statement still surprises me. Something that is intangible is so because it offers no material evidence of its existence. At least that is so in my use of the English language. I suspect it is so in, at least, every other modern spoken language of today.

We have heard from numerous people who obviously have no background of science but who as best they can try with language alone to reason out an answer to what I think was a quirky joke question. I have no problem with that although they would be better served if they first pulled up, yes even Wikipedia, a paragraph or two or three on light an issue on which you may remember I have some questions.

My concern was that your way of addressing the question and some of the ideas offered was not what I would have expected from a working scientist or certainly anybody with the working knowledge of physics that I know you have. Too murky.

Just my thoughts. I am not looking for a fight.

j.

I think it all depends on how fast the Oozalem bird can fly.

He flies around in ever decreasing circles until he disappears up his own fundamental orifice in a blue flash...........he then experiences darkness (in a blinding flash of light)

Wherever light goes, dark always gets there first! So my friends which is faster?

Absolute zero, 0 degrees K, is the total absence of heat. Anything above this is heat.

Total darkness is the absence of light, therefore there is only light, more or less.

Where the @#%$ have you been? That's what I've been trying to tell them!

Sorry I got in a little late, but this does seem the logical answer.

tommm

Absolute 0 is also theoretical and is, I think, the absence of energy, heat or otherwise...

You guys are not in Pakistan, where electrical power is "managed" such that each of us gets "NO power" for eight to ten hours. So in night hours, DARK spreads and is maintained continuously for two hours. This darkness does not go anywhere. So it has no speed. But when light comes, it goes instantly. So dark is a wave form with stationary "hours" and swift milliseconds. So you can say the speed "depends" on the country. Possibly in US it happens only by accident, like it happened in 1977. ++++++++ Stupidity and intelligence are two faces of the same coin that is legal currency. ++++++

This is an engineering forum and not an architect's forum..... i will probably get get points for a bad answer.

"All material in nature, the mountains and the streams and the air and we, are made of Light which has been spent, and this crumpled mass called material casts a shadow, and the shadow belongs to Light.

- Louis Kahn"

The speed of dark is the time it takes to open a refrigerator door.

I will accept that as the only sensible answer yet.

Yes it is a joke.

Dark is a concept.

The funniest answer was "Dark got there first."

Speed is relative also making the joke more funny.

No maths needed it is just a joke.

Like if your car traveled at the speed of light would the headlamps fill with photons if you turned them on ?

Light needs energy and mass to be produced. Darkness dose not have any phisical propeties and so dose not exist.

If darkness was to exist then it would be similar to the sea. and light would be a ship sailing on it.

The sea would be pushed into waves the same as the wake from a ships bow.

if dark existed it would need to travel faster than the ship to make the wave.

Why off topic Jack? That was a wonderful reply. I'll give it a GA any way.

Good to see you back BTW, Ky.

I see the backward ingrish got you on that one - allow me to remediate, also because I tend to agree.

A similar question, in horse racing, is "how fast is the track?"

Which is of course about latitude...

^{_{(huh - remediate; not in speelchucker?)}}