Relativity and Cosmology

Jorrie,

Fascinating, but this almost sounds like a philosophical question.

Since you infer that it may exceed the speed of light, then I suppose zero is out.

My other guesses would be -C or infinite. Or, perhaps, the sound of one hand clapping.

I can't wait to hear more about this.

I have heard the sound of 1 hand clapping

Okay Jorrie, I'll bite.

Let's say you have a row of lights shining on a screen. Turn each light off in turn and the the non-illuminated (darkened) area of the screen will progress from one edge of the screen to the other. Turn the lights off fast enough and the darkened area will progress faster than a beam of light launched parallel to the screen.

A loose sort of 'group-velocity-can-exceed-the-speed-of-light' solution, along with an ample helping of artistic license. Happy now? Hehe

So "nothing" propagates faster than "something"...sounds like my checking account! Actually makes sense...since darkness is the absence of energy it should not be bound by any physical laws, or maybe just entropy.

Hi -e.

Happy now? Hehe"

Not quite. I've got a "better one" and am thinking about how to use it to send information at a faster speed than c.

Let's see what others may come up with.

Jorrie

Dear Jorrie

You look quite serious about this so let me reveal something that sure make light to travel faster. Photons in in higher gravity travel faster than normal speed of light that we know else will never get pulled in. Considering relative motion, the darkness travels faster to reach a photon if you keep the speed of photon constant. Are you satisfied with this analogy?

I also suspect that negative energy or dark energy may also have different properties as that belongs to different world and the gate to entry is through zero kelvin matter. As not much is known about it so it is all speculation unless we fit it into some wave function which is accelerated version of the our world.

I think in black hole the dark-energy shows way to light at much faster speed and says to it that you had it enough and it my turn now.

Hi Shyam, you said: "You look quite serious about this so let me reveal something that sure make light to travel faster."

Now what makes you think that I looked serious about faster-than-light? (this is the 'tongue-in-the-cheek' emoticon, I think.)

I do not understand your: "Photons in in higher gravity travel faster than normal speed of light that we know else will never get pulled in." The first part is not true and the the last part is not comprehensible, I'm afraid. So no, I'm not satisfied with the analogy.

Finally, as far as I can tell, there is no 'dark energy' inside black holes. There is only dark matter there...

Jorrie

With such a tenuous hold on Reality, Shyam, I have to wonder how in the world you ever got a PhD. Mail order?

A thought experiment huh? How about this: dark is faster that light because its always just slightly ahead of aproaching light.

If a car is in front of you in traffic, does this mean that it is travelling faster? Isn't this basically what you're saying here? How's about the darkness receding as fast as the light 'behind' it advances? C'mon dude, draw from your own experience!

Sorry e, but I can't draw on a personal experience of what's going on at c. I don't think, however, you can use the same analogy as two cars moving moving along together.

Back to my statement though. If light is so dang fast why can't it ever catch the dark? (the reason is that light is Wily Coyote and dark is the Roadrunner).

Come to think of it though, in a closed room I guess light just scares dark away. Hmmmm...

Now if the dark is receding from the light faster than the light can advance toward the dark, there's gotta be a widening gap between the dark and the light, no? So what's filling that gap? Is it manufactured by ACME?

Perhaps we have it all backwards: a little humorous and inverted look at things seems to be in order, in keeping with the toungue-in-cheek spirit.

"Light" bulbs, are in fact "Dark Suckers".They suck the darkness out of a room when turned on.If you trace the wires from a ight bulb back to the source, you will find a larg generating plant spewing out darkness, which acculmulates on the other side of the globe.When a light bulb has inhaled all of the darkness that it can hold, it no longer funtions, but if you shake the bulb, you will hear a little bit of solid darkness rattling around inside, and may even see a trace of darkness on the inside of the bulb.This effect is easily observed in flourescent tubes. What happens to the darkness on the other side of the planet, you may ask?When the eath rotates towards our sun(a giant "Dark Sucker") the sun sucks the darkenss from the planet.However, the sun is not immune to burn-out.When it has absorbed it's limit, it collapses into a "dark hole", indicating that darkness has mass..Fortunately, that will be a long time from the present.

Very Clever.

You are a closet subversive, Jorrie. Fess up.

sorry, I just can see that.

Hi Guest, since it seems Eu forgot to answer your querie, I'll give it a try.

His experiment is valid for his definition of darkness, paraphrased as: "...progress of the darkened area of the screen when the lights illuminating it is turned off in sequence."

Turn all those lights off simultaneously and the darkness would progress across the screen's surface at infinite speed. This is similar to a very long line of people that all agreed to blink at the same time (same UT to the nanosecond). That blink could travel around the world in no time at all - infinitely fast.

We can however not send any information faster than light that way. Although not part of the original challenge, I'm still working on a way to do just that by means of darkness. If I'll succeed, we'll have to wait and see...

Jorrie

Jorrie, you said "Although not part of the original challenge, I'm still working on a way to do just that by means of darkness."

I've got it! You're going to use Morse code aren't you? I "dot" is light and a "dash" is dark.

That could constitute a dark day for information technology!

Sorry, I just couldn't resist...... coming over to the dark side.

No, really, sorry. Just can't help myself sometimes.

Anyway, looks like you've really stirred things up with this talk of darkness, Jorrie. I can't wait to see what you have up your sleeve.

Dark humor, Dark Vader.

When I think of light, I think of it as merely a band of frequencies that are higher than audio frequencies. Therefore I think of them as having relatively similar properties of propagation and restriction. (Of coase light frequencies can be focused or diffused much easier, so we can use them for a broader range of applications.)

When I think of dark room, versus a lighted room.... I think of a quiet room, versus a noisy room. Both rooms are void of any type of energy, until sound or light are introduced. I guess what I'm saying is that "darkness" seems just as empty as "quiet" does. Darkness as a "power" doesn't seem logical to me. Because that would mean that "quiet" is a power too.

Dear Jorrie

Perhaps darkness is to be defined here as an identity which exists or a phenomenon that it relates to.

I can only relate it to two things. Empty space or the capability of digesting the photon by something, that we know (like black hole) and we may learn more about such things. I do not know much about the big bang but that is something also relates to it, which creates dark space along with only known fastest source of knowledge acquisition, the photon. Fortunately, we can imagine beyond photon speed and can also visualize dark space as an identity but for physics, it is very difficult thing to take shape of an identity.

Photon can travel into more than 3D space (excluding time) and its speed changes when it enters into beyond 3D space. It recovers its speed on its return into 3D space.

Now that 3D space has other things around the photon and if those things change in spacial density near the photon to great extent then photon must also experience them. This is where photon enters the new dimensions and changes its form. Out these forms, we only know its normal form and formation of matter and anti-matter. There may be many other forms that we may discover in time by research.

Darkness is insidious it creeps, you only realise it when you can no longer see.

All you need is a proper goggle to see all space. It is not empty any way. It is filled by various force fields every where and perhaps with some thing you have to discover. Once you know all that and build vision help to see all that then it is like a water tank and you are inside it. Even in solids there is lot of space you don't see, and yet you see it as solid thing. I think we are not talking about the darkness for our eye but darkness to every thing else and that includes all types of sensing methods, direct and indirect. Do you drink water or do you drink space? Even if you can not see water, you know what is going in.

I think Jorrie has some different idea here. Perhaps he knows that time and space had no meaning before big bang. It is after big bang both time and space came to existence. So is the darkness.

Perhaps I can put up some interesting analogy here. Devil named darkness opened its big mouth and space of its mouth was exposed and it got filled by big bang photons and perhaps we want to know the speed at which devil of darkness opened its mouth that created big bang. Next time it is going to close its mouth to gulp all those photons and matter created by photons and there will be all space filled with nothing and we can wait for another big bang to happen.

*Perhaps he knows that time and space had no meaning before big bang. It is after big bang both time and space came to existence. So is the darkness.* But what if Time/Space came from another dimension, beyond the three, maybe the tenth, would it not still have value. Musical notes of String Theory.

*Perhaps he knows that time and space had no meaning before big bang. It is after big bang both time and space came to existence. So is the darkness.* But what if Time/Space came from another dimension, beyond the three, maybe the tenth, would it not still have value. Musical notes of String Theory. *I forgot to logIn*

"All you need is a proper goggle to see all space..."

Great.

You can also shine darkness of dark matter much better using dark photons or darkons from dark energy sources.

dark matter <---> dark energy <---> dark photon or darkons <---> dark vision <----> speed of darkness

dark energy = md X Cd ^ 2

md is nearly zero and dark energy negative but non-zero, hence to make for dark energy Cd the speed of darkons is very very high than C the velocity of light in so called vacuum, however it is an imaginary number to get negative energy as dark energy.

This dark energy described here is different from that NASA's perception and also dark matter is what we know as space and not black hole's high gravity matter.

"You can also shine darkness of dark matter much better using dark photons or darkons from dark energy sources."

-----

I think I'm gonna be sick.

Since visible light corresponds to a wavelength range of 400 - 700 nanometers anything above this range will be much faster but not visible to the human eye and perceived to be darkness.

No. You are comparing apples and oranges or wavelength and speed, as it were. Speed is not a function of wavelength.

Surely darkness is without light, that is no light at all. The wave lengths above 700 are in the infrared and can be seen with filters and recognised as a component of the visible light.

We now have electron vision, neutron vision, x-ray vision, gamma ray-vision, laser vision, magnetic filed vision, electric field vision, gravity vision, supper gravity vision.

There are some more like ghost vision, UFO vision, television, sixth sense vision etc.

If quantum mechanics is write then wave-function of anything and everything will spread out like monkey's tail and not only in space but also in time from minus infinity to plus infinity.

Believe it or not, people think that bats have ultrasound vision. I am sure if people keep placing the mobile near their head then two antenna going to pop-up from their head to have radio-vision or television right inside the head. This is the way all types of senses for our vision of environment have come into existence.

Man, Jorrie. I thought I had some bizarre theories. My drug-addled mind can actually comprehend most of Shyam's conjectures as my Bigfoot vision can attest. Gotta go, I'm late for supper gravity vision.

It is all jokes here. Never mind.

Space as we know is without matter, is also debated as full of matter. If that is true then there is another world out there.

Some people think that matter is some rigid thing and nothing can pass through it, is not true. Matter is just an energy in another form and there is enough space within it and to enter in it you need a way out to beat its laws.

We do not yet know the laws of space as they are perhaps meant for something else and are non-interacting, non-interfering with our laws of matter and energy. It is good that people should think of new ways to look at things and not to believe theories of no-man's land for granted. I am not advocating for any theory as they are more like fiction than science.

I sure will like to see things, using whatever means available and will love hearing theories also even though they may have nothing to do with reality.

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Darkness is not the absence of light but the absence of light hitting the retna at the back of your eye. If you were in a mine and the lights were turned off it would be complete darkness. If someone lit a match down a cross tunnel, a person at the other end of the cross tunnel would see the light but you would not see the light beams as they crossed your tunnel (you might see light bouncing off dust in the air if the light was bright enough but not if the match was a long way back from the entrance to your tunnel).

So in a sence you could say that the darkness closed in around that light beam faster than the light could spread down your tunnel.

How true are the words of John.

"and the light shineth in the darkness ; and the darkness comprehended it not" (John 1v5)

I think I'm gonna bail on this thread. Too many Voices From The Fringe posting here. Check back on Sept. 4?

Now just hold on a minute e, before you go bailing out! Lets just pull back from the CMB a little and rethink this.

Jorrie said "Not quite. I've got a "better one" and am thinking about how to use it to send information at a faster speed than c".

So far, I've not heard anyone pick up on this. I wonder if he's somehow discovered a way for "dark" to tunnel? Sure couldn't use a prism, or could you?

I believe Jorrie is somehow thinking about distorting spacetime since spacetime distortion is supported by general relativity and not bound, or limited, by c (also, since it's his area of expertise). I can't conceive of how information transfer could occur though. We're not talking about wormholes are we Jorrie? If so, what's dark got to do with it?

Since special relativity does not forbid the existence of particles that travel faster than light at all times perhaps they could very well be "dark" and we wouldn't realize it. Even so I'm not sure how it could be utilized.

Maybe we could modulate certain dark energy frequencies! Dark FM, think about the music.

-John

Dark FM, think about the music.

------

FM? Dude, that is soooo old school. I get my streaming audio over DarkNet courtesy of...

(Your World, Delivered. To The NSA)

But what's really dank is...

Most excellent!

However, what about transferring info via FTL darkness?

Perhaps a dark ansible maybe?

Hi John.

No, I was not thinking of wormholes or 'dark tachyons' here, but your "Lets just pull back from the CMB a little and rethink this." made me think...

In the 'old' Einstein-de Sitter model, where a closed universe would eventually have contracted, we could perhaps have viewed the 'outside', the 'hyperspace' into which the universe once expanded as the 'darkness'. During the contracting phase, wouldn't that 'darkness' have approached us at a speed greater than c?

Sending information that way? Never. Tunneling of darkness? Maybe.

Jorrie

If you rotate a laser beam (like a rotating lighthouse) across a vacuum, the beam will sweep transversely across the sky, at a faster and faster rate as the radius from the source increases. Presumably at some point it will be sweeping faster than the speed of light. The intervals between the beam sweeps are "darkness".

However, I don't think any communication can be conveyed faster than light this way, because each photon will take a long time to reach a distant destination, travelling exactly at the speed of light, no faster or slower. The sweep of the beam on the receiving end will lag behind the angle of the source, like a widening spiral. Thus the darkness can "communicate" no faster than the light itself.

Dear Jonmtkisco,

Individual photons will leave the source at the speed of light, c. At the same time, the photons will be imparted a tangential velocity proportional only to the source rotation rate - at the source. The tangential component does not increase for an individual photon regardless of its distance from the source (think of the difference between a spinning garden sprinkler and a spinning rope: The rope is attached to the spin axis, the water droplets are not. The tangential velocity of a point on the rope is a function of its distance from the spin axis; the tangential velocity of the the water droplets are not a function of distance at all, but retain whatever tangential velocity they had at the outset. Once launched, a photon retains its initial radial (c) and tangential (t) velocities, which, by the way, do not sum to a velocity greater than c. But you already knew this.

-e

Hello e,

I agree that each photon travels in a straight line. But by the time each photon reaches a distant receiver, the angle of the source will have rotated considerably forward from the angle of the photon beam currently being received.

Since each photon has no tranverse movement, there is no need to sum two speed vectors.

At a great enough distance, the "apparent" transverse speed of the beam can exceed the speed of light. Even though each photon travels only at the speed of light, and no information can be conveyed to the receiver any faster than that.

Since each photon has no transverse movement, there is no need to sum two speed vectors.

As the source is rotating, why does the photon not have a transverse component? It most certainly does!

Certain neutron stars - pulsars - are good examples of stellar rotating "lighthouses." Infalling matter (often the case when the neutron star is part of a tight binary system) forms a hotspot on the pulsar's surface, producing an intense, highly localized xray emission. As neutron stars often have considerable angular velocity (the fastest known "millisecond pulsar," PSR J1748-2446ad, has a rotational period of 1.397 milliseconds, ie 716 rev/sec, ie 42,949 RPM), they produce a sweeping beam whose photons have a significant tangential component. As PSR J1748-2446ad has a diameter somewhat less than 20 miles (any larger than this and the pulsar would fly apart), its surface has a tangential velocity of nearly 40% of the speed of light. You can bet xray photons emitted from this baby have a hefty tangential component.

At some distance from the pulsar, the shape of the beam is a tightly-wound spiral, but not because the photons have a large tangential component, but because they travel some distance - about 260 miles in the case of PSR J1748-2446ad - before the source again swings into view. The tangential component simply alters the apparent angle of emission from the source. That is all. It does not contribute to the overall spiral shape of the beam. Even the lowly garden sprinkler produces a spiral pattern, and for the same reason.

Hi -e.

"As the source is rotating, why does the photon not have a transverse component? It most certainly does!"

I think Jon and you simply have different definitions for 'transverse velocity', that's all.

In the frame of a static source, each photon has only radial velocity. In the frame of a rotating source, each photon may have radial and transverse velocity components. In the case of a receiver, it depends on how its coordinate system is oriented in space.

Jorrie

Yes. But in no case does the beam behave like a length of rope with one end attached to the spin axis. You know it, and I know it, but...?

Like a Pulsar, perhaps?

Yep. Like the pulsar in #39.

Everyone seems to be locked into a three Dimension Universe. The what if's doesn't really matter if one can step across boundaries faster then light, then back again just to see it turn off.

Jorrie,

I don't see how its possible, I look forward to reading your idea.

Roger

Hi Roger.

I've grown impatient and posted my idea in what is commonly known down here as an attack of 'spring fever'. See edit to my original Blog entry above.

Jorrie

Hi Jorrie,

It seems that if you switched off a flashlight, the darkness would progress at precisely c, as others have said. Judging by this thread, the darkness penetrates more than the light though! I can't wait to see what you had in mind.

S

Hi S.

"It seems that if you switched off a flashlight, the darkness would progress at precisely c,..."

A good definition of the 'speed of darkness', but the conclusion is debatable!

Jorrie

What are you possibly thinking of? That the Universe is expanding faster than the photons from some piddly bit of matter at its 4-D 'center' can travel 'outward?' Perhaps thinking that this superluminal expansion is equivalent to darkness - as if darkness were some kind of stuff which itself can change position, have a velocity, etc. - moving outward faster than light can catch up with it?

Jorrie, for shame!

Hi -e, I'm guessing that your

"What are you possibly thinking of? That the Universe is expanding faster than the photons from some piddly bit of matter at its 4-D 'center' can travel 'outward? ...'"

is in reply to my

"In the 'old' Einstein-de Sitter model, where a closed universe would eventually have contracted, we could perhaps have viewed the 'outside', the 'hyperspace' into which the universe once expanded as the 'darkness'. During the contracting phase, wouldn't that 'darkness' have approached us at a speed greater than c?" (Emphasis added).

Yep, it was a bit of 4-d gamesmanship. In the present ΛCDM model, this could not happen of course (apparently, no contraction, not even for a closed geometry).

Also, I agree that we should rather leave other dimensions out of the thought experiment.

Jorrie

Also, I agree that we should rather leave other dimensions out of the thought experiment.

-----

Awww!

Actually, Jorrie, I've been wondering all along if this had something to do with superluminal expansion (you have been spouting a bit about this of late, non?), but I just couldn't bring myself to think that you'd actually try to pull something like this off. Scurrilous knave!

Hi again -e.

"... but I just couldn't bring myself to think that you'd actually try to pull something like this off. Scurrilous knave! "

How about a little bet: a 'Texas-sized rib-eye' if I pull it off in a down-to-earth way against a 'Blue-Bull steak' if I can't?

We may perhaps determine the odds beforehand: a Blue-Bull steak weighs in at around 1.5 kg. What's the mass of a Texas-sized rib-eye?

Jorrie

Hi to all of you... Back to work after some holidays... (ouf......)

We consider darkness as the absence of light... Darkness is what follows a photon during its travel... Obviously darkness has the same "speed" as the light because "darkness follows the light"... So I don't get your claim, Jorrie... Is it a matter of definition of the "darkness"... What do you consider as "darkness"???...

But, afterall, it was a time in the history of Universe that "darkness" was travelling faster than light... It was the phase of INFLATION... During this very sort period of inflation space-time was expanding much faster than the speed of light...

Welcome back, George.

"What do you consider as "darkness"???..." Part of the fun is to define it...

"... During this very sort period of inflation space-time was expanding much faster than the speed of light..."

Space-time that expands is as slippery a concept as darkness. Actually, it's only the space part that's expanding and to say it is expanding faster than light is problematic, because it differs according to what scale you observe.

Even today, the physical distance to the most distant galaxies (if one could view them all at the same instant, which you can't) are changing at a rate far exceeding c. But does this mean space is expanding faster than light?

Jorrie

Hi, Jorrie...

During inflation the increment of the size of the universe was so extremely fast that different areas (of the universe) was "isolated" from each other, meaning that it was impossible to interact each other as the increment of the space was faster than the speed of light... If an imaginary observer could "observe" the inflation sitting somewhere in the imaginary "hyperspace" (where the creation of the universe took place) he would see such a thing... (it's a philosophical concept I suppose...)

Hi again George. "During inflation the increment of the size of the universe was so extremely fast that different areas (of the universe) was "isolated" from each other,...

I guess you are aware that inflation theory was invented to solve this 'horizon problem', not to create it!

If there was no inflation the cosmology equations (even today's), when wound back in time, would have the same expansion rate at time t=10^-32 seconds as what the inflation scenario predicts (actually, I think it was more likely 'tuned to predict').

Inflation solved the horizon problem by allowing the expansion rate to be very slow before t=10^-34 seconds or so, which allowed all areas to causally connect. Then vacuum inflation surged the expansion rate enormously in just about no time at all. When inflation stopped, at t=10^-32 seconds, two particles, one where we are today and another that is today near the horizon of the observable universe, would have separated at a rate around 10²⁴c.

Those same two particles today separate at about 3c, plus any peculiar relative velocity vector that they may have through space (which must have a modulus of less than c). So is that the rate at which 'space expands' or has 'expanded'? I do not think so, because particles in regions outside of our observable horizon must today be moving away even faster than 3c. Given that the size of the universe may be infinite, where does that leave the 'speed of expansion'? Infinite?

Jorrie

"Given that the size of the universe may be infinite, where does that leave the 'speed of expansion'? Infinite?"

If the universe is closed, then it is not infinite. In that case the 'space' outside of the universe could be called 'outer darkness' (a Biblical term). Most of that 'space' would not have any speed except the part that is being 'forced out' by the expanding universe, so that part would be about 3c if I understood you right.

Hi S.

"Most of that 'space' would not have any speed except the part that is being 'forced out' by the expanding universe, so that part would be about 3c if I understood you right."

It's only the present observable 'horizon population' that is moving away from us at ~3c, not the 'edge' of the universe.

There should be many more systems outside of that horizon. If we take the universe as closed and on the upper limit of the present uncertainty of Ω (1.02±0.02), the total universe is a hypersphere with radius of curvature ~ 1/(1.04-1) x 46/Π ~ 366 Gly, increasing at a rate of ~25 lightyear/year.

The hypersphere is expanding into a fictitious extra dimension, so if you want to call that 'darkness', it is receding from us at 25c. If Ω=1.02, then the rate would be double that and if Ω=1.0, it's infinite. It is however totally useless to us...

Jorrie

Send me a private email and I'll give you my shipping address.

In order for "speed of darkness" to be meaningful, it should mean something more than just the boundary where the moving "rope" of a photon stream begins and ends begins and ends of its own accord. By definition, as people have pointed out, that boundary will have exactly the same velocity characteristics as the photons of the rope have.

It seems to me that the same point applies in a rapidly expanding or (theoretically) contracting universe. Expansion/contraction each adds the same apparent "acceleration" to the velocity of a distant photon as it adds to an empty point in the vacuum immediately adjacent to that photon. So light and "darkness" are equally affected.

Maybe a better answer is the expansion horizon. As expansion continues to accelerate in the future, at some point in time the horizon will appear (from our vantage point) to move towards us at a rate faster than the speed of light. In a sense, the horizon is the ultimate form of darkness, because we can't see anything at all beyond it.

I recall reading somewhere that the horizon will not appear dark to us, instead it will forever preserve a "frozen" image of each light source as it looked exactly when the horizon reached it. I don't understand how that could be so, because even a frozen image would require an endless stream of photons coming from some source.

Hi Jon.

"I recall reading somewhere that the horizon will not appear dark to us, instead it will forever preserve a "frozen" image of each light source as it looked exactly when the horizon reached it. I don't understand how that could be so, because even a frozen image would require an endless stream of photons coming from some source."

This sounds quite bizarre, I agree. I can only guess that it is said because our observability horizon is the CMB and it looks the same over time, as if frozen. Anyway, the observability horizon is not a good candidate for measuring the speed of darkness, I think.

Jorrie

The subjectively "perceived" speed of darkness can be nearly infinite. Just close your eyes, and in milliseconds there will be darkness where formerly there was an entire observable universe. You may still see "floaters", however.

Supposedly there is no "absolute" or "objective" frame of reference in the universe, but recently I've noticed that directional coordinates are being based on the feature "map" of CMB, which is treated as if it's "standing still" while everything else is considered to be moving. For example, in describing the peculiar velocities of galaxies and superclusters.

The CMB is very isotropic and homogeneous. As far as I know, there is no point in the CMB background where the measured radiation is even close to zero. Therefore, there is no direction in which one can look into the sky to find true "darkness". (Assuming we're not limiting the discussion to visible wavelengths.) For that matter, every cubic meter of vacuum in the universe contains CMB radiation, so there isn't a single truly dark place in the universe. Vacuum space also is subject to quantum fluctuations, which could spontanteously release photons. Black holes could be considered to be "dark" places, except now even their event horizons are supposed to emit Hawking radiation. If you're (hypothetically) inside a black hole, it doesn't seem like it would be dark either, because there's lots of radiation in there to keep you company.

So true darkness might have existed only before before radiation first appeared in the universe. I suppose one could attribute that condition to the inflation epoch before the Higgs Field first contributed mass to virtual particles. Without mass, you can't have "real" radiation, only the virtual kind. If inflation = darkness, then its speed was astronomically high.

Hi Jon,

You said "The CMB is very isotropic and homogeneous. As far as I know, there is no point in the CMB background where the measured radiation is even close to zero. Therefore, there is no direction in which one can look into the sky to find true "darkness".

I'm just wondering how the UN-homogenous finding here correlates with your statement: "We already knew there was something different about this spot in the sky," [Lawrence] Rudnick said. The region had been dubbed the "WMAP Cold Spot," because it stood out in a map of the Cosmic Microwave Background (CMB) radiation made by the Wilkinson Microwave Anisotopy Probe (WMAP) satellite, launched by NASA in 2001.

Thanks,

-John

Hi JohnJohn. You can call me JonJon.

I'm no expert, but as I understand it, the variations in radiation density between the brightest and darkest points of the CMB are only 1/1000th the magnitude of the CMB itself. Those pretty pictures of they make of the CMB with its network of colored filaments are intentionally greatly exaggerated to highlight the anisotropies.

The so-called "cold spot" of the CMB is only teeny-weenie bit colder than the CMB's average. But those tiny variations from 380,000 years after the BB have subsequently consolidated into the major structures of the universe, such as superclusters, filaments, walls, and voids, including the huge one they recently observed. So they are really important.

Thanks JonJon,

Sorry about my last post. After I reread it I realized that I made it sound like you said "We already knew there was something different about this spot in the sky," [Lawrence] Rudnick said....", instead of making it clear that the quote was from the article.

Careless of me.

-John

Darkness has the ability to accelerate from a zero velocity too C in zero time (must stay in-front of the light). Therefore if capable of accelerating that fast it should be capable of speeds faster than C.

How to use it in communication? It is already used otherwise the signal would be DC.

Hi Hendrick,

You said "Darkness has the ability to accelerate from a zero velocity too C in zero time (must stay in-front of the light)."

I disagree. Darkness only dissipates as the light overtakes it, hence it dissipates at precisely c. (I believe europium may have already pointed this out).

-John

OK OK!

I appreciate all the comments that have been put forth on this subject. But to get to the real answer I feel we must all start to think out side the box.

Prior to Dr Einstein's theorys of relativity there were gatherings of the great scientists where theories were put forth and experiments proposed, and refuted. A lot of very creative thinking took place. Much of which was devoted to attempting to use existing knowledge to solve the basic issues. I think this lead to Einstein's thinking out side the existing BOX. And hence the theory of Relativity.....

Should we presume to believe that there was even photons or darkness prior to the BIG BANG ?????

Should we believe that our 3 or 4 dimentional view of the universe will answer the questions ??????

I know it is hard and the answer won't come easy but I feel that we must think outside the BOX on this one.

Get outside of the Galileian, Newtonian, even the Einsteinian views. Your name could be on the next big relolation...............

Pacesetter

Don't forget about String Theory

I'm a frayed knot.

I have one simple question. If something, say a fermione or boson, were traveling faster than the speed of light, then wouldn't it be traveling at a speed of darkness? So anything which travels at greater than the speed of light would be traveling at the speed of darkness. Therefore, the speed of darkness is simply greater than the speed of light.

Now for the interesting question. If I were traveling at greater than the speed of light, and saw that superluminous boson, which looked dark to me when I was traveling at less than the speed of light, would it appear as light to me or dark?

Hi guest, you asked: "If something, say a fermione or boson, were traveling faster than the speed of light, then wouldn't it be traveling at a speed of darkness?"

Hypothetical things travelling at faster than the speed of light is called 'tachyons'. Bosons and fermions can't. But if tachyons exist, why would they need to be dark?

We know that when super-fast particles enter a medium where the speed of light is lower than their entry speed, they lose that excess speed by giving off Cherenkov radiation that we can see.

Jorrie

"Hypothetical things travelling at faster than the speed of light is called 'tachyons'. Bosons and fermions can't. But if tachyons exist, why would they need to be dark?"

to an observer standing still or at least slower than the tachyon by a rate greater than c, then the observer would not witness luminosity. Even if the tachyon emitted light, it would always be ahead of its own light by t (v>c). Theoretically, if it doesn't produce luminosity in any given single frame of time, then it would not ever produce luminosity unless it slowed down to the speed of light. A tachyon could not produce luminosity in a specific space and time which it had already passed because it is no longer in that specific space and time. Thus, even if only in theory, the speed of darkness (assuming a particle's speed and not just absence of light) would exceed the speed of light. The greater the velocity, the greater the energy. Imagine 93%, or whatever the number actually is, of the universe being dark energy, (tachyons) which would not produce luminosity, yet have incredibly high energy? We would not see them. We are not able to detect them (yet), yet they would certainly have more than enough energy to hold galaxies together, ( and they probably would not equal close to the 93% theorized).

If it has been absolutely proven that fermions and bosons cannot achieve superluminous velocities, then there MUST be a smaller particle inside them and they are not truly elemental.

hi David.

Have you read the Wikipedia article on Tachyons? It's comprehensive and pretty authoritative, IMO.

Not only do hypothetical tachyons have an imaginary time frame, they have imaginary mass as well. They are hence not well suited as the 'missing mass' of the cosmos. Their imaginary time may perhaps make them represent 'darkness', I guess. It has however been theoretically proved that they are useless in transmitting information faster than light. That's only possible in SciFi...

Jorrie

So maybe dark energy is simply bosons (or something) traveling at greater than the speed of light.

And if this boson is light to me when I travel at greater than the speed of light, then most of the universe would appear as light, not dark, if viewed from a superluminous velocity. Then maybe Heaven is simply the next three dimensions which occur at greater than the speed of light. That would physically explain how heaven is "bright light", yet all we see when we look up is mostly darkness. hmmmm.

sorry, forgot to log in on the last post.

David A Rheault

There once was a lady named "Bright"

Who could travel much faster than light

She set out one day

In a relative way

And came back the previous night.

hey, Have you heard about that physicist who is building a machine which he believes can send messages back to the past because it will accelerate particles past the speed of light? He is serious. He really thinks that as soon as he gets it working, out will come messages from the future that he will send to himself later. they even had a show about it on the science channel.

Winning lottery tickets will become worthless once everyone else gets one!

btw, Now I have an idea of your age 'cause you are starting to repeat yourself. You quoted that limerick to me about 8 months ago.

ya know, it really sucks being an idiot who remembers absolutely everything.

I don't recall posting either one. hehe

They say your memory is one of the first 3 things to go when you get old.................I don't remember the other 2.

HTRN

for those with young'ens, here's a good site, tho ya might need a fast connections for the short clips. http://www.space.com/

Very interesting analogy Jorrie.

I can't see what would cause photons on the trailing edge to be lost. Would the pulse passing by a massive object cause photons to be lost? Furthermore, even if this occurs, I don't see any way to control how much of the trailing edge could be jettisoned (so to speak).

If you could somehow control this, then it looks a little bit like the "Morse code" I mentioned in an earlier post.

By changing the medium through which the pulse is traveling, the first thing to slow down is the wave front, right? If so, does the trailing edge slow down at precisely the same time as the wave front? If it does not, then we've accomplished the same thing as your analogy, i.e., the tail end (dark) is moving faster than the front (briefly). I suppose I'm asking if there's any elasticity to the pulse.

Come to think of it, if you shine the pulse through a prism, the light will be "turned" 90º but "dark" apparently keeps going straight. Therefore we can say that dark is unaffected by a prism. But then, if we look at the prism perpendicular to the exiting pulse we would not see the dark, so I don't see how this could be used for information transfer. Maybe I'm just off the deep end with this line of thought?

-John

One prosaic way to 'lose' photons would simply be to chop the end of the pulse with a shutter which closes some time after the leading edge passes on through.

So let's take this scenario to the limit: we lose all the photons along the way, ie, the darkness following the trailing edge overtakes the leading edge and we have a "pulse of darkness" (a moving concept with a superluminal 'leading edge,' no less) which arrives at a suitable detector before the first photon might have had it not stopped for coffee.

This reminds me of a SciFi short I read years ago called, "It's Nothing, Really," where the protagonist notices that paper commonly tears somewhere other than at the perforation. Observing that something (nothing, really) must be filling the perforations to make them stronger, he then proceeds to construct sheets of infinitely strong material having zero thickness and zero mass by perforating sheets of paper until no paper remains.

Hello e,

I think I see a problem with Jorrie's bullet train analogy. The train is propelled by the locomotive, thus when a trailing car drops off, the last car (dark) has instantly jumped forward by the length of the last car, and the remaining cars keep on truckin' (I got that). However, in the case of a light pulse, the wave front is being propelled by the light source, i.e., from behind.

Now, if we close a shutter as you say, the photons that are ahead of the shutter have lost all propulsion energy and there is only "dark". So what happens to the leading photons when the shutter closes?

When we re-open the shutter the "last car" now becomes the new wave front since it has propulsive energy (from the source).

Shutter open: photons rule, shutter closed: dark rules.

-John

Hi John.

"However, in the case of a light pulse, the wave front is being propelled by the light source, i.e., from behind." ????

These critters (photons) do not need propulsion, as I'm sure you know. When Eu's shutter cuts off the 'tail' end of the wave train, the front part just steams on at c (in free space anyway).

How can the 'tail end Charlies' be lost, apart from being shuttered? Possibly a change of medium, passing close to a black hole (perhaps) and probably some other novel ways that I can't think of now. To be sure, I do not know why this happens. Maybe the optics forum guys can help?

When the 'vacuum' wave train enters an optically denser medium (say glass), the tail end indeed catches up on the wave front a bit (as you said above), only to lose that advantage when leaving the glass again. Some photons are 'lost' inside the glass (actually, they hide there as energy).

Jorrie

Hi Eu.

"So let's take this scenario to the limit: we lose all the photons along the way, ie, the darkness following the trailing edge overtakes the leading edge and we have a "pulse of darkness"" (I really like this one!)

It's easy to show how to send information faster than the speed of the train (the real train) by using only the train. It's not quite by 'losing the whole train', but like this:

I sit on the platform while the train is steaming by. When the train has just passed me, I trigger a mechanism on the track that disconnects the rear half of the train. You are at the next station and observe the time of the rear end of the train. That signal (the fact that I triggered the mechanism) arrives at you faster than the speed of the train.

Now, using a pulse of photons, what type of shutter can I operate to 'disconnect the rear half of the pulse' after it has passed me, without having a 'speed of light delay' between my action and the shutter's reaction?

This 'subluminal' portion of the setup is the main 'fly in my ointment' and must be overcome; then we'll be in the pound seats.

Jorrie

Jorrie,

"This 'subluminal' portion of the setup is the main 'fly in my ointment' and must be overcome; then we'll be in the pound seats."

Fun as it may be, I think you are just wasting your time. Have you read this very comprehensive debunking of faster than light communication?

http://www.public.asu.edu/~strato/Internet/Faster%20than%20light%20A.%20Fettweis.pdf

Since it is so full of math, I have extracted only Fettweis's conclusions. Here it is:

6. Conclusions

We have shown by mathematical analysis that if a signal is transmitted through a waveguide arrangement, also if this involves transmission in the stopband (thus by means of evanescent modes, or else, by tunneling), the information carried by the signal can, under no circumstance whatsoever, be propagated with a speed exceeding that of light.

Any claims to the contrary such as those published in the professional literature and in public media are therefore invalid. The error in such claims is due to a wrong interpretation of what information delay actually is and how it relates to the signal itself. Published experimental results involving a Mozart symphony do not address the crucial issue, i.e., of showing that symphony to become audible at the destination sooner (by whatever small amount) than if it had been transmitted by light.

It is true that a correct experiment of that type cannot be carried out in practice because the delays encountered are far too small. One could think however of making similar experiments by using classical lumped-parameter high-pass 4lters. There is no doubt that such experiments, if properly carried out, would conform the results presented here.

-SL

Hi Scruffy, you wrote:

"Fun as it may be, I think you are just wasting your time. Have you read this very comprehensive debunking of faster than light communication?"

Yea, I've read (or rather scanned) that article and must 'reluctantly' agree. But then, just about everybody thought Einstein was wasting his time too...

Jorrie

I think what you are describing is really not violating the speed of light. When you think of a chain of photons, they all move at the same speed. If one of those photons on the trailing edge is picked off the chain, the trailing edge is just redefined as the next photon in line.

So, the trailing edge is just arbitrary and represents something intangible. It is just a pointer to some position in the chain.

Think of it in reverse. Suppose you pick off the leading edge photons one by one. Then the chain appears to move slower than C, but in reality each photon moves at C. Some photons just don't travel as far.

Hi Hero, nice to hear from you again.

"I think what you are describing is really not violating the speed of light."

Of course - nothing moves faster than light, because "It's Nothing, Really".

As Eu has pointed out, in the limit it can 'move' infinitely fast...

Jorrie

I think we only had two 'real' definitions of the speed of darkness so far: Eu's #2 and my edit of the OP. Here's another one to tickle your imagination and perhaps bend your brain...

Take a large hollow non-transparent sphere with a point source of light at its center. Install another hollow non-transparent sphere, much smaller than the outer one, concentrically and so that it can rotate around one axis. In this inner sphere, cut two slits next to each other and perpendicular to its 'equator' (the plane normal to its spin axis).

You now have a variant of the classical two-slit interference of light experiment. With a static inner sphere, there should be a pattern of bright and dark lines projected onto some area of the outer sphere's inside surface. Now rotate the inner sphere fast enough and you should find that the speed of the now rotating bright and the dark lines exceed the speed of light relative to the outer sphere's surface.

All you need to do is to measure one dark line's time to 'circumnavigate' the inner surface of the outer sphere. If the angular rate of the inner sphere is constant, the angular rate of that dark line should be the same, just phase shifted. It is easy to determine the required angular velocity (ω) of the inner sphere to make the dark line travel at v ≥ c, i.e. ω ≥ c/r_o rad/s, where r_o is the radius of the outer sphere and c the speed of light in free space.

If the experiment works, is this proof that the speed of darkness can exceed the speed of light in free space?

Jorrie

It doesn't seem like it would work, Jorrie. Since the front of the wavefront cannot exceed the speed of light, even allowing the back of the pulse to speed relatively toward the front it can do no more than catch up, as a limit, at which point the event is destroyed, yes?

The only speed advantage would seem to be one relative between the leading and trailing edges of the pulse. Since no object could be present at the leading edge to receive the pulse then the speeded up event has no way of being detected.

However, is it necessary to define it in terms of only a pulse (of light)? Were you to interrupt a continuous beam in order to superimpose a signal as an accelerated pulse or front of darkness then it would be just a matter of figuring out how to create the progressive "decoupling" at the dark front, no?

Hi rcapper.

"Since the front of the wavefront cannot exceed the speed of light, even allowing the back of the pulse to speed relatively toward the front it can do no more than catch up, as a limit, at which point the event is destroyed, yes?"

Europium has pointed out that if you destroy the event, then the darkness travels on at some superluminal speed...

"Were you to interrupt a continuous beam in order to superimpose a signal as an accelerated pulse or front of darkness then it would be just a matter of figuring out how to create the progressive "decoupling" at the dark front, no?"

Yep, this would work, if one can somehow control how the 'tail end photons get lost' en-route.

Jorrie

"if you destroy the event, then the darkness travels on at some superluminal speed..."

Once the event is destroyed nothing defines the dark front, presumably as differing from the background of darkness? So, then, how can we consider that it would travel anywhere. Or by that definition we could arbitrarily establish that there are an infinite number of superluminal dark fronts propagating infinitely in darkness which seems meaningless. Without a means to differentiate the boundary it seems that no front can exist, no?

It seems that if the event is destroyed, then by definition, no event persists.