Speed of light

There is such thing as the speed of light right? but is the such thing as speed of dark and how fast is it compared to light?

2 answers... and I may choose 2 of them!

"is there such thing as speed of dark" - Ive heard of Son of Dork

Is this supposed to be serious or not...I'm not sure. Being that there is no speed of dark considering that darkness is simply the absense of light.

I suppose you could argue that the light forces the darkness to move, which would make it the same speed as light ... but I wouldn't want to be the one trying to argue that perspective.

I'm not physicist, but I'm pretty sure there is no "force" involved in the transition from light to dark. It's simply an absense and is therefore instantaneous.

It's been a long time since I read anything on physics too, but I agree. I think the last person I heard using that line was confusing darkness with dark matter (which does have a speed, though I can't for the life of me remember what it is).

Well, technically, the speed of light is just the speed of dark. If you think about it, the dark has to move the equal amount of speed as the light moves to overcome it. Same goes visa versa. I would get in more depth, but I'm too tired at the moment.

Those are my thoughts though.

I read something somewhere about how light bulbs are 'dark absorbers' - they suck the dark out of a room, thus allowing it to be brighter. That's why it's dark when you cover it up - you're stopping the dark from getting in. And when they're full of darkness, they have to be replaced.

Terry Pratchett expands on the theory very well (The Science of Discworld).
Rave's started to touch on it but Dark is faster. Light takes a measurable time to get from A to B but the instant the light source is removed the dark is there, therefore speed of dark is faster than speed of light.
"As yet unmeasured, but believed to be faster than light owing to its ability to move so quickly out of lights way."

Well certainly the speed of light and the speed of darkness is the same. Thus because the entire room (in which you just switched off the light) ain't completely dark in the same instant.

If you measure on the surface of objects, there is still "light" arriving at the time, the bulb is already finished. Darkness pours in, at the same speed as light does (by the time you flick the switch once more). As the speed of light is beyond our receptive abilities, we usually do not perceive this phenomenon. One of the best comparisons is that of rain: By the time it starts raining at the location you are present (rain destination), the rain might have already stopped at it's origin (cloud). But personally you are perceiving that it IS raining right now.... (even though this moment is already history)

Light and Dark do depend on each other, there cannot be one without the other. No shadow without light as no light without a shadow. Without light/ dark we would not be able to make a difference, we would not distinct between one or the other. It is like Yin and Yang. But there are realms in which they are isolated, like in a black hole or within a star. In the former there is no light and in the latter there is no shadow.

However IMO the universe contains as much light as it contains darkness. Even though it appears as if the stars are less than the space around it, this doesn't matter. We (on earth or any other destination) are simply looking in one direction (i.e. "into" the sun). We can see the sun when looking at it - but even if there are clouds blocking our view, it's still there, shining (no, not the movie) - thus meaning that the particles and waves on which light travels are invisible, unless they are directly aimed at or reflected by an object back to us.

Whether or not the quality of darkness and light are the same is only a matter of perspective. When sitting in a completely isolated room with no light present, it might be depressing - but a single ray of light is able to illuminate (the soul). The reason that we are conditioned to light lies in the history and the conditioning by our ancestors. We greatly depend on light for navigation, but when looking at blind people, we notice that light is not the one and only foundation. Over all it simply doesn't matter whether there is (no) light. The only thing that matters is: How do you feel about it?
The entire question becomes more twisted, if one ponders about the spiritual values and qualities associated with the term "light" and "darkness". So far it has been potentially dangerous to associate "light" with "good" and "dark" with "bad" - as clearly seen in the exploitation and abuse of the "dark continent" and it's inhabitants...

Just if we're able to detach from the conditioning that derived from our ancestry, we will be able to see the true light - the one that is originating from inside of us, without any (polished) lamps or electricity companies (i.e. religions) who charge and keep us hostage for utilizing it.

I'm getting offtopic...

To close the loop: Light and dark usually depend on each other, yet they can exist in certain environments without one another - but when travelling they do this generally at the same speed.

i guess it depends on what you are refering to as the speed of darkness.. if you mean how long it takes for it to become dark after a light source is removed, then it is exectly equal to the speed of light. on the other hand, if you are refering to it on a much more localised and microscopic level (for this, lets assume a photon on impact 'disapears') the the speed of darkness would be equal to the time it takes for it to go from light to no-light; thus, the time it takes for a photon to be 'destroyed'

also tom... something interesting i *think* i learnt recently.. there is light within a black hole, we just cant observe it (thats assuming im getting the right jist of the book im reading)

... link/ quote your source

but certainly there is light at the end of the tunnel... in one of my ponderings upon black holes is came to me that they are just "the other end" of stars (in another dimension)... might not make too much sens(ej)

you can't observe it from the outside of the black hole because the light photons have mass and are pulled in (or rather prevented from leaving) by the gravitational field.

So there's an interesting question - light has mass but does dark???

Or, is dark simply "the absence of". Tom, I'd have said there was more dark than light in the universe or perhaps to be more precise there is more instances/"volume" of dark than light, but I'd agree that light has a greater effect on a person than dark. (Dark can have a very powerful effect on people too though).

But maybe that's a little off the topic of the speed...

And this was moved to chat..why?

There are posts that are more then 5 lines long.
Thus.. its a discussion!

'a star that was sufficiently massive and compact would have such a strong gravitational field that light could not escape: any light emitted from the surface of the star would be dragged back by the star's gravtiational attraction before it could get very far' - steven hawking - a brief history of time 10th aniversary edition

Well the thing is that in the universe there is no (complete) darkness. The only reason why space in between stars appears dark (or black) is that there is nothing that can reflect the particles back to us, or that the reflected light is so weak that we cannot perceive it with our (poor) eyes.

In short: the universe is full of light!

Look here:



This is a (closer) picture of the Orion nebula, taken by Hubble. So as we're looking to Orion with our (natural) eyes, we only see a couple of stars 2-D. There is no nebula - there are not even colours in the sky.

However, we perceive a picture - put into our minds for milleniae - a man with a belt. It's a conditioning. Because if we'd be looking at the Orion from the side, we'd see this:



The light is travelling from all places/ stars (that resemble Orion) at the same rate/ same speed. The stars themselves might not be in existence anymore (right now) but still we do receive their light. This I am saying as to explain my example what happens in a room after the bulb got switched off. Only if observed on the greatest scale one understands what happens on the smallest.

The question whether or not dark travels or merely absorbs (suck) light IMHO is an extension to the one question that keeps mankind busy since the dawn of time: What will prevail? Good (light) or evil (dark)?

Therefore we try to give them attributes, like "stronger" or "faster"...

But hey, I'm hijacking here and I really have no great idea about physics or metaphysics *returns to sad lurking mode and humms Satchmo's: it's a wonderful world"

Just check my vote on both: yes and no...

PS: Thanks Pete, Hawkins is a great guy. Always amazing.

[edited] please add some daftness and sprinkle some mad giggles here and there...

Gah, all this talk of Physics asstounds and confuses me. If we were talking philosophically I might be able to contribute more, but I dont think that's what this thread is about, so I'll shut up and pretend I know whats going on.

hmm, you may have lost me there, but definetlyi agree with you, on the whole 'light existance/non-existance' thing, depending on the position of the observer.. it is indeniable after all

there are too many variables and different points of view on this topic for me, so im just gona step back and watch

Was it Red Dwarf, Hitchikers Guide or some other sci-fi book which had ships that ran on bad news - the only thing faster than light?

I think it was Hitchhikers

And a wikkid concept!!

darkness doesn't exist so it can't have a speed.

Shadows are just the name we give to areas that have less light than somewhere else, it is not something that can exist in and of itself, therefore it can't have a speed.

If you sat in your room for an hour and nothing moved, how fast did if travel?

Same speed travelling... how could it be faster, if bad news is the only thing faster than light?

And same amount, because the universe works that way and is full of particle wavelengths that are just travelling in a different direction (so we can't see them).

Darkness is only the stuff around the light, filling the void.

phew, 5 line post, classified "chat" Aye, sirs

Darkess always happens before the light. Not really out of being faster but usually cus darkness sets off nice and early in the morning so its allready had a cup of tea by the time light gets there.

On the whole balance thing eventually light will be evrywhere, but at the moment darkness probbably fills most of the universe beyond the stars.

Poje, if you were billions of billions of light years into space far beyond where any light has yet reached from the stars and you looked around, you would see nothing. Not unless you yourself emit some sort f low level light source. It would be like being in a totaly dark room. (something very few people have experienced)

Genesis - "in the beginning was the void, and the void was without form or light"...

Dark is the void - the absence of light, but Tom is right that we may perceive an area of dark that actually has light particles passing through it if the light particles are travelling anywhere other than in a straight line to our point of view.

As for speed, there's always tachyons. From memory, they are one of the bits in a light particle and yet they are said to be faster than light. There are theories that say if you can seperate one Tachyon from it's partner tachyon and transport them trillions of miles/light years apart the tachyons are still in instant communication with each other somehow. Now that has got to be fast.

line 1: off topic but...how fast is something that is just sitting in your room?
line 2: well to be pedantic:
line 3: The earth's circumference (at the equator) is 25,000 miles and it rotates in 24 hours.so if you were to hang above the surface of the Earth at the equator without moving, you would see 25,000 miles pass by in 24 hours, at a speed of 25000/24 or just over 1000 miles per hour.
line 4: Earth is also moving around the Sun at about 67,000 miles per hour.
line 5: (not entirely my own words)