Where does light go in the dark?

[Cudzoziemiec]

Turn out a light, extinguish a candle; it goes dark immediately. So what happens to all the photons that were streaming out of it? Okay, so they're travelling at the speed of light(!) and they're out of range of your eyes in less time than your brain can process. But what if you're in a sealed, light-tight chamber? Where do the photons go then? Come to that, where do they come from in the first place? I don't think they exist. Not as a particle with physical presence, do they? Anyway, isn't light supposed to be a wave? So what is a photon?

[Kim]

They're absorbed by Stuff that isn't 100% reflective and impart energy.  Normally it just ends up as heat, but sometimes it causes interesting things to happen (eg. fluorescence, photoelectric effect, photosynthesis, whatever makes eyes work).

It's a wave and a particle depending on which way you look at it.  They're both Lies To Children, though.

[Jaded]

Turn out a light, extinguish a candle; it goes dark immediately. So what happens to all the photons that were streaming out of it? Okay, so they're travelling at the speed of light(!) and they're out of range of your eyes in less time than your brain can process. But what if you're in a sealed, light-tight chamber? Where do the photons go then? Come to that, where do they come from in the first place? I don't think they exist. Not as a particle with physical presence, do they? Anyway, isn't light supposed to be a wave? So what is a photon?

There’s no such thing as a sealed light-tight chamber.

The photons reach the side of the chamber, then as they pass through they are converted to Dark Photons.

[ian]

Well, if you leave the lights on all night, it's a fact that the room will overfill with photons and explode. Or so it seems might be the potential case when my wife chastises me for leaving a light on overnight.

Anyway, a photon isn't a thing, it's a quantum of electromagnetic force. Or is it? You can convert light (energy) into matter through pair production, the theory of which will, as a byproduct, melt your brain.

[Cudzoziemiec]

The photons reach the side of the chamber, then as they pass through they are converted to Dark Photons.

Photon recumbenteers!

[Kim]

Dark Photons.

These can be produced more conveniently with a Dark Emitting Diode.

[Cudzoziemiec]

Your answers are most en... tertaining.

[ian]

I think dark photons are an actual theoretical thing. Something to do with gauge field theories. Sadly, a deep knowledge of this doesn't impress women at parties. Tell me more, they never, ever demand. Unless they're particle physicist ladies, in which case, game on. Briefly, before your demonstrably limited knowledge of such matters results in a less than spectacular self-annihilation event.

Photons are their own antiparticle. You can slam them together and get electron-positron pairs and you've done your bit to create matter from energy. Admittedly, if it's tea time your effort might better be invested in making a loaf of bread.

[PaulF]

They hide until it gets light again. Probably behind that bicycle that appears to be standing up on its own.

In fact they’re probably what’s holding it up

[Croft]

Great scholars have considered this question:

Not excepting even the credulous Kraus (see his Do Selby's Leben), all the commentators have treated de Selby's disquisitions on night and sleep with considerable reserve. This is hardly to be wondered at since he held (a) that darkness was simply an accretion of 'black air', i.e., a staining of the atmosphere due to volcanic eruptions too fine to be seen with the naked eye and also to certain 'regrettable' industrial activities involving coal-tar by-products and vegetable dyes; and (b) that sleep was simply a succession of fainting-fits brought on by semi-asphyxiation due to (a). Hatchjaw brings forward his rather facile and ever-ready theory of forgery, pointing to certain unfamiliar syntactical constructions in the first part of the third so called 'prosecanto' in Golden Hours. He does not, however, suggest that there is anything spurious in de Selby's equally damaging rhodomontade in the Layman's Atlas where he inveighs savagely against 'the insanitary conditions prevailing everywhere after six o'clock' and makes the famous gaffe that death is merely 'the collapse of the heart from the strain of a lifetime of fits and fainting'. Bassett (in Lux Mundi) has gone to considerable pains to establish the date of these passages and shows that de Selby was hors de combat from his long-standing gall-bladder disorders at least immediately before the passages were composed. One cannot lightly set aside Bassett's formidable table of dates and his corroborative extracts from contemporary newspapers which treat of an unnamed 'elderly man' being assisted into private houses after having fits in the street. For those who wish to hold the balance for themselves, Henderson's Hatchjaw and Bassett is not unuseful. Kraus, usually unscientific and unreliable, is worth reading on this point. (Leben, pp. 17-37.)

As in many other of de Selby's concepts, it is difficult to get to grips with his process of reasoning or to refute his curious conclusions. The 'volcanic eruptions', which we may for convenience compare to the infra-visual activity of such substances as radium, take place usually in the 'evening' are stimulated by the smoke and industrial combustions of the 'day' and are intensified in certain places which may, for the want of a better term, be called 'dark places'. One difficulty is precisely this question of terms. A 'dark place' is dark merely because it is a place where darkness 'germinates' and 'evening' is a time of twilight merely because the 'day' deteriorates owing to the stimulating effect of smuts on the volcanic processes. De Selby makes no attempt to explain why a 'dark place' such as a cellar need be dark and does not define the atmospheric, physical or mineral conditions which must prevail uniformly in all such places if the theory is to stand. The 'only straw offered', to use Bassett's wry phrase, is the statement that 'black air' is highly combustible, enormous masses of it being instantly consumed by the smallest flame, even an electrical luminance isolated in a vacuum. 'This,' Bassett observes, 'seems to be an attempt to protect the theory from the shock it can be dealt by simply striking matches and may be taken as the final proof that the great brain was out of gear.'

A significant feature of the matter is the absence of any authoritative record of those experiments with which de Selby always sought to support his ideas. It is true that Kraus (ace below) gives a forty-page account of certain experiments, mostly concerned with attempts to bottle quantities of 'night' and endless sessions in locked and shuttered bedrooms from which bursts of loud hammering could be heard. He explains that the bottling operations were carried out with bottles which were, 'for obvious reasons', made of black glass. Opaque porcelain jars are also stated to have been used ,with some success'. To use the frigid words of Bassett, such information, it is to be feared, makes little contribution to serious deselbiana (sic).' Very little is known of Kraus or his life. A brief biographical note appears in the obsolete Bibliographie de de Selby. He is stated to have been born in Ahrensburg, near Hamburg, and to have worked as a young man in the office of his father, who had extensive jam interests in North Germany. He is said to have disappeared completely from human ken after Hatchjaw had been arrested in a Sheephaven hotel following the unmasking of the de Selby letter scandal by The Times, which made scathing references to Kraus's 'discreditable' machinations in Hamburg and clearly suggested his complicity. If it is remembered that these events occurred in the fateful June when the County Album was beginning to appear in fortnightly parts, the significance of the whole affair becomes apparent. The subsequent exoneration of Hatchjaw served only to throw further suspicion on the shadowy Kraus.

Recent research has not thrown much light on Kraus's identity or his ultimate fate. Bassett's posthumous Recollections contains the interesting suggestion that Kraus did not exist at all, the name being one of the pseudonyms adopted by the egregious du Garbandier to further his 'campaign of calumny'. The Leben, however, seems too friendly In tone to encourage such a speculation.

Du Garbandier himself, possibly pretending to confuse the characteristics of the English and French languages, persistently uses 'black hair' for 'black air', and makes extremely elaborate fun of the raven-headed lady of the skies who deluged the world with her tresses every night when retiring. The wisest course on this question is probably that taken by the little known Swiss writer, Le Clerque. 'This matter,' he says, 'is outside the true province of the conscientious commentator inasmuch as being unable to say aught that is charitable or useful, he must preserve silence.'

[ian]

Maybe we are asking the wrong question. Not where does light go, but from where does darkness come?

[Diver300]

“Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it.”

[PaulF]

Maybe we are asking the wrong question. Not where does light go, but from where does darkness come?

When the light hides it goes into the spaces where the darkness was and pushes it out.

[Aunt Maud]

It comes from the other side of a blackhole, of course.

[Mr Larrington]

I think dark photons are an actual theoretical thing. Something to do with gauge field theories. Sadly, a deep knowledge of this doesn't impress women at parties. Tell me more, they never, ever demand. Unless they're particle physicist ladies, in which case, game on. Briefly, before your demonstrably limited knowledge of such matters results in a less than spectacular self-annihilation event.

In the most recent Stuart MacBride novel, Tufty and PC Macintosh appear to be on the same wavelength ha ha vis-à-vis gravity and so forth.  Sadly the book ends before we discover whether they end up taking it any further.

[Asterix, the former Gaul.]

Light is universal.  Whilst you might think you are switching light on, in fact what you do is switch darkness off.

Obviously darkness is the opposite of light and so is in fact extremely heavy so as soon as it is switched off it falls to the ground instantly.  You can tell this because the ground always tends to be darker than the sky in daytime. 

[IanN]

I'm not so sure. Given that a photon exerts a force by virtue of its momentum (mv), and light observably pushes back the Dark,  if the mass of Dark is very high, the speed of Dark must be proportionally lower.  The OP observes that the speed of Dark is very high.

(on the interaction of Dark with matter, can we assume it follows a straight line in curved spacetime around a mass? Or does it have to be dark matter?)

[Cudzoziemiec]

Maybe we are asking the wrong question. Not where does light go, but from where does darkness come?

I'm asking the questions here! You're answering them – or leading our thoughts tidily towards the answers. And surely this is your specialist subject, what with you being so pally with Finistere and all those other princes and princesses of darkness?
All bow down before ian, Prince of the Anti-Photon!

Meanwhile, thanks to Kim for an actual answer. I think.

[Cunobelin]

I think we have solved the problem of night visibility

Car and bicycle  light emissions are absorbed by bicycles and cyclists rendering them neutral

This is why no matter how brightly you are lit and how much HiViz you wear motorists cannot see you

[ScumOfTheRoad]

Turn out a light, extinguish a candle; it goes dark immediately. So what happens to all the photons that were streaming out of it? Okay, so they're travelling at the speed of light(!) and they're out of range of your eyes in less time than your brain can process. But what if you're in a sealed, light-tight chamber? Where do the photons go then? Come to that, where do they come from in the first place? I don't think they exist. Not as a particle with physical presence, do they? Anyway, isn't light supposed to be a wave? So what is a photon?

Kim gave you a good answer.
I have a PhD in elementary particle physics, but its a long time ago and I probably can't add anything relevant here.
Rgarding waves and photons, the concept is 'wave particle duality'.  We have the constructs in classical physics of particles, which are point like (or very small) concentrations of matter.  Waves are disturbances in a field which carry energy.
At the quantum level, photons can be thought of as both particles and waves, depending on how you observe them.

The canonical example here is the double slit experiment.  If you pass waves through a pair of slits, on the other side you get an interference pattern, like ripples on water.
If you take your light-tight room, and arrange a light source which is so faint it emits one photon at a time, then if you allow that photon to aim at a double slit...
there is an interference pattern produced on the other side.
Quantum physics is very spooky (pun on Einsteins 'spooky action at a distance' fully intended) Seriously. It is. What this experiment is saying is that even though there is one particle it somehow 'knows' there are two slits.
In my mind, the mechanism is the probability wave function. Point-like particles do not exist at the quantum level. What we have are little balls of energy, which have wave function associated with them (or maybe they are the wave function). The wave function tells you the probability that the blob of energy is in a particular location.
So that is how the double slits are seen - there is a probability that the wave function goes through the other slit.

Similarly, look at quantum tunneling semiconductor devices. Real, live devices which are used every day depend on the action of electrons 'tunneling' through an energy barrier which in classical terms they cannot.  'Tunneling' here really means whoops - one moment the electron is on one side, the next moment - it is on the other. Or a combination of both (Schrodingers cat grin here). But 'is' is very blurry. Remember point like particles dont really exist - there is a wave function, which can exist across that narrow barrier. So the electron can pop up on the other side.


The real answer is that particles and waves are mathematical constructs which make sense of how the world works. You use the appropriate one depending on the energy levels and the scales at which you are looking.

[Cudzoziemiec]

Thank you, especially the last paragraph.

[mrcharly-YHT]

So what you are saying is, when you really really start poking at things, there are no particles, it's all waves.

We are all just a stream of consciousness just surfing the ocean of reality

[Asterix, the former Gaul.]

Turn out a light, extinguish a candle; it goes dark immediately. So what happens to all the photons that were streaming out of it? Okay, so they're travelling at the speed of light(!) and they're out of range of your eyes in less time than your brain can process. But what if you're in a sealed, light-tight chamber? Where do the photons go then? Come to that, where do they come from in the first place? I don't think they exist. Not as a particle with physical presence, do they? Anyway, isn't light supposed to be a wave? So what is a photon?

Kim gave you a good answer.
I have a PhD in elementary particle physics, but its a long time ago and I probably can't add anything relevant here.
Rgarding waves and photons, the concept is 'wave particle duality'.  We have the constructs in classical physics of particles, which are point like (or very small) concentrations of matter.  Waves are disturbances in a field which carry energy.
At the quantum level, photons can be thought of as both particles and waves, depending on how you observe them.

The canonical example here is the double slit experiment.  If you pass waves through a pair of slits, on the other side you get an interference pattern, like ripples on water.
If you take your light-tight room, and arrange a light source which is so faint it emits one photon at a time, then if you allow that photon to aim at a double slit...
there is an interference pattern produced on the other side.
Quantum physics is very spooky (pun on Einsteins 'spooky action at a distance' fully intended) Seriously. It is. What this experiment is saying is that even though there is one particle it somehow 'knows' there are two slits.
In my mind, the mechanism is the probability wave function. Point-like particles do not exist at the quantum level. What we have are little balls of energy, which have wave function associated with them (or maybe they are the wave function). The wave function tells you the probability that the blob of energy is in a particular location.
So that is how the double slits are seen - there is a probability that the wave function goes through the other slit.

Similarly, look at quantum tunneling semiconductor devices. Real, live devices which are used every day depend on the action of electrons 'tunneling' through an energy barrier which in classical terms they cannot.  'Tunneling' here really means whoops - one moment the electron is on one side, the next moment - it is on the other. Or a combination of both (Schrodingers cat grin here). But 'is' is very blurry. Remember point like particles dont really exist - there is a wave function, which can exist across that narrow barrier. So the electron can pop up on the other side.


The real answer is that particles and waves are mathematical constructs which make sense of how the world works. You use the appropriate one depending on the energy levels and the scales at which you are looking.

Ok, now can you solve the Irish Question?

[stu1102]

Interesting discussion

Light gives life as it underpins our own existence and earths existence, obviously the properties of light brightness, colour (Newtons prism experiments) , warmth and intensity we encounter daily inform our own existence.....brain hurts already reading the thread

[Ben T]

So the double slit experiment appears to suggest that light is a wave. What is there to suggest the contrary, that it's a particle? i.e. one could say it's not spooky at all because light is simply a wave.