Where does light go in the dark?

[LittleWheelsandBig]

Because if you set up a detector that tells you which of the two slits an individual photon goes through, the interference pattern goes away and the results look like individual particles fired through two slits with no interference pattern (so, not a wave). I have always been astounded by that 'How does it know?' aspect, even though I understand that quantum stuff is something that I'll never actually understand.

[sojournermike]

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.
. But 'is' is very blurry.

This sums it up nicely. Been a while since I did any quantum physics, but I quite liked Scumof the Road's brief dissertation

[sojournermike]

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.

Also, as well as that noted by LW&B, photoelectric effects tend to display quantised (i.e. particle type) effects as though individual photons each carry a particular amount of energy. That's not wave (continuous) behaviour.

[ian]

The same double slit experiment can be rigged to send a single photon. It goes through one slot or the other. Never both.

As mentioned, other effects like the photoelectric effect (which Einstein got his first Nobel for), say that photons behave as a particle

But as said, wave and particle are just human-intuitive ways of describing something that is really neither.

[quixoticgeek]

What's the speed of dark?

J

[pcolbeck]

I'm not sure where light goes in the dark but since light shows up really well in the dark it should be easy to find out.

[David Martin]

Dark Photons.

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

I just seem to have smoke overfilled diodes...

[mattc]

Because if you set up a detector that tells you which of the two slits an individual photon goes through, the interference pattern goes away and the results look like individual particles fired through two slits with no interference pattern (so, not a wave). I have always been astounded by that 'How does it know?' aspect, even though I understand that quantum stuff is something that I'll never actually understand.

Somebody smarter than I said something like:

"Anyone who is not frightened by quantum mechanics has not properly understood it."

I'm not sure where light goes in the dark but since light shows up really well in the dark it should be easy to find out.

[Efrogwr]

What's the speed of dark?

J

The reciprocal of the speed of light?

[Efrogwr]

E Minor's landlord has published several papers that suggest that the concept of the photon is an illusion. I think.

It would be helpful if some forumites who can cope with such things look him up. T W Marshall, Univerity of Manchester, Department of Mathematics.
I am currently trying to arrange a meeting with a future colleague* who's a maths graduate; she might have some useful knowledge, She's also deeply interested in astrophysics, so I'll bring up the subject of the direction of spin of black holes.

[Mr Larrington]

A new theory posits that light in the dark goes to the same place as Brexit impact assessments.

[Pingu]

A new theory posits that light in the dark goes to the same place as Brexit impact assessments.

In the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying ‘Beware of the Leopard?*




*Thank-you Trumpton on FB

[Pingu]

E Minor's landlord has published several papers that suggest that the concept of the photon is an illusion...

I thought it was time that's an illusion, lunchtime doubly so.