[neilep (OP)]

Dearest Lightologists and consumers of a Ton Of Vietnamese Pho !!


Take a look at Pholomena Tonoski:


She's a fine filly of a few photons !!

Pholemena Tonosky Caught At a TRILLION FRAMES PER SECOND !!




Pholemena Tonoski has been slowed down in a medium and captured in am age of a frame rate of a trillion frames per second:

SOURCE:https://youtu.be/EtsXgODHMWk?si=IQu9_sjD4L13DEui


So, I found out that light does NOT experience time because of it's speed....I dunno.. something to do with it being massless or something like that...I dunno !!..I'm a sheep innit ? !!


So, I then presumed that if it slows down then it should experience time...but apparently not !!!   what's that all about ?


Why Does Light NOT Experience Time When It Slows Down ?



whajafink ?


I'm a cloud with legs !
Sheepy

'Light' does NOT rhyme with 'Cabbage'

[paul cotter]

Good question there, my ovine friend. It is something I have thought about too, without much clarity. However the term "experience" is more of a human construct than a physical term. We can imagine travelling with a beam of light as Einstein pondered but what hard results can be had, I don't know. The Lorentz factor will have a finite value instead of an indeterminate value. I will await the input of those more knowledgeable on this subject.

[Halc]

First of all, a photon is a quantum concept and technically doesn't exist. Before being measured it isn't anywhere, and afterwards it is absorbed and gone. The measurement can say where it was, but never where it is.
So we talk about something more classical like a pulse of light.  The pulse shown in the photo is probably done via something like a stroboscopic effect where fast moving things like a car engine at full tilt can be made to appear to slow down (super slow-mo) using a strobe light. They don't use a strobe since you can't illuminate light by shining a light at it. It's more like a stop action motion picture.
The light you see in the photo represents light that did not make it to its destination, but rather got deflected to whatever is taking the pictures.

So, I found out that light does NOT experience time because of it's speed

More precisely, the speed of c relative to any object does not represent a valid inertial frame where things like distance, time, or experience are meaningful concepts. One can freely change inertial frames and back using the Lorentz transformation, but no transformation exists to such a frame.  So they put the light in a medium and then we have a valid frame relative to which the light makes no progress against the fast moving medium. That seems to be what these guys are doing.
Yes, you can reference such a frame, and our light pulse (Pholomena Tonoski) can 'experience' and such.

So, I then presumed that if it slows down then it should experience time...but apparently not !!!   what's that all about ?

Time can be experienced in such a frame, so the only thing stopping it is the same thing that stops a rock from experiencing it: Lack of googley eyes.  Point is, one can say put a human in the frame next to it and have a pet Tonoski waiting stationary next to him. Best not to watch him because any light going to the side that you can see is light permanently gone from it. It will fade quickly if defecting its very essence at that rate.

Why Does Light NOT Experience Time When It Slows Down ?

Who says it doesn't?  I mean, it's a light pulse in a valid frame. OK, a photon can't do it because it gets absorbed before it can be slowed by some interaction with the medium.

'Light' does NOT rhyme with 'Cabbage'

No, but it front-end rhymes with lituce.

[evan_au]

Why Does Light NOT Experience Time?

On a sidenote...  I heard an interesting podcast from Sean Carrol on "Does Time Exist?" (2 hours).

the ordinary Schrodinger equation says Hamiltonian acting on quantum state is the time derivative of the quantum state.
The Wheeler-DeWitt equation says, Hamiltonian acting on the quantum state equal zero. So, there is no time variable in the Wheeler-DeWitt equation. ... So, time has disappeared

Sean Carrol does not resolve this apparent contradiction in the podcast; it is a paradox of modern physics.

I don't pretend to understand much of it, but my primitive summary is:
- The Schrodinger equation is a local measure of a wavefunction (eg of an isolated electron or a photon) and has a time-dependent component, so wave-functions change with time in a local sense
- The Wheeler-DeWitt equation when applied to the entire universe is not time-dependent
     - But the particles in the universe are entangled by their past set of interactions with other particles
     - So the local changes in one particle are canceled by changes in some other particle with which it has become entangled in the past
     - Leaving not net change with time at the scale of the universe

I am sure that others here can make more sense of it than I can!
https://www.preposterousuniverse.com/podcast/2025/01/06/300-solo-does-time-exist/

[Eternal Student]

Hi.

     I've got to ask why it is that you ( @neilep ) ask a variety of fairly sensible, interesting and well informed questions?
I'm suspicious that you are deliberately giving people something to do.   This is meant in the nicest possible way:   It really can be nice for others to have some sensible thing to discuss.

   You could ask questions that are relevant to your everyday life:   For example, "why does my wooly coat get stuck on the fence?"    However, you don't.   Instead you've gone to some effort to find suitable topics.   Why would you spend some time seeking out suitable questions?   Perhaps you just already knew some issues and ideas that are currently being debated or are worthy of debate?   Are you an expert taking pitty on others seeking something to do - allowing them to write replies that they can imagine as being useful?

    Finally, you pretend to be a fairly simple sort of person or even a sheep.   Is that a metaphor?   Is it important that we perceive you as being an easily lead and influenced reader?    Perhaps, we (anyone who replies) are the ones actually behaving like sheep?    i.d.k.

    Anyway, it really can be nice to have some sensible questions and topics for discussion raised, so thank you very much.   I just have to ask the question that I'm sure a few other people have also considered -  why are you posting these sorts of questions in this sort of style?   What motive exists?

Best Wishes.

[Halc]

Why Does Light NOT Experience Time?

On a sidenote...  I heard an interesting podcast from Sean Carrol on "Does Time Exist?" (2 hours).

the ordinary Schrodinger equation says Hamiltonian acting on quantum state is the time derivative of the quantum state.
The Wheeler-DeWitt equation says, Hamiltonian acting on the quantum state equal zero. So, there is no time variable in the Wheeler-DeWitt equation. ... So, time has disappeared

Sean Carrol does not resolve this apparent contradiction in the podcast; it is a paradox of modern physics.

It is not a paradox, but simply two different ways of viewing the same thing, and it probably turns out that time is simply not fundamental, not that it meaningfully doesn't exist.

He speaks of this in his blog: https://www.preposterousuniverse.com/blog/2009/06/17/timelessness/
Being Carroll, yes, he does understand the technical arguments in a way that nobody here does, so I respect his reaction to them. He says these arguments are not the point.

"What I don't understand, and this is a sincere lack of understanding on my part, not an indirect claim that this perspective is wrong, is what's supposed to be so great about timelessness. What are we supposed to gain from thinking in this way? What problems is it supposed to solve?"

"Moreover, even if 'time' doesn't turn out to be fundamental, why would that tempt you into saying that it doesn't exist? Protons are made of quarks, but you don't hear particle physicists going around claiming that protons don't exist."

[neilep (OP)]

Hi.

     I've got to ask why it is that you ( @neilep ) ask a variety of fairly sensible, interesting and well informed questions?
I'm suspicious that you are deliberately giving people something to do.   This is meant in the nicest possible way:   It really can be nice for others to have some sensible thing to discuss.

   You could ask questions that are relevant to your everyday life:   For example, "why does my wooly coat get stuck on the fence?"    However, you don't.   Instead you've gone to some effort to find suitable topics.   Why would you spend some time seeking out suitable questions?   Perhaps you just already knew some issues and ideas that are currently being debated or are worthy of debate?   Are you an expert taking pitty on others seeking something to do - allowing them to write replies that they can imagine as being useful?

    Finally, you pretend to be a fairly simple sort of person or even a sheep.   Is that a metaphor?   Is it important that we perceive you as being an easily lead and influenced reader?    Perhaps, we (anyone who replies) are the ones actually behaving like sheep?    i.d.k.

    Anyway, it really can be nice to have some sensible questions and topics for discussion raised, so thank you very much.   I just have to ask the question that I'm sure a few other people have also considered -  why are you posting these sorts of questions in this sort of style?   What motive exists?

Best Wishes.

Thank ewe. Will reply appropriately in ' two shakes of a lambs tail '