[Kryptid]

Yes, if the Universe was a perfect vacuum with no troublesome gravity around, light would always go in straight lines.

Unfortunately, the Universe doesn't meet your requirements.  It's a bit more complicated.

That's still irrelevant to what I was saying. Gravity isn't what makes light travel at c.

[charles1948]

I guess I will see my question and answer in the future coming from a more celebrity scientist ?

Guess again.

Can you see Bored Chemist ever becoming a celebrity scientist?  Or more like a new Dr Strangelove. A dark and sinister figure. Who scares.

[Michael Sally (OP)]

Light passing through a medium is affected by the permeability of the medium and it is a fact that acceleration is required for something to speed up .

Why are you denying simple school boy physics such as what is required to accelerate ?

Okay, if this really is "simple school boy physics", then you should easily be able to find a reputable source that confirms there is an attractive force that accelerates light when it exists a medium. I'll be waiting.

I asked a new question about lights speed being a consequence of an external attractive force which the physics and observations agree with . I don't expect to find a present citation or reputable source when the reputable source and citations have not yet been created .

For one to create a reputable source one must first find a reputable science body such as a Cambridge science forum .
However , one did not expect to find a moderator on such a reputable science forum who doesn't know the physics of how acceleration works.

[Kryptid]

I asked a new question about lights speed being a consequence of an external attractive force which the physics and observations agree with . I don't expect to find a present citation or reputable source when the reputable source and citations have not yet been created .

But you said that it's "simple schoolboy physics". If that's true, then schoolboys should know about it and, by extension, existing physicists.

However , one did not expect to find a moderator on such a reputable science forum who doesn't know the physics of how acceleration works.

The photons don't actually change speed when they enter a material, so there is no acceleration involved:

[Michael Sally (OP)]

I asked a new question about lights speed being a consequence of an external attractive force which the physics and observations agree with . I don't expect to find a present citation or reputable source when the reputable source and citations have not yet been created .

But you said that it's "simple schoolboy physics". If that's true, then schoolboys should know about it and, by extension, existing physicists.

However , one did not expect to find a moderator on such a reputable science forum who doesn't know the physics of how acceleration works.

The photons don't actually change speed when they enter a material, so there is no acceleration involved:

 I will not bother watching the video  because my blinds stop daylight entering my room . 

How do you explain this is you claim photons don't change speed when entering a material ?

My blinds stops the intensity and most frequencies .

[Kryptid]

How do explain this is you claim photons don't change speed when entering a material ?

Because you are talking about a different phenomenon. When a material absorbs photons instead of transmitting them, the photons stop existing. They are converted into heat.

[Michael Sally (OP)]

Because you are talking about a different phenomenon. When a material absorbs photons instead of transmitting them, the photons stop existing. They are converted into heat.

You also said

The photons don't actually change speed when they enter a material, so there is no acceleration involved:

I'd call not existing anymore  a full stop and most definitively a change of speed.

Can I ask is this your regular job because you seem very confused on how acceleration works ?

You also said

The short of it is that light slows down in matter because it induces interference with itself and then speeds back up when it exits because that interference is no longer there.

Acceleration : increase in speed or rate.

so there is no acceleration involved:

[Kryptid]

A photon that doesn't exist isn't a photon. Surely you already knew that?

No, being a moderator isn't a job. It's a volunteer position. I understand acceleration just fine. The photons don't accelerate because they neither slow down nor speed up. So no need to invoke a mythical attractive force.

[Michael Sally (OP)]

A photon that doesn't exist isn't a photon. Surely you already knew that?

No, being a moderator isn't a job. It's a volunteer position. I understand acceleration just fine. The photons don't accelerate because they neither slow down nor speed up. So no need to invoke a mythical attractive force.

Light slows down passing through a medium , surely you already knew this ?

When light leaves a medium it speeds up .

An increase in speed or rate is an acceleration , are you arguing against this very established definition ?

[Kryptid]

If you had actually watched the video I posted, you'd realize that the speed of the bulk light wave is different than that of the individual photons. The total light wave changes speed due to interference patterns, but the individual photons don't.

So to answer the question of the OP again: no, the speed of light is not due to some mythical external force.

[charles1948]

How do explain this is you claim photons don't change speed when entering a material ?

Because you are talking about a different phenomenon. When a material absorbs photons instead of transmitting them, the photons stop existing. They are converted into heat.

But how does this "heat" get converted back into photons?
To take, if I may, a specific example -  a telescope.

A telescope, in its simplest form, consists of two glass lenses.  A lens at the front - the "object glass".
And a second lens at the back, nearest the eye, the "eyepiece".

The "object glass" transmits light, ie photons, through it. To produce an image.  Which can be examined, in magnified form, by means of the "eyepiece".
 
But this is what I don't get -

If the photons, when they enter the front lens - the object-glass  -  "cease to exist" as you claim, and are converted into mere heat inside the glass - how does the glass transmit a image which can be examined by the eyepiece?

[Michael Sally (OP)]

If you had actually watched the video I posted, you'd realize that the speed of the bulk light wave is different than that of the individual photons. The total light wave changes speed due to interference patterns, but the individual photons don't.

So to answer the question of the OP again: no, the speed of light is not due to some mythical external force.

That is impossible physics , a waves speed can't change without the ingredients of the wave also changing speed . A photon is not an independent  element of a wave , a photon is entangled with all the other photons of the wave .

A photons energy is expansive (x0,y0,z0,.....n) 


=



(I provided a graph to the above formula in the other thread I started)

[Kryptid]

Charles, I never said anything about photons ceasing to exist inside of glass. Glass is transparent. I was referring specifically to opaque materials when I said photons get converted into heat.

Thebox, I take it that you still haven't watched the videos I've posted. Not that I'm surprised.

[charles1948]

Charles, I never said anything about photons ceasing to exist inside of glass. Glass is transparent. I was referring specifically to opaque materials when I said photons get converted into heat.

Kryptid, if you'll forgive me for refreshing your memory, what you said in your post #65 was this:

"When a material absorbs photons instead of transmitting them, the photons stop existing. They are converted into heat"

Now, a material such as glass, does absorb photons.  This is a well-known phenomenon in optics. It accounts for why the glass used in telescope lenses, results in a slight dimming of the image viewed through them.

That's why refracting telescopes designed for astronomical purposes, where light transmission is important, usually leave out the extra lenses which are used in terrestrial telescopes to erect the image.  It's to avoid the loss of light caused by the extra lenses.

All this is obvious.  The only thing I'm disputing with you, is your apparent claim that when photons pass through a glass lens, the photons "cease to exist", as you say, and are converted into "heat".

If that were true, no optical instrument which employed glass lenses would work.  Not telescopes, or microscopes, or even simple "magnifying glasses".

According to you, these devices would just get hotter, as many of the photons attempting to pass through ceased to exist and got turned into heat.  The resultant heat would hopelessly blur and distort the image emerging from the lens.

Or have I misunderstood what you said?.  Best wishes!

[Kryptid]

Yes, you have misunderstood. Glass does absorb some photons and those that are absorbed are turned into heat. Those that make it all the way through do not.

[Michael Sally (OP)]

Charles, I never said anything about photons ceasing to exist inside of glass. Glass is transparent. I was referring specifically to opaque materials when I said photons get converted into heat.

Thebox, I take it that you still haven't watched the videos I've posted. Not that I'm surprised.

I have watched your provided video which I found annoying and a poor quality explanation but my name is Michael .

- is a simple explanation of a laser beams entropy and vector analysis .

A note to make is that the hf absorbed by the volume that the laser  is passing through , is considerably less in magnitude than the beam . 

We can consider this loss to be compared to computer science and packet loss .

Whilst the beam is flowing , tiny amounts of quanta are lost to the bigger picture  Δv=ΔF as in accordance with Newtons law of motion .

[Kryptid]

Care to do some calculations with that equation that you've provided? It would be nice if you could show that it is correct that way.

[Michael Sally (OP)]

Care to do some calculations with that equation that you've provided? It would be nice if you could show that it is correct that way.

I was hoping we , I and this forum could do some calculations together .

I can create the formulas that explain the processes physics accurately , I think we just need some values to input .

In reality though sometimes the physics is more important than the measures , math cannot improve the physics .

However, if we want to attempt to form a mathematical construct , we firstly need a starting point .

In laser science the starting point is the source of the laser beam and the amount of input energy to the device .

[Kryptid]

I can create the formulas that explain the processes physics accurately , I think we just need some values to input .

If you don't know how to do the math, then how do you know your equation is right?

[Michael Sally (OP)]

I can create the formulas that explain the processes physics accurately , I think we just need some values to input .

If you don't know how to do the math, then how do you know your equation is right?

I understand in physics the work done  and my formula explains the actual physical process in formula rather than words .

  in example simply explains that photon energy is divided by any volume , the volume being the function of the work done .

To explain a measure for this we'd firstly need to know or decide a value for a single photon .