Yet more questions about light

[Write4U]

They are talking about rest mass. Note, however, that if the mass of the photon is actually zero, then it can never be brought to rest; if, on the other hand, it does have a minuscule mass, then it would be theoretically possible to bring it to rest.

Question: Could it be mass that restricts the photon to travel a SOL or is it that at SOL a photon acquires mass which then restricts it from going faster?

Seems to me that in a true vacuum, theoretically a photon could travel at a much faster speed, which may have been the case during the "inflationary epoch" when the fledgling universe expanded at faster than SOL.

What other explanation can be fashioned to account for that initial expansion?

The cosmic microwave background and inflation​

How did the temperature fluctuations get there?

The period of time before the formation of the cosmic microwave background (CMB) plays a key role in determining how and why we see tiny fluctuations in the CMB.

At the very beginning, the Universe underwent a rapid inflation that lasted only until 0.00000000000000000000000000000001 seconds (10^-32 seconds).

After inflation the size of the Universe had increased by a factor of about 10^30 (1 followed by 30 zeroes – an enormous number!).

Minute, random quantum fluctuations in the structure of the Universe that were present at the moment when inflation started, were amplified up to cosmologically large scales during inflation.

Now the Universe comprised significantly large regions with slightly different properties from one to the other: in particular, the density of matter was slightly larger in some regions of the Universe than it was in others.

The cosmic microwave background and inflation

How did the temperature fluctuations get there?How exactly do the temperature fluctuations relate to density fluctuations?

www.esa.int

 

[exchemist]

Derailment alert.

 

[exchemist]

Question: Could it be mass that restricts the photon to travel a SOL

No.

 

[Pinball1970]

Seems to me

That's the problem.

Intelligent people read what the experts have published and makes its way into text books.

If you want to understand science, read what is already researched, published and in text books.

 

[James R]

Question: Could it be mass that restricts the photon to travel a SOL

The opposite. It's the fact that the photon has no mass that restricts it to travelling only at the speed of light.

... or is it that at SOL a photon acquires mass which then restricts it from going faster?

Photons do not acquire mass. If they did, they wouldn't (couldn't) travel at the speed of light.

Seems to me that in a true vacuum, theoretically a photon could travel at a much faster speed.

That's the problem with just guessing at random: your guesses have a 50% chance of being wrong.

, which may have been the case during the "inflationary epoch" when the fledgling universe expanded at faster than SOL.

The expansion of spacetime is not limited to the speed of light. Up until now, we have been talking about how light moves through space, not about how space moves.

What other explanation can be fashioned to account for that initial expansion?

See above. The explanation lies in cosmological models that use the general theory of relativity. It's complicated, and not a topic for this thread.