Relativistic Light Speed in a Bubble

[Walter The Moral]

Do we think that the speed of light in a speed bubble is the same for someone inside a bubble as it is for someone outside?

How could this be checked? The only way I can think of is putting a speed bubble inbetween two mirrors, and measuring the number of times the light bounces off each mirror. This same experiment could be conducted from inside the bubble, and the speeds could be compared.

What consequences would this have? We already know that there's some magic which prevents Blue and Redshift from happening, but what other things could be caused?

[alder24]

14 hours ago, Walter The Moral said:

Do we think that the speed of light in a speed bubble is the same for someone inside a bubble as it is for someone outside?

Yes, one of the fundamental tenets of Einstein's special theory of relativity is that the speed of light in a vacuum is not relative, it's absolute. This means that no matter where you are, how fast you're moving, or how much time dilation affects you, you will always measure the speed of light to be 300,000 km/s. Always. And because of that we have time dilation - if the speed of light cannot change, time and distance must change to account for discrepancies.  

However, that's for speed of light in a vacuum. In a medium, like air or water, the speed of light is slower due to interactions between light and that medium and thus is relative and dependent on the frame of reference of the observer. If you move fast or experience time dilation relative to the air through which light is traveling, you will see that light moving at different speeds. So an observer in a time bubble should get a different value for the speed of light in the air outside of the time bubble from the observer outside of the bubble. The consequences of this elude me, but it seems Wayne did experienced them at the end of TLM with his supercharged time bubble, TLM ch 71:

Quote

Something funny even happened to his eyesight, everything going all strange until he took another vial of Harmony’s metals and burned steel to see that way instead.

But the absolute speed of light in a vacuum is still the same in and out of the time bubble. 

Spoiler

Necarion

One other speed bubble question. Is the speed of light the same inside and outside a speed bubble?

Brandon Sanderson

Um, yes. The speed of light is the same. Good question, you're trying to figure out the FTL.

Necarion

Also, it would eliminate the redshift if the speed of light…

Brandon Sanderson

If the speed of light were similar. That's one thing we considered, but it felt too unintuitive, plus it's just not how I imagined things working. So, no it is not, but that's a good question. It is something we considered.

Footnote: Necarion’s note: there would be no redshift if the speed of light were directly proportional to the ‘speed of time’. Alas this theory doesn’t seem to be valid
Arcanum Unbounded San Francisco signing (Nov. 30, 2016)