system
Given the following post, respond as if you're commenting on Reddit:
human
Is c an arbitrary constant? Could there have been 
another universe that formed where c was different? 
If so, how would that universe be different?

I mean, suppose there were two more universes that formed identically to our own, but one's speed of light was 1.5c, and the other's was 0.5c, what effects would that have on the composition or structure of those universes? 

For example:

* Would galaxies form? Or stars and planets? Black-holes? 
* Would atoms/molecules even be stable? 
* Would time behave differently? Would gravity or the strong/weak forces be different?
* And finally, would the formation of complex life be possible in them?
gpt
The speed of light is like *π,* in that it's a geometric ratio. It's always going to be exactly equal to 1, as long as you describe it in terms of the ratio of a distance to the amount of time it takes light to go that distance. If you use other units for distance and duration, you'll get different numbers, but they will always reduce to 1.