Evolution of universe with differing SOL

tasp77

I have seen discussions of universes with different numbers of spatial dimensions, universes without a strong arrow of time, universes with differing physical constants, etc. but I was wondering

(here it comes, you are wondering)

(LOL)

would our universe be substantially similar with a drastically different speed of light?

(and everything else the same, protons and gravity and such)

For instance, if light propagated at 550 km/second ??

Or

if light traveled at 90,000,000,000 km/second ??

And by substantially similar, would there be stars, and fusion, and planets and orbits, and galaxies ?

mfb

There are unit systems where the speed of light is fixed to 1. It is just a conversion factor. If you don't change anything in natural units, nothing changes. Length and time do not have fundamental scales, unless you determine them via fundamental constants which include the speed of light.

ImaLooser

I looked into this once n a simplistic way. If c is different then many fundamental constants are different, and this would definitely make a difference. It was beyond me to say what. It would take a real expert to determine the consequences, and I think they have more practical things to do.