[GoLightly]

it is suggested that the speed of light might be slowing down

What do you think explains redshift variability best?

[Dimensio]

What do you think explains redshift variability best?

Please explain how redshift variability can be explained by lightspeed decay. Note that in my example I am referring specifically to creationist claims that lightspeed has been slowing down in such a way to make current astronomical observations consistent with a universe no more than 10,000 years of age.

[jophis]

Actually, if you look at modern physics, it is suggested that the modern universe is actually increasing it's rate of expansion. Not slowing down.

Redshift variability can be due to a few things. Gravitational pull among the galaxies being the main factor. For example, the Milky Way Galaxy is one of the largest galaxies we know, and we actually witness a blueshift (it is coming toward us) in a few of our smaller, neighboring galaxies. This is not because they are coming at us, but because the milky way has a certain gravitational pull over them).

This can happen in many systems of galaxies, causing redshift variation.

That being said, look at Edwin Hubble's research, you'll see that the universe is moving very uniformly.