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Speed of light has units of distance per time. Expansion rate has units of (distance per time) per distance.

For more info on why this statement makes little sense, see Sean Carroll's post here: http://www.preposterousuniverse.com/blog/2015/10/13/the-univ...

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And recession velocities have units of distance per time and exceed c at the Hubble sphere.

Such coordinate velocities are largely meaningless, though: The more interesting quantity is the relative velocity as evaluated via parallel transport along the trajectory of the photon you use to observe the receeding object, which goes to c at the cosmic event horizon.

See the article I linked for a possible interpretation.

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