David Hine writes in Message 45:
Hi Percy, you are correct saying the 13.778 billion light years number starts from anywhere. It the "Hubble Horizon Distance" in light years in any direction from the observer.
The Hubble distance is cH
-1. The units are (km/sec)/(1/sec) which simplifies to km, a measure of distance. Note that if the units of cH
-1 are distance, then the units of H
-1 cannot be distance
-1 but must be time
-1. Mathematically, nothing else is possible.
--Percy