(October 4, 2012 at 9:08 pm)Polaris Wrote:(October 4, 2012 at 8:42 pm)Cthulhu Dreaming Wrote: Why is that? It's no less a constant than the rate of acceleration due to Earth's gravity (9.8 m/s^2). It isn't the speed from the POV an observer that's constant, but rather the rate of acceleration per unit of distance (or time, in the case of my example).
It is only a constant at this relative point in time. The acceleration is not constant over the geologic timescale.
I'm sure you meant "cosmologic timescale". Point taken, though. It's observed to be constant at this point in time, and thought to have been so for quite some time (perhaps half the age of the universe). Of course, we don't know the latter with any certainty.
