if darkness travels a million miles...
but no light shines to greet its arrival...
has the darkness really moved?

i therefore submit that the speed of darkness is zero

but, then again...

if the light subsequently rushes forth...
greets the dark, waiting those miles away....
that potential distance traveled by the dark...
in some amount of time...
will indeed be measurable...

so, since the darkness beat the light, i submit that the speed of dark is the speed of light times two (or plus one mayhaps)

or....

when the light traveled to meet the dark....
so very many miles away...
seems the darkness disappeared...
potential gone astray...
in light, the darkness has no form...

so.... there is no darkness, thus, no speed...
back to the start...
i submit that the speed of dark is zero.