The speed of time? Don't you mean the pace of the mind?
A record player, we can rewind, on the turntables we find but time, oh time just seems to fly by, off the turning of the tables and through our grasping fingers.
No wonder we wonder, what is this conception?
Want to slow down time? Stare at a flower and count the stars. Start looking for novelty, both near and far.
Want to speed it up? Get a job. Find a routine. Ignore the seasons and fall asleep.
I've never lost a bet on the sun rising and setting, but one day that assumption might fill me with regret.
Even the battery of a clock will deplete, as time comes by and presses "delete".
The speed of time is what you want it to be. You can find an infinite amount of it in each second. You see?
I'll give Newton a pat on the back and Copernicus a cool hat, I might even give Einstein a wink but all science aside, the speed of time is the speed of a blink.