40,075.02 KM is the earth circumference. so 1000 meters is 1 KM. and 299,792,458 m / s is the speed of light.
so multiply 40,075.02 by 1000 to get the meters = 40,075,020 Meters is the Circumference of the earth.
Then divide 40,075,020 Meters by 299,792,458 Meters to get 0.133675877 seconds ? I think this is it.
edit...
and for a human to blink 100 to 150 milliseconds thats .1 to .15 of a second...