Light takes a millisecond to go 300km in air (it will only travel about 200 km in a fiber in that time), at long distances that time will dominate. An example:

Light takes a millisecond to go 300km in air (it will only travel about 200 km in a fiber in that time), at long distances that time will dominate. An example: http://oklo.org/2015/01/01/lightspeed/ http://oklo.org/2015/01/01/lightspeed/