Space–time scales inform about the order of magntude of the spatial and temporal properties of system’s behavior. The minimum physically meaningful spatial scale is of the order of 10-35 (1 preceeded by 35 zeroes) meters. A very tiny size indeed. In similar vein the minimal time scale is of the order of 10-43 seconds. On the other hand the currently maximal spatial extent is of the order of 1027 (1 followed by 27 zeroes) meters and the current time extent is of the order of 1017 seconds, the spatio-temporal extent of the observable Universe. This is a vast extent between what we call micro and macro spatial and time scales. Human beings with the spatial extent of their bodies of the order of 1meter and life span of the order of 109 seconds (tens of years) lies in between these extrema.
The tiniest size of an object a human being is able to see with a naked eye is 0.01 degrees (at distance of 15 centimeters it is approximately 0.03 milimeters or 30 micrometers, the width of a thin human hair). Any two objects smaller than that size seem continuous to us. With respect to our vision, any time gap between subsequent vizual stimuli shorter than 0.04 seconds or 40 miliseconds can not be noticed and we perceive the visual sequence as continuous.
Robert Hristovski 28.07.2016