In 1983, the meter is defined as the distance traveled by light in the vacuum during a time interval of 1/299,792,458 of a second. This current definition relies on the definition of the second and on the 2nd postulate of the special theory of relativity, that states that the speed of light in free space has the same value c in all inertial frames of reference. As a consequence, this definition fixes the speed of light in vacuum to be exactly 299792458 m/s.
a) Assuming the Earth to be a perfect sphere and using the information contained in the statement of the first problem then what is the ratio between the distance traveled by light in the vacuum in one second and the Earth’s circumference?
b) Light-nanosecond is the unit of length defined by the distance traveled by light in vacuum during 1 nanosecond (10^-9 s). For comparison its value is slightly less than a foot. What is your height written in light-nanoseconds?