Answer:
Explanation:
There is a fundamental length, the Planck length. It is the length that light (a photon) travels in a unit of time called the Planck time and conforms to the way to measure length in general, as given by the equation
L = ct
Where L is length (or distance), c the speed of light (3 X 10^8 meters/sec), and t the time the light travels in. The Planck length is exceedingly small (magnitude 10^-35 meters because the Planck time is short (10^-44 sec)
The Planck length, or any length based on the speed of light, is not subject to the imprecision we would find by measurement with a physical ruler, for example, because a ruler can expand or shrink or be bent or warped, etc.
Rather, length based on c (in a vacuum) is constant. This concept is another gift from Einstein’s theory of special relativity. It’s also the central concept in spacetime, though it would take some explaining for me to say why it is so.
