No matter how fast one is moving toward or away from a source of light, the speed of light will always appear the same, a constant 186000 miles per second.

Summary

This quote is referring to the concept known as the "invariance of the speed of light." It states that regardless of an observer's motion, their speed relative to a light source, the speed of light will always appear to be the same. This is a fundamental principle in physics according to Einstein's theory of relativity. It implies that there is no absolute frame of reference and challenges common-sense notions about the properties of motion. It played a crucial role in reshaping our understanding of space, time, and the interplay between matter and energy.