“The Velocity of Light Hypothesis”

In the late 19th century, there were scientists who believed that the speed of light was not constant. This belief was primarily due to observations that seemed to contradict the prevailing theory of electromagnetism, which suggested that the speed of light was constant in a vacuum. One notable example is the Michelson-Morley experiment, conducted in 1887 by Albert A. Michelson and Edward W. Morley. The experiment aimed to measure the relative motion of the Earth through the hypothetical luminiferous ether, which was believed to be the medium through which light waves propagated. The expected outcome of the experiment was that the speed of light would vary depending on the Earth's motion through the ether. However, the results of the Michelson-Morley experiment, along with subsequent experiments, including those conducted by other scientists like Lorentz and Fitzgerald, failed to detect any significant variation in the speed of light. These experimental findings challenged the prevailing belief in a stationary ether and instead supported the development of Albert Einstein's theory of special relativity, which posited that the speed of light is constant in all inertial frames of reference. Einstein's theory of special relativity, published in 1905, revolutionized our understanding of space, time, and motion. It established that the speed of light in a vacuum is an absolute constant, denoted as 'c,' and it is the maximum speed at which information and physical interactions can propagate in the universe.