Perhaps the most profound discovery of the modernist era is ’s theory of relativity.

In this item, we are to determine the word that best fit in the blank. The answer to this item is the Einstein which is actually a name of the world renowned scientist. 

Einstein's theory of relativity was devised by Albert Einstein in 1905. He determined that for all non-accelerating objects or observer, the speed of light would be the same regardless of the motion of the observer. The given concept was highlighted to hold true only to speed of light in a vacuum. As a result to this discovery, he concluded that time and space are interwoven into one single continuum.