## Why Einstein is such a big deal

Nearly 100 years after Albert Einstein presented the final version of general relativity to the Prussian Academy on November 25, 1915, his name remains synonymous with genius, and his face is still recognized worldwide.

In 1905, 10 years before Einstein finished his theory of general relativity, he published four papers that challenged the basis of classical physics and became the pillars of two scientific revolutions of the 20th century. Einstein’s discovery of the photoelectric effect, which earned him the Nobel Prize in physics in 1921, provided proof of the existence of the atom and laid the foundations for what would become the field of quantum mechanics. And Einstein’s founding paper on relativity, the special theory of relativity, transformed our understanding of the nature of space and time.

Had another scholar published those four papers within a lifetime, that person would have made it into the pantheon of physics. Einstein wrote them in a year, when he was 26 years old. His greatest work, the general theory of relativity, was still to come.

To understand the importance of general relativity, we have to go back to another great physicist, Sir Isaac Newton. Newton described a universal law of gravitation in his 1687 masterwork *Philosophiae Naturalis Principia Mathematica *(Latin for “Mathematical Principles of Natural Philosophy”)*.* Newton’s equations explained for the first time why the planets stayed in orbit, but the question remained as to how the force of gravity worked and how it was transmitted.

In Newton’s universe, space and time were absolute–an inert arena in which all physical phenomena took place. What was so revolutionary about relativity is that it introduced the idea that space and time are players in the cosmic stage, prodded and warped by matter. According to Einstein’s general theory of relativity, this natural warping of space-time, caused by the mere presence of mass, explains how the force of gravity is transmitted.

Hanoch Gutfreund, former president of The Hebrew University of Jerusalem and Academic Director of the Albert Einstein Archives, explains why Einstein is considered one of the greatest minds of all time, and how his legacy shapes physics to this day.

*Fusion’s original Relatively Speaking series celebrates the 100th anniversary of Albert Einstein’s general theory of relativity. *