Few would deny that Albert Einstein’s very name has become synonymous with genius. Janos Plesch, Einstein’s friend, once said: “He sleeps until he is awakened; he stays awake until he is told to go to bed; he will go hungry until he is given something to eat; and then he eats until he is stopped.” (1) Einstein would publish over 300 scientific papers, hundreds of non-scientific works, and numerous assisted works over the course of his illustrious career. Yet his theory of general relativity is one that has truly stood the test of time, even though his radical hypothesis was not definitively proven until 1919. Looking back on 100 years since the young Einstein (then only 36 years of age) would propose that gravity itself is not a force, as Sir Isaac Newton believed before him, but rather a curvature in the space-time continuum, countless great minds have unsuccessfully attempted to challenge Einstein’s theory. Having a theory last 100 years speaks volumes to Einstein as an epitome of brilliance. So, what was Einstein’s general theory of general relativity anyway?
Einstein’s theory of gravitation did not come to the young genius overnight. He spent almost ten years since the publication of his Special Theory of Relativity (1905), in which he posited that that the laws of physics are identical in all inertial systems; and that the speed of light in a vacuum is the same for all observers, regardless of the motion of the light source, pondering its complexities. Einstein however still had to tackle hugely significant problems of gravity and acceleration which haunted his earlier theory. His answer to those questions would come in 1915, and was indeed a culmination of many years of calculations and strong letters from colleagues and other great minds in the field who yearned to beat him to the punch. The general theory of relativity in more layman’s terms is best described by a more contemporary example:
“Imagine you are in an elevator and feel what you believe is the force of gravity, holding you to the floor. According to Einstein, since you cannot see outside the elevator, you cannot tell if you are feeling the force of gravity or if the elevator is being pushed toward your feet. Einstein stated that the two forces are actually identical. Furthermore, if you were in the elevator accelerating upward and a beam of light entered the elevator parallel to the floor, the light beam would appear to bend downward. This meant that light, which ordinarily traveled in straight lines, could curve if it traveled across a gravitational field. This curving path of light meant that that “field” was really a curving of space, which Einstein found was inseparable from time. The curvature would be caused by bodies with great mass.” (2)
As we all know a theory is only a theory until it can be proven. That opportunity came for Einstein in 1919 when a British Astronomer Sir Arthur Eddington would travel to the French island of Príncipe in Africa to observe an eclipse that afforded his team unparalleled views of starfields. Eddington would confirm that the stars and their location had indeed shifted (meaning a deflection of starlight), as a result of the bending of light in the gravitational field of the sun, just as predicted by Einstein. It was this astronomical mission to Príncipe – and related voyages by English astronomers to Brazil – that would catapult the young Einstein to international celebrity and fame. Leopold Infeld, who worked with Einstein, once noted in the context of the end of World War I that “people were weary of hatred, of killing. . . . Here was something which captured the imagination . . . [t]he mystery of the sun’s eclipse and of the penetrating power of the human mind.” (3)
Einstein’s theory of gravitational forces is a watershed moment in the history of physics, and of humankind’s yearning for understanding of the universe. Einstein’s general theory of relativity would spawn hundreds – if not thousands – of books, lectures, debates and new beginnings for the field of physics. cosmology, quantum physics, and others. Now 100 years after a monumental shift in our comprehension of the cosmos and of our world, we are still asking the hard questions that live in the shadow of Einstein’s theories. Gravity, time, space, energy, mass, etc. still preoccupy the great minds of our time. We now yearn to understand black holes, an expanding universe, and theories of the formation of planet Earth. Retrospectively this centenary is also a moment for us to celebrate the power of the human mind and the perseverance needed to bring us all one step closer to understanding our place in the universe. Three cheers for Albert Einstein and the many profound minds that have advanced not only science but humankind itself.
For more information on Albert Einstein’s General Theory of Relativity and related works please consult some of the sources below.
The Collected Papers of Albert Einstein at Princeton University
The Atlantic – Standing the Test of Time (and Space)
The Max Planck Society for the Advancement of Science – The Renewal of Einstein’s Theory of Relativity in the Post-War Era
Coursera – Understanding Einstein: The Special Theory of Relativity
2015 International Year of the Light – Einstein Centenary
Perimeter Institute for Theoretical Physics – 100 Years Later: The Theory of General Relativity
New York Times – Thousands of Einstein Documents Are Now a Click Away
Einstein Archives Online
Space.com – Einstein’s Theory of General Relativity
- A Century Ago, Einstein’s Theory of Relativity Changed Everything. New York Times. 2015. Retrieved from http://www.nytimes.com/2015/11/24/science/a-century-ago-einsteins-theory-of-relativity-changed-everything.html?_r=1
- Einstein announces the general theory of relativity 1915. PBS. 1998. Retrieved from http://www.pbs.org/wgbh/aso/databank/entries/dp15ei.html