Einstein’s theories of special and general relativity were singularly revolutionary and radical at their time of conception; established laws of physics and previous understandings of reality itself were uprooted. Albert Einstein, one of the most famous scientists of all time, proposed his theory of special relativity in 1905, and the theory of general relativity in 1910, contributing fundamental ideas, forming the basis of modern physics. By combining the ideas of Isaac Newton and John Clerk Maxwell, Einstein conceptualised a new reality. The seemingly inexplicable discrepancy between Maxwell’s finding that the speed of light (c) was constant regardless of motion, with Newton’s laws of motion, was reconciled through Einstein’s proposal of spacetime. Einstein challenged Newton’s understanding of the universe as a ‘clockwork universe,’ where a metre is always a metre and one second is the same anywhere in the universe – Einstein’s spacetime stated that space and time are not two separate dimensions, they are not separate from each other, but are unified in a dynamic, 4-dimensionsal continuum. This fabric of the universe is sensitive and respondent to the presence of mass and energy and dictates how mass and light moves through the universe. Time and time again, different phenomena such as the Eddington solar eclipse in 1919, has proven Einstein’s theory right.
The theory of special relativity also concluded that simultaneity, things happening at the same time, is relative to motion, which Einstein explained through a simple thought experiment: suppose one person is standing still, equidistant from two trees, and two bolts of lightening strike both trees at the same time. A second person who was also equidistant from the two trees, but was instead in a moving train, would have seen one tree struck before the other. This led to the conclusion that both time and distance are relative to motion. Such is the genius of Einstein – his musings, questioning, and inherent curiously led to such revolutionary ideas, explained through equally enlightening and simple terms.
What is particularly striking is the use of thought experiments themselves, as oppose to the empirical and experimental methods we are accustomed to today. For all of these theories were derived from sparse evidence, considering how revolutionary they were; evidence which even now, continues to arise, repeatedly proves Einstein’s genius. For he did not experience these things before formulating his theories – they were predictions, and this required immense creativity, intellect and imagination.
A decade after special relativity, Einstein had introduced acceleration into his theory, which resulted in the theory of general relativity. Einstein completely changed the Newtonian notion of gravity as a force, into the idea that gravity is the distortion of the fabric of spacetime, caused by massive objects. Understanding of this distortion has led to much scientific discovery, including the study of stars and galaxies that are behind massive objects, using gravitational lensing! This is when the light around a massive object, such as a black hole, becomes bent, which then acts as a lens to see things behind it.
Einstein’s genius has enlightened and enriched our understanding of the reality of the universe. His theories continue to guide us, more than a century later. His genius stretches into the future, inspiring infinite discoveries.