Why is it that nobody understands me, yet everybody likes me?” a bemused Albert Einstein asked a New York Times interviewer in 1944. Seven decades later, admiration for the scientist has soared enormously, even though his science remains as unfathomable to the general public as before. Its understanding is limited to the fraternity of physicists, many of whom are still grappling with the baffling implications of his theories.
Einstein can be credited with two unmatched achievements: First, he added such revolutionary new knowledge to the science of the physical world that it has forced us to change our conventional notions about the basic building blocks of the cosmos — space, time and matter. Second, he humanised high science and brought mass popularity to it, while retaining its mysterious quality. His fame is all the more exceptional because his achievement in science is not within the grasp of the ordinary mind. Newtonian physics was simple, formulaic and easy to associate with the movement of objects our hands could touch and feel.
In contrast, an understanding of Einstein’s theories of special and general relativity demands, besides piercing imagination, at least some knowledge of the exciting journey of physics in the 19th and 20th centuries. The year 1905 is hailed as a miraculous year in the history of physics because of five pathbreaking papers produced by Einstein, then only 26. One of them unveiled the special theory of relativity, which stated that due to the constancy of the speed of light for all observers (and nothing can exceed the speed of light), the notions of time and space depend on one’s state of motion.
One consequence of this is that the mass of any object is given by its total energy divided by the square of the speed of light. This is the equation E=mc2, whose simplicity, elegance and popularity are unsurpassed. A decade later, in November 1915, Einstein presented his general theory of relativity. Even more esoteric than the previous one, it completely capsizes our understanding of Newtonian gravity. Far from being an attractive force between two objects, gravity, the general theory of relativity tells us, should be understood as warps and curves in mutative space-time.
Here space and time lose their separate and absolute existence and become, with the meshing of the three dimensions of space with one dimension of time, a single flexible fabric of pure geometry. The fabric sags in the presence of massive objects of matter. It does boggle the mind to picture it, but when an object falls, it is simply stretching and creating a dip in space-time. American physicist, John Wheeler, has simplified this picture in a single sentence: “Curved space-time tells matter how to move; matter tells space-time how to curve.” Of course, this explanation, too, stretches our power of comprehension.
All this may seem abstract and arcane, but Einstein’s theories of relativity have highly useful practical applications. For example, the satellite-based and precision-intensive global positioning system (GPS) applies the knowledge provided by both special and general theories of relativity. GPS technology takes into account the fact that the curvature of space-time is less high above than it is at the Earth’s surface, where gravity is stronger. It is the reason why clocks onboard satellites run faster than clocks on the ground.
The beauty of general relativity is that it explains all gravitational phenomena, from the smallest (falling apples) to the largest (escaping galaxies). Einstein’s prediction that light from a star is bent by the gravitational field of the sun has been validated. His theory has helped explain the discovery of black holes, objects so dense that even light cannot escape their gravity. It has also provided a framework to discuss the cosmos and aided scientific affirmation of two other fantastic celestial facts: the big bang birth of our universe and also its subsequent expansion at an accelerated pace.
Einstein’s theory predicted the existence of gravitational waves whose discovery will provide an unprecedented view of the universe. India has a unique opportunity to participate in a high-profile international experiment, called Ligo (Laser Interferometer Gravitational Wave Observatory), to observe these waves. Two sites have been identified for the experiment, which is expected to yield a lot of technology spinoffs. One hopes that the Narendra Modi government seizes this opportunity for India to play a leading role in cutting-edge research.
We in India should be proud of Einstein’s special connection with our country. He interacted with three of the greatest contemporary Indians — Mahatma Gandhi, Rabindranath Tagore (his dialogue with the poet on whether the universe exists independent of the human observer is profoundly philosophical) and Jawaharlal Nehru. The basis of their affinity and admiration was their common commitment to a world without violence.
Indeed, one of Einstein’s lasting legacies was his leadership, along with Bertrand Russell, in issuing the Russell-Einstein Manifesto for nuclear disarmament and world peace. He advocated progressive ideals, socialism being one of them, with extraordinary courage. Obviously, the genius who was relentlessly exploring harmony in the universe through a unification of scientific laws was also dreaming of unity and harmony through justice in the human realm. This, too, is a reason why Einstein has remained the most admired legend of science.