Einstein, Relativity, and Black Holes

First published June 1, 2022

Astronomers announced in May 2022 that they had pierced the darkness and dust at the center of our Milky Way galaxy using the Event Horizon Telescope project and captured the first direct image of a supermassive black hole, an opening in space-time through which millions of stars had been lost, leaving behind only their gravity and violently bent space-time, as reported in the New York Times Science Section on May 10, 2022. (see figure) A black hole is a region of space-time where gravity is so strong that nothing, neither particles nor even electromagnetic radiation, such as light, can escape from it. We were so awed by this image and what it represented, it prompted us to pen this short article. 

Albert Einstein’s theory of general relativity predicted black holes in the early 1900’s, a century ago. Einstein’s early life was rife with difficulties. His father was unsuccessful and the family moved to Italy to try to reestablish his father’s business. Einstein was left in Germany. His school experiences were filled with tribulations. He excelled in mathematics and physics but not in other disciplines. Despite not having a high school diploma, he passed the entrance examination and graduated from the Swiss Federal Polytechnic School in 1900. He had given up his German citizenship when he moved to Switzerland and, eventually, was granted Swiss citizenship. He, however, could not get recommendations from his professors for an academic position. His independent attitudes and singular thought processes did not sit well with “Germanic” rigidity. He had the good fortune to have a family friend get him a job as an examiner in a Swiss patent office, so he could earn a living. He was able to accomplish his required duties, quickly, each day and spent much of the rest of the day thinking about matters that interested him. When in the Polytechnic School, he had examined the inconsistency he saw between Isaac Newton’s theory of gravity and James Clerk Maxwell’s theory of light, the two pillars of 19th century physics. One had to be wrong. In the process, Einstein deduced that the speed of light was a constant making Newton’s theory unsustainable. In 1905, Einstein published four papers in the Annalen der Physik, which would alter the course of modern physics and earn him a Nobel Prize in Physics in 1921, but not for his theory of relativity, not yet unequivocally accepted. One paper, entitled “On the Electrodynamics of Moving Bodies”, contained the mathematical theory of special relativity. Another “Does the Inertia of a Body Depend Upon Its Energy Content?” established that relativity theory led to the equation E = mc2, where E is energy, m is mass and c is the speed of light, 186,000 miles/second. This provided the first mechanism to explain the energy source of the sun and other stars. It also formed the basis for atomic energy and the nuclear age. In 1905, he, also, submitted a paper for his doctorate. His work was largely ignored until Max Planck gave it credence. Planck’s standing was such that Einstein was invited to lecture at international meetings, and rose rapidly in academia. He was offered positions at prestigious institutions and, ultimately, at the University of Berlin, where he served as director of the Kaiser Wilhelm Institute for Physics from 1913 to 1933. He famously said “If my theory of relativity is proven correct, Germany will claim me as a German and France will declare that I am a citizen of the world. Should my theory prove untrue, France will say that I am a German and Germany will declare that I am a Jew.” As the National Socialist (Nazi) Party came to influence and, later, power, his position and his life was threatened. The Nazi’s recruited scientists to denounce him. One Hundred Authors Against Einstein was published in 1931. When asked to comment on this denunciation of his theory by so many scientists, Einstein replied that to reject relativity one did not need the word of 100 scientists, just one fact. A Nazi organization published a magazine with Einstein’s picture and the caption “Not Yet Hanged” on the cover. The virulence of antisemitism and the labelling of his ideas as “Jewish Physics” led him to immigrate to the United States and the Institute for Advanced Studies, affiliated with Princeton University. In 1939, he warned President Roosevelt of the German effort to develop an atomic bomb. His standing added to the sense of urgency imparted to Roosevelt. As demonstrated by the recent project, Einstein’s concepts of the universe are the most fundamental and insightful yet conceived by the human mind. 

Sagittarius A (Sgr A). The first direct image of the supermassive dark hole (14 million miles in diameter) in the Galactic Center of the Milky Way was obtained by the Events Horizon Telescope project in collaboration with the National Science Foundation. The project linked eight existing radio observatories across the planet to form a single earth-sized virtual telescope. This project reminds us of our de minimis place in a vast universe.