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Relativity: The Special And The General Theory by Albert Einstein started as a series of short write-ups, but was eventually converted it into a book. Einstein’s book is intended to enlighten on the theory of relativity those “readers who are interested in the theory but are not conversant with the mathematical apparatus of theoretical physics.” The man who would soon become the face of genius divided his book into three parts. The first section handles special relativity. The second deals with general relativity, and the third focuses on the universe as a whole. Apart from giving insight into the theory, it lets the reader experience the thought processes of an all-time greatest mind.
For a period of four months, from March to June 1905, Albert Einstein published four papers that became the most influential in the history of science. The first paper provided a means to measure molecule size in liquid. The second revolved around determining the movement of liquid molecules. The third introduced the concept of photons, arguing that light travels as packets. Einstein’s discovery of photons eventually won him the Nobel Peace Prize. However, the fourth paper on special relativity tackled an issue that had remained mysterious since the dawn of civilization – space and time.
Relativity: The Special And The General Theory encompasses two theories. These are: Special Theory of Relativity made public in 1905, and General Theory of Relativity of 1915. Relativity and quantum theory grew to become the backbone of modern physics.
Einstein became the ultimate physicist to describe relativity. That’s not to say he was the first to conceive this idea. The much-revered Galileo Galilei had studied it centuries earlier as far back as 1632, eventually stating the principle of relativity. Also referred to as the principle of invariance, Galileo’s principle held that the fundamental laws of physics are similar in all inertia objects. However, Sir Isaac Newton did not consider this principle with the importance that it deserved, brushing it aside based on his famous laws of motion.
As this review shows, Albert Einstein had the same starting point in his theories, but they were somewhat more involved. He considered the speed of time, space-time, as well as the equivalence of acceleration and gravity. A couple of scholars might have been quick to brush aside these theories, but Einstein proved them wrong. They have had significant consequences, including bending of light, mass-energy equivalence, contraction of length, and dilation of time.
Not for Scientist only; easy and fun book to read
Written by the world’s most renowned genius, you would expect reading Relativity: The Special And The General Theory to be quite a daunting task to do. Surprisingly, Einstein finds a way to make the book accessible and pleasurable to read. He takes a general scientific and philosophical point of view and has a specific set of requirements for those in the public domain to understand his work.
He asserts that one ought to have an education equivalent to university matriculation examination and also exercise a great deal of patience. Einstein recommends the reader to be patient because he does not just jump into conclusion. Instead, he takes time to build his arguments, making it easy for anyone who cares to pay attention to follow to the end.
The author uses examples to a greater extent to drive his point home. He makes classic comparisons of measurements involving an observer on a train that’s moving at a constant velocity and another at rest near the train tracks. From these examples, he makes gentle and intuitive derivations that would motivate you to re-read the whole narration from scratch. Any complicated explanation and derivations are in the appendix.
The theory of special relativity gives an insight into the link between space and time for objects moving in a straight line and constant speed. These moving of objects are described based on the speed of light. Albert Einstein argued that as the moving object nears the said speed, it acquires an infinite mass and cannot go any further than how light is traveling. The physicist’s introduction of a comic speed went a long way in impacting different spheres of life, both physics and science fiction.
In science fiction, for example, it paved the way for a discussion on the possibility of time travel. In BBC’s most successful sci-fi TV series, Doctor Who, the main character, has the unique ability to travel through time and space. We cannot deny the fact that Einstein inspired the creators of this film. After all, how would they have determined that the Doctor gets to skip between different historical periods had it not been for the German-born theoretical physicist?
Einstein gives us pretty exciting things to think about due to his theory of relativity. Twins paradox is one of the most interesting ones. Imagine leaving Earth in a spacecraft that travels at the speed of light, then you turn around and get back from where you departed. Such an event would mean that so many years have gone by on Earth. The traveler who undertakes such an adventure would return much younger than their twins, hence the name ‘twins paradox.’
Returning is more theoretical than practical. One would have to travel at a speed that is greater than that of light. As at the moment, this has been proven to be an impossible undertaking.
The general theory of relativity explains gravity by considering how space can curve. This ‘curving’ doesn’t take place; instead, it is due to changing the geometrical outlook of space-time. The general theory is a theory he produced nearly a decade after he had made several considerations on the universe under the special theory of relativity.
Based on his main arguments on the special theory, the physicist applied it to accelerating masses. Doing so helped him discover that objects mass have an impact on their surrounding dimension (space-time) in such a way that they seem to pull other masses. He concluded that matter weighs down space-time fabric to create a curve in which nearby fabric slides.
Indeed, instruments cannot be used to measure space-time. However, several phenomena prove it. For instance, the light around a massive object such a black hole is bent in a way that it acts as a lens for the objects behind it. Astronomers use this method to study galaxies and stars lying behind massive objects. Gravitational lensing is the term used to describe such a phenomenon.
A quasar in the Pegasus constellation (Einstein’s Cross) best depicts Gravitational lensing. The distance of this quasar from Earth is about 8 billion light-years away. Its positioning is behind a galaxy, which is approximately 400 million light-years away. Photos of the quasar depict it as if it is around the galaxy, whereas that is not the case. The illusion happens because the galaxy’s intense gravity bends light as it comes from the quasar.
Gravitational lensing is a phenomenon through which scientists could potentially see some exciting things. For instance, they have been able to observe a supernova occurring four different times as magnified by a massive galaxy.
A book that has stood the test of time
There are a few scenarios in which Einstein’s descriptions are in contrast to the modern interpretation of special and general relativity. That’s not to say the author was wrong. The reader must understand that these theories have withstood the test of time, often argued against by revered men of science but still coming out victorious.
Einstein’s theory of relativity can be seen in real life. Consider the many shiny metals we so much admire. Most of the metals shine because their atoms are in orbital. That is, they keep on shifting in terms of energy levels. Gold, being a heavy atom, has its inner electrons moving at a faster speed so that relativistic mass increases significantly. The inner and outer electrons go through energy spikes, making it possible for wavelengths to be absorbed and reflected more strongly. In the end, the light that is reflected from gold appears to have less blue and violet, making the color of gold presumably yellow.
Albert Einstein’s book is the kind of book that both physicists and educated members of the public should enjoy reading with “patience and force of will,” as Einstein puts it. The author is not only a genius on matters to do with physical theories but also pleasantly describes them. He makes you fall in love with relativity despite not having a better grasp of his calculations.
Right from an introduction that instantly creates the desire to read more, to an appendix that nicely wraps it up, this is a book worth your time. It is the best way to become an expert in Einstein’s theories. After reading it, it might be interesting to also look at The Birth and Death of the Sun by George Gamow, another book with captivating narrations.