The Perfect Theory: A Century of Geniuses and the Battle over General Relativity

by Pedro G. Ferreira

How did one elegant theory incite a scientific revolution? Physicists have been exploring, debating, and questioning the general theory of relativity ever since Albert Einstein first presented it in 1915. Their work has uncovered a number of the universe’s more surprising secrets, and many believe further wonders remain hidden within the theory’s tangle of equations, waiting to be exposed. In this sweeping narrative of science and culture, astrophysicist Pedro Ferreira brings general relativity to life through the story of the brilliant physicists, mathematicians, and astronomers who have taken up its challenge. For these scientists, the theory has been both a treasure trove and an enigma, fueling a century of intellectual struggle and triumph.. Einstein’s theory, which explains the relationships among gravity, space, and time, is possibly the most perfect intellectual achievement of modern physics, yet studying it has always been a controversial endeavor. Relativists were the target of persecution in Hitler’s Germany, hounded in Stalin’s Russia, and disdained in 1950s America. Even today, PhD students are warned that specializing in general relativity will make them unemployable. Despite these pitfalls, general relativity has flourished, delivering key insights into our understanding of the origin of time and the evolution of all the stars and galaxies in the cosmos. Its adherents have revealed what lies at the farthest reaches of the universe, shed light on the smallest scales of existence, and explained how the fabric of reality emerges. Dark matter, dark energy, black holes, and string theory are all progeny of Einstein’s theory. We are in the midst of a momentous transformation in modern physics. As scientists look farther and more clearly into space than ever before, The Perfect Theory reveals the greater relevance of general relativity, showing us where it started, where it has led, and where it can still take us.

Genres: Science, Physics, Nonfiction, History, Audiobook, History Of Science, Biography

288 pages, Hardcover

First published January 1, 2014

About the author

PEDRO G. FERREIRA is a professor of astrophysics at the University of Oxford. An expert in cosmology, the early universe and general relativity, he writes frequently for trade and academic science publications and is a regular commentator for the BBC.

Reviews

[The Lion's Share · Rating 4 out of 5]

A Fantastic book for those who love science, especially physics.

This book explains how Einstein's theory of general relativity came about, the people that were involved, the people it inspired, the theories it inspired and how it is still used today for some of the most important tasks in modern physics and human exploration.

They say women are bitchy in the work space, but men can be just as bad. A lot of men in the scientific community try to disprove Einstein and Einstein did make some mistakes, but you can see how a handful of theoretical scientists took on board what Einstein had created, and from that handful came a revolution in science and discovery.

It tales off at the end, because in the first 200 pages the time line runs from the beginning of the century, through the world wars and through the cold war, therefore there were many more discoveries and greater experimentation due to the pressures of defence and warfare.

It’s amazing what we have accomplished in little over a century.

[Kevin · Rating 4 out of 5]

“Since the mathematicians have invaded the theory of relativity, I do not understand it myself anymore.” ~Albert Einstein

Pedro G. Ferreira’s The Perfect Theory is an astrophysics primer for those of us who have only a precarious grasp on general relativity, quantum mechanics, dark matter, and theoretical physics.

Being the curious novice that I am, I appreciate Ferreira’s reminder that there is no single unifying theory that incorporates all things cosmic. Every concept seems to have at least one detractor, foible or bugaboo. Then again, if it wasn’t intellectually challengeable, cosmology wouldn’t be a science—it would be a religion.

[Brian Clegg · Rating 4 out of 5]

Despite the quote from Marcus du Sautoy on the front referring to this book by astrophysics professor Pedro Ferreira as a ‘guide to the outer reaches of the universe’, this is far more a book about what goes on in human brains – and specifically the development and partial solutions of Einstein’s general theory of relativity, which turned our understanding of the nature of gravitation upside down.

For me it’s a three bears porridge book. We start off with a section that’s just right, then get a bit that’s far too long and end with a bit that’s far too short. (Okay, I know, the porridge was about temperature, not length, but this wasn’t supposed to be taken literally.) That ‘just right’ opening section gives us Einstein’s work and specifically the development of his masterpiece, the ‘perfect theory’, the general theory of relativity.

This takes a totally opposite approach to, say, Cox and Forshaw’s The Quantum Universe. Where that book does not shy away from presenting difficult detail, Ferreira’s swift, breezy and very readable style wafts us through without any detail at all. Biographically this results in a sanitisation of Einstein’s life (for instance, his first child is never mentioned, and Ferreira makes it sound as if he divorced his first wife before becoming romantically entangled with his cousin). Taking the advice given to Stephen Hawking literally, Ferreira doesn’t show a single equation, not even the central equation of general relativity. I think this is a pity – it is perfectly possible to explain what’s going on there without doing the maths. But his approach does make for an easy read.

The centre section is where Ferreira gets boggled down. While he (probably wisely) continues to omit the details of the theoretical developments themselves, he gives us far too much detail of how this person, and then that person, and then this other person, made some small addition to the understanding of general relativity. This part just seemed to go on for an unnecessarily long time – it was a bit like one of those endless Oscars speeches.

The narration starts to pick up again with gravitational waves. The sad rise and fall of Joseph Weber is very well chronicled, though I think Ferreira is over generous on the matter of LIGO, the extremely expensive gravity wave detector that has never detected anything. He is relentlessly optimistic that the upgrade will succeed – which is not a universal view by any means – and says nothing about the very interesting problems of detection which have all too often produced spurious results.

Finally, at the end, the book got really interesting again – and here, I think, Ferreira spent far too little time. This was particularly the case with the short chapter on alternatives to and developments of general relativity like MOND and TeVeS. This area could usefully have taken up a third of the book, rather than a single short chapter. Overall, though, a worthwhile addition to the popular science canon on gravity, quantum theory and cosmology.

[Todd N · Rating 5 out of 5]

(Birthday present to myself, along with The Age of Atheists: How We Have Sought to Live Since the Death of God because I know how to party!)

I'm going to break this down real simply, so that anyone can understand:

In the 19th century, scientists discovered an anomaly in Mercury's orbit that couldn't be explained by Newtonian physics, so the scientists of the day made up an as yet undiscovered planet (called Vulcan) that made Newton's equations come out just right.

In the 20th century, scientists discovered an anomaly in the orbits of stars in galaxies -- some of them were going too fast -- that couldn't be explained by Einsteinian physics, so the scientists of the day made up an as yet undiscovered type of matter (called dark matter) that made the equations come out just right.

Then in the early 21st century, scientists discovered an anomaly in the entire universe -- the expansion from the Big Bang was actually speeding up -- that couldn't be explained by Einsteinian physics, so the scientists of the day made up an as yet undiscovered type of energy (called dark energy) that made the equations come out just right.

This is what passes for cosmology these days?! C'mon guys. I'm sure it's a little more complicated than that, with equations and space stuff and all, and my math ended somewhere around multivariate calculus and nowhere near Riemann geometry. But I have to wonder if they are not seeing the forest for the trees here.

Of course the anomaly in Mercury's orbit was cleared up by Einstein's theory of general relativity, which is the subject of this very fascinating book. Really, it's a page turner. I read it in two sittings because I found it so gripping.

The interesting thing is that Einstein's greatest achievement was shunted aside for a long time due to (1) the fabulous success of quantum theory and (2) the pigheadedness of the early relativity guys, including and especially Einstein himself.

Every time the equations would point to something interesting, like black holes or an expanding universe -- stuff we take for granted nowadays, Einstein or one of his cronies would submarine some poor physicist's reputation, career, funding, what-have-you, until the idea was dead and buried. Then about a decade later some radio astronomer would make an observation that confirmed whatever it was that the physicists were trying so hard to suppress, and everyone would whistle and look around innocently and pretend nothing happened. I thought the open source Hadoop ops guys were jerkfaces, but they got nothing on 20th century relativists.

Some of the references in the book are tantalizing. I already knew about the Kaluza-Klein theory, in which an extra dimension is added to Einstein's equations and out pops Maxwell's equations. Ta-da! What I didn't realize was that this required one of the dimensions to be curled up really small, and that this was sort of foreshadowing of the string theory which is so dominant today.

But the big shocker to me was that Godel (of Incompleteness Theorem fame) used Einstein's equations on a spinning universe and calculated that time travel actually is possible(!!!). What the heck?! Of course since the physicists couldn't attack Mr. Godel on mathematical grounds they attacked his paper on aesthetic grounds. The best part is that the paper was presented to Einstein as a birthday present. I'm sure he would have preferred a lump of coal. Ha ha.

So where are we now relativity-wise (according to this book)? There's no quantum gravity (yet). It turns out that there is probably no space-time. The Einsteinians are in control of the universities and the research grants, so don't try getting any research money for your alternative gravity theories. The US refused to fund a really bad-ass laser interferometer in space, which is yet another reason to hate this Congress. String theory is a branch of aesthetics, so they might start teaching it at your local Art Academy of San Francisco (ha ha j/k).

But overall I get the impression that people really haven't scratched the surface of Einstein's equations, so maybe all the grant money you need is enough for a ream of paper and some pencils.

Highly recommended.

[Charlene · Rating 5 out of 5]

A+

Ferreira's book is possibly the best one I have read to date that focuses on the history of and challenges to the theory of general relativity.

In this book Ferreira gives some of the best explanations of the following subjects:

- Euclidian geometry turned on its head (ie., parallel lines intersect on a sphere)
- Einstein's field equations (how matter is distributed and the implications for an evolving universe)
- The debate over a static v evolving universe (de Sitter, Friedmann, Lemaitre.... excellent history!)
- Background radiation (this was the only subject Ferreira presented less well than other authors. It was still enjoyable).
- Chunks and strings in space (string and quantum loop gravity)

No one does a better job of presenting quantum loop gravity than Ferreira. His discussions of Smolin, Sakharov, and other scientists who challenged general relativity were by far the most comprehensive and easy to understand of any author I have ever read. He has a great gift for keeping it simple enough to understand while still preserving much of the actual theory for his reader. This book is excellent!

[Angela · Rating 4 out of 5]

I picked this up randomly because I am a sucker for popular science. In fact for most of high school I was totally going to be a theoretical physicist & read every pop physics I could get my hands on, then gave it up because I thought I was probably not good enough at math.

Fast forward 20 years to when I am not a theoretical physicist, but do have two math degrees and actually studied general relativity in college. I enjoyed this book because it was more about the social (and personal) history around the development of the theory of general relativity and all its many reverberations throughout the world of physics, though the author (a physicist) did a good job of explaining some very, very abstract math & science for a lay audience.

A lot of what was covered I'd read or heard before, but there was plenty of new stuff, particularly everything that's happened in the last ten years or so and the last parts about where things may be headed in the next few years. My only complaint is that, now that I DO understand quite a bit of math & have studied GR rigorously, I was craving more technical/mathematical discussion of things. (Which, I get that it just wasn't appropriate for the audience of this particular book.)

[Nilesh Jasani · Rating 3 out of 5]

A 20th century physics book without quantum mechanics is always an ambitious project. The author did well to keep out the QM largely if that was one of the objectives and the resultant exclusive focus on relativity leads to a somewhat different popular science book than what one is used to. That said, the book mysteriously skips any reasonably detailed discussion of the theory itself with almost entire discussions on the stories of its fall and rise.

In a way, most recent books on astronomy or cosmology cover the same grounds starting from the usual 1905 papers to the inadequacies of special relativity, the great proof through the bending of the light around the eclipsed sun, the accidental discovery of the CMB, black hole time horizon/radiation, the coming in/going out/re-coming in of the cosmological constant, dark energy/matter mysteries, loop quantum gravity versus superstring etc. This book covers the same topic in similar details - the difference is the context: rather than an attempt to explain the mysterious world, the attempt here is to explain the evolution of the relativity theory.

The main problem is scant description of the theory that is at the centre of the book. The author might have been warned by publishers or friends to keep the popular science book simple and without equations, but he could have easily inserted a skip-able chapter or two on the description and implications of the ten field equations. He should have discussed in detail why these equations are open to discoveries from within even a century later because of their interactions and non-linearities. He should have discussed the near infinite possible solutions of these equations including the most implausible, unproven wildest that exist today along with those that appeared impossible before but were proven right (which he discusses quite abundantly while showing the repeated fallibility of the great man himself).

To a degree a missed opportunity.

[Sonny · Rating 4 out of 5]

― “To look at black holes directly is a bit of a paradox. There is nothing there to see—black holes are invisible behind the Schwarzschild shroud. Just because we can’t see them doesn’t mean they aren’t worth looking at. In fact, we have a gigantic black hole sitting right in the middle of our galaxy, the Milky Way. It weighs about a hundred million times more than the sun and has a radius of about 10 million kilometers.”
― Pedro G. Ferreira, The Perfect Theory: A Century of Geniuses and the Battle over General Relativity

While I have developed a great love of history, which is reflected in my reading habits, my first true love in school was science and mathematics. With plans to pursue a career in engineering, I loaded up on math and science courses in both high school and college. I also took German language courses because it can help upgrade an engineer’s profile (Note: I left marine engineering after 14 years to pursue a career in healthcare data analytics for the next 30 years). When asked to write a term paper for my high school physics class, I wrote the paper on Albert Einstein’s theory of relativity. Unfortunately, I have forgotten much of what I learned while writing that paper. After all, it was more than 50 years ago. And, frankly, the field of physics has uncovered much new information since then. The field is now engaged in understanding dark matter, quantum mechanics and particle physics, black holes, gravitational waves, quasars and neutron stars. Determined to better understand general relativity and to grasp the new information being uncovered, I thought that Pedro Ferreira’s book, The Perfect Theory: A Century of Geniuses and the Battle over General Relativity might just be the book I needed to read.

Albert Einstein was a German-born theoretical physicist, widely acknowledged to be one of the greatest physicists of all time. Einstein is known widely for developing the theory of relativity. In 1905, Albert Einstein determined that the laws of physics are the same for all non-accelerating observers, and that the speed of light in a vacuum was independent of the motion of all observers. This was the theory of special relativity. It introduced a new framework for all of physics. Einstein then spent 10 years trying to include acceleration in the theory and published his theory of general relativity in 1915, for which he received the 1921 Nobel Prize in Physics. At the core of Einstein's general theory of relativity are a set of equations that explain the relationship among gravity, space, and time—perhaps the greatest intellectual achievement of modern physics. It introduced a new framework for all of physics and proposed new concepts of space and time. Some implications of general relativity were found immediately. It correctly determined the value of the perihelion of mercury. There were two astonishing experimental observations which relativity successfully predicted. Among other things, his equations predicted an expanding universe. Prior to this revelation, everyone assumed that stars and galaxies drifted at random. In 1919, when scientists were able to experimentally confirm the theory’s prediction of the bending of light rays by gravity, Einstein suddenly became a media superstar. Ever since, physicists have been exploring and debating Einstein's theory in their search to discover the origin of the universe and the evolution of stars and galaxies. Amazingly, none of the theory’s predictions have been proven wrong after 100 years.

― “Every time I give a public lecture about what I do, I am asked the same thing: ‘What was there before the Big Bang?’ I resort to the various explanations. There is the ‘There was no before, no time, before the Big Bang’ answer. Or there is my colleague Jocelyn Bell Burnell’s more Zen-like answer: ‘That is like asking what is north of the North Pole.’”
― Pedro G. Ferreira, The Perfect Theory: A Century of Geniuses and the Battle over General Relativity

Author Pedro Ferreira is a Portuguese astrophysicist and is Professor of Astrophysics at Oxford. Ferreira described the book as a “biography of general relativity.” His intent is not really to explain the theory as much as it is to describe the human drama surrounding Einstein’s theory. It is a popular account of how Einstein’s Theory of Relativity continues to generate new knowledge. His focus is more on the science and the scientists that make up general relativity's history. Ferreira principally describes what other people did with Einstein's general theory of relativity after he developed it. More than 100 years after its publication, scientists are still realizing its usefulness as a tool for understanding the cosmos. Astronomers began discovering phenomena that required relativity, including quasars, neutron stars, dark matter, and black holes. Ferreira explores several strands of how the theory has developed: dark matter and dark energy, quantum theory, gravitational waves, and string theory, although none of them in great detail. It’s an amazing story of the theory that inaugurated one of the great eras in the exploration of the cosmos.

[Scott Ransom · Rating 4 out of 5]

As an astronomer who works on testing general relativity with pulsars, I found this a great book. And I'll be recommending it to both my non-scientist and scientist friends. It is fun, upbeat, well-written, and a very nice summary of the history of GR and our status with it now. It is also full of nice anecdotes which help to flesh out the (fascinating) famous physicists who have been involved. Definitely recommended.

[Luis · Rating 5 out of 5]

This book will satisfy you innermost curiosity about the current understanding of the universe at large scale, as well as kindle your interest about quantum theory and mechanics.

Being an engineer myself, without any previous formal education on advanced physics or mathematics, P. Ferreira's work motivated me to follow this amazing road towards the understanding of nature.

I suggest you go for it, whatever your background is. No regrets.

[Michael Huang · Rating 4 out of 5]

This is the story of the general relativity — the theory that took Einstein 10 years to develop, and Eddington’s spectacular verification of its prediction made Einstein an overnight global super star.

From that theory, you can predict the formation of black holes and study the curvature of the universe. The book tells the stories to a general audience. And yet the interesting pieces are how Einstein and Eddington both refuse to believe in the conclusions drawn from the mathematical derivation of the theory, thinking those conclusions are mere math oddities not physically relevant. Legend has it that when someone commented to Eddington that the only 3 people in the world understood general relativity, Eddington paused, not for modesty, but blanking out on who the 3rd person is. Later development clearly showed that even these two pioneers didn’t fully understand general relativity, at least not its full implications. J. J. Thomson (discover of electron) was spot on when he said general relativity “is the result of one the highest achievements in human thought”.

[vonblubba · Rating 4 out of 5]

A very interesting journey on the history of general relativity, from its conception to modern developments that seem to indicate that a new theory May Be required.

There's no explanation of general relativity here, nor of the other theories mentioned, so a previous basic understanding Is required. I know a Little about relativity but close to nothing about string theory and quantum gravity, so I couldn't quite follow the last chapters in the book. Otherwise a great read.

[Willian Fonseca · Rating 5 out of 5]

It has been over 110 years since Relativity Theory was originally proposed by Albert Einstein.

From time to time, I read a book about a subject completely out of my daily life. In this way, I try to learn, remember or reinforce my knowledge about a subject I like, have interest or curiosity. The creation of the universe, dark matter and black holes are some of them.

The author actually unfolds in the evolution of our understanding of the physical rules that govern the universe (focusing on the theory of relativity) and not necessarily the mathematical formulas that prove their veracity. This made the book "easier" to read and understand for someone who has always had difficulty with physics.

It is very interesting to see how since its proposition in 1905 by Albert Einstein, to the present day, the theory of relativity and its derivative sciences contribute in a practical way in our daily lives and remains more relevant than ever. With each question answered and confirmed by mathematical models and practical experiments, even more complex questions arise that generate new fields for science. Going through Quantum Theory, nuclear energy, and String Theory, as time goes on and knowledge evolves and accumulates, an even modest contribution to the evolution of our understanding becomes increasingly difficult.

Physicists and scholars have often spent a good part of their lives, if not all of their lives, working on theories and concepts that led them to a dead end. A life of sacrifice and dedication is necessary for a tiny contribution of our understanding of the universe. Remembering that this contribution may be in the form of deconstruction of some previously accepted understanding. So a correction on the route sometimes puts us two steps back (but on the correct route).

There is also the human factor (faith, ego, pride, jealousy, preconception, economy, social, etc.), which over these many years have greatly hampered the development and progression of this theme.

As environmental engineer, I made parallel to "global warming" and "climate change," and the evolution of the Theory of Relativity. I finish this book surely more hopeful than I started. However, with a feeling about my expectation if humanity will be able to tackle the causes of climate problems in time.

On one hand, in the evolution of the understanding of the Theory of Relativity, a science considered accurate and relatively exclusive to the academic and research world, physicists many times disagree, often for human, and not necessarily scientific, issues, leading us to delays and significant changes (sometimes unnecessary) in our routes to achieve the main objective. On the other hand, some of these unnecessary changes gave us great contributions to the practical, daily life.

After this book, I understand that solving the climate problem is more complex than understanding the origins of the universe. This is because by the time we understand the problem (I believe we already know), find the answers (we know some), and agree on the solution (we are far away), perhaps, and very likely, it is going to be too late.

[Jake Dennie · Rating 4 out of 5]

Author is a great biographer for a physicist, really helping the reader to get to know the characters involved. Not much of a cohesive story/theme and I didn't get much from most of the stories, but there were enough scattered gems to make it well worth the read. The biggest theme for me is just how stubborn even the most brilliant people can be in privileging their intuition over the evidence. I'll probably never forget that Einstein, along with the vast majority of the physics community, refused to believe in the singularities proved by his own theory for decades; I'll keep using that story to get people to question their own intuition.

[ThatBookMan · Rating 5 out of 5]

Science - The general relativity theory specific, written in an accessible language. For anyone interested in modern cosmology this is a must read.

The Perfect Theory describes, explains and goes through the history of Einstein’s general relativity theory step by step. How it was born, how it survived the test of time, and how it is holding up a hundred years later. Science books may be quite difficult for most people but Pedro G. Ferreira did an impressive job with making this book accessible to the world. Wether you are a die-hard science lover or simply just interested in the universe.

[Sarrvesh · Rating 4 out of 5]

Pedro Ferreira presents an interesting overview of the evolution of General Relativity as the theory of Gravity.

[Gene Edwards · Rating 3 out of 5]

This book brings you up to date regarding the status of relativity. It does so in an easy to comprehend format.

[Eva Haneborg · Rating 5 out of 5]

Read like a biography written by an respectful and loving friend. Even if the author looks for some alternatives to the theory and at the end presents some intriging questions and obstacles for it, it feels like it is written with love for the theory. It isn't just a tale of mathematics and physics, but also the people behind it's every turn. This book makes me miss my pyhsics classes. At the same time wondrous and entertaining this was a joy to read.

[Hollywood · Rating 4 out of 5]

“This book is the biography of general relativity.” Overall, a good story of the individuals involved in the advancement of physics, including General Relativity, the Stand Model, String Theory and to today's Quantum Gravity. Not to technical so a good book for people just looking for a high-level overview. Knowledge enough to be dangerous.

"By measuring the positions of those stars, Eddington had found that the theory of gravity invented by British Science's patron saint, Isaac Newton, a theory that had been accepted as truth for over two centuries, was wrong. In its place, he claimed, belonged a new, correct theory proposed by Albert Einstein, known as the “general theory of relativity.”

“According to Einstein, space and time are intertwined in a cosmic dance as they respond to every single speck of stuff imaginable, from particles to galaxies, weaving themselves into elaborate patterns that can lead to the most bizarre effects.”

“Almost a third of the universe seems to be made up of dark matter, heavy, invisible stuff that swarms around galaxies like a cloud of angry bees. The other two-thirds is in the form of an ethereal substance, dark energy, that pushes space apart. Only 4 percent of the universe is made of the stuff that we are familiar with atoms.”

“The Scottish physicist Hames Clerk Maxwell showed that these two forces could be seen as different manifestations of one underlying force, electromagnetism, and that how they are perceived depends on how an observer is moving. A person sitting next to a bar magnet would experience magnetism but no electricity. But a person whizzing by would experience not only the magnetism but also electricity. Maxwell unified the two forces into one that remains equivalent regardless of an observer’s position or speed.”

“The latter postulate required some adjustments to Newton’s laws. In the classic Newtonian universe, speed is additive. Light emitted from the front of a speeding train moves faster than light coming from a stationary source. In Einstein’s universe, this is no longer the case. Instead, there is a cosmic speed limit set at 299,792 km per second. Bit then odd things happen. So, for example, someone travelling on a train moving at close to the speed of light will age more slowly when observed by someone sitting at a station platform, watching the train go by. And the train itself will look shorter when it is moving than when it is sitting still. Time dilates and space contracts.”

“Sitting in an accelerating spaceship should feel no different from sitting in a spaceship at rest, feeling the pull of gravity. As Einstein has realized, at its simplest level, acceleration is indistinguishable from gravity.”

“In essence, Einstein argued that what we perceive as gravity is nothing more than objects moving in geometry of spacetime. Massive objects affect the geometry, curing space and time. Einstein has finally arrived at his truly general theory of relativity.”

“We can think of light as a collection of waves with different wavelengths corresponding to a different energy state. Red light has a longer wavelength and lower energy state than blue light, at the other end of the spectrum. When we look at a star or galaxy, or any bright object, the light it emits is a mixture of these waves, some more energetic than others. What de Sitter found was that the light of any faraway object would be invariably pushed toward the red, appearing to have a longer wavelength and less energy than similar objects.”

“When a source of light is moving away from an observer, the wavelength in its spectrum appears to stretch. The new effect is that light will look redder. Conversely, is a source of light is moving toward the observer, its spectrum is shifted to shorter wavelengths and will look bluer. This effect, known as the Doppler effect, is something you have probably experienced in the context of sound.”

“Robert Oppenheimer wasn’t particularly interested in the general theory of relativity. He believed in it, as any sensible physicist would, but he didn’t think it was particularly relevant. Which would make it ironic that he would discover on of the strangest, most exotic predictions of Einstein’s theory: the formation of black holes in nature.”

“Oppenheimer showed that is a star is big and dense enough; it will collapse out of sight. As he put it, after a while “the star tends to close itself off from a communication with a distant observer; only its gravitational field persists.”

“Stars had until then been a bit of a mystery. For a start, no one had a clear idea of how they could emit such copious amounts of energy. It was Eddington who came up with a plausible mechanism for how stars are fueled. To understand his idea, we need to take a close look at the simplest atoms. A hydrogen atom is made up of two particles, a proton (which is positively charged) and an electron (which is negatively charged). The proton and electron are held together by electromagnetic force, which causes opposite charged to attract one another. The proton is approximately two thousand times heavier than the electron and so makes up almost all the weight of the hydrogen atom.”

“If most of the sun started in the form of hydrogen, it should be able to burn for almost 9 billion years before its conversion into helium is complete. Given that the Earth is currently about 4.5 billion years old, the numbers seem to add up.”

“After proposing a source for stars’ energy, he explained why they didn’t collapse: they could withstand the pull of gravity by radiating all the energy they produced outward.”

“Quantum physics divided nature into its smallest constituents and put it back together in an outlandish way. It emerged from the bizarre phenomena that were being observed in the nineteenth century when physicists discovered that compounds and chemicals reemit or absorb light in a peculiar fashion.”

“The most notorious result to come out of the new quantum physics was the uncertainty principle. In classical Newtonian physics, objects move in a predictable way in response to outside forces. Once you know the exact positions and velocities of a systems’ constituents and any forces on the system, you can predict all the systems’ future configurations. Prediction becomes particularly easy; all you need to know is each particle’s position in space and the direction and magnitude of its velocity. But in that new quantum theory it was impossible to know both the position and the velocity of a particle with perfect accuracy. A particularly persistent and stubborn experimenter in a lab who tires to pin down the position of a particle with perfect precision will have absolutely no idea what its velocity is.”

“Quantum physics brought uncertainty and randomness into the heart of physics. It was precisely this randomness that could be put to use in solving the problem of white dwarfs.”

“The Manhattan project focused its resources on producing the first atomic bomb, and in just under three years they had achieved their goal. When the two atomic bombs, Little Boy and Fat Man, were dropped in Hiroshima and Nagasaki in August of 1945, around two hundred thousand people were killed.”

“Einstein’s last years were shadowed by illness. In 1948 he was diagnosed with a potentially fatal aneurysm of the abdominal aorta. The aneurysm grow slowly over the years, and Einstein prepared himself for the inevitable. In mid-April, his aneurysm finally burst, and after a few days in the hospital, Einstein died.”

“It had been apparent from the moment Hubble made his groundbreaking measurement. Hubble found that the expansion rate of the universe was approximately 500 kilometers per second per megaparsec. This meant that a galaxy that was about a megaparsec distant from us (roughly 3 million light-years) would be speeding away from us at about 500 kilometers per second. From this number, now know as the Hubble constant, it was possible to use Friedman’s and Lemaitre’s models for the evolution of the universe, wind back the clock, and figure out the exact moment in time when the universe came into being. And by doing this it was possible to work out that the universe was about a billion years old.”

“Radio waves behave just like light waves, but their wavelengths are a billion times longer than those of visible light. The light we can actually see, which makes up the bulk of the sun’s rays, has a wavelength that is less than a millionth of a meter. Radio waves have gigantic wavelengths, ranging from a millimeter all the way up to hundreds of meters.”

“There was something of Einstein is the young Hawking, and indeed his childhood friends would often call him that. He hadn’t shone at school, and if anything, he had been relaxed, playful, and naughty, a slight, untidy boy who delighted in entertaining his colleagues. Hawking has become increasingly interested in science and, on applying to Oxford, had aced the entrance exam and interview. He found Oxford ridiculously easy and had done well enough to impress his tutors and lecturers. It was a Cambridge as a PhD student, under Sciama’s tutelage, that Hawking would be steered toward the cosmos and, finding his scientific voice, would spell out one significant consequence of Penzias and Wilson’s discovery.”

“The equations for quantum physics tells us how the quantum state of a system, such as an electron bound to a proton in a hydrogen atom, evolves with time. It makes a very clear distinction between space and time. Einstein’s special relativity brings space and time together into one indivisible thing – spacetime. It also combines the laws of mechanics and the laws of light into a coherent framework.”

“Particles in the universe can be divided into two types – fermions and bosons. As a rule of thumb, the particles that make up stuff are mostly fermions, and the particles that carry the forces of nature are mostly bosons. Fermions include the building blocks of atoms, such as electrons, protons, and neutrons.”

“The combination of the electroweak and strong theories became known as the standard model and made accurate predictions that were confirmed in laboratories like the gigantic particle accelerator at CERN in Geneva, Switzerland. This almost completely unified, yet powerful and predictive quantum theory of the three forces – electromagnetic, weak, and strong – was universally accepted.”

“Hawking’s calculation was able to show that the temperature with which a black hole shines is inversely proportional to its mass. So, for example, a black hole with a mass of the sun would have the temperature of a billionth of a Kelvin, and a black hole with the mass of the moon would have a temperature of about 6 degrees Kelvin. As the black hole shines, it sheds some of its mass. This process happens incredibly slowly. A black hole with the mass of the sun would take an inordinate long time to shed all its mass, or evaporate, as Hawking described it. But much smaller black holes could evaporate much more quickly.”

“Unlike electromagnetic waves, gravitational waves have proved incredibly difficult to find. They are very inefficient at carrying energy out of a gravitating system. As the Earth orbits around the sun at a distance of 150 million kilometers, it slowly loses energy through gravitational waves and drifts closer to the sun, but the distance between the Earth and the sun shrinks at a minuscule rate, about the width of a proton per day. This means that during its whole lifetime, the Earth will drift closer to the sun by a mere millimeter.”

“In fact, a large fraction of the universe appeared to be in the form of exotic substances we had never seen in a laboratory. Dubbed ‘dark matter’ and ‘dark energy,’ they were out there, affecting spacetime, yet strangely elusive and undetectable. The case for a dark universe emerged forcefully one afternoon when the large-scale structure of the universe was discussed. It was that one topic that had drawn me into cosmology in the first place.”

“The new model of the universe contained a cocktail of atoms, cold dark matter, and a cosmological constant. It was the universe that large-scale structure had been hinting at for a decade but that hardly anyone had been ready to embrace.”

“The cosmological constant was now universally accepted. The fundamental problem remained: the gross inconsistency with what Zel’dovich had predicted from adding up the energy of the virtual particles in the universe and the value that was actually observed, a mismatch of over a hundred orders of magnitude.”

“Stephen Hawking was offered the Lucasian Professorship of Mathematical Physics at Cambridge in 1979. One of the most prestigious chairs in theoretical physics in the world, it has been held by Isaac Newton and Paul Dirac and was now being offered to a realavist not yet in his forties.”

“Supersymmetry imagines a deep symmetry in nature that inextricably links all the particles and forces in the universe. Each elementary particle is suppose to have an invest twin: for every fermion there is a twin boson and vice versa. A theory first proposed in 1976 took supersymmetry one step further and mirrored spacetime itself, creating supergravity.”

“The talk addressed the hallowed belief in physics that given complete information about a physical system, it should always be possible to reconstruct the systems past. Imagine a flying ball by your head. If you know how fast it was moving and its direction of flight, it would be possible for you to reconstruct exactly where it came form and what it passed along the way. Or take a box filled with gas molecules. If you could measure the positions and velocities of every molecule of gas in the box, it would be possible to determine where every particle had been at any moment in the past.”

“In fact strong theory started off as a cottage industry in the late 1960s, trying to explain the behaviour of the whole zoo of exotic new particles that were appearing in particle accelerators experiments. The basic idea is that these particles, time pointlike objects, were better described in terms of microscopic, wiggly pieces of string. Particles with different masses would be nothing more than different vibrations of minute strings that floated around through space. The trick is that only one such object, one string, could describe all the particles. The more a strong wiggled, the more energetic it was and the heavier the particle it would describe. It was unification of sorts, but in a completely different way from what had ever been proposed.”

“A rough estimate let to the possible existence of 10 to the exponent of 500 solutions for each version of string theory, a truly obscure panorama of possible universes that became known as the landscape. String theory remained unable to make unique predictions.”

“Daniel Friedan, a prominent string theorist is the first string revolution of the 1980s, acknowledge sting theory’s shortcomings. As Friedan admits, the long-standing crisis of string theory is its complete failure to explain or predict any large distance physics…String theory cannot give any definite explanations of existing knowledge of the real world and cannot make and definite predictions. The reliability of string theory cannot be evaluated, much less established. String theory has no credibility as a candidate theory of physics. These skeptics remained in the minority and were easily drowned out. If you were to enter the field of quantum gravity in the 1980s or 1990s, you might be forgiven if you thought that the covariant approach had won and string theory was all there was.”

“If fact we have a gigantic black hole sitting right in the middle of our galaxy, the Milky Way. It weights about a hundred million times more than the sun and has a radius of about 10 million kilometers. And just like the Milky Way, all other galaxies should have black holes firmly in their centers like massive engines surrounded by gargantuan spirals of stars.”

“A grander possibility is that spacetime is much vaster than we previously envisioned and our universe is only one of countless universes that together make up the multiverse. All other multiverse, universes are breaking out into existence, growing to cosmic proportions, each one at its own pace and made up its own particular way. If we follow back the existence of our own universe, we find that it is embedded like a pustule in a much wider spacetime that has existed for all eternity. The multiverse is a wild, immense realm of what is ultimately stasis: a steady state of creation and destruction.”

[Chris Esposo · Rating 2 out of 5]

I thought I'd enjoy this book much more than I did. As of late Quantum Mechanics has taken prominence because of innovations in computing, and of the two great physical theories that emerged from the 20th century, it has by far been more impactful (thus far) to humanity, which included enabling micro computing architectures and devices, as well as life saving devices like the MRI to name two domains. General Relativity, on the other hand, has a far more limited on its impact on a daily-basis, including mostly the enabling of an accurate global positioning system. There may be others, but I'm ignorant of them as a layman to this field.
GR has always seemed more opaque and mystical to me as an outsider because of this lack of "every day touch", and also because science fiction has shrouded many of Einstein's notions with fantastical concepts of time travel, warp drives, and causality paradoxes. To be sure, many of these things may actually end up being true, and if some far future successor civilization to our own achieves just one of the above, GR will probably prove itself to be the greater innovation from their scope in history. Though, perhaps the consequences of the quantum phenomena of entanglement may still yet prove even more abstract and impactful yet, so it's hard to tell.
This book goes through the academic history of GR, from inception to right before the first detection in 2016 of gravity waves, validating consequences of the theory anticipated over 60 years prior to that event. The book does a good job of outlining the major academic institutions and individuals who played a major part of developing the theory and discovering consequences of it both theoretically and in the applied cosmological domains.
Since both Einstein and Relativity have been in the public imagination for so long, especially since the early 2000s when Einstein was proclaimed time person of the century, I found a lot of the things discussed here were redundant with other pop science books written by more sensationalist authors like Brian Greene. The book avoids all of the more crazy consequences of GR however and sticks mostly with the long validation process of the theory, mostly within the domains of cosmology. Here, the nature of black holes, and how they may evolve in physical space plays a major part, with people like Hawking's, Thorne, and Wheeler playing the well-known supporting roles. Yet, again, a lot of this stuff I had already been exposed to from the numerous books and documentaries by Nova on the subject over the years.
This comes to the main issue of this book for a well-read reader for the generalist reader of layman nonfiction in science. There's definitely a glut of books on this subject, and because of that, it's difficult to "add" to what has already been said. For the current reader especially (circa 2019 or after), because this text preceded the 2016 gravitational wave breakthrough, it really offers very little new to someone who grew up reading about Einstein and his work, as a general layman.
I was hoping more emphasis on the technical details of the theory, but this book does not deal much with mathematics, including less than would be desired on conceptual explanation. For instance, the book ends discussing how the notion of space-time seems to need major revising, because it "breaks down" at the quantum mechanical level, and it quotes Wheeler prediction that we will find it to be "foamy" when the right theory to marry these two domains is finally discovered. But it does not even attempt to explain in any functional way what those words or notions really means, no mechanical understanding can be gleaned by the reader from that conversation (a sin for physics text I'm sure).
The book is well written however, and would serve as a good first serious intro to this topic, primarily from a history of science/ideas perspective. For something more meaty, there may be some decent offerings in this subject from some of Leonard Susskind's books. Another superior book on the validation of GR is "The Hunt for Vulcan", which discussed the history of the analyzing the procession of the perihelion of Mercury, and how the classical Newtonian mechanics were not able to deal with this discordance between theory and data in an elegant way, but was simplistically resolved by GR. That book did a great job explaining the concepts of Lagrangian mechanics of the 19th century, and is highly recommended for people interested in the motivations for an alternative theory like GR from the people at the time. Conditional recommend

[Mark Yates · Rating 4 out of 5]

Excellent recap of the development, transformation, and impact of relativity theory. It is a great companion piece to Quantum: Einstein, Bohr, and the Great Debate about the Nature of Reality, by Manjit Kumar, if not quite as well told.

The author's open romanticism to the theory livens the journey from formulation in a patent office to how it describes the edges of the universe (and possibly the multiverse). The rivalries and discoveries could have been a bit more dramatic. The book also suffers a bit because gravitational waves have been discovered since the writing. And there is not a single mathematical example to illustrate the complexity and beauty of Einstein's equations. (An appendix with a basic Lorentz transformation would have been enough.)

Still, the book is very readable and highly recommended for anyone interested in the history of physics.

[John Jr. · Rating 3 out of 5]

Albert Einstein published his theory of general relativity in 1916, so it’s nearly 100 years old. In this clean and clear account for the interested layman, Pedro G. Ferreira presents what could be called a biography of the theory: its family, so to speak, and the environment into which it was born; the sensation surrounding its early years; a relatively quiet spell, in which it was to some degree ignored; and then a long period of tumult, in which unresolved conflicts that had been present all along began coming to the fore. Ferreira doesn’t use this metaphor of a life story—the book is really just a straightforward history—but it’s appropriate in that general relativity has been and still is a living thing, sometimes kicking at its father (Einstein was troubled by some of its implications), often giving enormous help to many others in their work, and showing little sign of fading away quietly despite its advanced age.

As with many genuine biographies, the story here is much more complicated and intriguing than you might expect, with some fascinating characters, lots of factoids, and even a little local color. Astronomer Arthur Eddington had to travel to the tropical island of Principe and confront cloudy weather in order to make observations that would test a prediction about gravity’s effect on light. Einstein, during his years at Princeton’s Institute for Advanced Study, used to walk and talk with logician Kurt Gödel, whose analysis of general relativity allows for time travel. A cosmologist named Alfred Schild, based at the University of Texas at Austin, set up a symposium whose first meeting was planned for December 1963 in Dallas, which was almost canceled as a result of President Kennedy’s assassination late in November. After some maneuvering, the symposium came off as scheduled; the attendees included Robert Oppenheimer, whose name I assume is pretty well known, along with such luminaries as John Wheeler and Roger Penrose, and the discussions led to the coining of the term “quasar.” (The book doesn’t mention it, but Penrose contributed to the decorative arts as well. Though they're challenging to work with in practice, one can use Penrose tiles to cover such things as a bathroom floor, a shower floor, or a large outdoor surface.) One more example: in the early 90s, a research group working on numerical modeling of relativity developed the Mosaic graphical browser for sites on the World Wide Web. Surely it was the most influential of early Web browsers, if not truly the first—contrary to common belief and to what Ferreira says. Many of Mosaic's features are still a fundamental part of Internet Explorer, Google Chrome, Safari, and Firefox. And so, in reading this, you are almost certainly using an offshoot of research into black holes.

[Chase Rendall · Rating 5 out of 5]

I absolutely loved this book. Most people who have studied physics or have an interest in it have at least a basic knowledge of Einstein and the general theory of relativity. Many are aware of Einstein and Hilbert battling to finalize their independent versions of general relativity in 1915 or Eddington confirming the gravitational bending of light in 1919. What was of particular interest to me and is probably a lot less known to the general public was the "golden age" of general relativity, spanning from the early 60s until the late 70s, and which was largely led by John Wheeler.

The most enjoyable chapter for me was reading about the story of Joseph Weber, who became interested in gravitational waves before almost anybody else, and led a completely incorrect path of research through his idea of "Weber bars". Kip Thorne has even described him as the "founding father of the field". Aside from this book, I had never even heard of the man in any other physics publication prior to reading this, so that chapter alone is something that anybody who cares about understanding the history of gravitational waves would be highly interested to read.

I don't understand enough about the history of GR to comment on whether anything was left out or not, but for me, this book presented perhaps the only thorough description of how the field has evolved in the years between its discovery in 1915 and the present, so for that, I give it five stars.

[Patrick Kelly · Rating 5 out of 5]

The Perfect Theory
Pedro G Ferreira

- [ ] A biography of the theory of relativity (TOR)
- [ ] Einstein put is brain to work on the back burner when he was at the patent office but it was still firing
- [ ] TOR proves that the laws of physics exist everywhere in the the universe
- [ ] Einstein fixed Newton
- [ ] TOR is a terrible career choice
- [ ] England physics departments
- [ ] Gravity, space, time, planets, Uranus
- [ ] Einstein’s ‘what we perceive as gravity is actually just objects moving around in space time’
- [ ] He let the math guide him and he was stunned at the beauty of the math of his equations - he was not a math person
- [ ] The cosmological constant and Einstein missing it
- [ ] Einstein did not accept the expanding universe
- [ ] Light, colors, spectrums - that is how we learned about distances and the universe
- [ ] Einstein could not accept the expanding universe or the Big Bang but TOR proved them
- [ ] He spend the last years of his life searching for a unified theory and increasingly became irrelevant in his own field. He also spent these years working against the atomic bomb and promoting pacifism
- [ ] He and Oppenheimer had a interesting relationship
- [ ] Kip Thorn, Oppenheimer, Hubble, Penrose - these are just a few of the names that came from/contributed to TOR
- [ ] Oppenheimer discovered black holes
- [ ] The elegance and beauty of math
- [ ] WWII deferred many leading scientists to work on radio singles, the atomic bomb, or other fields. Radio and the atomic bomb would both contribute to TOR and our understanding of the universe
- [ ] We are able to gauge the age of the universe by calculating the rate of expansion and then working backwards - I still don’t understand how this works. There is no one center of the universe and no one spot of origin - the universe is uniform
- [ ] What are the sounds from space? Radio waves and the universe talking to us
- [ ] Different schools of thoughts and different groups contributing to the field and active debate. There was an important conference at UNC in 1956 that held a lively debate

- [ ] I was doing inventory

- [ ] Pulsars and quasars - the study of stars and elements
- [ ] Dang, the universe is amazing
- [ ] The search for gravity waves
- [ ] Continually building upon TOR and solving the equations and problems that arose from Einstein’s theory
- [ ] Quasars and neutron stars
- [ ] Black holes circling each other
- [ ] Hawking showed that there is radiation that emits from black holes and that they are not black, just very dim
- [ ] I always forget that it is hard to see/detect black holes - what about primordial black holes? What about a small black hole outside of our solar system?
- [ ] It is amazing how quickly these ideas seeped into pop culture
- [ ] LIGO will eventually discover gravity waves - waves that Einstein predicted
- [ ] LIGO took resources away from other valuable experiments and projects. It was not wildly popular, it was controversial, and massively expensive but it works and will
- [ ] The deep search for gravity waves and the extremely subtle nature of them
- [ ] The mystery of gravity waves
- [ ] Is gravity waves what Coop discovers in the tesseract?
- [ ] The computers that were built to model blackholes and the universe built the technology that lead to the internet
- [ ] So much of this is people tinkering and building. This is a book about dozens of scientists but I also want to know about the thousands of people that built the telescopes, antenna, and other tools that lead to these discoveries

- [ ] Dark energy
- [ ] I still don’t understand what the cosmological constant is - it has to do with a gap in TOR and the expansion of the universe - I thought expansion had already been shown
- [ ] I have to go to wikipedia for it - it had to do with the accelerating expansion of the universe
- [ ] The cosmological constant is super important it is also lambda
- [ ] It has to do with dark matter and dark energy

- [ ] M theory, string theory, the pursuit to quantize gravity
- [ ] These are the new theories and ways of unifying the universe
- [ ] They have made space time irrelevant or have a different approach to it? This sounds important. It has to do with Hawking radiation being emitted from black holes. Entropy and storage
- [ ] I read that book at the being of the year that stated the whole universe is time and entropy and time was entropy? I did not understand it
- [ ] Hawking has a quote about m theory being one of the most complicated things to understand
- [ ] Huge debates over these subjects
- [ ] It’s amazing that Hawking could do all of that in his head instead of writing it down - he had to. I am curious about Hawking and states of meditation and what he could do or what went on in his head
- [ ] The grand unified theory would unit the four forces of the universe: gravity, nuclear, weak and strong magnetic forces
- [ ] The golden age of TOR was 60’s-70’s
- [ ] TOR is evolving, it needs a new look, it needs to be and is being refined and probed, there are still problems that need to be solved
- [ ] TOR has gone in waves, decades where it has been the primary focus of cosmology and decades where it is in the dust bins. It looks as if the future of cosmology will be driven by TOR and its refiners. The technology, satellites, and experiments, are mostly founded in and exploring aspects of TOR. TOR is driving our understanding of the universe

- [ ] It is a beautiful time to be alive and more discoveries are on the way, this is an ode to the complexity and beauty of TOR and cosmology. The author loves his work and this is a book for that love
- [ ] I love that science is a team effort and each person builds upon the previous, from the many things I have read there is little negativity and always appreciation for those that came before. Science is a beautiful thing
- [ ] I wanted to read another cosmology book and this was the perfect book, positive, narrative, historic, appreciative, detailed, understandable, cosmic, scientific, and filled with awe. Thank you

I still can't explain what the theory of relativity is

[Johannes Solano · Rating 5 out of 5]

This is the first popular science book I ever read back when I was 15. Professor Ferreira might not have the same authority or popularity of other high profile physicists like Stephen Hawking, Brian Greene, Sean M. Carroll, Roger Penrose, etc. but his book detailing the history and development of general theory of relativity, a little of quantum mechanics and some basic theories of cosmology in the 20th century is well written.
It is very accessible, lucid and pedagogical. If you want to learn about the historical aspect of certain ideas, important contributions of different physicists in the past century or just want to learn physics for the fun of it then this is for you. But, if you are in pursuit of a Physics career/degree then this might not have that much of math or scientific information to get you through. Overall, this book is written for the general audience and does not require any scientific background to start and; the author did a great job of presenting ideas in such an engaging way that the reader will never felt left behind in an esoteric way.

[João Pires · Rating 3 out of 5]

If we could say that general relativity has a biography, this book is that biography.

It tells us the reasons why the Newstons gravity theory needed to be replace, how Einstein created it, and the myriad of people that through all the years have been working on General Relativity. Either evolving it or taking it to its limits.

Another bonus is that this book don't have a single equation, no maths, nothing to much advanced, so anyone can read it.

Fun fact, the author is Portuguese, but the book was originally written in English.
Me as a Portuguese read for the first time a Portuguese translation of a book written by a Portuguese author.

[Javier · Rating 5 out of 5]

Todo lo que tiene que ver con la Relatividad y sus historias relacionadas me apasiona. Esa es la razón por la cual terminé en este libro. Más que intentar ser una explicación más de la teoría, el libro nos cuenta las historias de los hombres que la han desarrollado y de las diferentes aproximaciones que han hecho. Más que de fórmulas, se centra en las ideas, en los conflictos personales, en la grilla que existe entre las diferentes tribus de científicos. Todo lo que ha generado en el estado actual de la física.

Un gran libro, muy recomendable pasa saber cómo hemos llegado a ver al universo de una forma completamente diferente a la tradicional.

[Hubert · Rating 5 out of 5]

Really glad that I read this - it's an excellent view of historical discoveries of general relativity, balancing foci on science and the characters behind the pursuit for knowledge. We get to see into some of the internal politicking amongst, between, and within scientist and scientific groups that doesn't always make the media. It's a great text, and recommend to anyone with an interest in either contemporary physics or history of science.

[Nadav · Rating 4 out of 5]

While reading the first half of this book, I was disappointed. I obviously knew that I had bought a popular-science book and not a General Relativity textbook. But I had not expected so few details the theory iteself, its motivation how it really works. If you didn't know anything about what GR was coming into this book, the only details about the theory you'll know coming out of the books is that it's complicated, and it involves 10 equations (but you won't really know what those are), and that it involves tensors (but you won't know really what that is) and four dimensions.

Nevertheless, as the book progressed, it became more and more interesting. When I forgot my initial disappointment I started to really enjoy the book, and couldn't put it down until the end (I finished most of it in one weekend). It turns out that this book is a very interesting and readable survey (again, lacking many details) of 20th century astrophysics. While I was already familiar with most of the advances of 20th century physics covered in this book - such as the big bang, black holes, neutron stars, quasars, pulsars, the cosmic microwave background, inflation, gravitational waves, dark matter, dark energy, quantum gravity, and various "modified gravity" theories, it was really interesting reading about these advances in proper historical order and in context, showing how these things were discovered and by whom, and that they were all surprising at the time, and not as "obvious" as they are today.

I still think the book is mis-titled. It is not really about General Relativity, it's about the development of 20th century astrophysics and cosmology. Obviously General Relativity played a big part in this development, but so did Quantum Mechanics, and so did Mathematics, computers (as ability to do simulations and find approximate solutions to equations improve), and a lot of other things that allowed this progress. But then again, the book did open my eyes a bit about what exactly Einstein and his contemporary developed, and what only came later. For example, I wasn't fully aware that although black holes are a natural consequence of general relativity (and, I would argue, also of special relativity with its speed-of-light "speed limit" on escape velocity), Einstein did not believe they were necessary, or real. The book also made it clearer for me why Einstein and his contemporary opposed the big bang theory, culminating in Einstein's famous "biggest blunder" of adding the cosmological constant just to allow a eternal unchanging universe.

To summarize, if you do not expect to learn General Relativity from this book, and would like to read a very interesting historical survey of 20th century astrophysics and the people who worked on it - I really recommend this book.

[Michael Johnston · Rating 3 out of 5]

In The Perfect Theory, Pedro Ferreira attempts to explore the history of one of the great foundational theories of physics. As it notes in the book description, "Einstein's theory, which explains the relationships among gravity, space, and time, is possibly the most perfect intellectual achievement of modern physics...."

Ferreira is a fan of general relativity (even if he acknowledges that there are parts of Einstein's theory that are being legitimately challenged today). His wonder at the beauty and complexity of relativity shines through in every page of the book and it is easy to be infected by his joy and wonder. As Ferreira says rather breathlessly, "General relativity is a theory that has constantly thrown up surprises, outlandish insights into the natural world that even Einstein found difficult to accept."

This isn't an explanation of Einstein's theory (although there is a fair amount of layman's explanation), nor is it a biography of Einstein (although, not surprisingly, he makes many cameo appearances). Instead, as the author says, "this book is the biography of general relativity."

The book is fairly long but does a good job of explaining the most important components and proofs of the theory in layman's terms. It also does a nice job of giving brief insight into the brilliance and creativity of those physicists, cosmologists and mathematicians that sought to prove elements of general relativity as well as those that have sought to overturn it (particularly in the last 25 years).

I enjoyed learning about the scientists that have advanced the thinking behind general relativity as well as the ideas of those who believe that it is no longer the most accurate depiction of physical reality. All of the most profound theories on gravity, space and time are referenced and in some way explained here. String theory, quantum physics, and alternative dimensions all make an appearance in ways that add insight into where modern physics stands today.

This is not a deeply complex scientific explanation of physics, but rather an effort to give an understanding of very strange and complex ideas in a way that a general audience can follow. If you are a science buff or fascinated by Einstein, black holes, or complex and creative theories about our universe and our physical reality, I highly recommend this book.