Product Description

Dealing with cosmology, this book reveals astronomical observations that indicate the presence of a previously unknown force in the universe. It explains, in accessible terms, Einstein's theories and his development of the "cosmological constant".

Product Details

• Amazon Sales Rank: #477763 in Books
• Published on: 2000-10-26
• Original language: English
• Binding: Paperback
• 256 pages

Amazon.co.uk Review
Who would have thought a mathematical constant would make such an engaging character? God's Equation: Einstein, Relativity and the Expanding Universe, mathematician Amir Aczel's tale of the search for a scientific explanation of the universe, features the cosmological constant in a role as complex as Einstein's. The great genius referred to it as his "greatest blunder" but recent events in the world of astrophysics have brought the prodigal term back into the fold as an important part of his field equation. Aczel is a powerful storyteller and makes no secret of his admiration for Einstein; much of the book revolves around his conquest of general relativity. Integrating relativity with gravitation was no easy task (even for Einstein) but the author deftly steers the reader away from the sticky stuff and focuses attention on concepts of importance.

Aczel shows Einstein's aesthetic troubles with the cosmological constant, which preceded theoretical and experimental problems leading to its abandonment. The universe was caught in the act of expansion by Edwin Hubble and the constant, originally invoked to maintain a steady-state universe, was unnecessary. Fortunately, though, the mathematics underlying the constant had become important tools for physicists; observations in 1997 and 1998 by Saul Perlmutter, Neta Bahcall and others showed that the universe will continue expanding indefinitely and sent theorists back to the drawing board to revise their equations. The cosmological constant returned triumphant and, while its inventor might never have approved of it, today's scientific community gives it an honoured role in God's Equation. --Rob Lightner, Amazon.com

Review
In 1912, Albert Einstein wrote down an equation that describes the structure of the universe. But even he didn't recognize its full meaning. Aczel (Probability 1, 1998, etc.) has made a career of explaining the frontiers of mathematics. Here he tackles Einstein's field equation of general relativity not only in the context of modern physics, but in the history of mathematics. When Einstein began to incorporate gravity into his theories, he realized that it must have certain effects on light, ha particular, light leaving a massive object would he red-shifted; its frequency would become longer, as if the object were moving away. Space was curved, and that curvature could be described in terms of non-Euclidean geometry - built on alterations of Euclid's fifth postulate, which after trying unsuccessfully to prove for two millennia, mathematicians decided to treat as an arbitrary and unprovable assumption. The curvature of space and its effect on light made possible experimental verifications of relativity: for example, the positions of stars seen near the sun in an eclipse should differ from their positions when the sun was in another part of the sky. In 1919, a British expedition led by Arthur Eddington measured those star positions and proved Einstein's theories correct. Meanwhile, Einstein had been exploring the cosmological implications of his theory, in particular the question of whether the universe expands, contracts, or remains the same size. Here, for the first time, he did not believe his own calculations and felt it necessary to add a "cosmological constant" to his field equation - a fudge factor he later described as his greatest blunder when astronomers demonstrated that the universe was in fact expanding. More recent theorists suspect that the cosmological constant was needed, after all - but until another Einstein comes along, the field equation remains the closest thing we have to a divine blueprint for the universe. While the actual math is heavy going, Aczel gives a very readable account of the science and the scientists involved. (Kirkus Reviews)

Customer Reviews

Difficult but rewarding read
In this book, Aczel proposes that Einstein's Cosmological Constant, discarded and by the genius himself considered his greatest blunder, is in fact an integral part of the equation that defines the nature of the universe, its past and its future. Some mysterious force is accelerating the expansion of the universe, pushing out on space, countering gravity and making the universe accelerate towards infinity. Aczel argues that in addition to the four known forces: gravity, electromagnetism, the weak and the strong nuclear forces, there is a fifth: the cosmological constant which is the quintessence of the universe. He spoke to many experts in the fields of mathematics, physics, astronomy and cosmology and integrated the ideas of prominent scientists like Eddington, Penrose and Grossman. The chapters deal with stuff like Euclid's Riddle, Riemann's Metric, the expansion of space, the nature of matter and the geometry of the universe but it also serves as a type of biography of Einstein and a history of the development of his theories. There are quotes from Einstein' work and the text is enlivened by portraits, photographs and illustrations. Although an engaging and thought provoking text, it is sometimes difficult to grasp all of the intricacies as there are many formulas that a non-mathematician would not understand. Nevertheless a uniquely stimulating work that concludes with a helpful bibliography and thorough index. I also recommend Marcus Chown's The Universe Next Door, Mark Ward's Universality: Beyond Chaos and Martin J. Rees' Before The Beginning: Our Universe And Others.

Einsteins struggle for the final equation
Inspired by the fact that the universe is ever expanding,
Aczel wrote the history from Einstein to the present
of the thoughts around Einsteins cosmic constant. The main
part deals with Einsteins struggles with his main equation
and the discovery of the first proof for general relativity,
the bending of star light around the sun. This history part
is presented in kind of zooming in at those times and people,
so that one temporarely becomes part of the times of the
process of verificaton and recognition of general relativity.
From the statements about the cosmic constant the author
then leads the reader into modern times, but this time rather
zoomed out, mentioning many people an theories.
It's all gripping to read, but one does not get answers about
the phenomena which introduced the book, namely, how the
universe could possibly accelerate it's expansion.

einstein: not quite for beginners
Aczel's first book, Fermat's Last Theorem, received deservedly high praise although it deals with an historical curiosum. God's Equations is an account of Einstein achievements, a far more difficult subject on which the popular literature is considerable. Aczel's gift is to tell a good story simply without losing substance, and although this book is less easily accessible than his first, it is arguably better.

Einsten's first contribution in 1905---the special theory of relativity which says is essence that the speed of light is constant regardless of how fast the source of light moves towards or away from the observer---is set out simply and clearly as are its scientific antecedents; ie, the advances in physics (Michelson-Morley), non-Euclidian geometry (Riemann, Grossman), and mathematics (Gauss, Minkowski) which underlay the Special theory and, crucially, the later General Theory. The latter was published in the late 1920s and in effect links the Special Theory to Gravity, producing what is referred to today as the first unified field equation.

Two further points are worthy of mention. One is Aczel's extraordinary grasp of the history of science; to take but one example, Aczel traces the progress of Euclidian geometry from ancient Greece via Ptolemy of Alexandria and the Persian mathematician, Nasiraddin, its smuggling Cordoba by Adelhart of Bath in the 12th Century, from whence it was published in Latin in Venice in 1482. The second is Aczel's account of the relevance of Einstein achievements to the breathtaking world of modern physics and cosmology. All this is accomplished with the greatest simplicity in the space of just over 200 pages.