Publications Departmentby Joćo Magueijo
Perseus Publishing, Cambridge, Mass., 2003
Reviewed by Philip Morrison
Breaking the old speed limit posted by one Albert Einstein in his 20s, this book deploys a racy and provocative text to convey its popularized content of a new cosmology. Jocular, ironic, witty, self-centered, even indignant, Magueijo is all too ready to castigate his adversaries, those comfortable gatekeepers of learning. The author is no aspiring youth but a tenured professor of theoretical physics, age 35. In spite of his own stature within learned gates--University of Lisbon, then Cambridge on a prime fellowship, now enjoying tenure at great Imperial College in London--his voice is embittered. This journey of youthful success is recalled in complaint about the idiots, the sexually deficient, the money wasters. The thin volume is studded with familiar four-letter words, invoked with rude claims about the motives of colleagues, shadowy referees, editors and others encountered.
Our current scenario for cosmology clearly opened its second act among the high simplicities of the 1970s with two visible puzzles. Why is 3-D cosmic space accurately flat (like old Euclid's own), although it lies within Einstein's universal 4-D curved spacetime? Why is its content so uniform on large scale?
In 1980 Alan H. Guth of the Massachusetts Institute of Technology found a unitary explanation for both riddles. Named inflation, it postulates a minute interval of unusually sudden spatial expansion immediately before the slow, steady expansion of space carried all matter outward. That transient field eventually decayed to yield the complex mix of particles (including radiations) that still move through space. The early push is maintained in the Hubble expansion observably under way, now quite likely speeding up.
This very cosmos was in fact described well before any of its complex contents were known. In 1918 Einstein and his friend the Dutch astronomer Willem de Sitter found the broad space and time properties we now believe. Inflation is the repulsive side of gravity's attraction, a kind of matter that stretches cosmic space so fast and far that almost every flaw has been ironed out to approximate local flatness. Our current particle physics allows such behavior, making such a surprise acceptable. Today we freely use what seemed unrealizable in those days.
Nobody would have believed the account Einstein and de Sitter arrived at had it not fitted so neatly what we observe. Before and beyond all the starry galaxies, we see a distant uniform surface, the origin of almost all cosmic photons, pure thermal radiation with utter conformity to the established spectrum shape of old Max Planck's. The same temperature is seen at every point of the sky to better than one part in 100,000. Your coffee cream confirms: uniformity in fluids comes from stirring. It is easy to believe that those photons broke free of the expanding opaque plasma, to stream along while much slower action built the lumpy, gravitating assemblages we call galaxies. The time of that breakout was a rough half a million years after the inflationary flash.
It is the minor deviations from simplicity that give us any early detail. For the past half a dozen years, the task has been to analyze all those minor flaws as hints of the earliest matter and of its changes and motions as our present cosmos grew. There are no new real puzzles, although certainly a great deal remains to be learned--most importantly, the dark, enigmatic legacy of AE: his cosmological "constant."
The book at hand is a People's Manifesto by an articulate and inventive opposition to the complacent consistency I have just expressed. The author and his colleagues are now skeptical of inflation: it is a tale much too pat, an expansion at unlimited speed. To stir the dense, hot mix in the early epochs, you have to race and beat light itself out to the remote boundaries of inflation. Faster than light? Einstein and his partner admitted only one way this could happen: with repulsive gravity. It is in their theory.
Perhaps there is another way, suggests Magueijo. If matter in motion is too slow for light, why not make the speed of light faster and faster into the past? Throwing out heavyweight Einstein and his near constant speed of light is no easy task. Yet that is the burden of the new iconoclasts. Maybe they can make a cosmos with wildly varying speeds of light, and maybe they can keep the gas uniform, but they give no clear reward for so denying our well-tested Einstein on this theorist's journey into the past. Their strongest argument is the very flatness of space: it turns out that a cosmos with a changing speed of light must be a flat one and a uniform one as well, if energy is to be conserved. There is much more to be said about the untested physics of these variable vacuum light speeds. More than one form of theory is out there, to say nothing of the myriad options opened by multiple dimensions.
Magueijo sums up with the view that the AE establishment "think they own us; we think ... they are just a bunch of squares.... We have all the fun in the universe." I hope my comments demonstrate that his last remark is wrong; there is fun with Einstein, too, plus plenty of impressive experimental support. As for the true prize, the grandeur of cosmology, neither the Academy nor its clever hecklers have yet grasped its origins.
Copyright © 2003 Scientific American
Used by permission of the author
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