Posted on 02/28/2003 5:57:55 AM PST by Boot Hill
THE NEW YORK TIMES BOOK REVIEW
Faster Than the Speed of Light:
FASTER THAT THE SPEED OF LIGHT The story of a Scientific Speculation. By João Magueijo. Illustrated. 279pp. Cambridge, Mass.: Perseus Publishing. $26. |
By GEORGE JOHNSON
NY Times
February 9, 2003
One of the curiosities of life on earth is the obsession to lay down grids of rigid constraints -- the rules of chess or baseball, the form of a sonnet, or the Internal Revenue Service code -- and then try to stretch them to the limit. Those who excel at pushing the envelope -- chess masters, Olympic athletes, Washington tax lawyers, everyone it seems but contemporary poets -- are generously rewarded with riches and sometimes even public esteem.
The most sophisticated of these sports is theoretical physics, and João Magueijo, a young Portuguese professor at Imperial College in London, has the markings of a champ. Judging from his new book, "Faster Than the Speed of Light: The Story of a Scientific Speculation," this is an opinion with which he would readily agree.
In fact, if your reading list is already overpopulated, skip the book and cruise over to his Web page (http://theory.ic.ac.uk/~magueijo/) for a taste of the persona he presents to the world. As the page loads, a Java cartoon of a beer glass appears on the screen, emptying itself over and over as if the suds were being sucked up by a pulsating black hole. A photo of Magueijo "in action" shows him getting sloshed with some friends; there is a primer on cosmology, the study of the universe, and included on the site is a link to an Internet guide to the London rave scene.
This kind of thing is fairly commonplace. Theoretical physics is populated by some of the smartest people outside Wall Street, and it is de rigueur to show that you are fiercely independent and definitely not a nerd. Where Magueijo hopes to distinguish himself from his pack is by showing that the speed of light, long held as an inviolable entry in the cosmological rule book, is not sacrosanct after all. It has slowed as the universe has grown older. If this can be proved, Magueijo argues, then some of science's most vexing puzzles can be solved.
Consider the horizon problem, a staple of popular science books. Look out (with a suitably powerful telescope) at a galaxy 10 billion light-years away. According to the logic of the Big Bang theory, the light was emitted 10 billion years ago and is just now reaching this part of the universe.
Now turn around and look 10 billion light-years in the opposite direction. You have successfully observed two regions of the universe that themselves are 20 billion light-years apart. Since the whole universe is only 15 billion years old, they will never be able to see each other or (since nothing travels faster than light) interact in any way.
The weird implications of this become clearer if you imagine the earliest moments of the Big Bang. When the universe was a second old, and hence a light-second in radius, about 186,000 miles, opposite points on the circumference were twice that far apart, unbridgeable even by light. No matter how far back you go -- a millisecond, a microsecond -- the regions can never have been in contact. It is as if they exist as two separate universes.
The reason this bothers cosmologists is that, so far as they can tell, the universe in front of us and the universe behind us are pretty much the same. They differ in detail, of course -- this galaxy here, that constellation there -- but in the most general sense, creation appears to be homogeneous. Galaxies are distributed in a more or less uniform manner, and in whatever direction you point a thermometer, space is the same temperature. But if certain parts of the universe never interacted, then why is there so smooth a blend?
The favored explanation is a theory called cosmological inflation: suddenly for a few moments early in its history, the tiny universe began wildly expanding, far more rapidly than it does now. Those now isolated regions were originally close enough to touch.
Some theorists find this a bit contrived, and Magueijo is one of a handful proposing a different solution: if the speed of light used to be faster, then neighborhoods that now seem hopelessly far apart were originally together.
Those are the bare bones of the idea, which Magueijo elaborates throughout the book. Whether that notion is any less ad hoc than inflation is a matter of taste. Depending on how future experiments come out, his theory will one day be recorded as a stunning breakthrough or a forgettable detour down a cul-de-sac.
There is nothing wrong with writing about a work in progress. What better way to give readers a taste for the messiness of real science, before the story has been sanitized in the retelling? But whatever his gifts as a theorist, as an author Magueijo is only partly successful.
The curse of popular science writing is that almost nothing can be assumed. Here Magueijo rises to the task, using the first half of his book to lay out a nice refresher course. (A story about cows and electric fences makes the essence of special relativity about as clear as can be.) It's in Part 2, when he gets into the meat of the story, that the account becomes wearing.
With a bit of patience one can keep up with the gist of his idea, called V.S.L. for "varying speed of light." But what is apparently meant to be an enlightening account of a theory-in-the-making is blackened again and again by a bristly protagonist who, at least as he depicts himself, is very difficult to like.
Everywhere he turns, Magueijo tells us, he finds himself surrounded by stupidity. He refuses to submit papers to the journal Nature (the staff there is surely heartbroken) until the cosmology editor is castrated. (João the Iconoclast puts this in cruder terms.) The timid souls who fail to appreciate the daring of his speculations are likewise reviled. "Clearly something as wild as V.S.L. is an affront to their self-respect; so they need to see it fail." Or maybe they just think he's wrong.
Even his sympathizers come in for ridicule if their support is not avid enough. When an older colleague decides that, on second thought, he doesn't want to collaborate on a paper about V.S.L., this can only be because he is suffering from a midlife crisis (he just turned 40).
Magueijo is so openly contemptuous of the people who finance his intellectual recreations that he seems to be daring them to ground him for a week -- or cut off his allowance. "Personally, I would fire them all and give them a long prison sentence," he writes, "but you already know my thoughts on the matter." Yes, we know. This statement is near the end of the book, and we have been told many times.
This kind of material is probably meant to be described in a review or jacket blurb as "irreverent." But at least since James Watson's "Double Helix," the fact that scientists have rivalries, opinions and even personal lives is hardly surprising. Though we get some glimpses here of theorists grappling with an elusive idea, too much of the story comes off as puerile.
In the end, Magueijo assures us that, win or lose, it is he who will get the last laugh. If the theory is right his doubters will rush to claim credit, for "they are bandwagon passengers, those who play safe and lead an easy life." And if the theory is wrong? He'll burn that bridge when he comes to it.
George Johnson's book "A Shortcut Through Time: The Path to the Quantum Computer" will be published next month.
Planck time, or about 1E-43 seconds, the theoretically smallest possible unit of time. Compared to that, a nanosecond is an eon!
--Boot Hill
World's Most Powerful Telescopes Team Up With a Lens in Nature to Discover Farthest Galaxy in the Universe (source)A galaxy 13E9 ly distant in a 14E9 year old universe? Hmmmm!An international team of astronomers has discovered the most distant galaxy in the universe to date. They found it by combining the unique sharpness of the Hubble telescope with the light-collecting power of the W. M. Keck Telescopes with an added boost from a gravitational lens in space.
The results show the young galaxy is as far as 13 billion light-years from Earth, based on an estimated age for the universe of approximately 14 billion years. The Hubble picture at left shows the young galaxy as a red crescent to the lower right of center. The galaxy's image is brightened, magnified, and smeared into this arc-shape by the gravitational influence of an intervening galaxy cluster, which acts like a gigantic lens. The image at upper right is a close-up of the "gravitationally lensed" galaxy. In the picture at lower right, astronomers have "unsmeared" the galaxy, revealing the galaxy's normal appearance.
--Boot Hill
Suppose you take a line that's 50 feet long, and you position yourself at the center of it:
------------------------- * -------------------------
Next, you look to either direction, and see two things that are each 20 feet away from you:
-----|------------------- * --------------------|-----
This would lead you to conclude that the two things are 40 feet from each other. But the universe is curved - if you take either end of the line, and bring them together to form a circle with a diameter of 15 feet, then the two things that you are observing turn out to be only 10 feet from each other, not 40 feet.
Suppose you take a line that's 50 feet long, and you position yourself at the center of it:
------------------------- * -------------------------
Next, you look to either direction, and see two things that are each 20 feet away from you:
-----|------------------- * --------------------|-----
This would lead you to conclude that the two things are 40 feet from each other. But the universe is curved - if you take either end of the line, and bring them together to form a circle with a diameter of 15 feet, then the two things that you are observing turn out to be only 10 feet from each other, not 40 feet.
Typical crank behavior. "They don't believe me because of The Conspiracy, not because my theories are faulty!"
Or maybe they just think he's wrong.
Bingo.
No matter how weird or unconventional his theories, if they were self-consistent and explanatory, he'd have no trouble getting people to admit he had something interesting. Relativity and quantum theory were both completely bizarre and contrary to orthodox theory when they were introduced, but had no problem finding converts, because they *worked*, and no holes could be found in them.
This would also be a good place to repost your "Big Bang predictions versus observations" plots, in response to the Big Bang skeptics.
Perhaps you are unfamiliar with how cranky Sir Isaac Newton was when it came to discussions of "his" calculus. Without getting into any defense of João, I wouldn't write him off merely because he was a bit testy, especially where it concerned the journal Nature.
--Boot Hill
As Physicist says so much better than I, "The same thing that is south of the South Pole."
No "whoops" about it.
First, your calculations presume that the universe itself (as distinct from its contents) is a) flat and b) not expanding. Neither presumption is true. You're looking at things as if they were moving along a straight, flat, fixed highway, traveling east and then sending signals back by light-speed carrier pigeon.
Instead, you have to understand that the universe is like a balloon being blown up bigger and bigger, and the objects in it (including us) are ants on its surface.
Imagine that we're standing on the balloon's "north pole". Where are the objects which are the farthest possible distance from us? They're near the south pole (and incidentally all near each other).
Now deflate the balloon so that we can see how things were shortly after the Big Bang (when the universe was much smaller "around"). The most-distant objects weren't all that far from us then. But we aren't yet able to see them as they are at that instant, because light travels by little carrier pigeons (photons) that crawl along the surface of the balloon at the speed of light.
If the balloon (universe) had stayed small, we'd have been able to see them pretty shortly thereafter, but there was a catch. As the carrier pigeons were travelling towards us, the balloon was being inflated quite rapidly. As the carrier pigeons trudge along, the distance between them and us keeps getting stretched larger.
What would have been a few light-year journey had the balloon stayed the original size ends up being a journey of several billion years as the poor carrier pigeons keep trekking along at light-speed as the balloon keeps getting bigger and bigger and bigger as they travel. Eventually, though, they make it to us, and we finally get to see what the most-distant objects looked like many billions of years ago (back when the universe/balloon was young/smallest).
The balloon has been expanding for about 15 billion years, but it's still possible to see light from 10 billion (or more) years ago coming in from an direction, because that light has been fighting an uphill battle against the expansion of space all that time, even though the objects the light is coming from weren't all that far away from us (or each other, or anything else) at the time the light was emitted.
This is also how we can see light traces from the earliest moments of the Big Bang itself by looking far enough away in *any* direction (the "background radiation") -- we're seeing light arriving from the "south pole" (farthest/oldest possible origin) from back when the north and south poles were pretty much right on top of each other. This is like if you set off a huge explosion at the Earth's south pole, the sound of it would arrive at the north pole simultaneously from all directions.
I hope this helps clear things up some.
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