Posted on 02/19/2003 9:18:15 AM PST by RightWhale
Extra Dimensions Showing Hints Of Scientific Revolution
Chicago - Feb 19, 2003
The concept of extra dimensions, dismissed as nonsense even by one of its earliest proponents nearly nine decades ago, may soon help solve seemingly unrelated problems in particle physics, cosmology and gravitational physics, according to a panel of experts who spoke Feb. 15 at the American Association for the Advancement of Science annual meeting in Denver.
"It doesn't happen often that you get a confluence of ideas and experiments that come together and it's something that obviously would change your whole way of looking at the universe," said one of the panelists, Joseph Lykken, Professor in Physics at the University of Chicago and a scientist at Fermi National Accelerator Laboratory. Even though scientists lack direct evidence of extra dimensions, "we have a number of hints from experiments and theoretical ideas that make us think they're probably out there. That's why we're so excited about looking for them," Lykken said. On the theoretical side, string theory, developed over the past two decades, requires that space-time has extra dimensions if it is to include gravity. "It's just built into the way that string theory works," Lykken said.
Experiments, meanwhile, have produced the standard model of physics to describe the most elementary particles and the forces that hold them together. Physicists have come to suspect that something is missing from the standard model. "There seems to be more particles and forces than we really need, and they operate in more complicated ways than they need to," Lykken said. But extra dimensions may ultimately help explain these data complications. "That standard model itself may be our biggest hint that there's this world of extra dimensions," he said.
New experiments at Fermi National Accelerator Laboratory are producing data that just don't fit the standard model, said Maria Spiropulu an Enrico Fermi Fellow at the University of Chicago. "We have things in the data that leave our mouths hanging," she said. Whether extra dimensions or some other phenomenon emerges to clarify these murky data, scientists seem certain that they stand only a few years away from a scientific revolution. "What's going on right now in particle physics, gravitational physics and cosmology is like when quantum mechanics started coming together," Spiropulu said.
Quantum mechanics, developed in the 1920s, describes the physics of objects at the atomic level and dominates the concepts of modern physics. Spiropulu, who organized the AAAS session on the physics of extra dimensions, spoke at the session along with scientists from Fermi National Accelerator Laboratory, Harvard University and the universities of Chicago and Washington. Another panelist, Sean Carroll, Assistant Professor in Physics at the University of Chicago, said that extra dimensions could help solve two mysteries in cosmology: what were the initial conditions of the universe and what is the mysterious dark energy that is accelerating the expansion of the universe. The idea of an inflationary universe, one that expanded rapidly just moments after the big bang, has gained wide acceptance among cosmologists to explain how conditions in the early universe could be unexpectedly different from what they later came to be. But inflationary cosmology tells scientists nothing about the initial conditions of the universe. This is where extra dimensions come in, even though they might be microscopically small.
"If you had extra dimensions, then when the universe is very small at early times, the extra dimensions weren't small compared to the rest of the universe," Carroll said. "They must have played a big role. What was that role? Could the role have something to do how we perceive the initial conditions?" Extra dimensions may also explain dark energy. Physicists conjecture that dark energy is governed partly by occurrences in the familiar four dimensions and partly by occurrences in the extra dimensions, Carroll explained. "There is the tantalizing possibility that a complete change of perspective makes all of the problems collapse at once," he said.
I agree with you that, in the end, it will be astonishingly simple, as Einstein also believed it would be:
But in the days of the voice of the seventh angel, when he shall begin to sound, the mystery of God should be finished, as he hath declared to his servants the prophets. And the voice which I heard from heaven spake unto me again, and said, Go [and] take the little book which is open in the hand of the angel which standeth upon the sea and upon the earth. – Revelation 10:7-8
Would you mind posting your views to the "Freeper Views on Origins?" I think the collection may prove helpful to lurkers wanting to get a picture of all the different viewpoints.
I've been saying around here for a long time that "space and time are part of the creation and not something in which the Creator exists." Our difference of opinion on dimensions is minor by comparison to our agreement on that point!
Ed,
I had heard that as well. Another interesting note is that the magnitude of the problem (iow the question) seems to be exponentially more difficult with each century. The strange part is with each answer there are just more questions. Is there an end game? Or after another 20 centuries will mankind feel just as puzzled about the universe as we do now?
None the less I think something very exciting is on the verge of being discovered. Regards,
Boiler Plate
I'm still looking for that concept, based on pure thought, and logic which can bridge the Physical to the Spiritual, without envoking the pre-existence of Space-Time. If you have found some info. on this, please ping me, I will be very grateful.
This is an ongoing discussion between betty boop, Phaedrus and several others. I happen to have some "digs" for you. These are long threads, so I'm putting the link at a key point in the discussion. You might want to scroll forward or back for more information:
We'll both be watching for progress in this area. I'll give you a heads up if I see something with potential; likewise, I'd appreciate a heads up if you see something.
Just ahead of a bandwagon of theoreticians suggesting the discovery of extra dimensions might be just around the corner, a streetwise inquiry into the potential effects of these additional "spaces" has come up as empty as a gas tank during an oil embargo. Theorists are unlikely to be sobered by the new study of possible effects on gravity in tiny spaces, however. The research is useful in that it puts an upper limit on the distance at which strange new physical behaviors might yet be detected. Further, it explored only one possible manifestation of extra dimensions.
There are three known and obvious spatial dimensions -- the x, y, and z coordinates of basic geometry. Time is considered a fourth dimension. Various exotic theories suggest one or several other, hidden dimensions that would explain mysterious aspects of cosmology, like the relatively recent and inexplicable observation that the universe is accelerating at an ever-faster pace. At the annual meeting of the American Association for the Advancement of Science, held in Denver earlier this month, top physicists and cosmologists expressed optimism that extra dimensions would be soon be uncovered. "We have a number of hints from experiments and theoretical ideas that make us think they’re probably out there," said Fermi National Accelerator Laboratory physicist Joseph Lykken. "That’s why we’re so excited about looking for them."
String theory
Firm signals of invisible spaces might tie one of the most seemingly outlandish ideas, string theory, into reality. String theory is the leading contender seeking to unify the age-old theory of gravity with physical explanations for how very small particles behave. In string theory, elementary particles are not point-like, but instead are more akin to strings. The various forms of string theory each require the existence of at least six extra spatial dimensions. Each is invisible, theory holds, because it is rolled up, stringlike, into a space too small to see. Physicists call this "compactification."
String theorists have suggested that some of these extra dimensions might be detectable by the effect they have on gravity at bantam distances. Perhaps, they say, gravity is diluted as it propagates through several wee spatial dimensions. Another idea is that the extra dimensions could be revealed through "moduli fields," which describe the size and shape of the compact dimensions at each point in ordinary 3-D space, explains John Price of the University of Colorado at Boulder. Moduli fields can act in a way similar to the gravitational field, but are expected to generate forces somewhat stronger than gravity. Advances in technology now make it possible to search for these tiny forces under such micro-conditions.
Price and his colleagues, led by Joshua Long, report the results of the latest experiment, involving a newly built lab device called a high-frequency resonator, in the Feb. 27 issue of the journal Nature. The researchers observed no new forces at distances of about one-tenth of a millimeter. This puts an upper limit on the moduli effects that theorists call the dilaton and radion forces, which remain hypothetical (not to mention highly complex). With funding from the National Science Foundation, the University of Colorado team looked for effects so tiny they're about equal to the weight of one-billionth of a grain of sand. Price was careful to point out that the tests were not designed to prove string theory. "The ideas we test are just 'string inspired scenarios,' not precise predictions of string theory," he told SPACE.com. "It is not yet possible for string theory to make precise predictions of this kind, and I would say that no one knows if string theory will ever be able to that." He said further experiments at even smaller distances may yet "add more patches to the quilt of physics," and therefore it is worthwhile to continue the line of research because "something new and very fundamental could be discovered."
Extra-dimension revolution?
Whatever the fate of string theory, the idea of extra dimensions is gaining steam. Introduced nearly a century ago, the notion was initially laughed at by many physicists. Most aren't laughing any more. Why? For one reason, something is going on that standard physics models can't explain. Among the more compelling bits of inexplicable evidence is the fact that the universe is expanding at an accelerating rate. Some mysterious force, dubbed dark energy for now, is driving the cosmos apart, acting like antigravity. Nobody knows what it is. What they do know is that while gravity holds galaxies together at the local level, some mysterious force is driving galaxies apart on broad scales. Dark energy may involve interactions between dimensions we see and those we don't, some theorists say. At the AAAS meeting, several top cosmologists and physicists expressed optimism that the field would be revolutionized before long.
"There is the tantalizing possibility that a complete change of perspective makes all of the problems collapse at once," said Sean Carroll, an assistant professor in physics at the University of Chicago. These problems inevitably surround gravity, whose force was calculated by Newton more than three centuries ago. "Gravity may have been the first of the fundamental forces to be described mathematically, but it is still the most poorly characterized," says C. D. Hoyle of the University of Trento in Italy. That's because though pervasive, gravity is relatively weak compared to the other three fundamental forces (electromagnetism, and the strong and weak nuclear forces that govern atoms). In particular, scientists have long sought to determine whether Newton's inverse square law -- that the gravitational force between two bodies depends on the inverse-square of the distance between them -- holds up at very small distances, in the so-called quantum world. Newton developed it for astronomical distances, as between the Sun and a planet.
Hoyle, who analyzed the University of Colorado study for Nature, said the "elegant experiment" set the best constraints yet on any possible deviations in the behavior of gravity at small scales. "So far, Newton is holding his ground," Hoyle added. An understanding of gravity at the quantum level is expected to tie it into quantum mechanics and the full descriptions of the other forces. Developed in the 1920s, quantum mechanics describes the behavior of objects at the atomic level. "What’s going on right now in particle physics, gravitational physics and cosmology is like when quantum mechanics started coming together," said Maria Spiropulu, a University of Chicago researcher who organized the AAAS session on the physics of extra dimensions
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