Free Republic

String theory, the doubters say, makes no testable predictions. But this isn't exactly true... A few years ago string practitioners attempted to establish a relationship between the 10-dimensional string world and the 4-dimensional (3 spatial dimensions plus time) world in which we observe interactions among quark-filled particles like protons... This duality between string theory and the theory of the strong nuclear force, quantum chromodynamics (QCD), was recently used to interpret puzzling early results from [Brookhaven's Relativistic Heavy Ion Collider] ... Two new papers by Hong Liu and Krishna Rajagopal of (MIT) and Urs Wiedemann (CERN) address this problem. The first...

According to Stanford physics Professor Andrei Linde, one of the architects of the inflationary theory, our universe (and all the matter in it) was born out of a vacuum... In the same session, titled "Multiverses, Dark Energy and Physics as an Environmental Science," physics Professor Leonard Susskind of Stanford will talk about string theory and its relation to inflationary theory and physics Professor Lawrence Krauss of Case Western Reserve University will represent the skeptic view. The conventional theory of the Big Bang says that the newborn universe was huge, containing more than 10^80 [ten raised to the power of eighty]...

The Sacred Well Congregation, which has about 950 members across the country, prides itself on being an intellectual group. Ron Schaefer, a retired lieutenant colonel who flew F-4s and F-16s during a 26-year Air Force career, says Wicca "meshes perfectly with string theory." Dea Mikeworth, wife of an Army sergeant wounded by a roadside bomb in Iraq, says it reflects "archetypes in the collective unconscious." But Larsen is unabashed about the faith's central appeal. "You can't intellectually talk about witchcraft. You gotta show up," he says. "What Carl Jung, Joseph Campbell and a lot of us universalists think is, people...

If you went back in time and met your teenage parents, you could not split them up and prevent your birth - even if you wanted to, a new quantum model has stated.Researchers speculate that time travel can occur within a kind of feedback loop where backwards movement is possible, but only in a way that is "complementary" to the present. In other words, you can pop back in time and have a look around, but you cannot do anything that will alter the present you left behind. The new model, which uses the laws of quantum mechanics, gets...

Evicting Einstein A physics experiment on the drawing board for the International Space Station could help find the grand unifying "Theory of Everything." Listen to this story via streaming audio, a downloadable file, or get help.March 26, 2004:  Sooner or later, the reign of Einstein, like the reign of Newton before him, will come to an end. An upheaval in the world of physics that will overthrow our notions of basic reality is inevitable, most scientists believe, and currently a horse race is underway between a handful of theories competing to be the successor to the throne.In the running...

Attempts to measure the size, age, and “expansion” of the universe may be a good deal less precise than advertised. But the problem is much worse if the astronomers’ assumptions are incorrect. An astronomer at Ohio State University, using a new method that is independent of the Hubble relation (which relates redshift to distance), has determined that the Hubble constant (the rate at which the universe is expanding) is 15% lower than the accepted value. His measurements have a margin of error of 6%. To “determine the Hubble constant” these six galaxy clusters are a subset of the 38 that...

Harvard University researchers have halted a pulse of laser light in its tracks and revived it a fraction of a millimeter away. Here's the twist: they stopped it in a cloud of supercold sodium atoms, known as a Bose-Einstein condensate (BEC), and then restarted it in a second, distinct BEC as though the pulse had spookily jumped between the two locations. "It's odd," says atomic physicist Lene Hau, the team's leader. "We can actually revive the light pulse and send it back on its way as if nothing had happened." ~snip~ BEC clouds are prized because their atoms' delicate quantum...

Nate Merrill of Old Orchard Beach was browsing through a New Yorker magazine recently when he noticed a cartoon of a man walking by a joint named "Harvey's Place." A sign in the window advertised an evening discussion titled: "Is String Theory (expletive)?" Funny? Perhaps. Offensive? Merrill thought so. "I said I think the New Yorker has taken a step back," he said. "Five years ago, there's no way they would have published cartoons like that." There are times in life when a person needs to say something a little stronger than "Oh, fudge." And "fiddlesticks" doesn't pack quite the...

A new study demonstrates that the shapes of extra dimensions can be "seen" by deciphering their influence on cosmic energy released by the violent birth of the universe 13 billion years ago. The method, published today (Feb. 2) in Physical Review Letters, provides evidence that physicists can use experimental data to discern the nature of these elusive dimensions -- the existence of which is a critical but as yet unproven element of string theory, the leading contender for a unified "theory of everything." ...According to string theory mathematics, the extra dimensions could adopt any of tens of thousands of possible...

In 2006, string theorist Allan Adams of MIT in Cambridge, US, and others offered a more promising check. They showed that some particle collisions could reveal whether certain fundamental assumptions underlying string theory are wrong. Now, another team has shown that the energies needed to reveal such effects are achievable at the LHC, which is being built in Geneva, Switzerland. The team was led by Jacques Distler of the University of Texas in Austin, US. One of string theory's assumptions comes from Einstein's theory of relativity – that the speed of light is the same for all observers, a principle...

A new cosmological model demonstrates the universe can endlessly expand and contract, providing a rival to Big Bang theories and solving a thorny modern physics problem, according to University of North Carolina at Chapel Hill physicists. The cyclic model proposed by Dr. Paul Frampton, Louis J. Rubin Jr. distinguished professor of physics in UNC's College of Arts & Sciences, and co-author Lauris Baum, a UNC graduate student in physics, has four key parts: expansion, turnaround, contraction and bounce. During expansion, dark energy -- the unknown force causing the universe to expand at an accelerating rate -- pushes and pushes until...

The subject of the debate was the Anthropic Principle, which states that the observable universe has to be as it is in order to support life. That is, the fundamental constants of the universe are precisely chosen such that if they were tweaked only slightly, then life, the earth or even our galaxy would not have formed. Thus, these values are as we observe them only because we are here to observe them in the first place. Paul Davies, director of Beyond: The Institute for Fundamental Concepts in Physics at Arizona State University, was the first to speak, arguing that...

Scientists' theories such as Einstein's relativity and string theory mock up mathematical worlds where linear and multidimensional time travel are a reality... String theory is an attempt to bring quantum physics and relativity together, according to Blondin. String theory supports the view that the universe is made of multiple dimensions and opening a porthole between these dimensions could cross time barriers... These examples focus mainly on a one-dimensional travel experience, meaning a person can only travel forward and backward in one pathway. But with the introduction of string theory became the possibility of a multidimensional universe and multidimensional time travel.

For decades, scientists have taken issue with "string theory"-a theory of the universe which contends that the fundamental forces and matter of nature can be reduced to tiny one-dimensional filaments called strings-because it does not make predictions that can be tested. But researchers at the University of California, San Diego, Carnegie Mellon University, and The University of Texas at Austin have now developed an important test for this controversial "theory of everything." Described in a paper that will appear in the January 26 issue of the journal Physical Review Letters L, their test involves measurements of how elusive high-energy particles...

As exciting as the news of our immanent destruction is, science still has yet to fully explain how all of this works. According to the "slimy string theory" of modern physics, subatomic particles begin as a oozy, mucus-like substance and can eventually take recognizable forms of matter like solids, liquids, and gasses but only for a while, about four to eight billion years. With the calculations from the Doomsday Clock group, it now appears that our time is just about up. As soon as their famous clock strikes midnight, all those tiny elemental bits will return to their original state,...

The sun, it turns out, isn't yellow. The earth isn't a perfect sphere. Asteroids can and do have moons. Saturn will soon (in 100 million years, anyway) be shorn of its rings. The equinoxes do not consist of exactly 12 hours of daylight and 12 hours of darkness. Intergalactic space is so empty of matter that a random cube of it, "200,000 kilometers on a side, contains about the same number of atoms as the air that fills the usable volume of your refrigerator." ...Dark energy, dark matter, the failures of string theory, the origins of life -- Tyson happily...

String theorists state that electrons, photons, protons, and all other particles are not zero-dimensional point-like objects (which form the basis of the Standard Model) but rather tiny one-dimensional extended objects that behave like strings. A group of strings vibrate at a specific resonant frequency -- similar to the movement of strings to produce different sounds on musical instruments such as the violin and guitar -- depending on what type of particle they are, such as electron, photon, proton, and so forth. Over the years, string theorists have not generated any experimental data based on fundamental physical law that proves or...

Researchers found that the same law governing the gravitational pull between planets continues to work when objects are separated by as little as 56 micrometers. The finding rules out extra dimensions of 44 micrometers or larger, they report in this week's Physical Review Letters. Discovering extra dimensions with the relatively huge size of a few micrometers would offer spectacular confirmation for string theory, the still unproved body of equations that may unify gravity with the normally incompatible realm of quantum physics. "Even though we haven't seen anything, these results put boundaries on what people can legitimately propose," says experimental physicist...

Particle physics is in the doldrums. Since 1974 it has not made any major advance except to add to the particle zoo and to tweak the Standard Model. String theory has claimed the attention many young physicists, eager for both fresh challenges and new intellectual adventures. But save for a daunting set of equations, string theory to this day is devoid of even a scintilla of direct observational evidence. For these reasons, a lot is riding on the Large Hadron Collider (LHC) that was completed last year and will begin full operation this year... It’s the world’s biggest particle accelerator...

Ramanath Cowsik, a Washington University physicist, will poke and prod at some of the most daunting problems remaining in physics: What is causing the universe to fly apart, faster and faster each year?Why is gravity so weak and so different from the other basic forces in the universe? And what is the true shape of the universe? In an era of big science -- billion-dollar space telescopes and atom smashers -- Cowsik's approach is refreshingly small. The apparatus, called a torsion balance, is cheap and based on a centuries-old idea. He says the torsion balance will cost about $100,000. When...