Free Republic

Space and time are pervasive in our everyday experience, and yet it is hard to say exactly what they are. They resist definition in terms other than themselves. Moreover, they have various subtle and elusive properties, with which science continues to grapple. Relativity and quantum mechanics, the physics breakthroughs of the 20th century, revolutionized scientific thinking about these subjects. And this revolution has not played itself out, since cutting-edge physics today involves further radical rethinking of time and space. The Fabric of the Cosmos: Space, Time, and the Texture of Reality, by Brian Greene (Knopf, $28.95), is an excellent guide...

Welcome to the fourth dimension. And the fifth, and the sixth. A team of astrophysicists claims to have identified evidence that space is six-dimensional. Joseph Silk of the University of Oxford, UK, and his co-workers say that these extra spatial dimensions can be inferred from the perplexing behaviour of dark matter. This mysterious stuff cannot be seen, but its presence in galaxies is betrayed by the gravitational tug that it exerts on visible stars. Silk and his colleagues looked at how dark matter behaves differently in small galaxies and large clusters of galaxies. In the smaller ones, dark matter seems...

More than 60 years ago, G. H. Hardy, an English mathematician besotted with abstraction, wrote, " `Imaginary' universes are so much more beautiful than this stupidly constructed `real' one." Were Hardy around today, he'd find plenty of company. From astronomers peering out into space to particle physicists inspecting atomic innards, the more scientists study the universe, the more preposterous, random, and, yes, ugly it becomes. But hold it. How can the universe be thought ugly? This realm of wheeling galaxies whose stars explode gloriously to seed space with the building blocks of life? A cosmos that bore at least one...

December 7, 2004 Shiing-Shen Chern, 93, Innovator in New Geometry, Is Dead By KENNETH CHANG r. Shiing-Shen Chern, a mathematician whose seemingly purely abstract discoveries about the twistings of geometric surfaces have found wide use in physics and mathematics, died Friday at his home in Tianjin, China. He was 93.Dr. Chern also helped set up three mathematics institutes, two in China and one at the University of California, Berkeley. Nankai University, where Dr. Chern established an institute in 1985, reported his death."He's a towering figure in 20th-century mathematics," said Dr. Calvin C. Moore, a professor of mathematics at the...

Physicists have created the state of matter thought to have filled the Universe just a few microseconds after the big bang and found it to be different from what they were expecting. Instead of a gas, it is more like a liquid. Understanding why it is a liquid should take physicists a step closer to explaining the earliest moments of our Universe. Not just any old liquid, either. Its collective movement is rather like the way a school of fish swims 'as one' and is a sign that the fluid possesses an extremely low viscosity, making it what physicists call...

Public release date: 26-Oct-2004 [ Print This Article | Close This Window ] Contact: Steve Koppes skoppes@uchicago.edu 773-702-8366 University of Chicago Scientists zero in on why time flows in one direction The big bang could be a normal event in the natural evolution of the universe that will happen repeatedly over incredibly vast time scales as the universe expands, empties out and cools off, according to two University of Chicago physicists. "We like to say that the big bang is nothing special in the history of our universe," said Sean Carroll, an Assistant Professor in Physics at the University of...

The “Cartesian Split” Is a Hallucination; Ergo, We Should Get Rid of It by Jean F. Drew The Ancient Heritage of Western Science The history of science goes back at least two and a half millennia, to the pre-Socratics of ancient Greece. Democritus and Leucippus were the fathers of atomic theory — at least they were the first thinkers ever to formulate one. Heraclitus was the first thinker to consider what in the modern age developed as the laws of thermodynamics. Likewise Plato’s Chora, in the myth of the Demiurge (see Timaeus), may have been the very first anticipation of...

Most Powerful Eruption in the Universe Discovered Astronomers have found the most powerful eruption in the universe using NASA's Chandra X-ray Observatory. A super massive black hole generated this eruption by growing at a remarkable rate. This discovery shows the enormous appetite of large black holes, and the profound impact they have on their surroundings. The huge eruption was seen in a Chandra image of the hot, X-ray emitting gas of a galaxy cluster called MS 0735.6+7421. Two vast cavities extend away from the super massive black hole in the cluster's central galaxy. The eruption, which has lasted for...

An exotic theory, which attempts to unify the laws of physics by proposing the existence of an extra fourth spatial dimension, could be tested using a satellite to be launched in 2007. Such theories are notoriously difficult to test. But a new study suggests that such hidden dimensions could give rise to thousands of mini-black holes within our own solar system – and the theory could be tested within Pluto’s orbit in just a few years. Black holes of various masses are thought to have sprung into existence within 1 second of the big bang, as elementary particles clumped together...

How an alternate theory of the universe exposes the 'war of words' that underlies modern cosmology. Theoretical physicists have recently been frustrated by a bold hypothesis concerning black holes—specifically, that they don't exist. In March, at the 22nd Pacific Coast Gravity Meeting in Santa Barbara, Calif., George Chapline, an applied physicist at Lawrence Livermore National Laboratory, gave a talk based on ideas he's been incubating for several years. His goal: to amend astrophysics by applying theories of dark energy and condensed matter physics. His work reinvents black holes as so-called "dark energy stars," which are what is left over when...

Why a Large Hadron Collider? Seed asks some of the greatest physicists alive what we hope to learn from the LHC. by Edit Staff • Posted July 6, 2006 12:32 AM View of the ATLAS detector in the experiment hall, roughly 100 meters underground. ATLAS is one of the five particle physics experiments at the Large Hadron Collider. Credit: Guido Mocafico The Large Hadron Collider (LHC) currently under construction at CERN is the greatest basic science endeavor in history. Roughly half of the world's particle physicists, 7,000 individuals, make the Collider their workplace. This single-minded group of men and women...

Cambridge physicist Stephen Hawking and his CERN colleague Thomas Hertog have proposed a radical new approach to understanding the universe that studies it from the "top down" rather than the "bottom up" as in traditional models. The approach acknowledges that the universe did not have just one unique beginning and history but a multitude of different beginnings and histories, and that it has experienced them all. But because most of these other alternative histories disappeared very early after the Big Bang to leave behind the universe we observe today, the best way to understand the past, they say, is to...

THE ENERGY OF EMPTY SPACE THAT ISN'T ZERO [LAWRENCE KRAUSS:] I just returned from the Virgin Islands, from a delightful event — a conference in St. Thomas — that I organized with 21 physicists. I like small events, and I got to hand-pick the people. The topic of the meeting was "Confronting Gravity. " I wanted to have a meeting where people would look forward to the key issues facing fundamental physics and cosmology. And if you think about it they all revolve in one way or another around gravity. Someone at the meeting said, well, you know, don't we...

Newswise — Researchers at Northeastern University and the University of California, Irvine say that scientists might soon have evidence for extra dimensions and other exotic predictions of string theory. Early results from a neutrino detector at the South Pole, called AMANDA, show that ghostlike particles from space could serve as probes to a world beyond our familiar three dimensions, the research team says. No more than a dozen high-energy neutrinos have been detected so far. However, the current detection rate and energy range indicate that AMANDA's larger successor, called IceCube, now under construction, could provide the first evidence for string...

Tuesday, Apr 12, 2005 A century after Albert Einstein published his most famous ideas, physicists commemorated the occasion by trying to demolish one of them. Yesterday astronomers were to tell experts gathering at Warwick University in England to celebrate the anniversary of the great man's "miracle year" that the speed of light -- Einstein's unchanging yardstick that underpins his special theory of relativity -- might be slowing down. Michael Murphy, of the Institute of Astronomy at Cambridge University, said: "We are claiming something extraordinary here. fundamental "The findings suggest that there is a more fundamental theory of the way that...

Could two lookalike galaxies, barely a whisker apart in the night sky, herald a revolution in our understanding of fundamental physics? Some physicists believe that the two galaxies are the same - its image has been split into two, they maintain, by a "cosmic string"; a San Andreas Fault in the very fabric of space and time. If this interpretation is correct, then CSL-1 - the name of the curious double galaxy - is the first concrete evidence for "superstring theory": the best candidate for a "theory of everything", which attempts to encapsulate all the phenomena of nature in one...

stronomers have gazed out at the universe for centuries, asking why it is the way it is. But lately a growing number of them are dreaming of universes that never were and asking, why not? Why, they ask, do we live in 3 dimensions of space and not 2, 10 or 25? Why is a light ray so fast and a whisper so slow? Why are atoms so tiny and stars so big? Why is the universe so old? Does it have to be that way, or are there places, other universes, where things are different? Once upon a time...

The proof that faster-than-light (FTL) propagation is not allowed by nature is simple. Special relativity (SR) forbids it because, in that theory, time slows and approaches a cessation of flow for any material entity approaching the speed of light. So no matter how much energy is brought to bear, the entity cannot be propelled all the way to, much less beyond, the point where time ceases. The entity’s inertia simply increases towards infinity as the speed barrier is approached.[*] But most importantly, relativists are confident that SR is a valid theory because it has passed eleven independent experiments confirming most...

Is string theory the answer to the last big questions in physics, or a dead end? While some physicists believe that string theory could lead to a unifying 'theory of everything,' detractors say that string theory is sloppy and founded on unwarranted assumptions. One new book calls string theory 'not even wrong.' In this hour of Science Friday, we'll look at the pros and con of string theory, with physicists Lee Smolin and Brian Greene.

Scientists use quantum gravity to describe the universe before the Big Bang.Scientists may finally have an answer to a "big" question: If the Big Bang was the beginning of the universe, what could have caused it to happen? Using a theory called "loop quantum gravity," a group led by Penn State professor Abhay Ashtekar has shown that just before the Big Bang occurred, another universe very similar to ours may have been contracting. According to the group's findings, this previous universe eventually became so dense that a normally negligible repulsive component of the gravitational force overpowered the attractive component, causing...