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It was the summer of 1998, recalls Harvard University physicist Lisa Randall, when extra dimensions finally pulled her in. Extra dimensions -- beyond the four we encounter every day (three of space plus one of time) -- have been an ingredient of theoretical physics for decades: mathematician Theodor Kaluza proposed a fifth in 1919, string theory requires 10 of them, M-theory needs 11. But Randall hadn't much use for them, she says, until that summer when she decided they might be helpful to supersymmetry, one of the conundrums she was pondering. Randall contacted Raman Sundrum, a Boston University postdoctoral student...

Gamma-ray bursts could be the signature of ultradense stars. This X-ray image shows the 3C58 pulsar, the remnant of a supernova noted on Earth in AD 1181, which astronomers suspect may be a quark star. It lies about 10,000 light years from Earth.© NASA/SAO/CXC/P.Slane et al. Intense flashes of gamma rays in far-off galaxies might be produced by a bizarre kind of star, consisting of phenomenally dense material in which the particles that make up atomic nuclei have fallen apart. Two astrophysicists have proposed that gamma-ray (gamma-ray) bursts, whose origins have foxed astronomers for decades, might be the signatures of...

In what is widely regarded as the most important scientific discovery of 1998, researchers turned their telescopes to measure the rate at which cosmic expansion was decelerating and instead saw that it was accelerating. They have been gripping the steering wheel very tightly ever since. As deeply mysterious as acceleration is, if you just accept it without trying to fathom its cause, it solves all kinds of problems. Before 1998, cosmologists had been troubled by discrepancies in the age, density and clumpiness of the universe. Acceleration made everything click together. It is one of the conceptual keys, along with other...

Scientists are closer than ever to balancing the checkbook of cosmic matter. This is because two recent independent measurements of normal matter in the universe are in agreement. The results further strengthen the case for the Big Bang theory and for the nature of the universe as astronomers understand it today. The universe contains normal atomic matter, what makes you, your dog, the stars, and everything in between. Normal matter is what Carl Sagan was talking about when he said we are all star-stuff. But in addition to star-stuff, there is invisible dark matter that is known only because the ...

A GROUP of astronomers and cosmologists has warned that the laws thought to govern the universe, including Albert Einstein's theory of relativity, must be rewritten. The group, which includes Professor Stephen Hawking and Sir Martin Rees, the astronomer royal, say such laws may only work for our universe but not in others that are now also thought to exist. "It is becoming increasingly likely that the rules we had thought were fundamental through time and space are actually just bylaws for our bit of it," said Rees, whose new book, Our Cosmic Habitat, is published next month. "Creation is ...

The genius of Albert Einstein, who added a "cosmological constant" to his equation for the expansion of the universe but later retracted it, may be vindicated by new research published today in the journal Astronomy and Astrophysics. The enigmatic "dark energy" that drives the acceleration of the Universe behaves just like Einstein's famed cosmological constant, according to the Supernova Legacy Survey (SNLS), an international team of researchers in France and Toronto and Victoria in Canada, collaborating with large telescope observers in Oxford, Caltech and Berkeley. Their observations reveal that the dark energy behaves like Einstein's cosmological constant to a precision...

WASHINGTON, D.C. - Scientists may not have to go over to the dark side to explain the fate of the universe.The theory that the accelerated expansion of the universe is caused by mysterious "dark energy" is being challenged by New York University physicist Georgi Dvali. He thinks there's just a gravity leak.Scientists have known since the 1920s that the universe is expanding. In the late 1990s, they realized that it is expanding at an ever-increasing pace. At a loss to explain the stunning discovery, cosmologists blamed it on dark energy, a newly coined term to describe the mysterious antigravity force...

Grisha Perelman, where are you? Three years ago, a Russian mathematician by the name of Grigory Perelman, a k a Grisha, in St. Petersburg, announced that he had solved a famous and intractable mathematical problem, known as the Poincaré conjecture, about the nature of space. After posting a few short papers on the Internet and making a whirlwind lecture tour of the United States, Dr. Perelman disappeared back into the Russian woods in the spring of 2003, leaving the world’s mathematicians to pick up the pieces and decide if he was right. Now they say they have finished his work,...

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...