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Strings attached Wanted: Proof that the mother of all theories is correct. Pathik Guha reports But is that physics? That seemed to have been the caveat raised by Richard Feynman, Nobel laureate physicist, against the string theory, popularly known as the Theory of Everything. Though the experts, not particularly fond of hypes, don’t like the name that much, the string theory is one of the attempts to unify the two seemingly irreconciliable concepts — relativity and quantum mechanics — which between them explain everything from an apple’s fall to a picture’s formation on a TV screen. Albert Einstein, always...

The Growth of Inflation Twenty-five years after Alan Guth turned cosmology on its head, what's the latest story of the universe's first moments? by Davide Castelvecchi Photo: Fred Ullrich It was a true Eureka moment if there ever was one. On the night of December 6, 1979, an obscure Stanford Linear Accelerator Center postdoc was up late, sweating over an even more obscure problem about particles called magnetic monopoles. Looking at his calculations the next day, the usually low-key Alan Guth annotated the words "SPECTACULAR REALIZATION" at the top of the page. Guth had discovered cosmic inflation, an idea which...

Astronomers who think they know how the very early universe came to have so much interstellar dust need to think again, according to new results from the Spitzer Space Telescope. In the last few years, observers have discovered huge quantities of interstellar dust near the most distant quasars in the very young universe, only 700 million years after the cosmos was born in the Big Bang. "And that becomes a big question," said Oliver Krause of the University of Arizona Steward Observatory in Tucson and the Max Planck Institute for Astronomy in Heidelberg. "How could all of this dust have...

On Plato, the Early Church, and Modern Science: An Eclectic Meditation By Jean F. Drew God, purposing to make the universe most nearly like the every way perfect and fairest of intelligible beings, created one visible living being, containing within itself all living beings of the same natural order. Thus does Plato (d. 347 B.C.) succinctly describe how all that exists is ultimately a single, living organism. At Timaeus20, he goes on to say: “There exists: first, the unchanging form, uncreated and indestructible, admitting no modification and entering no combination … second, that which bears the same name as the...

Published online: 02 November 2004; | doi:10.1038/news041101-5 Supernova debris found on Earth Mark Peplow Ancient explosion may have affected climate and, possibly, human evolution. Cosmic fallout from an exploding star dusted the Earth about 2.8 million years ago, and may have triggered a change in climate that affected the course of human evolution. The evidence comes from an unusual form of iron that was blasted through space by a supernova before eventually settling into the rocky crust beneath the Pacific Ocean. Gunther Korschinek, a physicist from the Technical University of Munich in Germany, leads a team who in 1999 found...

You can breathe a sigh of relief: the Universe will last for at least the next 24 billion years, according to astrophysicists who have modelled the mysterious force of dark energy to work out the fate of the cosmos. Andrei Linde, a theoretical astrophysicist from Stanford University, California, leads a team who previously predicted that the Universe might end as soon as 11 billion years from now1. But the team's latest research into dark energy, published online at the preprint server arXiv2, gives us a stay of execution. The team's new calculation relies on recent observations from the Hubble Space...

LONDON (Reuters) - An international team of astronomers believe they have solved a mystery that has been perplexing scientists for 100 years -- the origin of cosmic rays. Scientists first discovered the energetic particles that bombard the Earth nearly a century ago but where they come from has been one of the big questions in astrophysics. Using an array of four telescopes in Africa, the scientists produced the first image showing that the source of cosmic rays could be the remnant of a supernova, a powerful explosion of a star at the end of its life. "This is the first...

Dark Matter Halo Puzzles Astronomers Summary - (Oct 26, 2004) Astronomers using the Chandra X-Ray Observatory have discovered a huge halo of dark matter around an isolated elliptical galaxy; an object that shouldn't have such a halo, according to optical observations. The galaxy, NGC 4555, is unusual that it's a large elliptical galaxy which isn't part of a larger cluster of galaxies. It's surrounded by a cloud of gas, twice the size of the galaxy itself, that's been heated to 10-million-degrees Celsius. This gas could only get that hot if it was being constrained by a halo of dark matter...

Earth's spin warps space around the planet, according to a new study that confirms a key prediction of Einstein's general theory of relativity. After 11 years of watching the movements of two Earth-orbiting satellites, researchers found each is dragged by about 6 feet (2 meters) every year because the very fabric of space is twisted by our whirling world. The results, announced today, are much more precise than preliminary findings published by the same group in the late 1990s. Frame dragging The effect is called frame dragging. It is a modification to the simpler aspects of gravity set out by...

New results from an instrument located high in the Chilean Andes are giving Canadian, American and Chilean researchers a clearer view of what the universe looked like in the first moments following the Big Bang. Cosmologists at U of T's Canadian Institute for Theoretical Astrophysics (CITA), along with fellow researchers from the United States and Chile, are using data from the Cosmic Background Imager (CBI) to observe a time in the universe's distant past when atoms were first forming. The findings reveal the first movements between these "seeds" that ultimately led to clusters of early galaxies. The new data also...

The mathematical physicist and cosmologist Roger Penrose, now professor emeritus at Oxford University, is best known to mathematicians for his discovery of Penrose tiles. These are two four-sided polygons that tile the plane only in a nonperiodic way, that is, without a fundamental region that repeats periodically like the hexagonal tiling of a bathroom floor, or the amazing tesselations of the Dutch artist M. C. Escher. To everyone’s surprise, including Penrose’s, his whimsical tiling turned out to underlie a previously unknown type of crystal. You can read all about this in my book Penrose Tiles to Trapdoor Ciphers. Penrose’s two...

It seems like the most obvious physical fact: The universe has four dimensions--three spanning space and one ticking away time. But the ultimate theory of gravity should explain why the universe is four-dimensional and how those dimensions arose, say researchers trying to unify the theories of quantum mechanics and relativity. Now, calculations in the 24 September PRL [Phys. Rev. Lett.] show that when all possible microscopic contortions of spacetime are added together, a large-scale four-dimensional universe can emerge. For nearly 80 years physicists have struggled to reconcile the prevailing theory of gravity with quantum mechanics. According to Einstein's general theory...

Unleashed viruses, environmental disaster, gray goo--astronomer Sir Martin Rees calculates that civilization has only a 50-50 chance of making it to the 22nd century. Death and destruction are not exactly foreign themes in cosmology. Black holes can rip apart stars; unseen dark energy hurtles galaxies away from one another. So maybe it's not surprising that Sir Martin Rees, Britain's Astronomer Royal, sees mayhem down on Earth. He warns that civilization has only an even chance of making it to the end of this century. The 62-year-old University of Cambridge astrophysicist and cosmologist feels so strongly about his grim prognostication that...

We are lucky to be alive. Extraordinarily lucky. So lucky, in fact, that some people can only see God's hand in our good fortune. Creationists are fond of pointing out that if you mess with the physical laws of the Universe just a little, we wouldn't be here. For example, if the neutron were just 1% heavier, or the proton 1% lighter, or the electron were to have 20% more electrical charge, then atoms could not exist. There would be no stars, and no life. But although creationists rejoice in the divine providence that has made the Universe exquisitely contrived...

Using 3,000 recently discovered quasars as searchlights on the distant universe, astronomers have mapped with unprecedented precision the distribution of the diffuse gas between galaxies. By combining these measurements with observations of the faint microwave glow of radiation left over from the Big Bang and other cosmological data, the researchers report that they have pinned down the age of the universe to an accuracy 5 times greater than ever before. By their reckoning, the cosmos is 13.6 billion years old, give or take 200 million years. The findings also uphold a leading model of cosmic evolution known as inflation, says...

We could be alone in the Universe after all. The discovery during the past decade of over a hundred planets around other stars has encouraged many scientists to think that habitable planets like ours might be common. But a recent study tells them to think again. Martin Beer of the University of Leicester, UK, and co-workers argue that our Solar System may be highly unusual, compared with the planetary systems of other stars. In a preprint published on Arxiv1 [footnote's link in original article], they point out that the alien planets we have seen so far could have been formed...

Two of the biggest physics breakthroughs during the last decade are the discovery that wispy subatomic particles called neutrinos actually have a small amount of mass and the detection that the expansion of the universe is actually picking up speed. Now three University of Washington physicists are suggesting the two discoveries are integrally linked through one of the strangest features of the universe, dark energy, a linkage they say could be caused by a previously unrecognized subatomic particle they call the "acceleron." Dark energy was negligible in the early universe, but now it accounts for about 70 percent of the...

SCIENTIFIC AMERICAN: What are the top questions bedeviling physicists today? LAWRENCE KRAUSS: Three that I find fascinating are: What is the nature of dark energy? How can we reconcile black hole evaporation with quantum mechanics? And, finally, do extra dimensions exist? They are all connected. And they are all going to require some new insights into quantum gravity. But someone is going to have to come up with a totally new and remarkable idea. And it's hard to predict when that is going to happen. In 1904 you couldn't have predicted that Albert Einstein would come up with a remarkable...

Using observations of 3,000 quasars discovered by the Sloan Digital Sky Survey (SDSS), scientists have made the most precise measurement to date of the cosmic clustering of diffuse hydrogen gas. These quasars--100 times more than have been used in such analyses in the past--are at distances of eight to ten billion light years, making them among the most distant objects known. Filaments of gas between the quasars and the Earth absorb light in the quasar's spectra, allowing researchers to map the gas distribution and to measure how clumpy the gas is on scales of one million light years. The degree...

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...