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Enlarge Left panel: Air molecules whiz around at a variety of speeds, and some are very fast. When they collide with both heavy and light elements - for example, xenon (purple) and silicon (orange) - these fast moving particles have enough momentum to affect both nuclei. Right panel: Dark matter particles are moving more slowly and are less able to affect the heavy xenon nucleus. As a result, detectors made from lighter materials like silicon may prove to be more effective at picking up signals of dark matter. Credit: Greg Stewart/SLAC National Accelerator Laboratory (Phys.org) —Now that it looks...

This talk by Professor Hawking is a unique opportunity to see him in person and be immersed in his mind’s world. Stephen Hawking will give a free talk entitled “My Brief History” on Tuesday, January 18, at 8:00 p.m. in Caltech’s Beckman Auditorium. Stephen Hawking is the Director of Research in the Centre for Theoretical Cosmology in the Department of Applied Mathematics and Theoretical Physics at the University of Cambridge. Professor Hawking has given the world insights into the birth of the universe, the deaths of black holes, and the future of the human race. His worldwide bestseller A Brief...

An artificial "black hole" designed to capture wayward atoms has been created. It paves the way for an atom trap that could yield previously unknown states of matter. A team led by Lene Hau of Harvard University has mimicked the death spiral of matter falling into a cosmic black hole by applying a voltage across a carbon nanotube – a rolled-up sheet of carbon atoms. This created a powerful electric field that tugged at nearby rubidium atoms, which had been chilled to a fraction of a degree above absolute zero: a positive charge on the surface of the nanotubes attracts...

Scientists celebrated at the world's biggest atom smasher at the European Organization for Nuclear Research (CERN) near Geneva on Tuesday as they started colliding particles at record energy levels mimicking conditions close to the Big Bang, opening a new era in the quest for the secrets of the universe. The European Organisation for Nuclear Research (CERN) said it had unleashed the unprecedented bursts of energy on the third attempt, as beams of protons thrust around the 27-kilometre (16.8-mile) accelerator collided at close to the speed of light. "This is physics in the making, the beginning of a new era, we...

Science fiction writers may have to rethink how their starship crews survive travel near or beyond the speed of light. Even the occasional hydrogen atom floating in the interstellar void would become a lethal radiation beam that would kill human crews in mere seconds and destroy a spacecraft's electronics, New Scientist reports. Just a few stray wisps of hydrogen gas -- fewer than two hydrogen atoms per cubic centimeter on average -- would translate into 7 teraelectron volts for a starship crew traveling at 99.999998 percent of the speed of light. That's as much fun for humans as standing in...

Atom smashers at a U.S. national lab have produced temperatures not seen since the Big Bang — 7.2 trillion degrees, or 250,000 times hotter than the sun's interior — in work re-creating the universe's first microseconds. The results come from the 2.4-mile-wide Relativistic Heavy Ion Collider at the Department of Energy's Brookhaven (N.Y.) National Laboratory. Since 2000, scientists there have hurtled gold atoms together at nearly the speed of light. These smash-ups heat bubbles smaller than the center of an atom to about 40 times hotter than the center of an imploding supernova. Scientists say the results have given them...

The typical Hollywood action hero skirts death for a living. Time and again, scores of bad guys shoot at him from multiple directions but miss by a hair. Cars explode just a fraction of a second too late for the fireball to catch him before he finds cover. And friends come to the rescue just before a villain’s knife slits his throat. If any one of those things happened just a little differently, the hero would be hasta la vista, baby. Yet even if we have not seen the movie before, something tells us that he will make it to...

GENEVA – The world's largest atom smasher has recorded its first high-energy collisions of protons, a spokeswoman said Wednesday. Physicists hope those collisions will help them understand suspected phenomena such as dark matter, antimatter and ultimately the creation of the universe billions of years ago, which many theorize occurred as a massive explosion known as the Big Bang. The collisions occurred Tuesday evening as the Large Haldron Collider underwent test runs in preparation for operations next year, said Christine Sutton of the European Organization for Nuclear Research, or CERN. Two beams of circulating particles traveling in opposite directions at 1.18...

Shortly after the first of the year (if not already), the Large Hadron Collider — the most powerful particle accelerator ever built — will smash protons together at record energies. If the Earth remains intact, doomsayers will once again have been falsified. Every time they forecast the demise of the planet, those prophets of Earthly annihilation prove themselves no more foresightful than mortgage bankers or phony psychics.

Was Newton right and Einstein wrong? It seems that unzipping the fabric of spacetime and harking back to 19th-century notions of time could lead to a theory of quantum gravity. Physicists have struggled to marry quantum mechanics with gravity for decades. In contrast, the other forces of nature have obediently fallen into line. For instance, the electromagnetic force can be described quantum-mechanically by the motion of photons. Try and work out the gravitational force between two objects in terms of a quantum graviton, however, and you quickly run into trouble—the answer to every calculation is infinity. But now Petr Hořava,...

How does a person with fixed political opinions influence the voting intentions of other people in an election? According to Mauro Mobilia, a theoretical physicist at the EPFL in Lausanne and Boston University, there are striking similarities between the influence of a zealot in the electorate and a fixed magnetic spin in an array of random spins. Mobilia believes this zealot model could give insights into a wide range of 'many-body' physical systems (M Mobilia 2003 Phys. Rev. Lett. 91 028701). In an election most people weigh up the pros and cons of the candidates before they choose who to...