What happens when you throw an elephant into a black hole? It sounds like a bad joke, but it's a question that has been weighing heavily on Leonard Susskind's mind. Susskind, a physicist at Stanford University in California, has been trying to save that elephant for decades. He has finally found a way to do it, but the consequences shake the foundations of what we thought we knew about space and time. If his calculations are correct, the elephant must be in more than one place at the same time.
In everyday life, of course, locality is a given. You're over there, I'm over here; neither of us is anywhere else. Even in Einstein's theory of relativity, where distances and timescales can change depending on an observer's reference frame, an object's location in space-time is precisely defined. What Susskind is saying, however, is that locality in this classical sense is a myth. Nothing is what, or rather, where it seems.
This is more than just a mind-bending curiosity. It tells us something new about the fundamental workings of the universe. Strange as it may sound, the fate of an elephant in a black hole has deep implications for a "theory of everything" called quantum gravity, which strives to unify quantum mechanics and general relativity, the twin pillars of modern physics. Because of their enormous gravity and other unique properties, black holes have been fertile ground for researchers developing these ideas.
It all began in the mid-1970s, when Stephen Hawking of the University of Cambridge showed theoretically that black holes are not truly black, but emit radiation. In fact they evaporate very slowly, disappearing over many billions of years. This "Hawking radiation" comes from quantum phenomena taking place just outside the event horizon, the gravitational point of no return. But, Hawking asked, if a black hole eventually disappears, what happens to all the stuff inside? It can either leak back into the universe along with the radiation, which would seem to require travelling faster than light to escape th
Our world may be a giant hologram
15 January 2009 by Marcus Chown
Magazine issue 2691. Subscribe and get 4 free issues.
For similar stories, visit the Cosmology Topic Guide
Has GEO600's laser probed the fundamental fuzziness of space-time? (Image: Wolfgang Filser / Max Planck Society)
1 more image
DRIVING through the countryside south of Hanover, it would be easy to miss the GEO600 experiment. From the outside, it doesn't look much: in the corner of a field stands an assortment of boxy temporary buildings, from which two long trenches emerge, at a right angle to each other, covered with corrugated iron. Underneath the metal sheets, however, lies a detector that stretches for 600 metres.
For the past seven years, this German set-up has been looking for gravitational waves - ripples in space-time thrown off by super-dense astronomical objects such as neutron stars and black holes. GEO600 has not detected any gravitational waves so far, but it might inadvertently have made the most important discovery in physics for half a century.
For many months, the GEO600 team-members had been scratching their heads over inexplicable noise that is plaguing their giant detector. Then, out of the blue, a researcher approached them with an explanation. In fact, he had even predicted the noise before he knew they were detecting it. According to Craig Hogan, a physicist at the Fermilab particle physics lab in Batavia, Illinois, GEO600 has stumbled upon the fundamental limit of space-time - the point where space-time stops behaving like the smooth continuum Einstein described and instead dissolves into "grains", just as a newspaper photograph dissolves into dots as you zoom in. "It looks like GEO600 is being buffeted by the microscopic quantum convulsions of space-time," says Hogan.
If this doesn't blow your socks off, then Hogan, who has just been appointed director of Fermilab's Center for Particle Astrophysics, has an even bigger shock in store: "If the GEO600 result is what I suspect it is, then we are all living in a giant c
A Poor Man's E-Bomb
An FCG is an astoundingly simple weapon. It consists of an explosives-packed tube placed inside a slightly larger copper coil, as shown below. The instant before the chemical explosive is detonated, the coil is energized by a bank of capacitors, creating a magnetic field. The explosive charge detonates from the rear forward. As the tube flares outward it touches the edge of the coil, thereby creating a moving short circuit. "The propagating short has the effect of compressing the magnetic field while reducing the inductance of the stator [coil]," says Kopp. "The result is that FCGs will produce a ramping current pulse, which breaks before the final disintegration of the device. Published results suggest ramp times of tens of hundreds of microseconds and peak currents of tens of millions of amps." The pulse that emerges makes a lightning bolt seem like a flashbulb by comparison.
Scientists from the LHC's Compact Muon Solenoid detector has now totted up all of the resulting particle interactions.
They wrote in the Journal of High Energy Physics that the run created more particles than theory predicted.
However, the glut of particles should not affect results as the experiment runs to even higher energies this year.
The LHC is designed to smash together particles and atoms circling its 27km-tunnel in a bid to find evidence of further particles that underpin the field of physics as it is currently formulated.
The December announcement of particle beam energies in excess of one trillion electron volts made the LHC the world's highest-energy particle accelerator.
First, they teleported photons, then atoms and ions. Now one physicist has worked out how to do it with energy, a technique that has profound implications for the future of physics.\n\nIn 1993, Charlie Bennett at IBM's Watson Research Center in New York State and a few pals showed how to transmit quantum information from one point in space to another without traversing the intervening space.\n\nThe technique relies on the strange quantum phenomenon called entanglement, in which two particles share the same existence. This deep connection means that a measurement on one particle immediately influences the other, even though they are light-years apart. Bennett and company worked out how to exploit this to send information. (The influence between the particles may be immediate, but the process does not violate relativity because some informatiom has to be sent classically at the speed of light.) They called the technique teleportation.
Astronomy Ireland says a major fireball was spotted over Ireland at around 6pm this evening.\n\nIt says the rock from space was seen blazing in the air by people all over the country.\n\nThere are reports that the fireball has landed in a field near Crimlin in Co Cavan.\n\n1\nAstronomy Ireland says it is unlikely to have injured anyone as it would have slowed down when it hit the atmosphere.\nValentia Coastguard said it has had reports of sightings from people living in Mullingar, Limerick, Ballybunion and Bantry.