Brooke
juan
LHC - Bring Time Travellers Or Destroy Earth MAY 2008
Eddie
LHC CERN introduction
BBC Horizon The Six Billion Dollar Experiment (excerpt - full feature pulled out of Google video)
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Particle Accelerator May Reveal Shape Of Alternate Dimensions
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ScienceDaily (Feb. 4, 2008)
When the world's most powerful particle accelerator starts up later this year, exotic new particles may offer a glimpse of the existence and shapes of extra dimensions.
Researchers from the University of Wisconsin-Madison and the University of California-Berkeley say that the telltale signatures left by a new class of particles could distinguish between possible shapes of the extra spatial dimensions predicted by string theory.
String theory, which describes the fundamental particles of the universe as tiny vibrating strings of energy, suggests the existence of six or seven unseen spatial dimensions in addition to the time and three space dimensions that we normally see.
Much as the shape of a musical instrument determines its sound, the shape of these dimensions determines the properties and behavior of our four-dimensional universe, says Gary Shiu, lead author of a paper appearing in the Jan. 25 issue of Physical Review Letters.
"The shape of the dimensions is crucial because, in string theory, the way the string vibrates determines the pattern of particle masses and the forces that we feel," says the UW-Madison physics professor.
Zeroing in on that shape should further our understanding and predictions of our four-dimensional world, Shiu says. "There are myriad possibilities for the shapes of the extra dimensions out there. It would be useful to know a way to distinguish one from another and perhaps use experimental data to narrow down the set of possibilities."
Such experimental evidence could appear in data from a new particle accelerator, the Large Hadron Collider, scheduled to begin operating later this year near Geneva, Switzerland.
In an accelerator, smashing atomic nuclei head-on at nearly the speed of light can briefly create new high-energy and highly unstable particles, which quickly decay into a shower of detectable lower energy ones. Characteristic patterns of decay serve as fingerprints of the fleeting exotic particles and, possibly, the shape of the unseen dimensions.
With colleagues Bret Underwood and Kathryn Zurek at UW-Madison and Devin Walker at UC-Berkeley, Shiu shows in the new study that the signature patterns from particles called Kaluza-Klein (KK) gravitons can distinguish between different proposed extra-dimensional geometries.
How" Shiu compares the effect to a darkened room in which patterns of sound resonating off the walls can reveal the shape of the room. Similarly, KK gravitons are sensitive to the extra-dimensional shape and, through their behavior and decay, may reveal clues to that shape.
The current study shows that, in simulations, even small geometric variations lead to visible differences in KK graviton signatures, Underwood says.
Based on these results, Shiu says, "At least in principle, one may be able to use experimental data to test and constrain the geometry of our universe."
Last year, Shiu and Underwood reported that clues to dimensional geometries might also be visible in patterns of cosmic radiation left over from the Big Bang. The new work complements the previous approach, they say.
"The more hints we get, the better idea we have about the underlying physics," says Shiu.
Adds Underwood, "If the cosmology and particle physics data agree, it's an indication we're on the right track."
The work was supported by the National Science Foundation, the U.S. Department of Energy, the Research Corporation, and a University of California Presidential Fellowship.
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Time travellers from the future 'could be here in weeks'
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Telegraph UK
By Roger Highfield, Science Editor
02/06/2008
http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/02/06/scitime106.xml
The first time travellers from the future could materialise on Earth within a few weeks.
Physicists around the world are excitedly awaiting the start up of the £4.65 billion Large Hadron Collider, LHC - the most powerful atom-smasher ever built - which is supposed to shed new light on the particles and forces at work in the cosmos and reproduce conditions that date to near the Big Bang of creation.
Prof Irina Aref'eva and Dr Igor Volovich, mathematical physicists at the Steklov Mathematical Institute in Moscow believe that the vast experiment at CERN, the European particle physics centre near Geneva in Switzerland, may turn out to be the world's first time machine, reports New Scientist.
The debut in early summer could provide a landmark because travelling into the past is only possible - if it is possible at all - as far back as the point of creation of the first time machine.
That means 2008 could become "Year Zero" for temporal travel, they argue.
Time travel was born when Albert Einstein's colleague, Kurt Gödel, used Einstein's theory of relativity to show that travel into the past was possible.
Ever since he unveiled this idea in 1949, eminent physicists have argued against time travel because it undermines ideas of cause and effect to create paradoxes: a time traveller could go back to kill his grandfather so that he is never born in the first place.
But, sixty years later, there is still no fundamental reason why time travellers cannot put historians out of business.
But the Russians argue that when the energies of the LHC are concentrated into a subatomic particle - a trillionth the size of a mosquito - they can do strange things to the fabric of the universe, which is a blend of space and time that scientists called spacetime.
While Earth's gravity produces gentle distortions in spacetime the LHC energy can distort time so much that it loops back on itself. These loops are known to physicists as "closed timelike curves" and they ought, at least in theory, to allow us to revisit some past moment.
The scheme chimes with one laid out in 1988, when Prof Kip Thorne and colleagues at the California Institute of Technology, Pasadena, showed that wormholes, or tunnels through spacetime, would allow time travel, a scheme popularised by Carl Sagan in his novel - made into a film - Contact.
Prof Aref'eva and Dr Volovich believe the LHC could create wormholes and so allow a form of time travel. "We realised that closed timelike curves and wormholes could also be a result of collisions of particles," Prof Aref'eva says.
There are still plenty of obstacles for the likes of Dr Who, however. Not least of them is the fact that these are mini wormholes, so only subatomic particles are small enough to travel through them.
Time travel could be possible ... in the future
How the Time Machine works
Time is running out - literally, says scientist
They tell The Daily Telegraph that whether subatomic time travel in the LHC would open the doors for human scale time travellers "is a deep and interesting question" but stress that "these problems, and many others as well, require further investigations."
Probably the best we can hope for is that the LHC may show a signature of the wormholes' existence, Dr Volovich says. If some of the energy from collisions in the LHC goes missing, it could be because the collisions created particles that have travelled into a wormhole and through time.
One sticking point until now for wormhole concepts is finding an exotic kind of material capable of keeping the maw of the wormhole open for time travel.
Dark energy - a mysterious antigravity force that is thought to pervade the universe - could, they say, be just what is needed to keep the entrance to a wormhole open, at least according to one family of ideas about its nature, where it is called phantom energy.
If a blend of colliding particles and phantom energy does create a wormhole in Geneva this year, an advanced civilisation could find it in their history books, pinpoint the moment, and take advantage of their technology to pay us a visit.
"The observational evidence still allows for phantom energy," says Robert Caldwell, a physicist at Dartmouth College in Hanover, New Hampshire. "As for Aref'eva and Volovich's speculation that the LHC will produce the stuff of time machines - ugh!"
A leading scientist who believes that time travel may be possible, Prof David Deutsch of Oxford University, comments: "It's speculative in the extreme, but not cranky. For various reasons I don't think the mechanism they propose would work (i.e. provide a pathway for messages from the future) even if their speculations are true."
Dr Brian Cox of the University of Manchester adds: "The energies of billions of cosmic rays that have been hitting the Earth's atmosphere for five billion years far exceed those we will create at the LHC, so by this logic time travellers should be here already. If these wormholes appear I will personally eat the hat I was given for my first birthday before I received it."
BBC Horizon End Day scenario - LHC Doomsday Machine?
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The experiment that could blow up the planet
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Sydney Morning Herald
by Daniel Dasey
September 13, 2006
http://blogs.smh.com.au/science/archives/2006/09/the_experiment.html
It's the experiment that could help scientists determine how matter was created at the birth of the universe. And it could - just possibly - blow up the Earth.
Scientists near Geneva are gearing up to use a 27 kilometre-long circular particle accelerator during 2007.
The device - the Large Hadron Collider - at the CERN experimental facility will be used to smash protons into each other at extraordinary speeds, replicating on a tiny scale some of the processes which occured during the Big Bang.
News agency Reuters said Brian Cox of Manchester University had told a meeting of the British Association for the Advancement of Science the accelerator could help science better understand the matter that makes up the universe
"We don't know what 95 per cent of the universe is made of - which is a bit embarrassing for a subject that claims to be fundamental," Cox said.
"There is dark matter.
"It is all over the place but we have no idea what it is."
It is theorised the Large Hadron Collider will create minute black holes that will quickly evaporate. It may also provide evidence of the existence of other dimensions during its expected operating lifespan of 10 to 20 years.
"It could be that there is a whole new universe a millimetre away from our heads, but at right-angles to the three dimensions that are here," Cox said.
However, Cox also admitted there was a tiny, tiny risk the device could create conditions that would obliterate the planet and all human life.
"The probability is at the level of 10 to the minus 40," Reuters reported him saying.
Potential threats put forward by the scientific community and other watchers of the experiment include the creation of a stable black hole or the creation of strange matter more stable than ordinary matter.
There's no doubt the experiments to be carried out using the particle accelerator will benefit scientific knowledge. There may also be incredible practical spin-offs which will benefit humankind.
But is the risk - as miniscule as it is - worth it?
A colleague of mine cynically remarked: "The odds against anyone winning lotto twice are immense. But it happens. Do a Google and you'll see."
What do you think?
Is it worth playing the odds?
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Wikipedia: LHC Safety Concerns
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http://en.wikipedia.org/wiki/Large_Hadron_Collider
Safety concerns
Concerns have been raised that performing collisions at previously unexplored energies might unleash new and disastrous phenomena.
These include the production of micro black holes, and strangelets (see below). Such issues were raised in connection with the RHIC accelerator, both in the media and in the scientific community. The general response to such fears has been to point out that collisions at these energies have been happening in nature for millennia, as Ultra-high-energy cosmic rays impact Earth's atmosphere and the moon's surface, so if there were any dramatic consequences we would already have seen them by now. Another study was commissioned by CERN in 2007 for publication on CERN's web-site by the end of 2007.
Micro Black Holes
Though the standard model predicts that LHC energies are far too low to create black holes, some non-standard theories lower the requirements, and CERN itself has published articles that the LHC could create micro black holes at the rate of one per second. According to the standard calculations these are harmless because they would quickly decay by Hawking radiation. The concern is that Hawking radiation (which is still debated is a hypothetical form of radiation and these calculations might be wrong, and if micro black holes do not decay they might accumulate inside the earth and eventually devour it.
Strangelets
Strangelets are a hypothetical form of strange matter that contains roughly equal numbers of up, down, and strange quarks and are more stable than ordinary nuclei. If strangelets can actually exist, and if they were produced at LHC, they could conceivably initiate a runaway fusion process (reminiscent of the fictional ice-nine) in which all the nuclei in the planet were converted to strange matter, similar to a strange star.
THE END?