| Blacklight |
05-20-08 12:03 AM |
From Wikipedia:
Quote:
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, potentially resulting in a doomsday scenario. Such issues were raised in connection with the RHIC accelerator, both in the media[16][17] and in the scientific community;[18] however, after detailed studies, scientists reached such conclusions as "beyond reasonable doubt, heavy-ion experiments at RHIC will not endanger our planet"[19] and that there is "powerful empirical evidence against the possibility of dangerous strangelet production."[20]
One argument against such fears is that collisions at these energies (and higher) have been happening in nature for billions of years apparently without hazardous effects, as ultra-high-energy cosmic rays impact Earth's atmosphere and other bodies in the universe.[21] A concern against this cosmic-ray argument is that, if dangerous strangelets or micro black holes were created at LHC, a proportion would have less than the Earth's escape velocity (of 11.2 km/s), and therefore would be captured by the Earth's gravitational field, whereas those created by high-energy cosmic rays would leave the planet at high speed, due to the laws of conservation of momentum at relativistic speeds[citation needed].
CERN's review concludes, after detailed analysis, that "there is no basis for any conceivable threat" from strangelets or black holes.[22][23] However, the concern about the verity of Hawking radiation was not addressed, and another study was commissioned by CERN in 2007 for publication on CERN's web-site by the end of 2007.[citation needed]
The risk of a doomsday scenario was indicated by Sir Martin Rees, with respect to the RHIC, as being at least a 1 in 50,000,000 chance,[24] and by Professor Frank Close, with regards to (dangerous) strangelets, that "the chance of this happening is like you winning the major prize on the lottery 3 weeks in succession; the problem is that people believe it is possible to win the lottery 3 weeks in succession."[25] Accurate assessments of these risks are impossible due to the present incomplete, or even hypothetically flawed, standard model of particle physics (see also a list of unsolved problems in physics).
Micro black holes
Main article: Micro black hole
Although the Standard Model of particle physics predicts that LHC energies are far too low to create black holes, some extensions of the Standard Model posit the existence of extra spatial dimensions, in which it would be possible to create micro black holes at the LHC[26][27][28] at a rate on the order of one per second. According to the standard calculations these are harmless because they would quickly decay by Hawking radiation. The concern is that among other disputed factors, Hawking radiation (whose existence is still debated[29]) is not yet an experimentally-tested or naturally observed phenomenon. The opponents to the LHC consider that micro black holes produced in a terrestrial laboratory might not decay as rapidly as calculated, or might even not be prone to decay. According to CERN, physicists in general do not question the assumption that black holes are generally unstable and those few who have pointed out issues with Hawking's radiation were only attempting to achieve a more rigorous proof of it.[30] CERN further argues that even if micro black holes were created and were stable, they would pose no threat to the Earth during its remaining 5 billion years of existence.[30][31] However, Dr. Adam D. Helfer's thesis concludes "no compelling theoretical case for or against radiation by black holes",[32][33] and Dr. Otto E. Rossler's thesis calculates that Earth accretion time could be as short as 50 months.[34]
Strangelets
Main article: Strangelet
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.
Legal challenge
On 21 March 2008 a complaint requesting an injunction against the LHC's startup was filed before the US District Court of Hawaii[35][36] by a group of seven concerned individuals. This group includes Walter L. Wagner who notably was unable to obtain an injunction against the much lower energy RHIC for similar concerns. See: RHIC - Fears among the public
The restraining order[37] is a demand for an injunction of 4 months time after issuance of the LHC Safety Assessment Group's (LSAG) Safety Review originally promised by January 1, 2008, to review the LHC's most recent safety documentation, after it has been issued, and a permanent injunction until the LHC can be demonstrated to be reasonably safe within industry standards.
|
|
