The safety of high energy particle collisions was a topic of widespread discussion and topical interest during the time when the
Relativistic Heavy Ion Collider (RHIC) and later the
Large Hadron Collider
The Large Hadron Collider (LHC) is the world's largest and highest-energy particle collider. It was built by the European Organization for Nuclear Research (CERN) between 1998 and 2008 in collaboration with over 10,000 scientists and hundr ...
(LHC)—currently the world's largest and most powerful
particle accelerator
A particle accelerator is a machine that uses electromagnetic fields to propel electric charge, charged particles to very high speeds and energies, and to contain them in well-defined particle beam, beams.
Large accelerators are used for fun ...
—were being constructed and commissioned. Concerns arose that such high energy experiments—designed to produce novel particles and forms of matter—had the potential to create harmful
states of matter or even
doomsday scenario
A global catastrophic risk or a doomsday scenario is a hypothetical future event that could damage human well-being on a global scale, even endangering or destroying modern civilization. An event that could cause human extinction or permanen ...
s. Claims escalated as commissioning of the LHC drew closer, around 2008–2010. The claimed dangers included the production of stable
micro black holes and the creation of hypothetical particles called
strangelets,
and these questions were explored in the media, on the Internet and at times through the courts.
To address these concerns in the context of the LHC, CERN mandated a group of independent scientists to review these scenarios. In a report issued in 2003, they concluded that, like current particle experiments such as the RHIC, the LHC particle collisions pose no conceivable threat.
[Blaizot JP, Iliopoulos J, Madsen J, Ross GG, Sonderegger P, Specht HJ (2003). ]
Study of Potentially Dangerous Events During Heavy-Ion Collisions at the LHC
'. CERN. Geneva
CERN-2003-001
A second review of the evidence commissioned by CERN was released in 2008. The report, prepared by a group of physicists affiliated to CERN but not involved in the LHC experiments, reaffirmed the safety of the LHC collisions in light of further research conducted since the 2003 assessment.
. CERN 2008 (CERN website). It was reviewed and endorsed by a CERN committee of 20 external scientists and by the Executive Committee of the Division of Particles & Fields of the
American Physical Society,
[CERN Scientific Policy Committee (2008). ]
SPC Report on LSAG Documents
'
CERN record
[Statement by the Executive Committee of the DPF on the Safety of Collisions at the Large Hadron Collider]
" issued by th
Division of Particles & Fields
(DPF) of the American Physical Society (APS) and was later published in the peer-reviewed ''
Journal of Physics G'' by the UK
Institute of Physics
The Institute of Physics (IOP) is a UK-based learned society and professional body that works to advance physics education, research and application.
It was founded in 1874 and has a worldwide membership of over 20,000. The IOP is the Physica ...
, which also endorsed its conclusions.
[LHC switch-on fears are completely unfounded]
. The Institute of Physics
The Institute of Physics (IOP) is a UK-based learned society and professional body that works to advance physics education, research and application.
It was founded in 1874 and has a worldwide membership of over 20,000. The IOP is the Physica ...
. PR 48 (08). 5 September 2008.
The report ruled out any doomsday scenario at the LHC, noting that the physical conditions and collision events which exist in the LHC, RHIC and other experiments occur naturally and routinely in the
universe
The universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy. The Big Bang theory is the prevailing cosmological description of the development of the universe. A ...
without hazardous consequences,
including
ultra-high-energy cosmic rays observed to impact Earth with energies far higher than those in any man-made collider.
Background
Particle colliders are a type of
particle accelerator
A particle accelerator is a machine that uses electromagnetic fields to propel electric charge, charged particles to very high speeds and energies, and to contain them in well-defined particle beam, beams.
Large accelerators are used for fun ...
used by physicists as a research tool to understand fundamental aspects of the universe. Their operation involves directed beams of
particles accelerated to very high
kinetic energy
In physics, the kinetic energy of an object is the energy that it possesses due to its motion.
It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its a ...
and allowed to collide; analysis of the byproducts of these collisions gives scientists good evidence of the structure of the subatomic world and the laws of nature governing it. These may become apparent only at high energies and for tiny periods of time, and therefore may be hard or impossible to study in other ways.
Because of the high energy levels involved, concerns have arisen at times in the public arena as to whether such collisions are safe, or whether they might, by reason of their extreme energy, trigger unforeseen problems or consequences.
Examples of colliders
Concerns were noted during the construction of the
Large Hadron Collider
The Large Hadron Collider (LHC) is the world's largest and highest-energy particle collider. It was built by the European Organization for Nuclear Research (CERN) between 1998 and 2008 in collaboration with over 10,000 scientists and hundr ...
(LHC), which began operations in 2008, is the world's largest and highest-energy
particle accelerator
A particle accelerator is a machine that uses electromagnetic fields to propel electric charge, charged particles to very high speeds and energies, and to contain them in well-defined particle beam, beams.
Large accelerators are used for fun ...
complex, intended to
collide opposing
beams of either
protons or
lead
Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate ...
nuclei with very high
kinetic energy
In physics, the kinetic energy of an object is the energy that it possesses due to its motion.
It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its a ...
.
[CERN Communication Group (January 2008).]
CERN FAQ — LHC: the guide
" (PDF). CERN. Geneva (44p).[ Achenbach, Joel (1 March 2008).]
The God Particle
. '' National Geographic Magazine''. It was built by the
European Organization for Nuclear Research (CERN) near
Geneva
Geneva ( ; french: Genève ) frp, Genèva ; german: link=no, Genf ; it, Ginevra ; rm, Genevra is the second-most populous city in Switzerland (after Zürich) and the most populous city of Romandy, the French-speaking part of Switzerland. Situ ...
, in
Switzerland. The LHC's main purpose is to explore the validity and limitations of the
Standard Model
The Standard Model of particle physics is the theory describing three of the four known fundamental forces ( electromagnetic, weak and strong interactions - excluding gravity) in the universe and classifying all known elementary particles. I ...
, the current theoretical picture for
particle physics
Particle physics or high energy physics is the study of fundamental particles and forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) and ...
. The first particle collisions at the LHC took place shortly after startup in November 2009, at energies up to per beam.
[CERN press release (2009)]
LHC ends 2009 run on a high note.
On 30 March 2010, the first planned collisions took place between two 3.5 TeV beams, which set another new world record for the highest energy man-made particle collisions.
[
] In 2012 the beam energy was increased to 4 TeV, after upgrades in 2013 and 2014 collisions in 2015 and 2016 happened at an energy of 6.5 TeV per proton.
[Record breaking collision at 13TeV](_blank)
CERN Press release
Similar concerns had previously also been raised in the context of the
Relativistic Heavy Ion Collider, with
Frank Close, professor of physics at the
University of Oxford
The University of Oxford is a collegiate research university in Oxford, England. There is evidence of teaching as early as 1096, making it the oldest university in the English-speaking world and the world's second-oldest university in contin ...
, to comment at the time that "the chance of
strangelet creation">/nowiki> strangelet creationis 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."[BBC ''End Days'' (Documentary)]
Relativistic Heavy Ion Collider
Concerns about possible adverse consequences were raised in connection with the RHIC
The Relativistic Heavy Ion Collider (RHIC ) is the first and one of only two operating heavy-ion colliders, and the only spin-polarized proton collider ever built. Located at Brookhaven National Laboratory (BNL) in Upton, New York, and used by a ...
particle accelerator.[ Matthews, Robert (28 August 1999).]
A Black Hole Ate My Planet
. ''New Scientist
''New Scientist'' is a magazine covering all aspects of science and technology. Based in London, it publishes weekly English-language editions in the United Kingdom, the United States and Australia. An editorially separate organisation publish ...
''.['' Horizon: End Day''. BBC. 2005.] After detailed studies, scientists reached such conclusions as "beyond reasonable doubt, heavy-ion experiments at RHIC will not endanger our planet" and that there is "powerful empirical evidence against the possibility of dangerous strangelet production."
Before the Relativistic Heavy Ion Collider started operation, critics postulated that the extremely high energy could produce catastrophic scenarios,
such as creating a black hole
A black hole is a region of spacetime where gravity is so strong that nothing, including light or other electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts that a sufficiently compact mass can defo ...
, a transition into a different quantum mechanical vacuum
A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or " void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often di ...
(see false vacuum), or the creation of strange matter that is more stable than ordinary matter
In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic par ...
. These hypotheses are complex, but many predict that the Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surf ...
would be destroyed in a time frame from seconds to millennia, depending on the theory considered. However, the fact that objects of the Solar System (e.g., the Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width ...
) have been bombarded with cosmic particles of significantly higher energies than that of RHIC and other man made colliders for billions of years, without any harm to the Solar System, were among the most striking arguments that these hypotheses were unfounded.
The other main controversial issue was a demand by critics for physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe.
Physicists generally are interested in the root or ultimate ca ...
s to reasonably exclude the probability
Probability is the branch of mathematics concerning numerical descriptions of how likely an Event (probability theory), event is to occur, or how likely it is that a proposition is true. The probability of an event is a number between 0 and ...
for such a catastrophic scenario. Physicists are unable to demonstrate experimental and astrophysical constraints of zero probability of catastrophic events, nor that tomorrow Earth will be struck with a "doomsday
Doomsday may refer to:
* Eschatology, a time period described in the eschatological writings in Abrahamic religions and in doomsday scenarios of non-Abrahamic religions.
* Global catastrophic risk, a hypothetical event explored in science and fict ...
" cosmic ray
Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our ow ...
(they can only calculate an upper limit for the likelihood). The result would be the same destructive scenarios described above, although obviously not caused by humans. According to this argument of upper limits, RHIC would still modify the chance for the Earth's survival by an infinitesimal amount.
Concerns were raised in connection with the RHIC particle accelerator, both in the media and in the popular science media. The risk of a doomsday scenario was indicated by Martin Rees
Martin John Rees, Baron Rees of Ludlow One or more of the preceding sentences incorporates text from the royalsociety.org website where: (born 23 June 1942) is a British cosmologist and astrophysicist. He is the fifteenth Astronomer Roya ...
, with respect to the RHIC, as being at least a 1 in 50 million chance. With regards to the production of strangelets, Frank Close, professor of physics at the University of Oxford
The University of Oxford is a collegiate research university in Oxford, England. There is evidence of teaching as early as 1096, making it the oldest university in the English-speaking world and the world's second-oldest university in contin ...
, indicates 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." After detailed studies, scientists reached such conclusions as "beyond reasonable doubt, heavy-ion experiments at RHIC will not endanger our planet" and that there is "powerful empirical evidence against the possibility of dangerous strangelet production."
History of discussion
The debate started in 1999 with an exchange of letters in Scientific American
''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it i ...
between Walter L. Wagner
Walter may refer to:
People
* Walter (name), both a surname and a given name
* Little Walter, American blues harmonica player Marion Walter Jacobs (1930–1968)
* Gunther (wrestler), Austrian professional wrestler and trainer Walter Hahn (born 1 ...
and F. Wilczek, in response to a previous article by M. Mukerjee. The media attention unfolded with an article in U.K. Sunday Times
''The Sunday Times'' is a British newspaper whose circulation makes it the largest in Britain's quality press market category. It was founded in 1821 as ''The New Observer''. It is published by Times Newspapers Ltd, a subsidiary of News UK, wh ...
of July 18, 1999 by J. Leake,[Sunday Times, 18 July 1999.](_blank)
/ref> closely followed by articles in the U.S. media. The controversy mostly ended with the report of a committee
A committee or commission is a body of one or more persons subordinate to a deliberative assembly. A committee is not itself considered to be a form of assembly. Usually, the assembly sends matters into a committee as a way to explore them more ...
convened by the director of Brookhaven National Laboratory, J. H. Marburger, ostensibly ruling out the catastrophic scenarios depicted. However, the report left open the possibility that relativistic cosmic ray impact products might behave differently while transiting earth compared to "at rest" RHIC products; and the possibility that the qualitative difference between high-E proton collisions with earth or the moon might be different than gold on gold collisions at the RHIC. Wagner tried subsequently to stop full energy collision at RHIC by filing Federal lawsuits in San Francisco
San Francisco (; Spanish language, Spanish for "Francis of Assisi, Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the List of Ca ...
and New York City
New York, often called New York City or NYC, is the most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the most densely populated major city in the U ...
, but without success. The New York suit was dismissed on the technicality that the San Francisco suit was the preferred forum. The San Francisco suit was dismissed, but with leave to refile if additional information was developed and presented to the court.
On March 17, 2005, the BBC published an article implying that researcher Horaţiu Năstase believes black holes have been created at RHIC. However, the original papers of H. Năstase and the New Scientist
''New Scientist'' is a magazine covering all aspects of science and technology. Based in London, it publishes weekly English-language editions in the United Kingdom, the United States and Australia. An editorially separate organisation publish ...
article cited by the BBC state that the correspondence of the hot dense QCD matter
Quark matter or QCD matter (quantum chromodynamic) refers to any of a number of hypothetical phases of matter whose degrees of freedom include quarks and gluons, of which the prominent example is quark-gluon plasma. Several series of conferences ...
created in RHIC to a black hole is only in the sense of a correspondence of QCD scattering in Minkowski space
In mathematical physics, Minkowski space (or Minkowski spacetime) () is a combination of three-dimensional Euclidean space and time into a four-dimensional manifold where the spacetime interval between any two events is independent of the ...
and scattering in the ''AdS''5 × ''X''5 space in AdS/CFT
In theoretical physics, the anti-de Sitter/conformal field theory correspondence, sometimes called Maldacena duality or gauge/gravity duality, is a conjectured relationship between two kinds of physical theories. On one side are anti-de Sitter ...
; in other words, it is similar mathematically. Therefore, RHIC collisions might be described by mathematics relevant to theories of quantum gravity
Quantum gravity (QG) is a field of theoretical physics that seeks to describe gravity according to the principles of quantum mechanics; it deals with environments in which neither gravitational nor quantum effects can be ignored, such as in the v ...
within AdS/CFT, but the described physical phenomena are not the same.
Large Hadron Collider
In the run up to the commissioning of the LHC, Walter L. Wagner (an original opponent of the RHIC), Luis Sancho (a Spanish science writer) and Otto Rössler (a German biochemist) expressed concerns over the safety of the LHC, and attempted to halt the beginning of the experiments through petitions to the US and European Courts.[Boyle, Alan (2 September 2008).]
Courts weigh doomsday claims
. ''Cosmic Log''. msnbc.com
MSNBC (originally the Microsoft National Broadcasting Company) is an American news-based pay television cable channel. It is owned by NBCUniversala subsidiary of Comcast. Headquartered in New York City, it provides news coverage and politic ...
.[Some fear debut of powerful atom-smasher]
'' CNN.com''. 30 June 2008.[ Overbye, Dennis (21 June 2008).]
Earth Will Survive After All, Physicists Say
. ''The New York Times
''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid ...
''. These opponents assert that the LHC experiments have the potential to create low velocity micro black holes that could grow in mass or release dangerous radiation leading to doomsday scenario
A global catastrophic risk or a doomsday scenario is a hypothetical future event that could damage human well-being on a global scale, even endangering or destroying modern civilization. An event that could cause human extinction or permanen ...
s, such as the destruction of the Earth.[Boyle, Alan (19 August 2008).]
Twists in the Doomsday debate
. ''Cosmic Log''. msnbc.com
MSNBC (originally the Microsoft National Broadcasting Company) is an American news-based pay television cable channel. It is owned by NBCUniversala subsidiary of Comcast. Headquartered in New York City, it provides news coverage and politic ...
.[Boyle, Alan (27 March 2008).]
Doomsday Fears Spark Lawsuit
. ''Cosmic Log''. msnbc.com
MSNBC (originally the Microsoft National Broadcasting Company) is an American news-based pay television cable channel. It is owned by NBCUniversala subsidiary of Comcast. Headquartered in New York City, it provides news coverage and politic ...
. Other claimed potential risks include the creation of theoretical particles called strangelets, magnetic monopoles, and vacuum bubbles.
Based on such safety concerns, US federal judge Richard Posner, Future of Humanity Institute research associate Toby Ord and others have argued that the LHC experiments are too risky to undertake. In the book '' Our Final Century: Will the Human Race Survive the Twenty-first Century?'', English cosmologist and astrophysicist Martin Rees
Martin John Rees, Baron Rees of Ludlow One or more of the preceding sentences incorporates text from the royalsociety.org website where: (born 23 June 1942) is a British cosmologist and astrophysicist. He is the fifteenth Astronomer Roya ...
had calculated an upper limit of 1 in 50 million for the probability that RHIC will produce a global catastrophe or black hole
A black hole is a region of spacetime where gravity is so strong that nothing, including light or other electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts that a sufficiently compact mass can defo ...
. However, Rees has also reported not to be "losing sleep over the collider," and trusts the scientists who have built it. He has stated: "My book has been misquoted in one or two places. I would refer you to the up-to-date safety study."
The risk assessments of catastrophic scenarios at the LHC sparked public fears, and some scientists associated with the project received protests - the Large Hadron Collider team revealed that they had received death threats and threatening emails and phone calls demanding the experiment be halted.[Highfield, Roger (5 September 2008).]
Scientists get death threats over Large Hadron Collider
. '' Telegraph.co.uk''. , Romania's Conservative Party held a protest before the European Commission
The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body ...
mission to Bucharest
Bucharest ( , ; ro, București ) is the capital and largest city of Romania, as well as its cultural, industrial, and financial centre. It is located in the southeast of the country, on the banks of the Dâmbovița River, less than north ...
, demanding that the experiment be halted because it feared that the LHC could create dangerous black holes.
Media coverage
Various widely circulated newspapers have reported doomsday fears in connection with the collider, including ''The Times
''The Times'' is a British daily national newspaper based in London. It began in 1785 under the title ''The Daily Universal Register'', adopting its current name on 1 January 1788. ''The Times'' and its sister paper '' The Sunday Times'' ...
'',[Sugden, Joanna (6 September 2008).]
Large Hadron Collider will not turn world to goo, promise scientists
. '' Times Online.'' ''The Guardian
''The Guardian'' is a British daily newspaper
A newspaper is a periodical publication containing written information about current events and is often typed in black ink with a white or gray background.
Newspapers can cover a wide ...
'',[Carus, Felicity (7 September 2008).]
Should we be concerned when the world's largest subatomic particle experiment is switched on in Geneva?
'' guardian.co.uk''. ''The Independent
''The Independent'' is a British online newspaper. It was established in 1986 as a national morning printed paper. Nicknamed the ''Indy'', it began as a broadsheet and changed to tabloid format in 2003. The last printed edition was publishe ...
'',[Connor, Steve (5 September 2008).]
The Big Question: Is our understanding of the Universe about to be transformed?
. ''The Independent''. ''The Sydney Morning Herald
''The Sydney Morning Herald'' (''SMH'') is a daily compact newspaper published in Sydney, New South Wales, Australia, and owned by Nine. Founded in 1831 as the ''Sydney Herald'', the ''Herald'' is the oldest continuously published newspaper ...
'',[Massive physics experiment on Wednesday]
. ''The Sydney Morning Herald''. 8 September 2008. and ''Time
Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, t ...
''.[Harrell, Eben (4 September 2008).]
Collider Triggers End-of-World Fears
. '' Time.com''. Among other media sources, CNN mentioned that "Some have expressed fears that the project could lead to the Earth's demise,"[Landau, Elizabeth (8 September 2008).]
Multibillion-dollar collider to probe nature's mysteries
. CNN. but it assured its readers with comments from scientists like John Huth, who said that it was "baloney". MSNBC
MSNBC (originally the Microsoft National Broadcasting Company) is an American news-based pay television cable channel. It is owned by NBCUniversala subsidiary of Comcast. Headquartered in New York City, it provides news coverage and politic ...
said that, "there are more serious things to worry about"[Boyle, Alan (12 September 2008).]
Big Bang sparks big reaction
. ''Cosmic Log''. msnbc. and allayed fears that "the atom-smasher might set off earthquakes or other dangerous rumblings". The results of an online survey it conducted "indicate that a lot of he public
He or HE may refer to:
Language
* He (pronoun), an English pronoun
* He (kana), the romanization of the Japanese kana へ
* He (letter), the fifth letter of many Semitic alphabets
* He (Cyrillic), a letter of the Cyrillic script called ''He'' ...
know enough not to panic". The BBC stated, "the scientific consensus appears to be on the side of CERN's theorists"[Rincon, Paul (23 June 2008).]
Earth 'not at risk' from collider
. ''BBC News''. who say the LHC poses "no conceivable danger". Brian Greene in the ''New York Times
''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid ...
'' reassured readers by saying, "If a black hole is produced under Geneva, might it swallow Switzerland and continue on a ravenous rampage until the Earth is devoured? It’s a reasonable question with a definite answer: no."[Greene, Brian (11 September 2008).]
The Origins of the Universe: A Crash Course
" ''The New York Times''.
On , a 16-year-old girl from Sarangpur, Madhya Pradesh, India
India, officially the Republic of India ( Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the ...
committed suicide, having become distressed about predictions of an impending "doomsday
Doomsday may refer to:
* Eschatology, a time period described in the eschatological writings in Abrahamic religions and in doomsday scenarios of non-Abrahamic religions.
* Global catastrophic risk, a hypothetical event explored in science and fict ...
" made on an Indian news channel ( Aaj Tak) covering the LHC.[Girl suicide 'over Big Bang fear']
. ''BBC News
BBC News is an operational business division of the British Broadcasting Corporation (BBC) responsible for the gathering and broadcasting of news and current affairs in the UK and around the world. The department is the world's largest broad ...
''. 11 September 2008.
After the dismissal of the federal lawsuit, '' The Daily Show's'' correspondent John Oliver
John William Oliver (born 23 April 1977) is a British-American comedian, writer, producer, political commentator, actor, and television host. Oliver started his career as a stand-up comedian in the United Kingdom. He came to wider attention ...
interviewed Walter L. Wagner, who declared that he believed the chance of the LHC destroying the Earth to be 50%, since it will either happen or it won't.
Specific concerns
Micro black holes
Although the Standard Model
The Standard Model of particle physics is the theory describing three of the four known fundamental forces ( electromagnetic, weak and strong interactions - excluding gravity) in the universe and classifying all known elementary particles. I ...
of particle physics predicts that LHC energies are far too low to create black hole
A black hole is a region of spacetime where gravity is so strong that nothing, including light or other electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts that a sufficiently compact mass can defo ...
s, 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 at a rate of the order of one per second.[ Barrau, Aurélien; & Grain, Julien (12 November 2004).]
The case for mini black holes
. ''CERN Courier''. CERN. According to the standard calculations these are harmless because they would quickly decay by Hawking radiation. Hawking radiation is a thermal radiation
Thermal radiation is electromagnetic radiation generated by the thermal motion of particles in matter. Thermal radiation is generated when heat from the movement of charges in the material (electrons and protons in common forms of matter) is ...
predicted to be emitted by black hole
A black hole is a region of spacetime where gravity is so strong that nothing, including light or other electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts that a sufficiently compact mass can defo ...
s due to quantum effects
Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, ...
. Because Hawking radiation allows black holes to lose mass, black holes that lose more matter than they gain through other means are expected to dissipate, shrink, and ultimately vanish. Smaller micro black holes (MBHs), which could be produced at the LHC, are currently predicted by theory to be larger net emitters of radiation than larger black holes, and to shrink and dissipate instantly. The LHC Safety Assessment Group (LSAG) indicates that "there is broad consensus among physicists on the reality of Hawking radiation, but so far no experiment has had the sensitivity required to find direct evidence for it."
According to the LSAG, even if micro black holes were produced by the LHC and were stable, they would be unable to accrete matter in a manner dangerous for the Earth. They would also have been produced by cosmic rays
Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our ow ...
and have stopped in neutron star
A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich. Except for black holes and some hypothetical objects (e.g. w ...
s and white dwarf
A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes ...
s, and the stability of these astronomical bodies means that they cannot be dangerous:
Strangelets
Strangelets are small fragments of strange matter—a hypothetical form of quark matter—that contain roughly equal numbers of up, down
Down most often refers to:
* Down, the relative direction opposed to up
* Down (gridiron football), in American/Canadian football, a period when one play takes place
* Down feather, a soft bird feather used in bedding and clothing
* Downland, a ty ...
, and strange quark
A quark () is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. All common ...
s and that are more stable than ordinary nuclei (strangelets would range in size from a few femtometers to a few meters across). If strangelets can actually exist, and if they were produced at the LHC, they could conceivably initiate a runaway fusion process in which all the nuclei in the planet would be converted to strange matter, similar to a strange star.
The probability of the creation of strangelets decreases at higher energies. As the LHC operates at higher energies than the RHIC or the heavy ion programs of the 1980s and 1990s, the LHC is less likely to produce strangelets than its predecessors. Furthermore, models indicate that strangelets are only stable or long-lived at low temperatures. Strangelets are bound at low energies (in the range of 1–10 MeV), while the collisions in the LHC release energies in the range of 7–14 TeV. Thermodynamics
Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws o ...
very strongly disfavors the formation of a cold condensate that is an order of magnitude cooler than the surrounding medium. As an example, it is about as likely as producing an icecube in a furnace.
Concerns not meeting peer review
Otto Rössler, a German chemistry professor at the University of Tübingen
The University of Tübingen, officially the Eberhard Karl University of Tübingen (german: Eberhard Karls Universität Tübingen; la, Universitas Eberhardina Carolina), is a public research university located in the city of Tübingen, Baden-W� ...
, argues that micro black holes created in the LHC could grow exponentially.[ Rössler, Otto (2008).]
A Rational and Moral and Spiritual Dilemma
".[ Rössler, Otto (2008).]
Abraham-Solution to Schwarzschild Metric Implies That CERN Miniblack Holes Pose a Planetary Risk
".[Patorski, Gregor (10 September 2008).]
Grösstes Verbrechen der Menschheit
(in German). ''20 Minuten
)
, logo = 20Minuten Logo ab mai 2013.jpg
, image =
, caption = 20 Minutes logo (since May 2013)
, alt =
, type = Free daily newspaper
, format = Tabl ...
''.[Publicity für eine fragwürdige Hypothese]
(in German). '' NZZ Online''. . On 4 July 2008, Rössler met with a CERN physicist, Rolf Landua, with whom he discussed his safety concerns.[Schmidt, Von Wolf (7 September 2008).]
Der Prophet des Planetentods
(in German). '' Taz.de''. Following the meeting, Landua asked another expert, Hermann Nicolai, Director of the Albert Einstein Institute, in Germany, to examine Rössler's arguments. Nicolai reviewed Otto Rössler's research paper on the safety of the LHC and issued a statement highlighting logical inconsistencies and physical misunderstandings in Rössler's arguments. Nicolai concluded that "this text would not pass the referee process in a serious journal." Domenico Giulini also commented with Hermann Nicolai on Otto Rössler's thesis, concluding that "his argument concerns only the General Theory of Relativity (GRT), and makes no logical connection to LHC physics; the argument is not valid; the argument is not self-consistent."[Giulini, Domenico; and Nicolai, Hermann (August 2008). ]
On the arguments of O.E. Rössler
'. On , a group of German physicists, the Committee for Elementary Particle Physics (KET), published an open letter further dismissing Rössler's concerns and carrying assurances that the LHC is safe. Otto Rössler was due to meet Swiss president Pascal Couchepin in August 2008 to discuss this concern,[Couchepin trifft Cern-Kritiker Rössler]
(in German). '' NZZ Online''. . but it was later reported that the meeting had been canceled as it was believed Rössler and his fellow opponents would have used the meeting for their own publicity.[Kein Gespräch zwischen Couchepin und Cern-Kritiker]
(in German). '' NZZ Online''. .
On , Rainer Plaga, a German astrophysicist, posted a research paper on the arXiv
arXiv (pronounced " archive"—the X represents the Greek letter chi ⟨χ⟩) is an open-access repository of electronic preprints and postprints (known as e-prints) approved for posting after moderation, but not peer review. It consists o ...
Web archive concluding that LHC safety studies have not definitely ruled out the potential catastrophic threat from microscopic black holes, including the possible danger from Hawking radiation emitted by black holes. In a follow-up paper posted on the arXiv
arXiv (pronounced " archive"—the X represents the Greek letter chi ⟨χ⟩) is an open-access repository of electronic preprints and postprints (known as e-prints) approved for posting after moderation, but not peer review. It consists o ...
on , Steven Giddings and Michelangelo Mangano responded to Plaga's concerns. They pointed out what they see as a basic inconsistency in Plaga's calculation, and argued that their own conclusions on the safety of the collider, as referred to in the LHC safety assessment (LSAG) report, remain robust. Giddings and Mangano also referred to the research paper "Exclusion of black hole disaster scenarios at the LHC", which relies on a number of new arguments to conclude that there is no risk due to mini black holes at the LHC. On 19 January 2009 Roberto Casadio, Sergio Fabi and Benjamin Harms posted on the arXiv
arXiv (pronounced " archive"—the X represents the Greek letter chi ⟨χ⟩) is an open-access repository of electronic preprints and postprints (known as e-prints) approved for posting after moderation, but not peer review. It consists o ...
a paper, later published on ''Physical Review D'', ruling out the catastrophic growth of black holes in the scenario considered by Plaga. In reaction to the criticisms, Plaga updated his paper on the arXiv
arXiv (pronounced " archive"—the X represents the Greek letter chi ⟨χ⟩) is an open-access repository of electronic preprints and postprints (known as e-prints) approved for posting after moderation, but not peer review. It consists o ...
on 26 September 2008 and again on 9 August 2009. So far, Plaga's paper has not been published in a peer-reviewed journal.
Safety reviews
CERN-commissioned reports
Drawing from research performed to assess the safety of the RHIC collisions, the LHC Safety Study Group, a group of independent scientists, performed a safety analysis of the LHC, and released their findings in the 2003 report ''Study of Potentially Dangerous Events During Heavy-Ion Collisions at the LHC''. The report concluded that there is "no basis for any conceivable threat". Several of its arguments were based on the predicted evaporation of hypothetical micro black holes by Hawking radiation (which yet was not confirmed experimentally) and on the theoretical predictions of the Standard Model
The Standard Model of particle physics is the theory describing three of the four known fundamental forces ( electromagnetic, weak and strong interactions - excluding gravity) in the universe and classifying all known elementary particles. I ...
with regard to the outcome of events to be studied in the LHC. One argument raised against doomsday fears was that collisions at energies equivalent to and higher than those of the LHC 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.
In 2007, CERN mandated a group of five particle physicists not involved in the LHC experiments—the LHC Safety Assessment Group (LSAG), consisting of John Ellis John Ellis may refer to:
Academics
*John Ellis (scrivener) (1698–1791), English political writer
*John Ellis (naturalist) (1710–1776), English botanical illustrator
*John Ellis (physicist, born 1946), British theoretical physicist at CERN
* Jo ...
, Gian Giudice, Michelangelo Mangano and Urs Wiedemann, of CERN, and Igor Tkachev, of the Institute for Nuclear Research in Moscow—to monitor the latest concerns about the LHC collisions.[ On , in light of new experimental data and theoretical understanding, the LSAG issued a report updating the 2003 safety review, in which they reaffirmed and extended its conclusions that "LHC collisions present no danger and that there are no reasons for concern".][ The LSAG report was then reviewed by CERN’s Scientific Policy Committee (SPC), a group of external scientists that advises CERN’s governing body, its Council.][CERN Council looks forward to LHC start-up]
. PR05.08 (20 June 2008). CERN 2008. The report was reviewed and endorsed by a panel of five independent scientists, Peter Braun-Munzinger, Matteo Cavalli-Sforza, Gerard 't Hooft, Bryan Webber and Fabio Zwirner, and their conclusions were unanimously approved by the full 20 members of the SPC. On , the LSAG's "Review of the safety of LHC collisions" was published in the '' Journal of Physics G: Nuclear and Particle Physics'' by the UK Institute of Physics
The Institute of Physics (IOP) is a UK-based learned society and professional body that works to advance physics education, research and application.
It was founded in 1874 and has a worldwide membership of over 20,000. The IOP is the Physica ...
, which endorsed its conclusions in a press release that announced the publication.
Following the July 2008 release of the LSAG safety report, the Executive Committee of the Division of Particles and Fields (DPF) of the American Physical Society, the world's second largest organization of physicists, issued a statement approving the LSAG's conclusions and noting that "this report explains why there is nothing to fear from particles created at the LHC". On , a group of German quantum physicists, the Committee for Elementary Particle Physics (KET),[Website of the Committee for Elementary Particle Physics (KET)](_blank)
(in German). published an open letter further dismissing concerns about the LHC experiments and carrying assurances that they are safe based on the LSAG safety review.[Hawley, Charles (6 August 2008).]
. ''Spiegel Online
''Der Spiegel (online)'' is a German news website. Before the renaming in January 2020, the website's name was ''Spiegel Online'' (short ''SPON'').
It was founded in 1994 as the online offshoot of the German news magazine, ''Der Spiegel'', wi ...
''.[Mättig, Peter (1 August 2008).]
Official statement of the German Committee for Elementary Particle Physics (KET)
" (in German). Committee for Elementary Particle Physics (KET).
Other publications
On , Steven Giddings and Michelangelo Mangano issued a research paper titled the "Astrophysical implications of hypothetical stable TeV-scale black holes", where they develop arguments to exclude any risk of dangerous black hole production at the LHC. On , this safety review was published in the '' Physical Review D'', and a commentary article which appeared the same day in the journal ''Physics'' endorsed Giddings' and Mangano's conclusions. The LSAG report draws heavily on this research.[
On , a paper titled "Exclusion of black hole disaster scenarios at the LHC" was published in the journal ''Physics Letters B''.] The article, which summarizes proofs aimed at ruling out any possible black hole disaster at the LHC, relies on a number of new safety arguments as well as certain arguments already present in Giddings' and Mangano's paper "Astrophysical implications of hypothetical stable TeV-scale black holes".
Legal challenges
On , a complaint requesting an injunction to halt the LHC's startup was filed by Walter L. Wagner and Luis Sancho against CERN and its American collaborators, the US Department of Energy
The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and manages the research and development of nuclear power and nuclear weapons in the United State ...
, the National Science Foundation
The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National ...
and the Fermi National Accelerator Laboratory
Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a United States Department of Energy national laboratory specializing in high-energy particle physics. Since 2007, Fermilab has been operat ...
, before the United States District Court for the District of Hawaii
The United States District Court for the District of Hawaii (in case citations, D. Haw.) is the principal trial court of the United States Federal Court System in the state of Hawaii. The court's territorial jurisdiction encompasses the stat ...
.[Sancho v. U.S. Department of Energy et al. (1:2008cv00136)]
. ''Justia Federal District Court Filings & Dockets''. 21 March 2008. The plaintiffs demanded an injunction against the LHC's activation for 4 months after issuance of the LHC Safety Assessment Group's (LSAG) most recent safety documentation, and a permanent injunction until the LHC can be demonstrated to be reasonably safe within industry standards.[Documentation submitted by plaintiff]
". LHCDefense.org. The US Federal Court scheduled trial to begin .
The LSAG review, issued on after outside review, found "no basis for any concerns about the consequences of new particles or forms of matter that could possibly be produced by the LHC". The US Government, in response, called for summary dismissal of the suit against the government defendants as untimely due to the expiration of a six-year statute of limitations (since funding began by 1999 and has essentially been completed already), and also called the hazards claimed by the plaintiffs "overly speculative and not credible".[ Overbye, Dennis (27 June 2008).]
Government Seeks Dismissal of End-of-World Suit Against Collider
. ''The New York Times
''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid ...
''. The Hawaii District Court heard the government's motion to dismiss on , and on 26 September the Court issued an order granting the motion to dismiss on the grounds that it had no jurisdiction over the LHC project. A subsequent appeal by the plaintiffs was dismissed by the Court on 24 August 2010.
On , a group of European citizens, led by German biochemist Otto Rössler, filed a suit against CERN in the European Court of Human Rights
The European Court of Human Rights (ECHR or ECtHR), also known as the Strasbourg Court, is an international court of the Council of Europe which interprets the European Convention on Human Rights. The court hears applications alleging that a ...
in Strasbourg.[Gray, Richard (9 September 2008).]
Legal bid to stop CERN atom smasher from destroying the world
. '' Telegraph.co.uk''. The suit, which was summarily rejected on the same day, alleged that the Large Hadron Collider posed grave risks for the safety of the 27 member states of the European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been ...
and their citizens.
Late in 2009 a review of the legal situation by Eric Johnson, a lawyer, was published in the ''Tennessee Law Review''. In this paper, Johnson stated that "Given such a state, it is not clear that any particle-physics testimony should be allowed in the courtroom", in reference to the dual problems that (a) the scientific arguments regarding the risks are so complex that only persons who have devoted many years to particle physics study are competent to understand them, but (b) any such persons, by reason of this huge personal investment, will inevitably be highly biased in favor of the experiments, and also endangered by severe professional censure if they threaten their continuation. In February 2010 a summary of Johnson's article appeared as an opinion piece in New Scientist
''New Scientist'' is a magazine covering all aspects of science and technology. Based in London, it publishes weekly English-language editions in the United Kingdom, the United States and Australia. An editorially separate organisation publish ...
.
In February 2010, the German Constitutional Court ( Bundesverfassungsgericht) rejected an injunction petition to halt the LHC's operation as unfounded, without hearing the case, stating that the opponents had failed to produce plausible evidence for their theories. A subsequent petition was rejected by the Administrative Court of Cologne in January 2011. An appeal against the latter ruling was rejected by the Higher Administrative Court of North Rhine-Westphalia in October 2012.Web portal of the Justice Ministry of North Rhine-Westphalia (in German)
.
References
External links
CERN webpage.
"The LHC is safe" (video)
talk by John Ellis John Ellis may refer to:
Academics
*John Ellis (scrivener) (1698–1791), English political writer
*John Ellis (naturalist) (1710–1776), English botanical illustrator
*John Ellis (physicist, born 1946), British theoretical physicist at CERN
* Jo ...
at CERN, on 14 August 2008.
{{Doomsday
CERN
Large Hadron Collider
Safety