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
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 ...
(RHIC) and later the
Large Hadron Collider (LHC)—currently the world's largest and most powerful
particle accelerator
A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies, and to contain them in well-defined beams.
Large accelerators are used for fundamental research in particle ...
—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
In physics, a state of matter is one of the distinct forms in which matter can exist. Four states of matter are observable in everyday life: solid, liquid, gas, and plasma. Many intermediate states are known to exist, such as liquid crystal, ...
or even
doomsday scenarios. Claims escalated as commissioning of the LHC drew closer, around 2008–2010. The claimed dangers included the production of stable
micro black hole
Micro black holes, also called mini black holes or quantum mechanical black holes, are hypothetical tiny (<1 ) 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
''Journal of Physics G: Nuclear and Particle Physics'' is a peer-reviewed journal that publishes theoretical and experimental research into nuclear physics, particle physics and particle astrophysics, including all interface areas between these fi ...
'' 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 Physic ...
, 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 Physic ...
. 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. ...
without hazardous consequences, including ultra-high-energy cosmic ray
In astroparticle physics, an ultra-high-energy cosmic ray (UHECR) is a cosmic ray with an energy greater than 1 EeV (1018 electronvolts, approximately 0.16 joules), far beyond both the rest mass and energies typical of other cosmic ray parti ...
s observed to impact Earth with energies far higher than those in any man-made collider.
Background
Particle collider
A collider is a type of particle accelerator which brings two opposing particle beams together such that the particles collide. Colliders may either be ring accelerators or linear accelerators.
Colliders are used as a research tool in particle ...
s are a type of particle accelerator
A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies, and to contain them in well-defined beams.
Large accelerators are used for fundamental research in particle ...
used by physicists as a research tool to understand fundamental aspects of the universe. Their operation involves directed beams of particles
In the physical sciences, a particle (or corpuscule in older texts) is a small localized object which can be described by several physical or chemical properties, such as volume, density, or mass.
They vary greatly in size or quantity, from s ...
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 acc ...
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 (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 charged particles to very high speeds and energies, and to contain them in well-defined beams.
Large accelerators are used for fundamental research in particle ...
complex, intended to collide opposing beams of either protons or lead
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...
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 acc ...
.[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
''National Geographic'' (formerly the ''National Geographic Magazine'', sometimes branded as NAT GEO) is a popular American monthly magazine published by National Geographic Partners. Known for its photojournalism, it is one of the most widely ...
''. It was built by the European Organization for Nuclear Research
The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in a northwestern suburb of Gene ...
(CERN) near Geneva
, neighboring_municipalities= Carouge, Chêne-Bougeries, Cologny, Lancy, Grand-Saconnex, Pregny-Chambésy, Vernier, Veyrier
, website = https://www.geneve.ch/
Geneva ( ; french: Genève ) frp, Genèva ; german: link=no, Genf ; it, Ginevr ...
, in Switzerland. The LHC's main purpose is to explore the validity and limitations of the Standard Model, 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) an ...
. 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
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 ...
, with Frank Close
Francis Edwin Close, (born 24 July 1945) is a particle physicist who is Emeritus Professor of Physics at the University of Oxford and a Fellow of Exeter College, Oxford.
Education
Close was a pupil at King's School, Peterborough (then a gr ...
, professor of physics at the University of Oxford
, mottoeng = The Lord is my light
, established =
, endowment = £6.1 billion (including colleges) (2019)
, budget = £2.145 billion (2019–20)
, chancellor ...
, to comment at the time that "the chance of strangelet_creation.html" ;"title="/nowiki> 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 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
''End Day'' is a 2005 docu-drama produced by the BBC. It aired on the National Geographic Channel, on the TV series, ''National Geographic Channel Presents'', and BBC Three that depicts a set of five doomsday scenarios. The documentary follows ...
''. BBC #REDIRECT BBC #REDIRECT BBC
Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
...
. 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 transition into a different
quantum mechanical
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, qua ...
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
In quantum field theory, a false vacuum is a hypothetical vacuum that is relatively stable, but not in the most stable state possible. This condition is known as metastable. It may last for a very long time in that state, but could eventually ...
), or the creation of
strange matter
Strange matter (or strange quark matter) is quark matter containing strange quarks. In nature, strange matter is hypothesized to occur in the core of neutron stars, or, more speculatively, as isolated droplets that may vary in size from femtome ...
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 part ...
. 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 surfa ...
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 of ...
) 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 cau ...
s to reasonably exclude the
probability
Probability is the branch of mathematics concerning numerical descriptions of how likely an 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 1, where, roughly speakin ...
for such a catastrophic scenario. Physicists are unable to demonstrate experimental and
astrophysical
Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline said, Astrophysics "seeks to ascertain the nature of the h ...
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 own ...
(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 Royal, ...
, with respect to the RHIC, as being at least a 1 in 50 million chance. With regards to the production of
strangelets,
Frank Close
Francis Edwin Close, (born 24 July 1945) is a particle physicist who is Emeritus Professor of Physics at the University of Oxford and a Fellow of Exeter College, Oxford.
Education
Close was a pupil at King's School, Peterborough (then a gr ...
, professor of physics at the
University of Oxford
, mottoeng = The Lord is my light
, established =
, endowment = £6.1 billion (including colleges) (2019)
, budget = £2.145 billion (2019–20)
, chancellor ...
, 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 ...
between
Walter L. Wagner and
F. Wilczek,
in response to a previous article by M. Mukerjee. The media attention unfolded with an article in
U.K.
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
Sunday Times 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
Director may refer to:
Literature
* ''Director'' (magazine), a British magazine
* ''The Director'' (novel), a 1971 novel by Henry Denker
* ''The Director'' (play), a 2000 play by Nancy Hasty
Music
* Director (band), an Irish rock band
* ''D ...
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
Federal or foederal (archaic) may refer to:
Politics
General
*Federal monarchy, a federation of monarchies
*Federation, or ''Federal state'' (federal system), a type of government characterized by both a central (federal) government and states or ...
lawsuits in San Francisco
San Francisco (; Spanish for " 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 fourth most populous in California and 17th ...
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 Un ...
, 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 #REDIRECT BBC #REDIRECT BBC
Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
...
believes black holes have been created at RHIC. However, the original papers of H. Năstase and the
; in other words, it is similar mathematically. Therefore, RHIC collisions might be described by mathematics relevant to theories of
within AdS/CFT, but the described physical phenomena are not the same.
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
(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.
These opponents assert that the LHC experiments have the potential to create low velocity
stated, "the scientific consensus appears to be on the side of CERN's theorists"
who say the LHC poses "no conceivable danger".
'' 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."
) covering the LHC.
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.
posit the existence of extra spatial dimensions, in which it would be possible to create