Scientific Research: Repairs to large hadron collider - full text
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Officials at the European Organisation for Nuclear Research (CERN) headquarters in Geneva, Switzerland, announced on Dec. 5 that the Large Hadron Collider (LHC) - the world's most powerful particle accelerator - would be repaired by the end of June 2009.
Immediate Context
The LHC had been inaugurated by Swiss President Pascal Couchepin and French Prime Minister Francois Fillon on Oct. 21. CERN director general Robert Aymar had said at the inauguration ceremony: "Today is a day for CERN to thank its member states for their continued support for basic science, and for providing the stable framework that makes science of this kind possible."
However, the LHC had not been in operation at its inauguration because "a serious fault between two superconducting bending magnets" had developed and the LHC had been shut down on Sept. 19. The first attempt to use the LHC had been on Sept. 10.
At 27 km in circumference, the LHC was designed to create collisions between two powerful beams - moving in opposite directions - of subatomic particles called "hadrons" (either protons or lead ions). As the beams circulated around the collider they gained energy with every lap, producing higher speeds than scientists had been able to achieve previously, and therefore more energetic collisions. Physicists hoped to test the "Big Bang" theory of the creation of the universe by investigating the effects of the collisions on the subatomic particles.
Reaction and outlook
The particle physicists at CERN hoped that experiments using the LHC would provide information on such questions as: What gives matter its mass? What is the matter in the universe made of? and How has matter evolved?
The physicists wanted to extend the Standard Model - a framework devised in the 1970s to explain how subatomic particles interacted. The Standard Model had worked well but questions remained about the nature of gravity and the formation of matter and anti-matter. Scientists believed that at the start of the universe, matter and anti-matter existed in equal amounts, but as particles interacted nearly all the anti-matter was destroyed, so that there is almost none left in the existing matter-dominated universe.
One of the most important particles in the Standard Model - the Higgs boson - had been proposed in theory, but its existence had yet to be confirmed experimentally. Physicists hoped that the LHC would help them form a "unified theory" to link together ideas about space, time, matter, anti-matter, and gravity.
Historical Context
The atom - from a Greek term meaning something that cannot be divided - was supposed by ancient thinkers such as Epicurus, Democritus, Aristotle, and Lucretius to be the basic component of all other substances in the world.
Aristotle (384 BC-322 BC) proposed theories about space, movement, and what objects were made of, arguing that things on Earth were made of four "elements" (earth, fire, air, and water) and were naturally drawn to move towards the centre of the Earth. The notion of the Earth as the centre of an essentially mechanical universe was supported by Christian churches and remained dominant in the West through the Middle Ages.
Meanwhile, physics was advanced by Muslim scientists, such as Ibn al-Haytham (also known as Alhazen) (965-1040), who investigated mass, motion, light, and vision, and established the principles of the experimental method. Chinese scientists developed a separate tradition.
Nicolaus Copernicus (1473-1543) revived interest in astronomy in the West by putting forward the controversial theory that the Earth revolved around the Sun. When Galileo Galilei (1564-1642) announced that his observations using telescopes supported Copernicus's view, the Christian establishment was outraged, declared him a heretic, and placed him under house arrest for the rest of his life.
Sir Isaac Newton (1642-1727) had substantial success unifying the rules of physics so that they could be applied at an astronomical as well as a terrestrial scale. He observed that the energy of an object was proportional to the force with which it was being impelled. However, while Newton's physics helped understanding of what was visible to the human eye, it did not explain observations in the microscopic world. Over the subsequent century, study of magnetised and electrified objects revealed that particles such as electrons and protons were not observing the classical laws of physics.
Max Planck's (1850-1947) formulation of quantum theory, first propounded to the German Physical Society in 1900, again revolutionised scientific thought. The theory was first put forward by Planck to account for certain phenomena in the study of the radiation of heat, but was subsequently found applicable to all known physical and chemical phenomena on an atomic scale. Planck's formula stated that energy was not liberated by a continuous process but was emitted in a series of discontinuous "quanta" or amounts, dependent on the oscillations of the electrons. This concept was used by Albert Einstein (1879-1955) in his law of the photo-electric effect (1905), by Niels Bohr (1885-1962) in his studies of atomic physics, and by Lord Ernest Rutherford (1871-1937) and other scientists, and in later years in the mathematical theories developed by Louis de Broglie (1892-1987), Erwin Schrodinger (1887-1961), Werner Heisenberg (1901-76), and Paul Dirac (1902-84).
Einstein's Theory of Relativity of 1905 discarded the ideas of absolute space and absolute time. Einstein posited that areas of high gravity could warp space and that space could influence the speed at which matter moved and time passed.
In 1929 US astronomer Edwin Hubble (1889-1953) developed his theory of a velocity-distance relationship that strongly supported the concept of an expanding universe. The observation that stars, planets, and galaxies were moving away from a central location supported the theory of a violent start to the universe. This later became known as the "Big Bang" theory.
Under the "Big Bang" theory, an extremely dense and hot mass expanded while forming the galaxies that exist today. It was hoped by physicists at CERN that understanding energy releases at the atomic level would help explain the origins of the universe.
Research into the military applications of atomic energy became politically and strategically important during World War II (1939-45) as governments attempted to create atomic bombs. The US scientist Robert Oppenheimer (1904-67) led an international team of scientists in Los Alamos, New Mexico, who developed a fissile atomic weapon. Nuclear secrets were shared with the victors of World War II: the USA, UK, and France. Scientists working for the US authorities went on to develop an even more powerful weapon, the hydrogen bomb.
CERN was established in 1954 to promote research in particle physics for non-military purposes. Its core principles were declared to be: "collaboration among European States in nuclear research of a pure scientific and fundamental character ... The Organisation shall have no concern with work for military requirements and the results of its experimental and theoretical work shall be published or otherwise made generally available."
CERN members included Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland, and the UK.
CERN scientists developed new ways to detect particles, explored matter/anti-matter asymmetry, and for the first time observed and captured anti-hydrogen atoms. CERN's Large Electron-Positron collider (LEP) was completed in 1989 and was located in the same 27 km tunnel that was later used to house the LHC.
The idea of the LHC emerged in the early 1980s but the project was not approved until 1996.
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