Influence on Science

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Particle physics is sometimes criticized as expensive and irrelevant, though the same criticism is rarely made of astronomy and space exploration, which are more costly. What then is expected of a branch of science in terms of impact and cost? What is the impact of particle physics on philosophical, astronomy, cosmology, scientific practice, technology, business, and daily life?

Philosophical Impact

Particle physics challenges intuition. The experimental observations of atomic physics force the acceptance of the intellectual framework of quantum mechanics. As energy is raised into the realm of particle physics, relativity must also be accepted as the norm and not as a difficulty to be hedged about and avoided. A range of new phenomena, such as the creation of new matter out of energy, the existence of antimatter (predicted by Dirac from the combination of relativity and quantum mechanics), time dilation for fast-moving objects, and the speed of light as a limit, plus a wealth of more technical detail, attest to the accuracy of the theory with extraordinary precision. These phenomena, many predicted by theory before they were observed, force a full adoption of special relativity as a sound working basis on which to proceed. Matter-antimatter oscillations provoke consideration of the reality of quantum mechanical amplitudes as more than merely a convenient mathematical construction behind a theory governed by nonnegative probabilities.

This willingness to stretch the imagination using mathematical rigor as a touchstone is one of the stimuli given by particle physics. Three-dimensional space becomes four-dimensional space-time. Mathematical difficulties still to be overcome create interest in strings in ten dimensions or surfaces in eleven. By working in this space, and "compactifying" the unobserved dimensions, theorists hope to unify the theory of the smallest objects (quarks and leptons) with the gravity that dominates the universe at large distances. Is this approach correct? Only future experimental data can verify or disprove that.

If one makes such a unified Theory of Everything (TOE) is it worthy of the name? This is controversial territory. This extension of the reductionist approach must be approached with care. Could it explain everything including life, love, music, and free will? It is difficult to tell. One aspect of the question that has received attention recently is the Anthropic Principle. In its weak form this states that the laws of nature are such as to permit human existence. This appears to need very careful tuning of some of the numbers found in nature. For example, if the charge on the electron differed by more than a percent or two from its actual value, stars could not produce both carbon and oxygen, so human life could not exist. Is this evidence of divine design, or is it solved by assuming endless repetitions of universes with randomly different laws, most of which have no one to observe them? Isaac Newton referred to physics as "experimental philosophy." This is a very appropriate name.

Impact on Cosmology and Astronomy

In cosmology, the greatest impact of particle physics is found. Particle physics provides the rules that governed the crucial first seconds after the Big Bang. Distances were then tiny and energies gigantic, so that full play was given to the realm of high-energy physics. What exists now is a result of what happened then. Astronomers are convinced of the historical reality of the Big Bang because its echo is seen in the cosmic microwave background in the blackness between the stars. The Big Bang started with radiation ("Let there be light"), which created matter and antimatter equally. Yet today no antimatter can be found in nature, even after exhaustive searches. The solution to this puzzle lies in particle physics theory. Particle physics methods have been the driving force in the question of inflation (of why the universe is so uniform) and of its large-scale structure.

Astronomy poses questions such as "What makes stars shine?" "What is a supernova?" and "Is there dark invisible matter all around us?" The first two questions are answered, and the last addressed, by particle physics.

Impact on Science

The treaty which set up the European Laboratory for Particle Physics (CERN) in 1954 is one of the earliest examples of European cooperation. Europe needed this scale and structure of operation if it were to compete with America where scientific activity had been given a tremendous boost by the atomic bomb project. Only by combining its nations' strength could Europe hope to stem the "brain drain." Yet curiously, out of this competition has come wider cooperation. Even during the Cold War, large-scale collaborations existed with the Soviet Union based on a shared enthusiasm for science. The HERA electron-proton collider in the Deutsches Elektronen-Synchotron Laboratory (DESY) in Hamburg, Germany, was built by voluntary international agreement with Germany as the lead partner. By 2000, countries from all around the world, including the United States and Russia, were joining the now twenty CERN member states to build a common project (the Large Hadron Collider). Financial and operational "Memoranda of Understanding" provide the formal structure within which autonomous national funding agencies manage their own institutes and obligations. Big commonly owned and operated facilities at the world's best research sites are now a feature of many fields of science, such as telescopes (for example, the European Southern Observatory) and the European Synchrotron Radiation Source.

Doing science within a large international collaboration as a research student is training for leadership in the "real world." To find one place among say 400 co-workers, to collaborate usefully, to question the work of others, to offer one's own work for criticism and suggestion to a group from several nations, and finally to lead an international activity to successful completion and publication gives the training needed for being effective in large national and multinational commercial organisations.

Computer data handling is an area in which for forty years particle physics has been pushing the limits of what the computer scientists can deliver. The process continues through the World Wide Web and the computer grid. The approach to managing immense data sets with complex calibration methods, and the international access to them, makes particle physics the ideal testing ground for developing the analytic and computational techniques needed for, say, elucidating protein structure at new synchrotron x-ray sources.

Impact of Particle Physics Technology

The World Wide Web is the greatest gift of particle physics to humankind. It was invented by Tim Berners-Lee at CERN to provide easy document exchange around a widely dispersed international group of collaborators and transformed the Internet from an academic tool into a telecommunications revolution. The Web is free to all users, in contrast to some proprietary software used for, say, word processing. This libertarian approach stemmed deliberately from the open collaborative approach pioneered by particle physicists. Berners-Lee's view is that the Web would never have taken off if CERN had tried to exploit it. e-business conducted over the web amounted to $657 billion in 2000. The optoelectronics industry is a major supplier to the Internet and in 2000 was worth $140 billion and growing at 25 percent per year.

Superconducting magnet technology was pushed by and for particle physics. The electric current producing the magnetic field in superconducting magnets will circulate forever without any power loss or need for external supply. This is accomplished by cooling certain materials to within a few degrees of the absolute zero of temperature. Rutherford cable is the key to stably operating magnets, now in use in nuclear magnetic resonance imaging machines at hospitals worldwide.

The 1992 Nobel Prize in Physics was awarded to Georges Charpak of CERN for his invention of detector techniques for particles that he had made and then adapted for medical imaging purposes. Positron-emission tomography is one such noninvasive technique. It brings antimatter out of the research laboratory and into hospitals as a diagnostic tool. To make it affordable requires the accelerator techniques enabled by superconducting magnets, detector instrumentation such as that developed by Charpak, and the fast data handling power pioneered by particle physics. Radiation therapy for cancer treatment was an early spin-off from accelerator technology: new techniques are still being developed.

Theoretical particle physics has an interesting spin-off application in high finance. The same techniques used in solving abstruse problems in particle theory have shown ability to predict the movements of financial markets. Merchant banks like to hire particle theorists. Another application of particle theory computational methods is in warship design.

The list of spin-off applications is indeed diverse. It provides a classic illustration of the need to give rein to curiosity-driven science. Highly focused application-driven research of course is vital for future prosperity, but real innovation can often come from research planned for a different reason. As with lasers, (theorized in 1905 by Einstein, invented over 50 years later but with no obvious use, and now used in every CD player as well as in carrying web messages around the world), one can have surprises.

See also:Benefits of Particle Physics to Society; Culture and Particle Physics; Philosophy and Particle Physics; Universe


Greene, B. The Elegant Universe: Superstrings, Hidden Dimensions and the Quest for the Ultimate Theory (Jonathan Cape, London, 1999).

Barrow, J. D., and Tipler, F. The Anthropic Cosmological Principle (Oxford University Press, New York, 1986).

Fraser, G. The Quark Machines: How Europe Fought the ParticlePhysics War (Institute of Physics Publishing, Bristol, UK,1997).

Fraser, G., ed. The Particle Century (Institute of Physics Publishing, Bristol, UK 1998).

Naughton, J. A Brief History of the Future: The Origins of the Internet (Weidenfield and Nicolson, London, 1999).

David H. Saxon