may wonder whether it is in man's interest to know nature's secrets, if
he is ready to benefit from them or if this knowledge will harm him....
I am among those who believe that humanity will draw more benefit than harm
from these discoveries.' (2)
Artist's impression of the interaction
between an alpha particle and an atom.
2000, on the first floor of the Palais de la Découverte, displayed to
visitors as they leave the exhibition, this quotation by Pierre Curie
sums up what may well be on the visitor's mind at the end of a fascinating
tour of the progress made by 20th-century science in penetrating matter's
most intimate secrets.
Professor Curie's prediction of the potential dangers proved correct,
and nuclear weapons no doubt represent the embodiment of knowledge used
for evil purposes. But this exhibition also shows to what extent the researcher's
ultimate optimism was well-founded. Man's understanding of radioactivity
- this 'signal' sent by the ballet of tiny elementary particles, charged
with mass, electricity and energy, and gravitating to the heart of certain
mutating unstable atoms - has permitted a triple scientific revolution.
This was expressed in the three sections of the exhibition - entitled
and - with reference to
the three principal types of radioactive radiation.
A portrait of Dr Chicotot, a
pioneer of treatment for cancer, in 1908.
- The universe
To understand the nature of matter is also to enhance one's understanding
of the universe. Increased understanding of the radiation created by the
action of the disintegration and transmutation of atoms results from a
twofold investigation: into the infinitely small and into the infinitely
On the one
hand, physicists have made constant progress in identifying elementary
particles and the fundamental forces by which they interact. On the other,
in the vast expanses of the universe, astrophysicists have been tracing
the mutations of matter since the original Big Bang.
Today's treatment. Beams of protons
and carbon ions, produced by accelerators, permit the effective
treatment of eye cancer and deep tumours. Such technologies originated
in the nuclear sciences which continue to make a major contribution
to progress in medicine.
Since life first appeared on earth it has evolved not just in an ocean
of radiation coming from the cosmos, but also in the natural radioactivity
of a planet which, like any other, was born as a result of the laws and
randomness of this cosmos. Volcanic eruptions, geysers and earthquakes
are all reminders that, in bowels of the earth (just 4.5 billion years
old) is also a 'nuclear machine' in which the transmutations of matter
release vast quantities of energy.
At the same
time, intense radioactivity can be a threat to life, its power of penetration
being such that it attacks the very heart of the cells of which we are
composed. And the reason our planet has succeeded in being hospitable
to life is also because it is an oasis in the universe where the ambient
radiation level allows it to be sustained. Meanwhile, all around us, the
rocks of the earth's crust (from which we extract the fuel for nuclear
power plants) retain the memory of this transmuting activity. The most
notorious phenomenon, linked to the nature of the local geology, is radon,
a gas emitted by the breakdown of uranium 238, which can be found in the
cellars of houses.
As a result
of the knowledge acquired, science has become highly sophisticated in
the field of radioprotection, allowing us to determine reliable limits
for natural and artificial radiation, which, in guaranteeing the effectiveness
of the defence mechanisms of living cells when faced with radioactive
attack, do not pose a danger to health.
Crouching Aphrodite - The Louvre
Museum Radiation with gamma rays is able to eliminate fungi, larvae,
insects and bacteria, and to protect works of art against deterioration.
- In practice
Progress in fundamental physics over recent decades has permitted
the creation of irreplaceable scientific tools which can be used for a
vast range of activities. We have become so used to their presence that
we are usually unaware of their origins or of the principles by which
they operate. In dentists' surgeries and museums, supermarkets and airports,
technologies drawing on our knowledge of radioactivity are all around
us. Medical imaging, the identification of gene sequences, the piloting
of biological markers aimed at destroying cancerous tumours, the analysis
of the atmosphere's chemical composition, smoke detection, food conservation,
the inspection of the wear on materials, the luminosity of information
panels, the dating of works of art, the detection of anti-personnel mines...
The list is seemingly endless.
is without including the key question of the role of nuclear physics in
energy production. Nuclear fuel currently meets 35% of European needs,
principally in France, the United Kingdom and Belgium. In the nuclear
industry, radiation had in theory been effectively and safely harnessed
- until the Chernobyl disaster proved otherwise. What is more, the crucial
problem of nuclear waste remains unsolved. But then again, in the light
of the threat of global warming, does nuclear energy - which emits no
greenhouse gases - deserve to be ranked among the discarded technologies?
the physicists' point of view
of nuclear and sub-nuclear physics at Milan University, Ettore Fiorini
is one of Europe's foremost researchers on particle physics. Among
other things, he coordinates a European research network on cryogenic
detectors with the aim of measuring the mass of neutrinos.
mention of radioactivity more often frightens rather than fascinates
Fiorini : It is true that the term radioactivity immediately
arouses feelings of concern and threat. This reaction is because
the word is associated in people's minds with the terrible devastation
caused by the atom bomb dropped on Japan and, more recently, the
Chernobyl disaster - the only major nuclear accident we have seen.
As a physicist, I share the same sense of dread at such a mortally
dangerous use of scientific knowledge, whether for military purposes
or due to the evident and irresponsible mistakes in terms of the
security measures which caused the Chernobyl disaster.
the fact that we discovered radioactivity means that it does exist
and has always existed in nature. This discovery has been the source
of formidable progress in our knowledge of particle physics and
all the very beneficial applications which have derived from it.
The general public must be reconciled with this essential scientific
knowledge by making the effort to explain to them in detail what
this knowledge consists of and the many extremely useful applications
it enables - provided all the safety measures are applied to ensure
that the radiation, limited to very low doses, is free of danger.
It is up to the physicists to do this explaining.
are the principal - or the most unexpected - fields in which you
believe the control of radioactivity is able to bring essential
The list of the remarkably positive applications of nuclear physics
would be too long to give. But let me just remind you of the impact
of nuclear medicine and radiotherapy on the treatment of cancer,
and the powerful nuclear magnetic resonance tool for many kinds
of medical diagnostics. Environmental sciences is another key application
of the study of radioactivity: the detection of radon, for example,
and the applications that have followed, or the identification of
very low levels of contamination by analysing neutron activation.
The applications of radioactivity and the associated detection techniques
are also very important in the new discipline of archeometry.
the energy produced by nuclear fusion is often cited as a potential
source of genuinely clean energy which could become available at
some distant point in the future. In what way would this be radically
different from the present nuclear power industry in terms of radioactivity?
The possibility of supplying vast quantities of energy by harnessing
nuclear fusion is an option which for some years now has not appeared
to be entirely beyond our reach, but it is difficult to predict
when it could become a reality. However, as you are dealing with
an energy based on the control of nuclear reactions, it is premature
to say that it would be completely free of risk. What is clear is
that the fusion reaction cannot get out of control and can, in the
event of a problem, be stopped immediately. As to waste products,
if any - produced by neutron activation for example - they are certainly
going to be less dangerous and complex to manage than fission products.
The Institut National de physique nucléaire et de physique des
particules (FR), the Istituto nazionale di fissica nucleare (IT), the
Gesellschaft für Schwerionenforschung (DE) and the University of
Vienna (AT), under the aegis of the NuPECC (Nuclear Physics European Collaboration
Committee) and the Société européenne de Physique.
(2) Speech given by Pierre Curie at the award-giving ceremony for the
Nobel Prize for Physics in 1903, presented to Pierre and Marie Curie for
the discovery of radium.