Two overriding considerations shaped the development of early research on the biological effects of microwave radiation—possible medical application and uncertainty about the hazards of exposure to radar. Reports in the late 1940s and early 1950s of hazards resulting from microwave exposure led to the near abandonment of medical research related to microwave diathermy at the same time that military and industrial concern over hazards grew, culminating in the massive research effort known as ‘the Tri-Service program’ . (...) Both the early focus on medical application and the later search for hazards played important roles in dictating how this field of research developed as a science. (shrink)

"This volume tells the untold story of how observations of the cosmic microwave background radiation were interpreted in the decades following its serendipitous discovery, before the Hot Big Bang model became the accepted orthodoxy. The authors guide the reader through this history, including the many false trails and blind alleys that occurred along the way. Readers will discover how the Big Bang theory was shaped by alternative theories that exposed its weaknesses – including some that persist even today. (...) By looking carefully at what it takes to reject an incorrect theory and the assumptions and processes at each stage, the authors examine the epistemological factors at play between an emerging scientific orthodoxy and since discarded alternatives. Their analysis of the cosmic microwave background provides a uniquely well-documented case study of theory building for a wide readership spanning cosmology, the history of physics and astronomy, and the philosophy of science more broadly.". (shrink)

Are theories judged on the basis of empirical tests of their predictions, as proposed by Karl Popper and others, or are new theories adopted by younger scientists while old theories fade away when their advocates die, as Max Planck suggested? A famous historical episode, the rejection of steady state cosmology and the revival of the big bang cosmology following the 1965 discovery of the cosmic microwave background radiation, is examined to determine whether the scientific community followed Popper’s or (...) Planck’s principle. It is found that by 1975 almost all supporters of the steady state had either switched to the big bang or stopped publishing on cosmology. This case therefore seems to exemplify Popper’s principle, although it should be noted that two of the founders of steady state cosmology had strongly proclaimed their adherence to that principle. The case does not support the Popperian claim that successful novel predictions provide better evidence for a theory than deductions of known facts. (shrink)

In 1965, the discovery of a new type of uniform radiation, located between radiowaves and infrared light, was accidental. Known today as Cosmic Microwave background, this diffuse radiation is commonly interpreted as a fossil light released in an early hot and dense universe and constitutes today the main ’pilar’ of the big bang cosmology. Considerable efforts have been devoted to derive fundamental cosmological parameters from the characteristics of this radiation that led to a surprising universe that (...) is shaped by at least three major unknown components: inflation, dark matter and dark energy. This is an important weakness of the present consensus cosmological model that justifies raising several questions on the CMB interpretation. Can we consider its cosmological nature as undisputable? Do other possible interpretations exist in the context of other cosmological theories or simply as a result of other physical mechanisms that could account for it? In an effort to questioning the validity of scientific hypotheses and the under-determination of theories compared to observations, we examine here the difficulties that still exist on the interpretation of this diffuse radiation and explore other proposed tracks to explain its origin. We discuss previous historical concepts of diffuse radiation before and after the CMB discovery and underline the limit of our present understanding. (shrink)

During the past decade, M.W. Evans and his coworkers have been developing so-called “Evans” or “ECE theory” that intends to serve as an unified field theory. One of its predictions is an existence of a radiation magnetic field called a “B(3)-field” which should accompany a circularly polarized electromagnetic radiation. This field should affect free electrons in two ways: (1) the electrons should behave in the B(3)-field in the same way as in a classical magnetic field (i.e., Larmor precession) (...) and moreover, (2) the electrons should undergo quantum interaction with the B(3)-field with the formation of a spin connection resonance. This paper presents an experimental test of the B(3)-field existence by observing the changes in trajectories of free electrons in special detector, when strong (up to 200 W/m2) continuous circularly polarized microwave radiation of a frequency of 2.45 GHz is applied. We have not detected any sign of B(3)-field in presented experiment. It follows that if the B(3)-field really exists, it should be at least 4 orders of magnitude smaller than the Evans’ theory predicts. (shrink)

The physical origin of inertial forces is shown to be a consequence of the local interaction of Dirac's real covariant ether model(1) with accelerated microobjects, considered as real extended particlelike solitons, piloted by surrounding subluminal real wave fields packets.(2) Their explicit form results from the application of local inertial Lorentz transformations to the particles submitted to noninertial velocitydependent accelerations, i.e., constitute a natural extension of Lorentz's interpretation of restricted relativity.(3) Indeed Dirac's real physical covariant ether model implies inertial forces if (...) one considers the real accelerated noninertial motions of general relativity, defined within the absolute local inertial frames associated with the observed local isotropy of the 2.7° K background microwave radiation.(4) Inertia thus appears as a necessary consequence of the real particle motions described by the E.d.B.B. formalism of quantum mechanics. (shrink)

Quantum theories constructed on the noncommutative spacetime called the Groenewold–Moyal plane exhibit many interesting properties such as Lorentz and CPT noninvariance, causality violation and twisted statistics. We show that such violations lead to many striking features that may be tested experimentally. These theories predict Pauli forbidden transitions due to twisted statistics, anisotropies in the cosmic microwave background radiation due to correlations of observables in spacelike regions and Lorentz and CPT violations in scattering amplitudes.

The uncertainty on measurements, given by the Heisenberg principle, is a quantum concept usually not taken into account in General Relativity. From a cosmological point of view, several authors wonder how such a principle can be reconciled with the Big Bang singularity, but, generally, not whether it may affect the reliability of cosmological measurements. In this letter, we express the Compton mass as a function of the cosmological redshift. The cosmological application of the indetermination principle unveils the differences of the (...) Hubble-Lemaître constant value, $$H_0$$, as measured from the Cepheids estimates and from the Cosmic Microwave Background radiation constraints. In conclusion, the $$H_0$$ tension could be related to the effect of indetermination derived in comparing a kinematic with a dynamic measurement. (shrink)

The claim of inflationary cosmology to explain certain observable facts, which the Friedmann-Roberston-Walker models of `Big-Bang' cosmology were forced to assume, has already been the subject of significant philosophical analysis. However, the principal empirical claim of inflationary cosmology, that it can predict the scale-invariant power spectrum of density perturbations, as detected in measurements of the cosmic microwave background radiation, has hitherto been taken at face value by philosophers. The purpose of this paper is to expound the theory of (...) density perturbations used by inflationary cosmology, to assess whether inflation really does predict a scale-invariant spectrum, and to identify the assumptions necessary for such a derivation. The first section of the paper explains what a scale invariant power-spectrum is, and the requirements placed on a cosmological theory of such density perturbations. The second section explains and analyses the concept of the Hubble horizon, and its behaviour within an inflationary space-time. The third section expounds the inflationary derivation of scale-invariance, and scrutinises the assumptions within that derivation. The fourth section analyses the explanatory role of `horizon-crossing' within the inflationary scenario. (shrink)

The existence of big bang relic neutrinos—exact analogues of the big bang relic photons comprising the cosmic microwave background radiation—is a basic prediction of standard cosmology. The standard big bang theory predicts the existence of 1087 neutrinos per flavour in the visible universe. This is an enormous abundance unrivalled by any other known form of matter, falling second only to the cosmic microwave background (CMB) photon. Yet, unlike the CMB photon which boasts its first (serendipitous) detection in (...) the 1960s and which has since been observed and its properties measured to a high degree of accuracy in a series of airborne/satellite and ground based experiments, the relic neutrino continues to be elusive in the laboratory. The chief reason for this is of course the feebleness of the weak interaction. At present, the observational evidence for their existence rests entirely on cosmological measurements, such as the light elemental abundances, anisotropies in the cosmic microwave background, and the large-scale matter power spectrum. In this paper we argue that Direct Detection of relic neutrino background is indeed impossible by any means, because of two chief reasons: (a) there was no such thing of cosmic singularity, hence the hot big bang/primeval atom model was based on false premises (quantum birth assumption); (b) the neutrino existence itself is not unquestionable, in particular if we consider a realism view of vector potential, A, in classical electrodynamics. (shrink)

Cosmology as Weltanschauung is as old as the world. Cosmology as a physical discipline, however, is a child of this century, born in 1917, when Albert Einstein and Willem de Sitter first applied the theory of general relativity to the space-time of the entire universe. When did the child come of age and become a fully-fledged science? A popular myth shared by many practitioners holds that this did not happen until 1965, when the discovery of the 2.7K cosmic microwave (...) background radiation validated the concept of the hot big bang. Earlier accomplishments culminating in the 1965 event include the derivation of evolving relativistic models by Alexander Friedmann and George Lemaître, Edwin Hubble’s discovery of the redshift-magnitude relationship and George Gamow’s theory of the primordial nucleosynthesis containing the prediction of the microwave background left from the hot and dense past of the universe. This linear development is thrown into sharper relief in textbooks, by referring to an inarticulate.. (shrink)

Two years ago, astrophysicists studying Type Ia supernovas discovered that our universe is a much stranger place than we had imagined, with invisible vacuum energy accelerating its expansion. (See my column about this in the May-1999 Analog.) However, new astrophysical observations from the BOOMERanG experiment (Balloon Observations Of Millimetric Extragalactic Radiation and Geomagnetics), a balloon-borne cryogenic microwave telescope measurement that flew at an altitude of about 24 miles over the Antarctic, indicate that our universe is also rather ordinary, (...) in that its space is maximally flat. The term “flat” as used here means that the space of our universe is neither positively curved like a ball or negatively curved like a potato chip. It appears that in our universe, the tendencies of space toward positive curvature from gravitational attraction and towards negative curvature from expansion kinetic energy are precisely in balance, leaving space on the average completely free of curvature. (shrink)

The message is that physics has an „outward bound” of scientific inquiry in the field of cosmology. I present it in the historical development. Physics and astronomy, developing since the seventeenth century, inherited from the early Greek philosophers the conception that the Universe as a whole is invariable. In nineteenth century this conception in conjunction with the conception of eternity of the Universe gave rise to contradictions with other laws of physics indicating that cosmology is not a branch of physics (...) since the notion of the Universe is not a physical one. Cosmology returned to physics as its important branch due to the advent of general relativity theory and the discovery of the cosmic microwave background radiation. Modern cosmology generates fundamental problems creating real limits to inquiries in physics viewed as an empirical science. The very notion of the Universe shows that the scientific method reaches there limits of its applicability. Does „to exist” mean „to be observed by someone”? Should the definition of the Universe be based on a current physical theory, e.g. on Einstein’s general relativity, giving rise to a kind of mathematical instability? Is the fashionable concept of the „multiverse” a physical one or is a purely metaphysical notion in a scientific disguise? If the Universe is unique, is it meaningful to describe it in the framework of physics, which by its method always assumes that the number of objects it describes, is unlimited? Apart from these permanent philosophical problems there are concrete urgent problems generated by cosmology: the nature of dark matter and dark energy. These two species of „substance” appear only in cosmology and do not fit the laboratory physics; contrary to the three centuries long tradition of modern science, now cosmology inspires physics in a troublesome way. A separate class of limits to physics is generated by the theorem in general relativity that the Universe emerged from an initial curvature singularity of the spacetime. At the singularity the whole scientific inquiry breaks down. Cosmology of the very early Universe suggests that in its evolution two specific epochs took place, that of quantum gravity and an inflationary epoch. The underlying them two physical theories are incomplete and seem to be inherently untestable. Furthermore, the experimentally verifiable physics cannot explain the origin of the initial conditions determining properties of the Universe which emerged from the singularity. (shrink)

We consider the problem of possible topology for our Universe. It is shown that due to algebraic topology we can strictly define the shape of physical space whereas observations of anisotropy of microwave background radiation gives us an answer to the question whether our Universe is finite or not?

Ordinary clocks do not measure time in the common and Newtonian sense, and there is a similar problem for spatial measurements due to effects of motion and gravitation. Einstein’s theories of relativity are based on the denial of the possibility of the ‘absolute’ measurements that would be required. Nevertheless, here it is shown how such measurements can be performed. For this purpose, a “light clock” (or equivalent) is linked with a “space-time odometer” that counts the zero crossings in the field (...) of the cosmic microwave background radiation. The readings of these two instruments allow to calculate the time interval and the length of their path in Euclidean space even in the presence of local variations in gravitational potential. (shrink)

Quantum theory plays an increasingly significant role in contemporary early-universe cosmology, most notably in the inflationary origins of the fluctuation spectrum of the microwave background radiation. I consider the two main strategies for interpreting standard quantum mechanics in the light of cosmology. I argue that the conceptual difficulties of the approaches based around an irreducible role for measurement - already very severe - become intolerable in a cosmological context, whereas the approach based around Everett's original idea of treating (...) quantum systems as closed systems handles cosmological quantum theory satisfactorily. Contemporary cosmology, which indeed applies standard quantum theory without supplementation or modification, is thus committed - tacitly or explictly - to the Everett interpretation. (shrink)

The main foundations of the standard \CDM model of cosmology are that: the redshifts of the galaxies are due to the expansion of the Universe plus peculiar motions; the cosmic microwave background radiation and its anisotropies derive from the high energy primordial Universe when matter and radiation became decoupled; the abundance pattern of the light elements is explained in terms of primordial nucleosynthesis; and the formation and evolution of galaxies can be explained only in terms of gravitation (...) within a inflation + dark matter + dark energy scenario. Numerous tests have been carried out on these ideas and, although the standard model works pretty well in fitting many observations, there are also many data that present apparent caveats to be understood with it. In this paper, I offer a review of these tests and problems, as well as some examples of alternative models. (shrink)

Macroscopic irreversible processes emerge from fundamental physical laws of reversible character. The source of the local irreversibility seems to be not in the laws themselves but in the initial and boundary conditions of the equations that represent the laws. In this work we propose that the screening of currents by black hole event horizons determines, locally, a preferred direction for the flux of electromagnetic energy. We study the growth of black hole event horizons due to the cosmological expansion and accretion (...) of cosmic microwave background radiation, for different cosmological models. We propose generalized McVittie co-moving metrics and integrate the rate of accretion of cosmic microwave background radiation onto a supermassive black hole over cosmic time. We find that for flat, open, and closed Friedmann cosmological models, the ratio of the total area of the black hole event horizons with respect to the area of a radial co-moving space-like hypersurface always increases. Since accretion of cosmic radiation sets an absolute lower limit to the total matter accreted by black holes, this implies that the causal past and future are not mirror symmetric for any spacetime event. The asymmetry causes a net Poynting flux in the global future direction; the latter is in turn related to the ever increasing thermodynamic entropy. Thus, we expose a connection between four different “time arrows”: cosmological, electromagnetic, gravitational, and thermodynamic. (shrink)

Space is one of the most fundamental concepts over which scientific knowledge has been constructed. But it is also true that space concepts extrapolate by far the scientific domain, and permeate many other branches of human knowledge. Those are fascinating aspects that could di per se justify the compilation of a long bibliography. Another one is the passion for books. My interest in some physical, historical and philosophical problems concerning the concept of space in Physics, and its properties, can be (...) traced back to the early 1980. Since that time, I have being studying, with several collaborators, the influence of space dimensionality in different physical phenomena, like the Casimir Effect, neutron diffraction, Cosmic Microwave Background Radiation and the stability of Schrödinger’s and Dirac’s hydrogen atom in arbitrary number of dimensions, as well as epistemological aspects of the works of Kant, Ehrenfest an others on this particular subject. Meanwhile, I gave lectures about the History of the Concepts of Space in Physics at the Centro Brasileiro de Pesquisas Físicas (CBPF), at the Program of History of Sciences, Technics and Epistemology of the Federal University of Rio the Janeiro (UFRJ) and also at the Physics Institute of the State University of Rio de Janeiro (UERJ). As a consequence of both this interest and my love for books, I continuously bought books on space for my personal library which contains now quite one half of all the books quoted here. In 1996, Roberto Moreira and I published the Sources for the History of Space concepts in Physics: From 1845 to 1995 in the series Notas de Física of the CBPF (NF # 084/96), which is still available online. This was a first initiative to share our bibliography on space. At that time, it contained 1075 references, including 414 books entirely devoted to space, 380 articles in periodical journals and proceedings and 281 miscellaneous citations. After fifteen years, I decided to focus my attention here to collect what in my opinion are the 601 essential books which could be useful for anyone interested on learning about space. An important restriction is imposed here by language: only texts written in English, French, German, Italian, Spanish, Portuguese and Latin were considered. References are given in chronological order covering the period between 1739 and 2010. For each year, the books are listed in alphabetical order of authors’ name. An onomastic index is included at the end of the book. -/- Francisco Caruso Rio de Janeiro, October 2011 . (shrink)

Cosmology, the study of the universe, has a past, which is reviewed here. The standard model—the Big Bang, or the hot, dense early universe that is still expanding—is based on observations that are basically consistent but which require additional input to improve the agreement. Out of the early universe came the galaxies and stars that shine today. The future of the universe depends on the density of matter: too much mass leads to the Big Crunch; too little leads to eternal (...) expans ion and cooling. The dark‐matter problem prevents us from knowing which will be the fate of the universe. Thelimits of what may be called “scientific” are addressed. (shrink)

We live in extraordinary times for cosmologists. A vast amount of new astronomical data is pushing our model of the universe to its limits. An interest in cosmology is growing. The Little Book of Cosmology by Lyman Page is a concise up-to-date approachable introduction to the topic.

We present a Bayesian analysis of the epistemology of analogue experiments with particular reference to Hawking radiation. Provided such experiments can be externally validated via universality arguments, we prove that they are confirmatory in Bayesian terms. We then provide a formal model for the scaling behaviour of the confirmation measure for multiple distinct realisations of the analogue system and isolate a generic saturation feature. Finally, we demonstrate that different potential analogue realisations could provide different levels of confirmation. Our results (...) thus provide a basis both to formalise the epistemic value of analogue experiments that have been conducted and to advise scientists as to the respective epistemic value of future analogue experiments. (shrink)

An alternative approach to analyze the nonrelativistic quantum dynamics of a rigid and extended charged particle taking into account the radiation reaction is discussed with detail. Interpretation of the field operators as annihilation and creation ones, theory of perturbations and renormalization are not used. The analysis is carried out in the Heisenberg picture with the electromagnetic field expanded in a complete orthogonal basis set of functions which allows the electromagnetic field to satisfy arbitrary boundary conditions. The corresponding coefficients are (...) the field operators which satisfy the usual commutation relations. A nonlinear equation of motion for the charged particle is obtained. A careful consideration of the quantum effects allows the derivation of a linear equation of motion which is free of both runaway solutions and preacceleration, even for a point charge. Also, the electromagnetic mass, which is defined as the coefficient of the acceleration operator, vanishes for a point particle. However, this does not mean that the results are free of ambiguities which are exhibited and discussed. (shrink)

A point charge accelerating under the influence of an external force emits electromagnetic radiation that reduces the increase in its mechanical energy. This causes a reduction in the particle's acceleration. We derive the decrease in acceleration due to radiation reaction for a particle accelerating parallel to its velocity, and show that it has a negligible effect.

It is pointed out that relativistic classical electron theory with classical electromagnetic zero-point radiation has a scaling symmetry which is suitable for understanding the equilibrium behavior of classical thermal radiation at a spectrum other than the Rayleigh-Jeans spectrum. In relativistic classical electron theory, the masses of the particles are the only scale-giving parameters associated with mechanics while the action-angle variables are scale invariant. The theory thus separates the interaction of the action variables of matter and radiation from (...) the scale-giving parameters. Due to this separation, classical zero-point radiation is invariant under scattering by the charged particles of relativistic classical electron theory. The basic ideas of the matter-radiation interaction are illustrated in a simple relativistic classical electromagnetic example. (shrink)

There is uncertainty and disagreement about the question which preventive actions are rationally justified with regard to moderately elevated levels of nuclear radiation. This may have at least four causes: ignorance, insufficient information, inconclusiveness and indeterminability. After the nuclear disaster with the Fukushima nuclear power plant the advice, given by some authorities, to leave Tokyo was largely based on the former two factors: ignorance and insufficient information. By contrast, the uncertainty and disagreement amongst experts about the size of the (...) area to be evacuated was mainly caused by the latter two factors: inconclusiveness and indeterminability. Inconclusiveness concerns the question whether moderately elevated radiation levels cause real and significant health risks that require drastic measures. Indeterminability concerns the problem of rationally weighing disparate benefits and costs of the preventive measures, to wit, expected health benefits versus the costs and burdens of mass evacuation. The International Commission on Radiological Protection (ICRP) recommends that no measures should be taken unless they produce a positive net benefit. Exposure to moderately increased levels of radiation may increase the risk of fatal cancer in the future, while mass evacuation has burdensome and disruptive consequences for the society and for the persons who have to leave their residential and/or working area for a long time. Ordering of mass evacuation seems rationally and ethically justified only if the expected future benefits outweigh the present and future burdens. Small or uncertain future health benefit may be outweighed by large costs and burdens of mass evacuation. Because we have to take into consideration not only public but also individual costs and benefits, it is important to take into account the personal absolute increase in health risk of elevated radiation in addition to relative risk. Unlike relative risk, absolute risk reveals the individual chance of getting a radiation-based disease. The increase in absolute risk – that is, the difference between the chances of getting the disease with and without the exposure to the increased level of radiation – is a useful measure to reveal the personal chance of health benefit from evacuation. This personal benefit must be balanced against the personal costs and burdens. The key question is which levels of radiation absorption and health risks outweigh the burdens of mass evacuation. There seems consensus amongst experts about the justification of mass evacuation in cases of expected individual radiation absorption > 500 mSv over a year. Similarly, experts agree that expected extra radiation absorption < 10 mSv does not justify mass evacuation. But between these two extremes there is a wide range of 50-fold increasing radiation levels in which it is not clear whether the personal and public benefits from mass evacuation outweigh the personal and public costs. This may partly explain why experts and authorities gave conflicting advice about the radius of the area around the Fukushima nuclear power plant within which people had to be evacuated. The uncertainty about the right thing to do with respect to a wide range of moderately elevated levels of radiation seems to be caused not only by inconclusiveness but also by indeterminability, that is, impossibility of determinately weighing disparate costs and benefits. (shrink)

In _Radiation and Revolution_ political theorist and anticapitalist activist Sabu Kohso uses the 2011 Fukushima nuclear disaster to illuminate the relationship between nuclear power, capitalism, and the nation-state. Combining an activist's commitment to changing the world with a theorist's determination to grasp the world in its complexity, Kohso outlines how the disaster is not just a pivotal event in postwar Japan; it represents the epitome of the capitalist-state mode of development that continues to devastate the planet's environment. Throughout, he captures (...) the lived experiences of the disaster's victims, shows how the Japanese government's insistence on nuclear power embodies the constitution of its regime under the influence of US global strategy, and considers the future of a radioactive planet driven by nuclearized capitalism. As Kohso demonstrates, nuclear power is not a mere source of energy—it has become the organizing principle of the global order and the most effective way to simultaneously accumulate profit and govern the populace. For those who aspire to a world free from domination by capitalist nation-states, Kohso argues, the abolition of nuclear energy and weaponry is imperative. (shrink)

BackgroundEach individual’s unique health-related beliefs can greatly impact the patient-clinician relationship. When there is a conflict between the patient’s preferences and recommended medical care, it can create a serious ethical dilemma, especially in an emergency setting, and dramatically alter this important relationship.Case presentationA 56-year-old man, who remained comatose after out-of-hospital cardiac arrest, was rushed to our hospital. The patient was scheduled for emergency coronary angiography when his adolescent daughter reported that she and her father held sincere beliefs against radiation (...) exposure. We were concerned that she did not fully understand the potential consequences if her father did not receive the recommended treatment. A physician provided her with in depth information regarding the risks and benefits of the treatment. While we did not want to disregard her statement, we opted to save the patient’s life due to concerns about the validity of her report.ConclusionsVariations in beliefs regarding medical care force clinicians to incorporate patient beliefs into medical practice. However, an emergency may require a completely different approach. When faced with a patient in a life-threatening condition and unconscious, we should take action to prioritize saving their life, unless we are highly certain about the validity of their advance directives. (shrink)

Solar radiation management (SRM) may help to reduce the negative outcomes of climate change by minimising or reversing global warming. However, many express the worry that SRM may pose a moral hazard, i.e., that information about SRM may lead to a reduction in climate change mitigation efforts. In this paper, we report a large-scale preregistered, money-incentivised, online experiment with a representative US sample (N = 2284). We compare actual behaviour (donations to climate change charities and clicks on climate change (...) petition links) as well as stated preferences (support for a carbon tax and self-reported intentions to reduce emissions) between participants who receive information about SRM with two control groups (a salience control that includes information about climate change generally and a content control that includes information about a different topic). Behavioural choices are made with an earned real-money endowment, and stated preference responses are incentivised via the Bayesian Truth Serum. We fail to find a significant impact of receiving information about SRM and, based on equivalence tests, we provide evidence in favour of the absence of a meaningfully large effect. Our results thus provide evidence for the claim that there is no detectable moral hazard with respect to SRM. [Open access]. (shrink)

After WWII, global concerns about the uses of nuclear energy and radiation sources in agriculture, medicine, and industry brought about calls for radiation protection. At the beginning of the 1960s radiation protection involved the identification and measurement of all sources of radiation to which a population was exposed, and the evaluation and assessment of populations in terms of the biological hazard their exposure posed. Mexico was not an exception to this international trend. This paper goes back (...) to the origins of the first studies on the effects of radiation and on radioprotective compounds in the Genetics and Radiobiology Program of the National Commission of Nuclear Energy founded in 1960, at a time when the effects of radiation on living beings and radiation protection demanded the attention of highly localized groups of scientists and the creation of international as well as national institutions, and its connection to dosimetry and radiation protection until the 1990s. This historical reconstruction examines the circulation of knowledge, scientists, and their material and cognitive resources, to show that radiobiology, with dosimetry and radiation protection as cases in point, not only were carried out with high international standards in parallel with international agencies, but also reflected local material needs, including the standardization of new experimental techniques. (shrink)

The complete description of the interaction between an external electromagnetic field and a charged particle causing it to radiate is one of the most fundamental problems in classical electrodynamics. Here we provide a simple coupled model that describes via the Lagrangian of the physical system the full radiation reaction process resulting from the particle–field interactions which simulate the electromagnetic ones. The particle and field evolution equations obtained from the Lagrangian are studied as an initial value problem giving rise to (...) the particle's radiation reaction equation, which includes the complete interaction with the field. Using stability theory we analyze this equation and prove that every solution is global uniform asymptotically stable, evidencing that the particle coupled to the field radiates. The model proves to be interesting, for it clearly illustrates the particle–field interaction process and shows the radiation's origin. (shrink)

Matthew Lavine’s The First Atomic Age is intended as a corrective to what has by now become a familiar story of postwar US nuclear culture. The popular enthusiasm for and fear of all things nuclear, as described in such works as Paul Boyer’s By the Bomb’s Early Light , was not in fact a new development but rather a repeat of a phenomenon that first manifested half a century earlier. Working with newspapers, magazines, trade journals, advertisements, product labels, pulp fiction, (...) poetry, and scientific biography, Lavine unequivocally demonstrates the ubiquity of references to both X-rays and radiation in popular culture in the first half of the twentieth century. This, he argues, constitutes the “First Atomic Age”.Lavine divides the book into three long chapters according to how much the public might reasonably know about radiation and radioactivity. In the first period, the era of discovery, the lack of con .. (shrink)

Evolution is littered with polyphyletic parallelism: many roads lead to functional Romes. We propose consciousness embodies one such example, and represent it here with an equivalence class structure that factors the broad realm of necessary conditions information theoretic realizations of Baars’ global workspace model. The construction suggests many different physiological systems can support rapidly shifting, highly tunable, and even simultaneous temporary assemblages of interacting unconscious cognitive modules. The discovery implies various animal taxa exhibiting behaviors we broadly recognize as conscious are, (...) in fact, expressing different forms of the same underlying phenomenon. The variety of possibilities suggests minds today may be only a small surviving fraction of ancient evolutionary radiations – bush phylogenies of consciousness pruned by selection and chance extinction. Although few traces of the radiations may be found in the fossil record, exaptations and vestiges are scattered across the living mind. (shrink)

Enzymatic misrepair of ionizing‐radiation‐induced DNA damage can produce large‐scale rearrangements of the genome, such as translocations and dicentrics. These and other chromosome exchange aberrations can cause major phenotypic alterations, including cell death, mutation and neoplasia. Exchange formation requires that two (or more) genomic loci come together spatially. Consequently, the surprisingly rich aberration spectra uncovered by recently developed techniques, when combined with biophysically based computer modeling, help characterize large‐scale chromatin architecture in the interphase nucleus. Most results are consistent with a (...) picture whereby chromosomes are mainly confined to territories, chromatin motion is limited, and interchromosomal interactions involve mainly territory surfaces. Aberration spectra and modeling also help characterize DNA repair/misrepair mechanisms. Quantitative results for mammalian cells are best described by a breakage‐and‐reunion model, suggesting that the dominant recombinational mechanism during the G0/G1 phase of the cell cycle is non‐homologous end‐joining of radiogenic DNA double strand breaks. In turn, better mechanistic and quantitative understanding of aberration formation gives new insights into health‐related applications. BioEssays 24:714–723, 2002. © 2002 Wiley Periodicals, Inc. (shrink)

We study the response of a uniformly accelerated model particle detector in a spacetime with compact spatial sections. The basic thermal character of the response re-emerges, in spite of the fact that the spacetime does not possess event horizons. Our model also permits a study of detector response to twisted field states.

The analysis of this article is entirely within classical physics. Any attempt to describe nature within classical physics requires the presence of Lorentz-invariant classical electromagnetic zero-point radiation so as to account for the Casimir forces between parallel conducting plates at low temperatures. Furthermore, conformal symmetry carries solutions of Maxwell’s equations into solutions. In an inertial frame, conformal symmetry leaves zero-point radiation invariant and does not connect it to non-zero-temperature; time-dilating conformal transformations carry the Lorentz-invariant zero-point radiation spectrum (...) into zero-point radiation and carry the thermal radiation spectrum at non-zero temperature into thermal radiation at a different non-zero temperature. However, in a non-inertial frame, a time-dilating conformal transformation carries classical zero-point radiation into thermal radiation at a finite non-zero-temperature. By taking the no-acceleration limit, one can obtain the Planck radiation spectrum for blackbody radiation in an inertial frame from the thermal radiation spectrum in an accelerating frame. Here this connection between zero-point radiation and thermal radiation is illustrated for a scalar radiation field in a Rindler frame undergoing relativistic uniform proper acceleration through flat spacetime in two spacetime dimensions. The analysis indicates that the Planck radiation spectrum for thermal radiation follows from zero-point radiation and the structure of relativistic spacetime in classical physics. (shrink)

We argue that purely local experiments can distinguish a stationary charged particle in a static gravitational field from an accelerated particle in (gravity-free) Minkowski space. Some common arguments to the contrary are analyzed and found to rest on a misidentification of “energy.”.

Vacuum radiation causes a particle to make a random walk about its dynamical trajectory. In this random walk the root mean square change in spatial coordinate is proportional to t 1/2, and the fractional changes in momentum and energy are proportional to t −1/2, where t is time. Thus the exchange of energy and momentum between a particle and the vacuum tends to zero over time. At the end of a mean free path the fractional change in momentum of (...) a particle in a gas is very small. However, at the end of the mean free path each particle undergoes an interaction that magnifies the preceding change, and the net result is that the momentum distribution of the particles in a gas is randomized in a few collision times. In this way the random action of vacuum radiation and its subsequent magnification by molecular interaction produces entropy increase. This process justifies the assumption of molecular chaos used in the Boltzmann transport equation. (shrink)

The present expression of radiation of an accelerated point charge is only approximately valid. The exact expression of radiation of an accelerated point charge is derived based on special relativity, and using the Larmor formulation for the radiation of an charged particle being accelerated, but instantaneously at rest. The totaled radiation power obtained by the exact expression is the same as Liénard’s generalization of the Larmor formula.

Solar radiation management is a form of geoengineering that involves the intentional manipulation of solar radiation with the aim of reducing global average temperature. This paper explores what precaution implies about the status of solar radiation management. It is argued that any form of solar radiation management that poses threats of catastrophe cannot constitute an appropriate precautionary measure against another threat of catastrophe, namely climate change. Research of solar radiation management is appropriate on a precautionary (...) view only insofar as such research aims to identify whether any forms of solar radiation management could be implemented without creating new or exacerbating existing threats of catastrophe. (shrink)

This is a response to an article by Wade Allison in which he argues that we should accept drastically higher doses of ionizing radiation than what we currently do. He employs four arguments in defence of his position: comparisons with background radiation, the positive experiences of radiotherapy, the presence of biological defence mechanisms against radiation, and a concession by Swedish authorities that their approach to reindeer meat after the Chernobyl fallout was unnecessarily strict. It is shown that (...) each of the four arguments is fallacious. In conclusion, the traditional weighing of risks against benefits in radiation protection is defended. (shrink)

Using the diffusion model associated by the author with the wave equations, a part of current quantum radiation theory is reformulated so that the characteristic divergences in the associated calculations no longer arise. The reformulation does this by stipulating, on purely physical grounds, that a transition involving a “virtual” quantum must include a high frequency “cutoff” factor in its interaction Hamiltonian. For a transition involving a “real” quantum, the stipulation is that the “cutoff” factor is not to be included.

We examine the problem of deducing the geodesic motion of test particles from Einstein's vacuum field equations and its extension to include gravitational radiation reaction. In the latter case we obtain an equation of motion for a particle which incorporates radiation reaction of the electrodynamical type, but due to shearing radiation, together with a mass-loss formula of the Bondi-Sachs type.

In order to implement cost-benefit analysis of protective actions to reduce radiological exposures, one needs to attribute a monetary value to the avoided exposure. Recently, the International Commission on Radiological Protection has stressed the need to take into consideration not only the collective exposure to ionising radiation but also its dispersion in the population. In this paper, by using some well known and some recent results in the economics of uncertainty, we discuss how to integrate these recommendations in the (...) valuation of the benefit of protection. (shrink)

We show that the electromagnetic radiation field, conventionally introduced as a perturbation in quantum mechanics, is actually at the basis of the operator formalism. We first analyze the linear resonant response of the (continuous) variables x(t), p(t) of a harmonic oscillator to the full radiation field, i.e. the zero-point field plus an applied field playing the role of the driving force, and then extend the analysis to the response of a charged particle bound by a non-linear force, typically (...) an atomic electron. This leads to the establishment of a one-to-one correspondence between the response functions and the respective quantum operators, and to the identification of the quantum commutator with the Poisson bracket of the response functions with respect to the normalized variables of the driving field. To complete the quantum description, a similar procedure is used to obtain the field operators as the response functions to the same normalized variables. The results allow us to draw important conclusions about the physical content of the quantum formalism, in particular about the meaning of the quantum expectation values and the coarse-grained nature of the quantum-mechanical description. (shrink)

Solar radiation management (SRM) has been proposed as a means of mitigating climate change. Although SRM poses new risks, it is sometimes proposed as the ‘lesser evil’. I consider how research and implementation of SRM could be regulated, drawing on what I call a ‘precautionary checklist’, which includes consideration of the longer term political implications of technical change. Particular attention is given to the moral hazard of ‘regulatory drift’, in which strong initial regulation softens through complacency, deliberate deregulation (‘regulatory (...) gift’) and the limited constituency of people with the skills to regulate (‘thin markets’). I propose the strengthening of civil society groups to keep regulators in check. (shrink)

Narratives surrounding ionizing radiation have often minimized radioactivity’s impact on the health of human and non-human animals and the natural environment. Many Cold War research policies, practices, and interpretations drove nuclear technology forward by institutionally obscuring empirical evidence of radiation’s disproportionate and low-dose harm—a legacy we still confront. Women, children, and pregnancy development are particularly sensitive to exposure from radioactivity, suffering more damage per dose than adult males, even down to small doses, making low doses a cornerstone of (...) concern. Evidence of compounding generational damage could indicate increased sensitivity through heritable impact. This essay examines the existing empirical evidence demonstrating these sensitivities, and how research institutions and regulatory authorities have devalued them, willingly sacrificing health in the service of maintaining and expanding nuclear technology. Radiation’s disproportionate impacts should now be the research and policy focus, as society is poised to make crucial and long-lasting decisions regarding climate change mitigation and future energy sources. (shrink)