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The concept of exotic charged dust is introduced here to represent dark matter. The term "exotic" means that the dust is not composed of normal matter, and the charge--for lack of a better term--is not an electric charge. It is also shown that the often-used approximate expression for dark matter density corresponds to an exact solution of the coupled Einstein-Maxwell equations for charged dust. The Einstein field equations tells us is that for a flat universe the cosmological constant acts as a gravitating negative energy distribution that is gravitationally repulsive; following Schwinger, it is shown that the vacuum must have a negative energy spectrum if QFT is to be gauge invariant., Comment: 15 pages, 3 figures. arXiv admin note: text overlap with arXiv:1107.0315, arXiv:1909.01077

There are no known analytic solutions to the force-free magnetic field equations in coordinates representing Dupin cyclides. The fact that the curvature lines of Dupin cyclides are all circles is used here to derive a force-free magnetic field on the surface of an elliptic Dupin cyclide., Comment: 19 pages, 9 figures. Followon to arXiv 2305.15455

While there are no known analytic solutions for force-free fields in toroidal coordinates, with a reasonable boundary condition it is possible to find a solution for the surface field and, with a restriction on the form of the field, to the interior of the torus as well., Comment: 19 pages; 7 Figures

It has been argued since 1948, when it was experimentally demonstrated, that the Casimir effect-where two non-charged conducting plates have a weak but measurable force on each other dependent on the inverse fourth power of the distance between them-shows the reality of vacuum zero-point fluctuations. This "proof" of the reality of vacuum fluctuations has been repeated in many quantum field theory books and papers subsequent to 1948. The attractive force is generally ascribed to the difference in zero-point energy of the electromagnetic field between the plates and the vacuum external to them. As is well known, zero-point vacuum fluctuations are incompatible with relativistic physics and are at the root of the "cosmological constant" problem. Most texts on quantum mechanics and quantum field theory eliminate the vacuum energy by normal ordering or some other mechanism. These issues are explored in this paper and it is pointed out that a means to resolve them already exists., Comment: 16 Pages, 1 Figure updated

Modern developments in nonequilibrium thermodynamics have significant implications for the origins of life. The reasons for this are closely related to a generalized version of the second law of thermodynamics recently found for entropy production during irreversible evolution of a given system such as self-replicating RNA. This paper is intended to serve as an introduction to these developments., Comment: To appear in the Canadian Journal of Physics: 20 pages, 3 figures

The equations describing the two-dimensional vortices first described by Chaplygin in 1899 and 1903 are shown to have solutions of higher order that differ from a simple dipole. It is also shown that for these higher-order vortices a very small asymmetry dramatically changes the topology of the stream function. These vortices could be important for understanding the phenomenon of atmospheric blocking., Comment: 21 pages, 16 figures

Variation in total solar irradiance is thought to have little effect on the Earth's surface temperature because of the thermal time constant--the characteristic response time of the Earth's global surface temperature to changes in forcing. This time constant is large enough to smooth annual variations but not necessarily variations having a longer period such as those due to solar inertial motion; the magnitude of these surface temperature variations is estimated., Comment: 15 pages, 13 Figures

Dark matter, first postulated by Jacobus Kapteyn in 1922 and later by Fritz Zwicky in 1933, has remained an enigma ever since proof of its existence was confirmed in 1970 by Vera Rubin and Kent Ford by plotting the rotation curve for the Andromeda galaxy. Here, some concepts from string theory and topological change in quantum cosmology are used to formulate a new model for dark matter. The density profiles of dark matter halos are often modeled as an approximate solution to the Lane-Emden equation. Using the model proposed here for dark matter, coupled with previous work showing that the approximate solution to the Lane-Emden equation can be an exact solution of the Einstein-Maxwell equations, provides a new insight into the possible nature of dark matter., Comment: 31 pages, 8 figures

It has been suggested that the north-polar hexagon found on Saturn is an unusual Rossby wave. If this is to be the case, one must not only explain how a Rossby wave can be hexagonal in shape, albeit with curved corners, but also why it is hexagonal rather than in the form of some other polygon. It is likely that a spectrum of Rossby waves with different amplitudes and wavelengths resulting from the velocity profile of the hexagonal jet is responsible for its shape., Comment: 21 Pages, 9 Figures. Expanded and corrected

The chiral anomaly is a purely quantum mechanical phenomenon that has a long history dating back to the late 1960s. Surprisingly, it has recently made a macroscopic appearance in condensed matter physics. A brief introduction to the relevant features of this anomaly is given and it is shown that its appearance in condensed matter systems must involve force-free magnetic fields, which may help explain the long current relaxation times in Dirac and Weyl semimetals., Comment: 10 pages, 1 figure. Clarifications and minor corrections have been made in this version

The idea that particles are the basic constituents of all matter dates back to ancient times and formed the basis of physical thought well into modern times. The debate about whether light was a wave or a stream of particles also lasted until relatively recently. It was the advent of de Broglie's work and its implications that revolutionized the concept of an elementary particle -- but unfortunately did not banish the idea of a point particle despite its difficulties in both classical and quantum physics. Some of these problems are discussed in this essay, which covers chiral oscillations, Penrose's "zigzag" picture of particles satisfying the Dirac equation, and some ideas derived from string theory., Comment: 38 pages, 11 figures

The Einstein field equations have no known and acceptable interior solution that can be matched to an exterior Kerr field. In particular, there are no interior solutions that could represent objects like the Earth or other rigidly rotating astronomical bodies. It is shown here that there exist closed surfaces upon which the frame-dragging angular velocity and the red-shift factor for the Kerr metric are constant. These surfaces could serve as a boundary between rigidly rotating sources for the Kerr metric and the Kerr external field., Comment: 15 pages, 5 figures. This revision restructures the paper and corrects minor typos and errors

This essay examines our fundamental conceptions of time, spacetime, the asymmetry of time, and the motion of a quantum mechanical particle. The concept of time has multiple meanings and these are often confused in the literature and must be distinguished if any light is to be thrown on this age-old issue. The asymmetry of time also has different meanings that depend on context-although the fundamental time asymmetry is associated with the expansion of the universe. These and related issues are discussed in both classical and quantum mechanical contexts., Comment: 44 pages; 7 figures. arXiv admin note: text overlap with arXiv:0912.5099, arXiv:0809.1877. Revised and expanded

The density profiles of dark matter halos are often modeled by an approximate solution to the isothermal Lane-Emden equation with suitable boundary conditions at the origin. It is shown here that such a model corresponds to an exact solution of the Einstein-Maxwell equations for exotic charged dust. It is also shown that, because of its necessarily very small charge to mass ratio, the fact that the particles are charged does not necessarily rule out such material as a candidate for dark matter., Comment: 11 pages, 2 figures

Plane electromagnetic and gravitational waves interact with particles in such a way as to cause them to oscillate not only in the transverse direction but also along the direction of propagation. The electromagnetic case is usually shown by use of the Hamilton-Jacobi equation and the gravitational by a transformation to a local inertial frame. Here, the covariant Lorentz force equation and the second order equation of geodesic deviation followed by the introduction of a local inertial frame are respectively used. It is often said that there is an analogy between the motion of charged particles in the field of an electromagnetic wave and the motion of test particles in the field of a gravitational wave. This analogy is examined and found to be rather limited. It is also shown that a simple special relativistic relation leads to an integral of the motion, characteristic of plane waves, that is satisfied in both cases., Comment: 22 Pages, 5 figures. Minor corrections and clarifications. To appear in the Canadian Journal of Physics

The existing understanding of interglacial periods is that they are initiated by Milankovitch cycles enhanced by rising atmospheric carbon dioxide concentrations. During interglacials, global temperature is also believed to be primarily controlled by carbon dioxide concentrations, modulated by internal processes such as the Pacific Decadal Oscillation and the North Atlantic Oscillation. Recent work challenges the fundamental basis of these conceptions., Comment: 15 pages, 8 figures. V2 corrects a typo on p. 9

This essay is an attempted to address, from a modern perspective, the motion of a particle. Quantum mechanically, motion consists of a series of localizations due to repeated interactions that, taken close to the limit of the continuum, yields a world-line. If a force acts on the particle, its probability distribution is accordingly modified. This must also be true for macroscopic objects, although now the description is far more complicated by the structure of matter and associated surface physics., Comment: 17 pages, 3 figures

It has been argued that the limited set of proteins used by life as we know it could not have arisen by the process of Darwinian selection from all possible proteins. This probabilistic argument has a number of implicit assumptions that may not be warranted. A variety of considerations are presented to show that the number of amino-acid sequences that need have been sampled during the evolution of proteins is far smaller than assumed by the argument., Comment: 14 Pages; International Journal of Astrobiology / FirstView Article / October 2012, pp 1 5

Emergent behavior that appears at a given level of organization may be characterized as arising from an organizationally lower level in such a way that it transcends a mere increase in the behavioral degree of complexity. It is therefore to be distinguished from systems exhibiting chaotic behavior, for example, which are deterministic but unpredictable because of an exponential dependence on initial conditions. In emergent phenomena, higher-levels of organization are not determined by lower-levels of organization; or, more colloquially, emergent behavior is often said to be "greater than the sum of the parts". The concept plays an especially important but contentious role in the biological sciences. This essay is intended to demystify at least some aspects of the mystery of emergence., Comment: Updated and expanded. Some parts rewritten to improve clarity. 10 Pages

The role of the North Atlantic Oscillation, the Pacific Decadal Oscillation, volcanic and other aerosols, as well as the extraordinary solar activity of the late 20th century are discussed in the context of the warming since the mid-1970s. Much of that warming is found to be due to natural causes., Comment: 18 pages, 8 Figures

In 2005, the Royal Society published a report titled "Ocean acidification due to increasing atmospheric carbon dioxide". The report's principal conclusion-that average ocean pH could decrease by 0.5 units by 2100-is demonstrated here to be consistent with a linear extrapolation of very limited data. It is also shown that current understanding of ocean mixing, and of the relationship between pH and atmospheric carbon dioxide concentration, cannot justify such an extrapolation., Comment: Corrected misprints in Eqs. (1) and (A10). 14 pages, 4 figures (better quality available at gemarsh.com)

The assumption that the vacuum is the minimum energy state, invariant under unitary transformations, is fundamental to quantum field theory. However, the assertion that the conservation of charge implies that the equal time commutator of the charge density and its time derivative vanish for two spatially separated points is inconsistent with the requirement that the vacuum be the lowest energy state. Yet, for quantum field theory to be gauge invariant, this commutator must vanish. This essay explores how this conundrum is resolved in quantum electrodynamics., Comment: Some additions and changes have been made to clarify the discussion. 14 pages, 2 figures

It has been shown that for the Reissner-Nordstrom solution to the vacuum Einstein field equations charge, like mass, has a unique space-time signature [Found. Phys. 38, 293-300 (2008)]. The presence of charge results in a negative curvature. This work, which includes a discussion of effective mass, is extended here to the Kerr-Newman solution., Comment: To appear in Foundations of Physics. Misprints have been corrected. 14 pages, 4 figures

During most of the Phanerozoic eon, which began about a half-billion years ago, there were few glacial intervals until the late Pliocene 2.75 million years ago. Beginning at that time, the Earth's climate entered a period of instability with the onset of cyclical ice ages. At first these had a 41,000 year cycle, and about 1 million years ago the period lengthened to 100,000 years, which has continued to the present. Over this period of instability the climate has been extraordinarily sensitive to small forcings, whether due to Milankovitch cycles, solar variations, aerosols, or albedo variations driven by cosmic rays. The current interglacial has lasted for some ten thousand years-about the duration of past interglacials-and serious policy considerations arise as it nears its likely end. It is extremely unlikely that the current rise in carbon dioxide concentration-some 30% since 1750, and projected further increase over the next few decades-will significantly postpone the next glaciation., Comment: 19 pages, 6 figures

It will be argued here that the cosmological constant problem exists because of the way the vacuum is defined in quantum field theory. It has been known for some time that for QFT to be gauge invariant certain terms--such as part of the vacuum polarization tensor--must be eliminated either explicitly or by some form of regularization followed by renormalization. It has recently been shown that lack of gauge invariance is a result of the way the vacuum is defined, and redefining the vacuum so that the theory is gauge invariant may also offer a solution to the cosmological constant problem., Comment: 17 pages, 2 figures. Some clarification in one section of the original submission and minor corrections

Charge, like mass in Newtonian mechanics, is an irreducible element of electromagnetic theory that must be introduced ab initio. Its origin is not properly a part of the theory. Fields are then defined in terms of forces on either masses--in the case of Newtonian mechanics, or charges in the case of electromagnetism. General Relativity changed our way of thinking about the gravitational field by replacing the concept of a force field with the curvature of space-time. Mass, however, remained an irreducible element. It is shown here that the Reissner-Nordstrom solution to the Einstein field equations tells us that charge, like mass, has a unique space-time signature., Comment: To appear in Foundations of Physics. 15 pages, 1 figure. Minor changes and additions

The sun's role in the earth's recent warming remains controversial even though there is a good deal of evidence to support the thesis that solar variations are a very significant factor in driving climate change both currently and in the past. This precis lays out the background and data needed to understand the basic scientific argument behind the contention that variations in solar output have a significant impact on current changes in climate. It also offers a simple, phenomenological approach for estimating the actual-as opposed to model dependent-magnitude of the sun's influence on climate., Comment: 16 pages, 8 figures, 1 table

In contrast to the Schwarzschild solution, the infinite red-shift surfaces and null surfaces of the Kerr solution to the axially-symmetric Einstein field equations are distinct. Some three-dimensional depictions of these surfaces are presented here for observers following the time-like Killing vector of the Kerr and Kerr-Newman solutions. Some similarities of the latter to the Reissner-Nordstrom solution are also discussed. In the case of the Kerr solution, the inner infinite red-shift surface terminates at the ring singularity. This is not the case for the Kerr-Newman solution where the infinite red-shift surface and the ring singularity have no points in common. The presence of charge severs the relation between the singularity and the infinite red-shift surface. This paper is also intended to fill a void in the literature where few, if any, adequate representations of the infinite red-shift surfaces and their relation to the singularity and horizons exist., Comment: 17 pages, 8 figures (Minor wording changes)