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Gerald E. Marsh

Publications and source records attributed to Gerald E. Marsh.

29 records · Page 2Linked to original sources
arXiv2011

Dark Matter and Charged Exotic Dust

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.

gr-qc↗
arXiv2010

Interglacials, Milankovitch Cycles, and Carbon Dioxide

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.

physics.gen-ph↗
arXiv2009

Quantum Mechanics and Motion: A Modern Perspective

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.

physics.gen-ph↗
arXiv2009

Climate Change: Sources of Warming in the Late 20th Century

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.

physics.gen-ph↗
arXiv2008

Negative Energies and Field Theory

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.

math-ph↗
arXiv2008

The Vacuum and the Cosmological Constant Problem

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.

gr-qc↗
arXiv2008

Climate Stability and Policy: A Synthesis

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.

physics.gen-ph↗
arXiv2008

Charge, geometry, and effective mass

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.

gr-qc↗
arXiv2007

The infinite red-shift surfaces of the Kerr and Kerr-Newman solutions of the Einstein field equations

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.

gr-qc↗
arXiv2007

Climate Change: The Sun's Role

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.

physics.gen-ph↗