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Results for “RELATIVITY THEORY”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1966

Lectures on Relativity Theory

Relativity theory lectures involving Lorentz transformations, Minkowski space, and tensor analysis

RELATIVITY THEORY↗
NASA NTRS1983

Rastall's and related theories are conservative gravitational theories although physically inequivalent to general relativity

The proper framework for testing Rastall's theory and its generalizations is in the case of non-negligible (i.e. discernible) gravitational effects such as gravity gradients. These theories have conserved integral four-momentum and angular momentum. The Nordtvedt effect then provides limits on the parameters which arise as the result of the non-zero divergence of the energy-momentum tensor.

Smalley, L. L.↗
NASA NTRS1989

Observations and theories related to Antarctic ozone changes

In 1985, there was a report of a large, sudden, and unanticipated decrease in the abundance of springtime Antarctic ozone over the last decade. By 1987, ozone decreases of more than 50 percent in the total column, and 95 percent locally between 15 and 20 km, had been observed. The scientific community quickly rose to the challenge of explaining this remarkable discovery; theoreticians soon developed a series of chemical and dynamical hypotheses to explain the ozone loss. Three basic theories were proposed to explain the springtime ozone hole. (1) The ozone hole is caused by the increasing atmospheric loadings of manmade chemicals containing chlorine (chlorofluorocarbons (CFC's) and bromine (halons)). These chemicals efficiently destroy ozone in the lower stratosphere in the Antarctic because of the special geophysical conditions, of an isolated air mass (polar vortex) with very cold temperatures, that exist there. (2) The circulation of the atmosphere in spring has changed from being predominantly downward over Antarctica to upward. This would mean that ozone poor air from the troposphere, instead of ozone rich air from the upper stratosphere, would be transported into the lower Antarctic stratosphere. (3) The abundance of the oxides of nitrogen in the lower Antarctic stratosphere is periodically enhanced by solar activity. Nitrogen oxides are produced in the upper mesosphere and thermosphere and then transported downward into the lower stratosphere in Antarctica, resulting in the chemical destruction of ozone. The climatology and trends of ozone, temperature, and polar stratospheric clouds are discussed. Also, the transport and chemical theories for the Antarctic ozone hole are presented.

Hartmann, D.↗
NASA NTRS1970

Elasticity theory in general relativity

Elasticity theory in general relativity formulated from classical nonlinear three dimensional theory, discussing thermodynamics and weak field limit

Hernandez, W. C., Jr.↗
NASA NTRS1976

Analysis of accelerated motion in the theory of relativity

Conventional treatments of accelerated motion in the theory of relativity have led to certain difficulties of interpretation. Certain reversals in the apparent gravitational field of an accelerated body may be avoided by simpler analysis based on the use of restricted conformal transformations. In the conformal theory the velocity of light remains constant even for experimenters in accelerated motion. The problem considered is that of rectilinear motion with a variable velocity. The motion takes place along the x or x' axis of two coordinate systems.

Jones, R. T.↗
DOE OSTI2025

Cornering relative symmetry theories

The symmetry data of a 𝑑-dimensional quantum field theory (QFT) can often be captured in terms of a higher-dimensional symmetry topological field theory. In top-down (i.e., stringy) realizations of this structure, the QFT in question is localized in a higher-dimensional bulk. In many cases of interest, however, the associated (𝑑+1)-dimensional bulk is not fully gapped and one must instead consider a filtration of theories to reach a gapped bulk in 𝐷 =𝑑 + 𝑚 dimensions. Overall, this leads us to a nested structure of relative symmetry theories which descend to coupled edge modes, with the original QFT degrees of freedom localized at a corner of this 𝐷-dimensional bulk system. We present a bottom-up characterization of this structure and also show how it naturally arises in a number of string-based constructions of QFTs with both finite and continuous symmetries.

M-theory↗
NASA NTRS2006

General Theory of Relativity: Will It Survive the Next Decade?

The nature of gravity is fundamental to our understanding of our own solar system, the galaxy and the structure and evolution of the Universe. Einstein's general theory of relativity is the standard model that is used for almost ninety years to describe gravitational phenomena on these various scales. We review the foundations of general relativity, discuss the recent progress in the tests of relativistic gravity, and present motivations for high-accuracy gravitational experiments in space. We also summarize the science objectives and technology needs for the laboratory experiments in space with laboratory being the entire solar system. We discuss the advances in our understanding of fundamental physics anticipated in the near future and evaluate discovery potential for the recently proposed gravitational experiments.

dark matter↗
NASA NTRS2005

Foundations of Tensor Analysis for Students of Physics and Engineering With an Introduction to the Theory of Relativity

Tensor analysis is one of the more abstruse, even if one of the more useful, higher math subjects enjoined by students of physics and engineering. It is abstruse because of the intellectual gap that exists between where most physics and engineering mathematics leave off and where tensor analysis traditionally begins. It is useful because of its great generality, computational power, and compact, easy to use, notation. This paper bridges the intellectual gap. It is divided into three parts: algebra, calculus, and relativity. Algebra: In tensor analysis, coordinate independent quantities are sought for applications in physics and engineering. Coordinate independence means that the quantities have such coordinate transformations as to leave them invariant relative to a particular observer s coordinate system. Calculus: Non-zero base vector derivatives contribute terms to dynamical equations that correspond to pseudoaccelerations in accelerated coordinate systems and to curvature or gravity in relativity. These derivatives have a specific general form in tensor analysis. Relativity: Spacetime has an intrinsic geometry. Light is the tool for investigating that geometry. Since the observed geometry of spacetime cannot be made to match the classical geometry of Euclid, Einstein applied another more general geometry differential geometry. The merger of differential geometry and cosmology was accomplished in the theory of relativity. In relativity, gravity is equivalent to curvature.

Kolecki, Joseph C.↗
NASA NTRS1979

The rotational motion of an earth orbiting gyroscope according to the Einstein theory of general relativity

The classical Poisson equations of rotational motion are used to study the attitude motions of an earth orbiting, rapidly spinning gyroscope perturbed by the effects of general relativity (Einstein theory). The center of mass of the gyroscope is assumed to move about a rotating oblate earth in an evolving elliptic orbit which includes all first-order oblateness effects produced by the earth. A method of averaging is used to obtain a transformation of variables, for the nonresonance case, which significantly simplifies the Poisson differential equations of motion of the gyroscope. Long-term solutions are obtained by an exact analytical integration of the simplified transformed equations. These solutions may be used to predict both the orientation of the gyroscope and the motion of its rotational angular momentum vector as viewed from its center of mass. The results are valid for all eccentricities and all inclinations not near the critical inclination.

Hoots, F. R.↗