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Petroleum Pre-Period
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
The fundamental units of the universe consist of ‘dark energy’ and ‘dark matter’. Dark energy and dark matter are inter-convertible under suitable conditions of natural forces. The dark energy is responsible for the expansion and development of the universe by pushing the space matter and galaxies away from each other. It is a repulsive force against the inward gravitational pull or contraction. Dark matter is highly condensed, of high density and with great inward gravitational pull. It emits no light and is not visible. Dark matter is detected only by its capacity for the gravitational pull of the other visible object in space.
Detectors
Published in C. R. Kitchin, Astrophysical Techniques, 2020
As previously mentioned, studies of distant supernovae provide a history of the acceleration/deceleration of the Universe over time and, this in turn, can put constraints on the nature of dark energy. Such data has already come from surveys like the SDSS and forms the current observational basis for the existence of dark energy. For example, the Dark Energy Camera (DECam) has been operating on the 4-m Victor M. Blanco telescope since 2012, conducting the Dark Energy Survey (DES). It uses 62 CCDs as its detectors (Section 1.1.8) with a field of view 2.2° across and its main purpose to search for distant supernovae. The Hobby-Eberly telescope (Section 1.2.3.2) has recently been upgraded to have a field of view about a third of a degree across and is currently conducting the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX).
Cosmic Microwave Background
Published in Ronald L. Snell, Stanley E. Kurtz, Jonathan M. Marr, Fundamentals of Radio Astronomy, 2019
Ronald L. Snell, Stanley E. Kurtz, Jonathan M. Marr
Subsequent studies of the Universe have yielded a number of significant modifications to the Big Bang model. In the 1970's, evidence for dark matter Dark matter (discussed in Section 8.1.2) became strong enough that dark-matter dominated cosmological models were developed. In the late 1990's, from studies of the redshifts and distances of many very distant Type Ia supernovae, Adam Riess and colleagues4 and Saul Perlmutter and colleagues5 found their data required that the expansion rate of the Universe is currently accelerating. Although no successful physics model has yet succeeded in explaining this phenomenon, it fits a mathematical model involving the cosmological constant, Λ. Cosmological constant (Λ)Dark energy The unknown source of Λ is called dark energy. The most widely accepted models of the Universe today are those that are dominated by dark energy and secondarily by dark matter. These models collectively are referred to as ΛCDM. ΛCDMUniverse!ΛCDM The “C” refers to cold, to describe more massive dark matter particles, in contrast to the very low mass candidates, which would have been relativistic, and referred to as “hot”, at important epochs of the early universe. The details of the Universe's history and future depend on the amount of dark energy, dark matter, and baryonic matter.
The Response of Matter to Spatially Distributed Transient Energy Addition: An Asymptotic Analysis”: Part 1, Inert Gases
Published in Combustion Science and Technology, 2022
The interaction of matter and energy is fundamental to the physics occurring in systems with radically diverse length and time scales, as well as magnitudes of energy deposition. Cosmologists believe that the accelerating expansion of the universe can be attributed to the action of dark energy on the various forms of matter present (Riess et al. 1988). Supernovas, are transient astronomical events characterized by powerful and luminous stellar explosions occurring during the last evolutionary stages of a massive star or when a white dwarf is triggered into runaway nuclear fusion (Riess et al. 2004). Massive amounts of thermonuclear energy are produced within a star causing an explosion which distributes its substance into the surrounding volume of space and often produces sufficient radiation in the visible spectrum to make the supernova visible from Earth in the daytime sky (Howell 2013). Nuclear fusion may be ignited by the deposition of sufficient energy on an appropriately short time scale (Ledingham et al. 2020). A recent experiment employed powerful lasers focused on a BB sized spot of heavy hydrogen to produce a hotspot the diameter of a human hair. It generated more than 10 quadrillion watts of fusion power for 100 trillionths of a second. Lightning causes the air though which it passes in a tiny fraction of a second to be heated to temperatures estimated to be as large as 50,000 F or 28,033 K (Uman 1969) accompanied by a high pressure relative to that in the undisturbed air. The subsequent expansion of the hot gas (the piston effect (Kevorkian and Cole 1981)) is the source of a shock wave (heard as a “bang”as it passes the ear) followed by a high velocity turbulent gas flow, one source of familiar rolling thunder. The piston effect is also responsible for the blast wave generated by nuclear or conventional explosions. Thermonuclear energy deposition in the former and chemical energy in the latter are the sources of a pronounced gasdynamical response (Kassoy 2010) in the initially undisturbed gas. Instabilities occurring in rocket engine combustion chambers are examples of the dynamic response of the combustion gases to chemically generated sources of energy (Sirignano 2015).