The Formation and Evolution of Cosmic Strings PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download The Formation and Evolution of Cosmic Strings PDF full book. Access full book title The Formation and Evolution of Cosmic Strings by G. W. Gibbons. Download full books in PDF and EPUB format.
Author: Barry R. Parker Publisher: Springer ISBN: 1489933328 Category : Science Languages : en Pages : 303
Book Description
I remember once watching a presentation of the creation of the universe in a planetarium. It was a fascinating experience: lights flashing, particles appearing to rush by as an explosive roar echoed throughout the planetarium. Then suddenly ... black ness. And after a few seconds ... tiny lights--stars blinking into existence. I tried to imagine myself actually going back to this event. Was this really what it was like? It was an interesting facsimile, but far from what the real thing would have been like. The creation of the universe is an event that is impossible to imagine accurately. Fortunately, this has not discouraged peo ple from wondering what it was like. In Creation I have attempted to take you back to the begin ning-the big bang explosion-so that you can watch the uni verse grow and evolve. Starting with the first fraction of a sec ond, I trace the universe from its initial dramatic expansion through to the formation of the first nuclei and atoms. From here I go to the formation of galaxies and the curious distribu tion they have taken in space. Finally I talk about the formation of elements in stars, and the first life on the planets around them.
Author: National Aeronautics and Space Administration (NASA) Publisher: Createspace Independent Publishing Platform ISBN: 9781725623156 Category : Languages : en Pages : 32
Book Description
Cosmic strings are linear topological defects which are predicted by some grand unified theories to form during a spontaneous symmetry breaking phase transition in the early universe. They are the basis for the only theories of galaxy formation aside from quantum fluctuations from inflation based on fundamental physics. In contrast to inflation, they can also be observed directly through gravitational lensing and their characterisitc microwave background anisotropy. It was recently discovered that details of cosmic string evolution are very differnt from the so-called standard model that was assumed in most of the string-induced galaxy formation calculations. Therefore, the details of galaxy formation in the cosmic string models are currently very uncertain. Bennett, David P. Unspecified Center NASA-CR-183367, NAS 1.26:183367, FERMILAB-CONF-88/85-A ...
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
The author have studied by means of numerical simulations the dynamical evolution of a network of cosmic strings, both in the radiation and matter era. Our basic conclusion is that a scaling solution exists, i.e., the string energy density evolves as t−2. This means that the process by which long strings dump their energy into closed loops (which can gravitationally radiate away) is efficient enough to prevent the string domination over other forms of energy. This conclusion does not depend on the initial string energy density, nor on the various numerical parameters. On the other hand, the generated spectrum of loop sizes does depend on the value of our numerical lower cutoff (i.e., the minimum length of loop we allow to be chopped off the network). Furthermore, the network evolution is very different from what was assumed before), namely the creation of a few horizon sized loops per horizon volume and per hubble time, which subsequently fragment into about 10 smaller daughter loops. Rather, many tiny loops are directly cut from the network of infinite strings, and it appears that the only fundamental scale (the horizon) has been lost. This is probably because a fundamental ingredient had been overlooked, namely the kinks. These kinks are created in pairs at each intercommutation, and very rapidly, the long strings appear to be very kinky. Thus the number of long strings per horizon is still of the order of a few, but their total length is fairly large. Furthermore, a large number of kinks favors the formation of small loops, and their sizes might well be governed by the kink density along the long strings. Finally, we computed the two-point correlation function of the loops and found significant differences from the work of Turok.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
Cosmic strings are linear topological defects that are predicted by some grand unified theories to form during a spontaneous symmetry breaking phase transition in the early universe. They are the basis for the only theories of galaxy formation aside from quantum fluctuations from inflation that are based on fundamental physics. In contrast to inflation, they can also be observed directly through gravitational lensing and their characteristic microwave background anistropy. It has recently been discovered by F. Bouchet and myself that details of cosmic string evolution are very different from the so-called ''standard model'' that has been assumed in most of the string induced galaxy formation calculations. Therefore, the details of galaxy formation in the cosmic string models are currently very uncertain. 29 refs., 9 figs.