Hy.princeton. Biographical Sketch Prof. Paul J. Steinhardt Department of Physics Paul J. Steinhardt, the Albert Einstein Professor in Science and Director of the Princeton Center for Theoretical Science, is on the faculty of both the Department of Physics and the Department of Astrophysical Sciences at Princeton University. He received his B.S. in Physics at Caltech in 1974; his M.A. in Physics in 1975 and Ph.D. in Physics in 1978 at Harvard University.
Steinhardt is a theorist whose research spans problems in particle physics, astrophysics, cosmology and condensed matter physics. He has written over 200 papers, has edited 4 books, and has three U.S. patents (with two patents pending). Click HERE for curriculum vitae. Before the Big Bang | Cosmology. "Cyclic-universe models were popular in the 1920s and '30s," Steinhardt says. "But they were based on the idea of a Big Bang followed by a Big Crunch followed by another Big Bang. " In these models, the same matter is endlessly recycled, so the entropy of the universe—its tendency toward disorder over time—increases from one cycle to the next. "The result is that each subsequent cycle gets longer," Steinhardt says. "And if you go back into the past, each cycle gets shorter.
Ultimately, you still have to have a beginning. " The model works so well that one might expect cosmologists to embrace it wholeheartedly. That, say some physicists, is an understatement. Joel Primack, a physicist and cosmologist at the University of California at Santa Cruz, isn't even all that interested in whether it's right or wrong.
Steinhardt and Turok respond that their theory could gain credence from LISA, a proposed space probe that would look for gravity waves from the early universe. Notre univers a-t-il connu plusieurs Big Bang ? Notre univers a-t-il connu plusieurs Big Bang ? - 1 Photo Et si notre univers avait connu plusieurs Big Bang et Big Crunch ? (Crédits : NASA) Un univers dans une boucle infinie ? Si l'on en croit Paul Steinhardt et Neil Turok, respectivement des universités de Princeton dans le New Jersey et de Cambridge en Angleterre, l'univers que nous connaissons aujourd'hui est au coeur d'une boucle de mille milliards d'années, faisant partie d'un cycle au cours duquel se succèdent Big Bang et Big Crunch. « Depuis les années 60, on pense que le big bang est le point de départ car les lois physiques s'y trouvent mises à mal », explique Turok.
Si ce modèle cyclique développé par Paul Steinhardt et Neil Turok est si intéressant, c'est surtout parce qu'il apporte une solution originale au problème de la constante cosmologique. Le paradoxe de la constante cosmologique En 1996, la communauté scientifique découvrait que l'expansion de l'univers s'accélérait. Pourquoi un tel écart ? A voir aussi sur Internet. LE BIG BANG - LES CLEFS DE L'UNIVERS.