| | Another Look at the Big Bang | Was the big bang a big bang? Was it a kind of explosion? An explosion assumes that some material transforms internal energy into motion of its parts. There has not been any such process in the early history of the universe. In fact, the better description is that space-time is expanding, rather than matter moving… Due to the importance of spatial expansion, the whole phenomenon cannot be called an explosion at all. And obviously there neither was nor is any air in interstellar space, so that one cannot speak of a ‘bang’ in any sense of the term. Was it big? The visible universe was rather small about fourteen thousand million years ago, much smaller than an atom. In summary, the big bang was neither big nor a bang; but the rest is correct. Was the big bang an event? The big bang is a description of what happened in the whole of space-time. Despite what is often written in careless newspaper articles, at every moment of the expansion, space is always of non-vanishing size; space never was a single point. People who pretend this are making ostensibly plausible, but false statements. The big bang is a description of the expansion of space-time, not of its beginning. Following the motion of matter back in time, general relativity cannot deduce the existence of an initial singularity… Most importantly, quantum theory shows that the big bang was not a true singularity, as no physical observable, neither density nor temperature, ever reaches an infinitely large (or infinitely small) value. Such values cannot exist in nature. In any case, there is a general agreement that arguments based on pure general relativity alone cannot make correct statements on the big bang. Nevertheless, most newspaper article statements are of this sort. Was the big bang a beginning? Asking what was before the big bang is like asking what is north of the North Pole. Since nothing is north of the North Pole, nothing ‘was’ before the big bang. This analogy could be misinterpreted to imply that the big bang took its start at a single point in time, which of course is incorrect, as just explained. But the analogy is better than it looks; in fact, there is no precise North Pole, since quantum theory shows that there is a fundamental indeterminacy as to its position. There is also a corresponding indeterminacy for the big bang. In fact, it does not take more than three lines to show with quantum theory that time and space are not defined either at or near the big bang… The big bang therefore cannot be called a ‘beginning’ of the universe. There never was a time when the scale factor R(t) of the universe was zero. This conceptual mistake is frequently encountered. In fact, quantum theory shows that near the big bang, events can neither be ordered nor even be defined. More bluntly, there is no beginning; there has never been an initial event or singularity, despite the numerous statements professing the contrary. | — Christoph Schiller, Motion Mountain: The Adventure of Physics | Indexes/09 |
1 comments:
In fact, quantum theory, in the past the Big Bang, neither can be ordered or even be defined. More bluntly that it was not yet begun; have never preliminary events or singular, despite repeated in a statement bears the contrary.
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