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From: Todd W. Thompson To: All Msg #71, Mar-31-93 01:41PM Subject: Big Bang/Big Crunch theory discredited? From: todd@csrnxt1.ae.utexas.edu (Todd W. Thompson) Message-ID: Newsgroups: talk.origins Prelude: I'm taking a class entitled Atheism and its Critics at Rice University. It requires a paper at the end. My subject is creationism. Note that I'm not asking for my paper to be written for me, but references for replies WOULD be nice so that I can do appropriate research. Ok, on the the important part: I just read an article entitled Philosophical and Scientific Pointers to Creatio ex Nihilo by William Lane Craig. It appeared in the Journal of the American Scientific Affiliation in March of 1980. I have no idea what his qualifications are, nor those of the scientists he quotes. His basic point in the article is that the universe MUST have had a beginning. He proves his point using four proofs, 2 philosophical and dealing with the nature of actual infinity, and 2 scientific. I'll address the scientific here. Basic summary of the first: In 1929 Hubble observed that the universe was expanding in all directions. The conclusion from that was that at some point in the past, the ENTIRE KNOWN UNIVERSE WAS CONTRACTED DOWN TO A SINGLE POINT, from which is has been expanding ever since. [emphasis his] So, if you go far enough back, the universe finally reaces a point of infinite density (ie. nothingness. If something were there, it wouldn't be infinite density) He then notes that this disturbed many scientists, as it was too close to the Christian idea of the creation of something from nothing for comfort. So, he looks at the two alternatives, the steady state model and the oscillating model. He discredits the steady state model (and quotes from physicist Jaki here, any idea what his reputation is?) through the existence of background radiation which indicates the universe was once in a very hot and very dense state. In the steady state model, no such state could have existed. "According to Ivan King, 'The steady-state theory has now been laid to rest, as a result of clear-cut observations of how things have changed with time.'" Question: Is this summary a valid disproof of the steady-state model? Then he goes on to attack the oscillating model. He says that the key question is whether or not the univese is open or closed. If it is closed, then the expansion will reach a certain point, and then the force of gravity will pull everything together again. (note that he is not speaking of thermodynamically closed here. That's later) But if the universe is open, then the expansion will never stop, but will just go on and on forever. "Scientific evidence seems to indicate that the universe is open. The crucial factor here is the density of the universe. Scientists have estimated that if there are more than about three hydrogen atoms per cubic meter on the average throughout the universe, then the universe would be closed. That may not sound like very much, but remember that most of the universe is just empty space. I shall not go into all the technicalities of how scientists measure the density of the universe, but let me simply report their conclustions. According to the evidence, the universe would have to be at least ten times denser than it is for the universe to be closed. Therefore, the universe is open by a wide margin. Let me share with you the conclusion of Alan Sandage: (1) The universe is open, (2) the expansion will not reverse, (3) THE UNIVERSE HAS HAPPENED ONLY ONCE and the expansion will never stop." "The evidence therefore appears to rule out the oscillating model, since it requires a closed universe. But just to drive the point home, let me add that the oscillating model of the universe is only a theoretical possibility, not a real possibility. As Dr. Tinsley of Yale observes, in oscillating models ' even though the mathematics SAYS that the universe oscillates, there is no known physics to reverse the collapse and bounce back to a new expansion. The physics seems to say that those models start from the big bang, expand, collapse, then end.'" Ok, there's the first argument. The second one deals with thermodynamics. First the author goes through a fairly good summary of the basic principles of entropy and heat death and so on. Actually, rereading this, the second argument rests on the conclusions of the first, so the evaluation of the above would be nice. HOWEVER, he says that "as several scientists have pointed out, each time the model universe expands it would expand a little further than before. Therefore, ir you traced the expansions back in time they would get smaller and smaller and smaller. Therefore, in the words of one scientific team, "The multicycle model has an infinite future, but only a finite past." As yet another writer points out, this implies that the oscillating model of the universe still requires an origin of the universe prior to the smallest cycle." So, there it is. Are these logical, scientific conclusions or theological propoganda? With reasons, please, and references, if you can. Or, if you are unable to tell me the answer, could you direct me to someone who would know? Did anyone even get this far? :) Sorry for such a lengthy article, but I thought it was fascinating. Perhaps this is an appropriate line to employ against creationists. IF it could be shown that there is a causal force that spun the universe, the mechanics of evolution or life on earth would be completely unimportant theologically, since evolution no longer threatens the concept of the divine hand doing its work, too. Or maybe that's just wishful thinking. It's something to think about, anyways. Todd -- "When the last of a thousand candles burns out, the darkness will always return; though a thousand voices sing all the hymns of life, silence always waits upon the inevitable failing of their breath." -Barbara Hambly, _The Silicon Mage_ ==================================================================== From: Tim Thompson To: All Msg #72, Mar-31-93 05:43PM Subject: Re: Big Bang/Big Crunch theory discredited? Organization: Jet Propulsion Laboratory From: tjt@scn1.Jpl.Nasa.Gov (Tim Thompson) Message-ID: <1pdhcdINNne4@elroy.jpl.nasa.gov> Reply-To: tjt@scn1.Jpl.Nasa.Gov Newsgroups: talk.origins Basically, the "big bang" model is alive and well. The primary complaint against a steady state, to the best of my knowledge, is that it is not so consistent with both known microwave background radiation, and primordial elemental abundances (and baryon/lepton ratios, I believe). There are proponents of steady state cosmology; Fred Hoyle just published two lengthy papers in the las month or so in Astrophysics and Space Science, however, the large majority accept the big bang, perhaps with "inflation" tossed in. As for oscillating cosmologies, I am unaware of any work in the area. The current going opinion is that there is not enough mass to close the universe, so it is open, and wil expand forever. You might be interested in a fascinating paper on the subject, "Time Without End: Physics and biology in an open universe" by Freeman J. Dyson, in Reviews of Modern Physics, vol. 51, no. 3, July, 1979, pp 447-460. Dyson points out that the interesting time scales in an open universe are very long. For instance, stars "evaporate" from galaxies in on the order of 10**19 years. Even in an open universe, we have a lot of time to play around. --- ------------------------------------------------------------ Timothy J. Thompson, Earth and Space Sciences Division, JPL. Assistant Administrator, Division Science Computing Network. Secretary, Los Angeles Astronomical Society. Member, BOD, Mount Wilson Observatory Association. INTERnet/BITnet: tjt@scn1.jpl.nasa.gov NSI/DECnet: jplsc8::tim SCREAMnet: YO!! TIM!! GPSnet: 118:10:22.85 W by 34:11:58.27 N ================================================================== ] Basic summary of the first: ] In 1929 Hubble observed that the universe was expanding in all directions. ] The conclusion from that was that at some point in the past, the ENTIRE ] KNOWN UNIVERSE WAS CONTRACTED DOWN TO A SINGLE POINT, from which is has been ] expanding ever since. [emphasis his] If he managed to draw this conclusion solely from this fact, then I'm already underwhelmed with his powers of deduction. If all you know is that the universe appears to be expanding at this time, then there are still myriad possibilities open--one of them being the above hypothesis, another being a version of the steady-state model in which everything is expanding and new matter is being continuously introduced to keep the average density of space a constant, another being that the known universe has been expanding from an "original" finite and nonzero size, and yet another being that all matter is constantly shrinking with corresponding modifications of physical constants to make everything appear as it does. Now, at this time it certainly looks like the "big bang" theory is the one that best fits the available evidence, but not only does it take a lot more evidence than observations suggesting an expanding universe, it also doesn't require the known universe ever to have been contracted down to a single point. ] So, if you go far enough back, the ] universe finally reaces a point of infinite density (ie. nothingness. If ] something were there, it wouldn't be infinite density) I don't understand the logic behind this at all. It may be worth noting that many popular theories of quantum behavior posit that leptons (electrons, muons, taus, and their associated neutrinos) and quarks are dimensionless points themselves. Following the reasoning above, quantum electrodynamics would imply that electrons don't exist, an idea that much of the scientific community would be inclined to dispute. ] He then notes that ] this disturbed many scientists, as it was too close to the Christian idea ] of the creation of something from nothing for comfort. I seriously doubt that any scientist actually had this particular feeling. While the "big bang" model was doubtlessly found aesthetically and emotionally unappealing by some, it is extremely unlikely that anybody held reservations about the model because it was too close to Craig's opinion of what "christian ideas" are. ] So, he looks at the ] two alternatives, the steady state model and the oscillating model. ] ] He discredits the steady state model (and quotes from physicist Jaki here, ] any idea what his reputation is?) through the existence of background radiation ] which indicates the universe was once in a very hot and very dense state. In ] the steady state model, no such state could have existed. "According to ] Ivan King, 'The steady-state theory has now been laid to rest, as a result ] of clear-cut observations of how things have changed with time.'" ] ] Question: Is this summary a valid disproof of the steady-state model? No. The cosmic background radiation is pretty good evidence in favor of the big bang model and against the steady state model, but I don't think it qualifies as a "disproof"--indeed, I'd be surprised if some of steady-state's more stalwart adherents hadn't come up with several steady-state models that were consistent with the cosmic background radiation. While big bang is certainly ahead in the polls, I don't think we can claim that all steady state models have been disproven. ] Then he goes on to attack the oscillating model. He says that the key question ] is whether or not the univese is open or closed. If it is closed, then the ] expansion will reach a certain point, and then the force of gravity will ] pull everything together again. (note that he is not speaking of ] thermodynamically closed here. That's later) But if the universe is open, ] then the expansion will never stop, but will just go on and on forever. ] "Scientific evidence seems to indicate that the universe is open. The crucial ] factor here is the density of the universe. Scientists have estimated that ] if there are more than about three hydrogen atoms per cubic meter on the ] average throughout the universe, then the universe would be closed. That ] may not sound like very much, but remember that most of the universe is just ] empty space. I shall not go into all the technicalities of how scientists ] measure the density of the universe, but let me simply report their ] conclustions. According to the evidence, the universe would have to be at ] least ten times denser than it is for the universe to be closed. Or, if we wanted to be accurate, the universe would have to contain at least ten times current estimates of visible matter in the universe. "Dark matter" such as neutrinos produced during the big bang, nonluminous gas and dust, yet undiscovered particles, and/or black holes could all quite possibly contain more than enough mass to close the universe. ] Therefore, ] the universe is open by a wide margin. Let me share with you the conclusion ] of Alan Sandage: (1) The universe is open, (2) the expansion will not reverse, ] (3) THE UNIVERSE HAS HAPPENED ONLY ONCE and the expansion will never stop." ] "The evidence therefore appears to rule out the oscillating model, since it ] requires a closed universe. But just to drive the point home, let me add that ] the oscillating model of the universe is only a theoretical possibility, not ] a real possibility. As Dr. Tinsley of Yale observes, in oscillating models ] ' even though the mathematics SAYS that the universe oscillates, there is ] no known physics to reverse the collapse and bounce back to a new expansion. ] The physics seems to say that those models start from the big bang, expand, ] collapse, then end.'" I can't really comment on this one except to say that our understanding of the forces and interactions that would occur at or near the times of the big bang or big crunch is very limited--the physical conditions are just not like anything you can simulate or test in a laboratory and work on grand unified field theories is still very young. Since we currently know very little about the physical principles that would operate under such conditions, I don't think that Dr. Tinsley's quote drives a stake through the heart of the oscillating model--and, given how it's worded, I suspect that he doesn't think that it does either. ] Ok, there's the first argument. The second one deals with thermodynamics. ] First the author goes through a fairly good summary of the basic principles ] of entropy and heat death and so on. Actually, rereading this, the second ] argument rests on the conclusions of the first, so the evaluation of the ] above would be nice. HOWEVER, he says that "as several scientists have pointed ] out, each time the model universe expands it would expand a little further ] than before. Therefore, ir you traced the expansions back in time they would ] get smaller and smaller and smaller. Therefore, in the words of one ] scientific team, "The multicycle model has an infinite future, but only a ] finite past." As yet another writer points out, this implies that the ] oscillating model of the universe still requires an origin of the universe ] prior to the smallest cycle." But is this, in fact, predicted by every oscillating universe model or just some of them? (Also, since the "laws" of thermodynamics are statistical abstractions operating under "normal" conditions rather than physical laws in the way that conservation of mass is, can we be sure they would apply under big bang and big crunch conditions--indeed, can we even be sure that conservation laws are still meaningful under those conditions?) ] So, there it is. Are these logical, scientific conclusions or theological ] propoganda? With reasons, please, and references, if you can. Or, if you ] are unable to tell me the answer, could you direct me to someone who would ] know? From what you've written here, it sounds like Craig is given to taking great leaps of logic to his desired conclusions, regardless of how many other possibilities the evidence points to as well. The logic seems to be more sleight-of-hand and bold assertion than a genuine effort to analyze the evidence, so I would suggest reading the book closely and never taking Craig's word on whether his premises really imply his conclusions. Trygve

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