Issue #9 of DIALOGOS: An Interactive Journal of the
Sciences, Philosophy, and Theology
(First Posted May 6, 1998: Updated Nov. 10, 1998)
Richard W. Kropf, Editor
With this issue we return to the observation made in the very first issue of DIALOGOS, which took exception to science writer John Horgan's opinion in his book, The End of Science, that all the major questions addressed by science in recent times have been already solved. It remains the opinion of this writer (and editor of this journal) that the "open" vs. "closed" universe issue looms as the single, and perhaps ultimately most important question yet to be resolved, one that shall equal the importance of the "Big Bang" theory itself. In the year and a half since that first issue of DIALOGOS was posted, events have moved very quickly towards a resolution.
Accordingly, what we intend to accomplish in this issue is to first of all summarize, in as simple terms as possible, with the help of experts in the field, the present scientific data and its scientific implications. Then, this article (in Part II) will go on to attempt to outline what this editor sees as the major philosophical and theological questions which are raised by the scientific issue and its possible resolution. As new data (and comments) come in, the article will be periodically updated.
We also wish, at this point, to give special thanks to DIALOGOS science consultant and oftimes respondent Patrick Stonehouse, for his help in preparing this issue, and congratulate him on his discovery of a new comet (C/1998 H1). (See NASA Comet Homepage and The Harvard-Smithsonian Center For Astrophysics .)
The Philosophical and Theological Implications of An Open Universe
When the initial draft of this essay was begun in October of 1997, the issue as to whether or not the universe was open or closed was still considered to be pretty much an open question. Even though the search for enough "dark matter" to cause the Big Bang to eventually reverse itself -- thus to "close" or recollapse the universe upon itself -- seemed to be becoming more and more like the proverbial search for the needle in the haystack, many cosmologists still held out for the possibility of such an outcome. Then, early in January of this year, at the conclusion of the annual meeting of the American Astronomical Association, it was announced that no less than five independnet studies, each approaching the issue from a different angle, had all come to the conclusion that the universe is almost without question "open", or as one follow-up report put it "destined to expand forever." (See Astronomy Magazine : News reports of Feb. 17, 1998: see also the feature article "The Future of the Universe" in the August 1998 issue of Sky & Telescope magazine, pages 32-39 by Fred Adams [U. of Michigan] and Gregory Laughlin [U. of California, Berkeley]).
Then, on the last day in February, the American Academy of Science in it's Science Online version of Science Magazine, reported further details of one of those studies, that conducted by the Harvard-Smithsonian Center for Astrophysics, which studied fourteen different supernovas in galaxies ranging from 7 to 10 billion light years in distance. This study turned out to indicate that not only are the galaxies in which these supernovas are located are not gradually slowing down, as almost all astrophysicists assumed they were, but to the contrary, these latest measurements seem to indicate that the rate of expansion, as dated from the Big Bang, may even be accelerating . Or, as another study, that of certain radio galaxies by two teams at Princeton University, indicated, if the expansion rate is not actually accelerating now, it may very well begin to do so in the future.
All this would be the opposite of what one might expect if there were any possibility of a future closure of the observable universe. Or as the Feb. 27 CNN summary put it, the news has left cosmologists and astronomers absolutely "stunned." Why and how could this be?
The Cosmological Question -- and Present Answers
To appreciate the degree of shock all this has caused, we first need to take a quick look at the general outlines of modern cosmology -- understood as the science that studies the large scale structure and evolution of the universe. The fate of the universe, particularly in terms of the "Big Bang" theory first proposed by Georges Lemaitre and gradually adopted in one form or another by nearly all cosmologists today, depends on several factors or parameters. The most important of these is the so-called "Hubble Constant" or expansion rate named after the astronomer Edmund Hubble who was the first to prove (others before him had only guessed at it) that a lot of those fuzzy objects they were seeing through telescopes were not just clouds ("nebulas") of gas but actually other galaxies like our own Milky Way. Not only that, but that, Hubble's observations, when interpreted in terms of "red-shift" or the so-called "Doppler effect", indicated that most of them are speeding away from us at a dizzying rate that seems to be increasing the farther away they are.
Nevertheless, this expanding universe poses some very difficult problems. Not the least of them being philosophical -- as like "what caused the Big Bang?" But even in strictly scientific terms there are other problems as well. One of them is that given not enough speed (too low an expansion rate) the Big Bang would have collapsed, as a result of its own gravitational forces, into nothing of consequence right from the start. Yet given too much speed, it is highly unlikely that galaxies and stars would never have formed before whatever matter there was would be spread so thin that nothing could have begun to coalesce. Therefore, the actual expansion rate has to fall within a very critical range for the universe to have been around long enough for we observers of the universe to have evolved. While the most widely accepted version of the Big Bang theory, Guth's "inflationary universe", holds for an initial expansion rate faster than the speed of light, the present expansion rate has rate has been estimated to be anywhere from 50 to 80 kilometers per second per megaparsecs of distance -- which translates to anywhere from about 364,000 to 583,000 mph for every light year in distance from us! Nevertheless it has been taken more or less for granted up to now that despite this increase of speed in terms of distance, that in terms of time, the more this expansion rate slows down. After all, what would cause it to speed up again? It is this latter estimate that has been now upset -- but we'll come back to the meaning of that after we look at the other two factors and the additional problems they pose.
First, for this expansion rate to fall within this critical range, it is generally assumed that the universe must also have a certain "critical density" -- that to say, to have had enough matter in it for the expansion to be counter-balanced by gravitational force. Then by comparing the first (the speed or expansion rate) and the present density, we should not only be able to calculate not just how old the universe is, but also how long it is destined to keep expanding, or even if it might not just stop expanding and end up reversing itself, collapsing into a state where it might just start a whole new Big Bang. In other words, a "closed" universe giving birth to whole new universe once this one finally wears out.
But the second problem has been that most estimates of the expansion rate have not jibed very well with estimates of the density of the universe in a way that would indicate that the "critical mass" thought best to insure the future longevity of the universe. This density factor, is usually expressed under the symbol of the Greek letter Omega and assigned the numerical value of 1. But compared to this hypothetical value, visible matter in the universe is more like .01, while all the matter necessary to explain the observed movements of the galaxies would still amount to about .1, with .2 being given as the higher end estimate for argument's sake. In fact, all the efforts to add up the total amount of matter that we are sure exists only comes to somewhere between 1/10 to 1/5 of the amount that would be needed to keep the universe stable enough to last like this more or less forever -- even less than to cause it to collapse in hopes of creating a new one!
The proposed solutions to this quandary so far have taken several directions. One, quite actively pursued over the past decade, has been to spend an awful lot of time and money trying to find "dark matter" convinced that it just had to be out there someplace, even though no one seemed very sure just in what form this unseen or even unseeable stuff might be. Some suggested multitudes of brown and red dwarfs -- the burnt-out remains of dead stars that are so small that they remain largely invisible even within our own galaxy. Others postulate various forms of matter -- particles so minute as to remain undetectable, yet in such great numbers as to tip the balance in favor of the universe being closed. The mysterious "neutrino" particle, in particular, has been a prime candidate. Recent evidence presented at a meeting held in conjunction with work being done in Takayama, Japan, suggests that neutrinos do in fact possess some mass -- reportedly about 1/500,000 th. of that an electron -- and even given this infinitesmal amount may be numerous enough to outweigh the rest of the whole universe. Still even doubling the previously estimated mass of the universe seems hardly enough mass to reverse its expansion. Perhaps so-called "Black Holes" remain a feasible alternative. Yet for some reason or other, astrophysicists seem to no longer to have much hope of solving the problem, even with their help.
Another tactic, quite prominent in the past few years, has been to drastically readjust the expansion rate estimates, as well as the age estimates of the universe, radically downwards, because, if one has less matter to work with, a slower expansion rate translates into a lower figure to reach "critical mass". Not that this was being done arbitrarily. Some of the distance estimates of supernovas in galaxies just outside our local group seem to indicate their host galaxies are closer than once thought. But these new calculations were giving us age and expansion rates so low that we were being told that the whole universe might be several billion years younger than some of the oldest nearer stars, like some of those found in globular clusters only a couple of thousand light-years away. So something was obviously wrong with that approach..
Yet there is still another strategy that could be employed, although most cosmologists have been hesitant to employ it, and that is to invoke a "Cosmological Constant" like that proposed by Einstein who originally, like others at his time, thought the universe was more or less static -- that it always existed and always would exist. But Einstein could only account for this presumed stability by postulating a repulsive force to counter-act gravity in order to keep the universe from collapsing upon itself. While Eddington's, Lemaitre's and Friedmann's calculations all took exception to the conclusions Einstein was drawing from his own theories, it was only later on, finally convinced by Hubble's discovery of the redshift of most of the other galaxies that the universe was in fact expanding, that Einstein abandoned his "constant" as having been the greatest blunder of his career.
Nevertheless, in the face of this latest speculation about an accelerating universe, some are again talking about a revival of the cosmological constant, but so far it is not clear in what sense. Is it to explain an accelerating expansion rate if further studies turn out to show that this in fact the case? Or will it be invoked to in hopes that there might be something to counteract the expansion and to reassure us that the universe might some day be persuaded to slow down and even reverse itself? If this be the case, with the cosmological constant envisioned as a kind of "virtual mass", then we have the constant being invoked in a way that is quite the opposite from that employed by Einstein -- which was to keep the universe from collapsing, not to insure that some day it would do so. Instead, those who would reintroduce this constant presumably see it as an anti-expansion force. In this case they could end up with more than what they bargained for, as according to an article titled "Cosmic Puffery" that appeared in Scientific American's web-site about a year ago, some particle physicists have recently been touting the idea of a "vacuum energy" so powerful that if Einstein had used it for his constant, the universe would have collapsed on the spot!
It was partly to try to resolve these problems that all these new studies, made possible by the Hubble Space Telescope as well as the bevy of recently constructed huge earth-based telescopes, were commissioned and undertaken. But other than resulting in a slight downward estimate of the ages of some of the oldest stars, from 14 billion to about 13 billion years old, plus reasserting with new confidence that the universe is at least 14 to 15 billion years old, what seems to have really emerged from this latest flurry of activity is a growing, almost overwhelming, conviction among astronomers and astrophysicists (95% certainty according to Peter Garnavich of the Harvard-Smithsonian Center for Astrophysics) that the universe is indeed "open" and that the long cherished dream of a universe that somehow can last forever is now almost completely gone.
In the second part of this essay, we will look at the philosophical and theological implications of this turn of events.
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