Tag Archives: Time

News

Did the universe have a beginning or has it always existed?

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Here’s a short article from the Massachusetts Institute of Technology’s Physics arXiv blog. (H/T Wes)

Excerpt:

The Big Bang has become part of popular culture since the phrase was coined by the maverick physicist Fred Hoyle in the 1940s. That’s hardly surprising for an event that represents the ultimate birth of everything.

However, Hoyle much preferred a different model of the cosmos: a steady state universe with no beginning or end, that stretches infinitely into the past and the future. That idea never really took off.

In recent years, however, cosmologists have begun to study a number of new ideas that have similar properties. Curiously, these ideas are not necessarily at odds with the notion of a Big Bang.

For instance, one idea is that the universe is cyclical with big bangs followed by big crunches followed by big bangs in an infinite cycle.

Another is the notion of eternal inflation in which different parts of the universe expand and contract at different rates. These regions can be thought of as different universes in a giant multiverse.

So although we seem to live in an inflating cosmos,  other universes may be very different. And while our universe may look as if it has a beginning, the multiverse need not have a beginning.

Then there is the idea of an emergent universe which exists as a kind of seed for eternity and then suddenly expands.

So these modern cosmologies suggest that the observational evidence of an expanding universe is consistent with a cosmos with no beginning or end. That may be set to change.

Today, Audrey Mithani and Alexander Vilenkin at Tufts University in Massachusetts say that these models are mathematically incompatible with an eternal past. Indeed, their analysis suggests that these three models of the universe must have had a beginning too.

Their argument focuses on the mathematical properties of eternity–a universe with no beginning and no end. Such a universe must contain trajectories that stretch infinitely into the past.

However, Mithani and Vilenkin point to a proof dating from 2003 that these kind of past trajectories cannot be infinite if they are part of a universe that expands in a specific way.

They go on to show that cyclical universes and universes of eternal inflation both expand in this way. So they cannot be eternal in the past and must therefore have had a beginning. “Although inflation may be eternal in the future, it cannot be extended indefinitely to the past,” they say.

They treat the emergent model of the universe differently, showing that although it may seem stable from a classical point of view, it is unstable from a quantum mechanical point of view. “A simple emergent universe model…cannot escape quantum collapse,” they say.

The conclusion is inescapable. “None of these scenarios can actually be past-eternal,” say Mithani and Vilenkin.

Since the observational evidence is that our universe is expanding, then it must also have been born in the past. A profound conclusion (albeit the same one that lead to the idea of the big bang in the first place).

They link to this peer-reviewed paper featuring Alexander Vilenkin at the end of the article, which was published in the Proceedings of the 10th Incternational Conference on Gravitation, Astrophysics and Cosmology, Quy-Nhon, Vietnam, December 2011.

The paper concludes:

Did the universe have a beginning?

At this point, it seems that the answer to this question is probably yes. Here we have addressed three scenarios which seemed to offer a way to avoid a beginning, and have found that none of them can actually be eternal in the past. Both eternal inflation and cyclic universe scenarios have Hav > 0, which means that they must be past-geodesically incomplete. We have also examined a simple emergent universe model, and concluded that it cannot escape quantum collapse. Even considering more general emergent universe models, there do not seem to be any matter sources that admit solutions that are immune to collapse.

So where do we stand? There is no eternal universe. There was a beginning to space and time. The entire physical universe came into being out of nothing at some point in the past.

Here’s my previous post on the BVG theorem that explains a bit more about how this data applies to the question of God’s existence.

Podcasts

Brian Auten interviews philosopher Robin Collins on the fine-tuning argument

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The latest interview from Apologetics 315 is up, and it’s a must-listen.

Details:

Today’s interview is with Robin Collins, professor of philosophy at Messiah College. His training is in physics and in philosophy and he is a leading advocate for using the fine-tuning of the universe as a design argument for theism. He talks about his background and training, the fine-tuning argument, the different types of fine-tuning with examples and illustrations (laws, constants and initial conditions), two different ways of presenting the fine-tuning argument, answering common objections to the argument, the uniqueness of life, variations of the multiverse hypothesis, the failure of multiverse theory to explain away fine-tuning, objections to Victor Stenger, upcoming books, simplifying the fine-tuning argument for practical use, common mistakes when presenting the argument, the most common objection (who designed God?), and more.

Get the MP3 file from Apologetics 315.

Dr. Collins is extremely cautious and circumspect in his assessment of the fine-tuning argument. He takes the objections to the argument, like the multiverse, seriously and that comes across in the interview. He is familiar with criticisms of the argument and he has engaged with skeptics like Victor Stenger in his published work. I highly recommend it. It is a little more suited to intermediate-level Christians, but not so advanced that it’s impossible for non-math beginners to follow the broad thrust of what’s being said.

About Robin Collins:

Robin Collins (PhD, University of Notre Dame, 1993), is professor of philosophy at Messiah College, Grantham, PA specializing in the area of science and religion. He has written over twenty-five articles and book chapters on a wide range of topics, such as the fine-tuning of the cosmos as evidence for the existence of God, evolution and original sin, the Doctrine of Atonement, Asian religions and Christianity, and Bohm’s theory of quantum mechanics. Some of his most recent articles/book chapters are “Philosophy of Science and Religion” in The Oxford Handbook of Science and Religion, “Divine Action and Evolution” in The Oxford Handbook of Philosophical Theology (2009) “The Multiverse Hypothesis: A Theistic Perspective,” in Universe or Multiverse? (Cambridge University Press), and “God and the Laws of Nature,” in Theism or Naturalism: New Philosophical Perspectives (Oxford University Press, forthcoming). He recently received a grant from the John Templeton Foundation to finish a book that presents the case for design based on physics and cosmology, tentatively entitled The Well-Tempered Universe: God, Cosmic Fine-tuning, and the Laws of Nature.

You can read Robin Collins’ testimony here.

The fine-tuning argument

Here’s a short article where Collins gives TWO examples of the fine-tuning. He is very modest in his argument, merely asserting that the fine-tuning is more compatible with theism than it is with atheism.

Excerpt:

Science is commonly thought to have undercut belief in God. As Nobel Prize winning physicist Steven Weinberg famously remarked, “the more we find out about the universe, the more meaningless it all seems.” Yet, the discoveries of modern physics and cosmology in the last 50 years have shown that the structure of the universe is set in an extraordinarily precise way for the existence of life; if its structure were slightly different, even by an extraordinarily small degree, life would not be possible. In many people’s minds, the most straightforward explanation of this remarkable fine-tuning is some sort of divine purpose behind our universe.

This fine-tuning falls into three categories: the fine-tuning of the laws of nature, the fine-tuning of the constants of physics, and the fine-tuning of the initial conditions of the universe. “Fine-tuning of the laws of nature” refers to the fact that if the universe did not have precisely the right combination of laws, complex intelligent life would be impossible. If there were no universal attractive force (law of gravity), for example, matter would be dispersed throughout the universe and the energy sources (such as stars) needed for life would not exist. Without the strong nuclear force that binds protons and neutrons together in the nucleus, there would not be any atoms with an atomic number greater than hydrogen, and hence no complex molecules needed for life. And without the Pauli-exclusion principle, all electrons would fall to the lowest orbital of an atom, undercutting the kind of complex chemistry that life requires.

Some fundamental physical numbers governing the structure of the universe—called the constants of physics—also must fall into an exceedingly narrow range for life to exist. For example, many have estimated that the cosmological constant—a fundamental number that governs the expansion rate of empty space—must be precisely set to one part in 10120 in order for life to occur; if it were too large, the universe would have expanded too rapidly for galaxies and stars to form, and if it were too small, the universe would have collapsed back on itself. As Stephen Hawking wrote in his book A Brief History of Time, “The remarkable fact is that the values of these numbers [i.e. the constants of physics] seem to have been very finely adjusted to make possible the development of life.” Finally, the initial distribution of mass energy at the time of the big bang must have an enormously special configuration for life to occur, which Cambridge University mathematical physicist Roger Penrose has calculated to be on the order of one part in 1010123. This is an unimaginably small number.

I know what you’re thinking: How do we know that non-Christian scientists acknowledge the fine-tuning of gravity in the way that Collins describes?

Well, the New Scientist actually talks about the fine-tuning of the force of gravity. And they’re not Christians.

Excerpt:

The feebleness of gravity is something we should be grateful for. If it were a tiny bit stronger, none of us would be here to scoff at its puny nature.

The moment of the universe‘s birth created both matter and an expanding space-time in which this matter could exist. While gravity pulled the matter together, the expansion of space drew particles of matter apart – and the further apart they drifted, the weaker their mutual attraction became.

It turns out that the struggle between these two was balanced on a knife-edge. If the expansion of space had overwhelmed the pull of gravity in the newborn universe, stars, galaxies and humans would never have been able to form. If, on the other hand, gravity had been much stronger, stars and galaxies might have formed, but they would have quickly collapsed in on themselves and each other. What’s more, the gravitational distortion of space-time would have folded up the universe in a big crunch. Our cosmic history could have been over by now.

Only the middle ground, where the expansion and the gravitational strength balance to within 1 part in 1015at 1 second after the big bang, allows life to form.

Here’s a very long paper by Collins on the fine-tuning argument, where he answers several objections to the argument, including the multiverse/many-universe hypothesis.

If you want a longer response to the multiverse argument, but you don’t want to shell out big bucks for Collins’ chapter in the “Blackwell Companion to Natural Theology“, then you can just get James Sinclair’s essay in “Contending With Christianity’s Critics“.

Commentary

A review of Lawrence Krauss’ book “A Universe From Nothing”

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Lawrence Krauss is a physicist who affirms that the entire physical universe appeared out of nothing. How well does his theory hold up?

This review of Krauss’ book was written by a non-theist in the liberal New York Times.

Excerpt:

Lawrence M. Krauss, a well-known cosmologist and prolific popular-science writer, apparently means to announce to the world, in this new book, that the laws of quantum mechanics have in them the makings of a thoroughly scientific and adamantly secular explanation of why there is something rather than nothing.

[…]Never mind. Forget where the laws came from. Have a look instead at what they say. It happens that ever since the scientific revolution of the 17th century, what physics has given us in the way of candidates for the fundamental laws of nature have as a general rule simply taken it for granted that there is, at the bottom of everything, some basic, elementary, eternally persisting, concrete, physical stuff. Newton, for example, took that elementary stuff to consist of material particles. And physicists at the end of the 19th century took that elementary stuff to consist of both material particles and electro­magnetic fields. And so on. And what the fundamental laws of nature are about, and allthe fundamental laws of nature are about, and all there is for the fundamental laws of nature to be about, insofar as physics has ever been able to imagine, is how that elementary stuff is arranged. The fundamental laws of nature generally take the form of rules concerning which arrangements of that stuff are physically possible and which aren’t, or rules connecting the arrangements of that elementary stuff at later times to its arrangement at earlier times, or something like that. But the laws have no bearing whatsoever on questions of where the elementary stuff came from, or of why the world should have consisted of the particular elementary stuff it does, as opposed to something else, or to nothing at all.

The fundamental physical laws that Krauss is talking about in “A Universe From Nothing” — the laws of relativistic quantum field theories — are no exception to this. The particular, eternally persisting, elementary physical stuff of the world, according to the standard presentations of relativistic quantum field theories, consists (unsurprisingly) of relativistic quantum fields. And the fundamental laws of this theory take the form of rules concerning which arrangements of those fields are physically possible and which aren’t, and rules connecting the arrangements of those fields at later times to their arrangements at earlier times, and so on — and they have nothing whatsoever to say on the subject of where those fields came from, or of why the world should have consisted of the particular kinds of fields it does, or of why it should have consisted of fields at all, or of why there should have been a world in the first place. Period. Case closed. End of story.

What does it mean? It means this. Physical laws are merely a description of how physical entities operate. They do not explain where the physical entities being described came from. Physical laws are like traffic laws – they describe how cars are supposed to drive around on roads – but they don’t create the cars!

In any case, if you would like to find out how well Krauss’ ideas hold up in a debate, you can watch him debate William Lane Craig right here:

Or listen to the debate and read my very very snarky summary here.

The debate itself was a slaughter. Krauss was one of the least rational opponents Craig has ever faced.