A (Very) Simplified Guide to Inflationary Cosmology

[Walter]

This thread is about Inflation theorem and how it helps explain much about the evolution of the universe in its very earliest moments. I’ll also cover how Christian apologists often get various details wrong about Inflation and so make faulty arguments about it, building upon their misunderstandings and errors.

To begin, let’s go back to the 1960’s and 70’s and look at how the science of cosmology was progressing in its mission to explain the origin of everything.

If you recall, in my previous thread about Stephen Hawking and Roger Penrose’s Singularity theorem, I began by going right back to the year 1929. At this time Edwin Hubble discovered that the universe was expanding, with every point in space moving away from every other one. Looking at this movement in reverse and going backwards in time it becomes obvious that the galaxies get closer and closer together. Go back far enough in time and the temperatures, densities and pressures rise as the universe becomes more and more compressed. Eventually the heat and energy levels become so high that physical laws as we know them break down and not even General Relativity can describe what is happening.

We have arrived back at the hot Big Bang, which may well be the beginning of the universe.

This much was known in the 60’s and 70’s and strong support for this model came from the 1964 discovery of the Cosmic Microwave Background Radiation. The fading afterglow of the Big Bang that was picked up by the radio telescope of Arno Penzias and Robert Wilson.

Cosmic microwave background

But there was a major problem with this model.

As bigger and better optical telescopes allowed scientists to see deeper into the universe, they began to see something odd. When they looked at galactic clusters and superclusters in the very distant universe, they saw that, on average, the distribution of matter was very uniform indeed. Allowing for the voids, threads and walls of galactic superclusters spread across the cosmos and averaging everything out, any cubic volume of space of a large enough size looked almost identical to any other cubic volume, anywhere else in the universe.

This meant that opposite ends of the cosmos were virtually identical. They shared exactly the same mass, density, and temperature. Or, as scientists say, they are in thermal equilibrium.

But how could this be? If neither matter nor energy can travel faster than the speed of light, then there is no possible physical mechanism by which two widely separated regions of the universe could achieve thermal equilibrium. Two regions in thermal equilibrium will display essentially the same density and distribution of matter and energy because the physical conditions in both regions are virtually identical. Just as was being seen by scientists studying the very distant universe. This mystery became known as the Horizon problem.

Horizon problem

How can two completely separate regions of space, situated on opposite sides of the universe, on the edge of our visual horizon be so very similar?

When the Hubble space telescope was launched in 1990 one of its first tasks was to test this mystery to see if two different regions of deep space, 180 degrees apart, were in thermal equilibrium with each other, looking exactly the same as each other in terms of their distributions of matter and energy. Thus, were created some of the most iconic images observed by Hubble – the Deep Fields.

[Walter]

What you see in the previous post is the Hubble Deep Field North and the Deep Field South.

Any object in either image that possesses four spikes of light radiating from its centre is a foreground star from our galaxy, the Milky Way. Every other object you see is a distant galaxy. From the majestic spirals and lens-shaped elliptical galaxies, the irregularly-shaped ones, those interacting with each other and right down to the faintest of faint blobs in the extreme distance. These are all galaxies.

The essential point to realize, when comparing both images is that even though they differ on a small scale, with the pattern of galaxies in each looking different, STATISTICALLY they are identical. The number, distribution, ages and brightness’s of the galaxies, when averaged out, are the same.

Which means that both regions, even though they are at opposite ends of the universe from each other, one near the celestial North Pole of the sky and one near the celestial South Pole, look the same. Even though they are separated by over 50 billion light years, they are almost twins.

But how can that be?

The search for an answer to this question and the solution to the Horizon Problem were the driving forces in the formulation of Inflationary cosmology. As I will explain very soon. In the meantime I’m happy to answer any questions arising from what I’ve written here so far.

Thank you,

Walter.

[Walter]

To continue…

The solution to the Horizon Problem came through a clue given to us by observing the Cosmic Microwave Background Radiation (CMBR) which had been discovered in 1964. The CMBR is the cooling afterglow of the hot Big Bang.

As scientists studied the CMBR they were struck by its extreme smoothness. Everywhere they looked in sky it seemed to be exactly the same, displaying the same temperature and the same unvarying lack of any distinguishing features. It was like being inside some kind of gigantic ping pong ball.

The CMBR originates from the very earliest phases of the universe’s evolution, when it had existed for the tiniest fraction of a second. And it was (as far as we could tell in the 60’s and 70’s) a totally uniform temperature everywhere. If something has a uniform temperature then all parts of it are in thermal equilibrium with each other.

Thermal equilibrium. Now where have we heard those words before?

We heard it in my earlier explanation of what today’s universe looks like on the largest scales. Even though the two Hubble Deep Field images show differences on the small scale of galaxies and galactic clusters, when averaged out their distribution of matter and energy on a big enough scale. Or, putting it another way, if you average out the small differences all across the sky, today’s universe looks as smooth and uniform as the CMBR used to be, 13 billion years ago.

Coincidence?
Or is there something going on here?
Can we make any kind of connection between a microscopically small early universe that was smooth and uniform and today’s incredibly vast universe that is also smooth and uniform?

Actually, yes we can.

All we need is some kind natural force that can blow up (i.e., inflate) our baby universe from an extremely small size to a fantastically enormous one. Enter INFLATION THEOREM, the scientific description of how we think this happened. So, what is this Inflation theorem? Perhaps the best way of answering that question is to ask, in very simple terms, what it was required to do.

It was required to… push.

If you’ve read my other thread about the Hawking – Penrose Singularity Theorem you might recall that they tried to use General Relativity to “push” the universe, by reversing the way gravity normally works. Under normal circumstances gravity can only pull. Matter only ever acts attractively, pulling upon other matter. The gravitational attraction between the Earth and the Moon being the best known example of this.

Gravity attracts and pulls everything – from the smallest molecule up to the biggest galactic supercluster. Hawking and Penrose tried to use a kind of ‘reverse gravity’ to push the universe open at the moment of the Big Bang, as a way of explaining the expansion of the universe. Because, for there to be an expansion there must be a push and not a pull.

But their theorem failed to deliver the goods.

Inflation theorem appears to succeed where Singularity theorem failed. In my next post I’ll explain, in the very broadest terms, how Inflation ‘pushed’ the early universe open, causing it to expand and leading to the universe we see around us today.

As usual, I’ll pause before then to allow others the chance to ask questions arising from what I’ve written today. I’ll do my best to answer them.

Thank you,

Walter.

[Walter]

In effect the cosmological constant is a kind of force that counteracts the natural instability of GR, exactly stabilizing the entire universe to keep it static and unmoving. But when Edwin Hubble found that the universe WAS expanding in 1929, Einstein realized his mistake. He called using the cosmological constant to stabilize the universe his greatest blunder. If he had stuck to his guns and published GR with an expanding universe he would have predicted what Hubble found decades in advance. It would have been another triumph worthy of a Nobel prize. But he lost his nerve and the rest is history.

Above is a quote from my earlier thread about the Hawking – Penrose Singularity theorem.

It has to do with the cosmological constant, which seems to be a kind of natural force intrinsic to the very fabric of space. The constant was hypothesized to exist by Einstein in the first decade of the 20th century because he needed it to counteract the instability of the theorem he was working on then, General Relativity.

But what was hypothetical in the early 1900’s was put onto a much stronger evidential footing in 1998 when it was discovered that the expansion of the universe, instead of slowing down or even coasting, was actually accelerating – in defiance of all expectations. To accelerate the expansion requires a push. Therefore, something must be pushing space apart in the same way that Einstein’s cosmological constant counteracted the pull of gravity in his equations for GR.

By pushing.

However, back in the late 1970’s the discovery of the universe’s accelerating expansion was almost two decades away. Even so, scientists were working on a theorem that could fuse together General Relativity with certain aspects of particle physics. Quantum mechanics and GR have yet to be fully joined together into a working theorem of Quantum Gravity, but there is an approach in cosmology that creates a partial union of those two things.

Semiclassical gravity

The most important applications of semiclassical gravity are to understand the Hawking radiation of black holes and the generation of random Gaussian-distributed perturbations in the theory of cosmic inflation, which is thought to occur at the very beginning of the Big Bang.

Inflation theorem posits the existence of an energy field in the very earliest moments of the universe’s existence which would act like a super, ultra, hyper cosmological constant on steroids. It would push the universe apart so quickly that two regions separated by less than the size of an atom would end up on opposite sides of the universe, billions of light years apart.

These regions, being initially so close together, would have been in thermal contact with each other. They would have been in thermal equilibrium. Which means that the averaged-out distribution of energy within them would be, essentially identical.

Just like the Hubble Deep Fields.

Which, even though they are on opposite sides of the universe, billions of light years apart, are essentially identical. From the close similarity of two infinitesimally small regions to the close similarity of two fantastically vast regions we can see that Inflation theorem appears to have solved the Horizon Problem.

In my next post I will dip a little into how it does this. What I have to say will necessarily be the briefest, most superficial, and highly simplified overview of this. But before then I will hit the Pause button in case there are questions arising from what I’ve written here today.

Thank you,

Walter.

[Walter]

Because Inflation theorem is Semi-Classical it fuses together General Relativity with the Quantum Mechanics of high energy particle physics. Because of this it posits that Inflation began, not with an initial singularity of infinite density that springs into existence out of nowhere, but with a quantum fluctuation in a pre-existing quantum domain.

Therefore, the infinities that cause the breakdown of GR in Singularity theorem are avoided.
The quantum fluctuation initiates the exponential growth of an energy field with peculiar and counter-intuitive properties. In GR extremely high concentrations of mass exert extremely high degrees of gravitational pull, which is described as the bending and warping of space and time.

However, in the very early universe temperatures were so great that matter could not exist. The energy flux was too great for quarks to settle into protons and neutrons to form the nuclei of atoms. But since matter and energy are effectively equal in GR, the extreme energies found in the early universe create extreme gravities too.

But when quantum effects are also considered something weird and wonderful happens.

Instead of this extreme gravity being attractive and pulling, quantum effects reverse this and cause it to repel and push. This push causes the expansion which drives Inflation. Thus, we have a quantum-sized baby universe that has begun to inflate itself. This process of inflation, once begun, can never stop and accelerates exponentially.

The quantum energy field causing this repulsion and expansion is confusingly called the Inflaton. Not Inflation, but Inflaton. Just drop the letter i.

Almost all of the quantum fluctuations that naturally occur within the inflating volume of space that is the baby universe are smoothed out and equalised. We see this effect billions of years later, with regions on the opposite sides of our observable universe being equal in appearance and in the distribution of galaxies. Just remember the Hubble Deep Fields.

Perhaps now would be a good time to illustrate the inflationary process using simplified diagrams. As well as solving the Horizon problem in cosmology inflation also solves the Flatness problem.

Flatness problem

The diagrams relate to the Flatness problem, but can also be used to understand more about Inflation itself and how it solves the Horizon problem.

I reckon that what I’ve just written and illustrated will prompt some questions, so I think I’ll pause here.

Thank you,

Walter.

[Walter]

Well, I can think of three questions that might come up relating to all that I’ve posted so far.

1.
Where does the energy come from to inflate a quantum fluctuation so that it grows bigger than the observable universe?

2.
How can the baby universe created by this fluctuation expand (much) faster than the speed of light?

3.
What are the expanding, grid-covered globes in the diagrams meant to represent?

First things first.
The total energy cost of creating a universe like ours using inflation is… zero.
Nothing. Nada. Zip. Nothing at all. A saying coined by Alan Guth, one of the originators of Inflation theorem, goes like this. “The universe is the ultimate free lunch.” Here’s why.

Zero-energy universe - Wikipedia

The zero-energy universe theory proposes that the total amount of energy in the universe is exactly zero, with positive energy (matter/radiation) perfectly cancelled by negative energy (gravity). This hypothesis suggests the universe could have emerged from “nothing” without violating conservation laws. While matter represents positive energy, gravity acts as a negative energy that holds systems together, reducing the total energy to zero. Because the net energy is zero, the universe could have spontaneously appeared without requiring energy input.

Now to the second question.
According to General Relativity it is impossible for anything to travel faster than the speed of light within the universe. But that restriction only applies to things like matter and energy that are moving THROUGH the universe, through space and time.

But space itself (or more correctly space-time) has no restrictions on how fast it can grow or shrink. And since inflation theorem is describing the faster-than-light expansion of space itself, no restrictions are imposed on how fast it can expand. Which is why a baby universe many times smaller than an atom can grow to become billions of light years across in the blink of an eye.

Nothing is violated. Not General Relativity, not Thermodynamics and not Energy Conservation.

And finally…
The grid-covered globes in the diagrams are illustrations of the three dimensional volume of our baby universe growing exponentially fast to become the universe we inhabit. It’s impossible to show this properly on the flat, 2-D computer screens you are all looking at. So the diagrams are necessarily 2-D themselves.

But if you look I’ve drawn in a black disk that represents our observable universe, which is estimated to be 94 billion light years in diameter. That disk sits neatly just inside one grid square, making that square 100 billion light years on each side. Which gives us a sobering idea of just how vast the entire universe must be, seeing as the grid squares defining it’s true size stretch away into the far distance.

Then, if you follow the white arrow to the right you’ll see that I’ve pulled a bit of trick and tried to show our observable universe, not as a flat disk, but as a sphere. We are at the exact centre of the observable universe, but not at the centre of the entire universe, which recedes w-a-a-a-y beyond the limits we can see.

Oh and please don’t think that the prettily coloured dots are stars.

No. Each coloured pixel is a highly magnified and exaggerated representation of a supercluster of galaxies. Not a single galaxy like the Milky Way, but a grouping of thousands of galaxies. On this scale we would be hard pushed to even see the very largest galactic supercluster. Which is why the coloured dots are only crude representations and should not be thought of as the real things.

Thank you,

Walter.

[Walter]

So, what’s all this got to do with the hot Big Bang?

To answer that question we first need to understand that in the old model of the Big Bang, as advocated by Singularity theorem, the beginning of space and time in the initial singularity WAS the Big Bang itself. But in Inflation theorem this is not so. Inflation itself and the hot Big Bang are separate events, with the former causing the latter.

We can see this described here…

https://en.wikipedia.org/wiki/Chronology_of_the_universe

If you scroll down to the Tabular Summary, the first entry in the chronology in Inflation. It precedes Reheating, which is what we call the hot Big Bang. So, let us go through the sequence of events.

INFLATION

Cosmic inflation expands space by a factor of the order of 10²⁶ over a time of the order of 10⁻³⁶ to 10⁻³² seconds.

Please note that any references to the size, diameter or volume of the universe here refer ONLY to the dimensions of the observable universe and NOT to the entire universe. This is vitally important. The true size and extent of the entire universe remain unknown and is probably unknowable. Therefore, from now on, unless I specifically say so, all references to size, extent, volume, and dimensions ONLY refer to the observable universe.

The Inflationary phase lasts a very brief interval indeed before the Inflaton field becomes unstable.

This should be no surprise, because Inflation theorem owes much to particle physics. As a general rule of thumb in that discipline, the heavier (more massive) the particle, the less stable it is and the more prone it is to abruptly decaying into other forms of energy. So, the Inflaton field, having massively boosted the size of the universe to vast dimensions in an incredibly short time, destabilises and decays explosively, dumping a tremendous amount of energy into the newly created volume of what will become the observable universe. This decay is referred to, somewhat confusingly, as re-heating.

REHEATING

Reheating converts the energy in the inflation field into a thermal bath of Standard Model particles, initiating the Hot Big Bang.

The words ‘thermal bath’ have a special meaning in the science of thermodynamics, but that need not concern us here. However, the image of a bath is useful because it can help us to understand the major difference between the old and discredited model of the hot Big Bang of Singularity theorem and the current model as described by Inflation theorem.

In that former model the universe began from a point of infinite density called the initial singularity. The universe then grew from there, expanding radially, just as shown in many books and diagrams. Also as shown on tv and in videos, where a point-like explosion occurs, sending matter and energy outwards in an expanding sphere.

But a bath is not an infinitely small point. It is a volume, with a size and with dimensions.

And this is the case in the universe modelled by Inflation theorem. Here, the volume of space generated by the Inflaton field, that will later become the observable universe, is where the hot Big Bang happens. That is, the hot Big Bang happens simultaneously EVERWHERE in the observable universe. At every location, at exactly the same time. Not a particular point or location, but EVERYWHERE AT THE SAME TIME.

Waitaminute! I hear you cry. How is this possible?

It’s possible because we need to remember that these are extremely rapid events occurring, not on a vast, slow and macroscopic scale, but on a very small, microscopic scale. So, when the Inflaton field decays it does so abruptly, much, much faster than a second or even a nanosecond. This means that the field decays explosively across a tiny volume of space that only later will become the observable universe.

Doing this, the field effectively decays EVERYWHERE in the observable universe at once.

This explains how the hot Big Bang then occurs everywhere in the observable universe, simultaneously. The distance between any two locations in the baby universe this early on were so tiny that information, change and energy could be equalised between them.

It is only later, when the observable universe assumed its vast size, that the transfer of information and energy between two distantly separated locations becomes a problem. The speed of light will not allow it to happen instantly. In nature, two locations cannot be affected simultaneously by the same thing.

But in the very early universe, with its ultra-small size and the ultra-fast nature of particle decay, they could. Because these two locations were not separated by vast distances. They were closer together than the protons and neutrons in the nucleus of an atom. That’s how small the observable universe was back then. So an abrupt event like the decay of the Inflaton field would effectively be experienced EVERYWHERE AT ONCE in the baby universe.

Which means that hot Big Bang that resulted from the field’s decay would also be experienced EVERYWHERE AT ONCE and not at one discrete location, as an infinitely hot and dense point-like singularity that expanded from that location.

Now, these are highly exotic and counter-intuitive concepts which may be difficult to understand. I get that. Therefore, I’m going to stop here and await any questions arising from this post.

Thank you,

Walter.

[Walter]

Apologies for the delay in continuing this thread.

More to follow soon.

I plan to discuss the pros and cons of Inflation and then move on to what will probably be the final part, which is what Christian apologists misunderstand about it and how they cannot disentangle it from the hot Big Bang as described by it’s predecessor, Singularity Theorem.

Please maintain a holding pattern.

Thank you,

Walter.

[Walter]

In brief, here are the pros and cons of inflation theorem.

Horizon problem

Inflation solves the Horizon Problem, explaining why the universe looks the same in all directions, just as we saw with the Hubble Deep Fields, earlier. A spherical universe radiating out from an initial singularity cannot do this because it would possess a centre, a radius, and a circumference (boundary) and none of those things have been observed. All we can observe is the universe looking everywhere the same, with no centre or boundary.

Flatness problem

It solves the Flatness Problem, explaining why we can see no curvature to the overall shape of the universe. As the expanding grid-marked globe diagrams show, what begins as a spherical volume of space is flattened out by Inflation, leaving the universe with no detectable curvature.

General relativity

It agrees with General Relativity. Because the Inflationary universe has no apparent centre and no boundary the status of all observers within it are exactly the same, just as demanded by GR. In that paradigm there is no absolute frame of reference (which a centre or a boundary would be to all observers) and the viewpoints of all observers are all relative to each other and not to anything in space or any fixed property of space, like a centre or a boundary.

Semiclassical gravity

It brings General Relativity and Quantum Mechanics together in the partial union of Semiclassical Gravity. The ultimate aim in physics is to seamlessly join GR and QM in a Unified Field theorem of Quantum Gravity. Inflationary physics goes part of the way towards doing that and so is a step in the right direction.

Initial singularity

It does away with the problem of the infinities of the initial singularity that plagued it’s predecessor, Singularity theorem.

Big Bang

It explains the hot Big Bang without the need for an initial singularity.

Also, when it was first formulated in the late 70’s and early 80’s the Inflaton energy field that did all the work of inflating the universe and then decaying into a hot Big Bang was essentially an unknown. It worked on paper, but such an energy field has never been observed in nature.

One reason for this is because it’s impossible to simulate the conditions of the very early universe here on Earth. The energies, temperatures and densities involved are simply too great. Another reason is that even the hottest and most energetic explosions and events seen in the universe today come nowhere near approaching those present in the earliest moments of our universe’s existence.

Nothing – not supernovae, hypernovae, gamma ray bursts or even LFBOTs (Luminous Fast Blue Optical Transients) come anywhere close. Which therefore means that Inflation theorem remains untestable by comparing it to anything we can observe nowadays.

However, this one interesting twist to the story that arrived in 2012.

Higgs boson | Higgs field

The discovery of the Higgs boson heralded the discovery of the Higgs Field. This is the only known type of fundamental quantum scalar energy field. The Inflaton field discussed in this thread is theorised to be exactly that. It would have been a fundamental quantum scalar energy field. So, the discovery of the Higgs field, although not directly related to the Inflaton, does show that such energy fields CAN exist in nature.

Those, in brief, are the points in favour of Inflation theorem.

Now for the cons.

It remains largely theoretical and despite solving a number of major cosmological problems, is not supported by hard evidence. It’s status remains hypothetical.

BICEP and Keck Array

There was a false alarm in 2014, when the BICEP2 science team claimed that they had detected B-mode polarisation patterns in the Cosmic Microwave Background Radiation (CMBR). If this claimed had held up these patterns would have been the ‘smoking gun’ for Inflation.

If the universe had experienced a short and intense burst of inflation very early in its evolution, this would have imprinted a signal on the CMBR that could be detected today by measuring patterns of polarisation across the sky. These are the B-mode patterns that the BICEP2 team thought they had found.

Further investigation revealed that it was just intervening interstellar dust that was detected, mimicking the shape and direction of the B-mode patterns. Subsequent studies and observations have so far failed to detect any clear cut evidence of these patterns in the CMBR.

So, inflation remains to be clearly supported by any significant body of evidence.

It promises much, appears to solve much and the math seems to work. But as we all know, without actual data and evidence, it cannot be according any other status than theoretical. Evidence is the anvil upon which theorems are forged or broken. But without an anvil a theorem can neither be broken or forged.

Thus, Inflation currently lives in the grey area of being our ‘best guess’ according to insufficient evidence.

Thank you,

Walter.

[Walter]

Now we move on to what I thought was going to be the last post I’ll make about Inflation theorem – how it is usually misunderstood by Christian apologists.

For the sake of clarity, I must first point out that Young Earth Creationist Christians do not make apologetic arguments about Inflation theorem. Theirs is an across-the-board denial of any science that contradicts their literalist reading of the Bible. As such Inflation is just lumped together with astronomy, cosmology, geology, genetics and evolutionary biology as the work of the devil, designed to make people go astray from the truth, which can only be found in the pages of scripture.

Leaving these blinkered, anti-science zealots aside, the Christians who do try to incorporate Inflation theorem into their apologetic arguments are Old Earth Creationists. They accept that the universe is 13.8 billion years old, that the Earth is 4.5 billion years old and evolution is real. But some of them try to claim that humans are some kind of ‘special creation’ delivered by the hand of god and not by the blind workings of evolution.

However, in this thread we need only concern ourselves with how these OEC Christians try to grapple with Inflation theorem and use (misuse) it to make misguided arguments to validate their beliefs.

The main thrust of most OEC apologetics is to use the Big Bang as the gap into which to insert God. Because there are so many unknowns about this event and because it appears to line up with Genesis 1:1, the Big Bang is a prime target for Christian apologetic arguments. However, even from get go a major problem rears its ugly head and so is usually ignored, glossed over or downplayed by the apologists.

Science is a strictly agnostic discipline that can say nothing at all about any religious or theological matters. The science of the Big Bang is therefore the same for a scientist who happens to a Christian and one who happens to be a Muslim. Or a Jew or a Hindu or a Sikh or a follower of any religion. As such, since science cannot and does not identify which God might have been the cause of the Big Bang, any religion can coopt the scientific data and claim that their God did it. That their god is the creator.

This means that, for instance, any follower of the Abrahamic monotheisms can claim that Allah or Jesus or Yahweh was the creator – all with equal authority. So instead of Big Bang cosmology pointing unequivocally to a specific god it simply levels the playing field, making any creator a candidate for the job.

Knowing this, the apologists are therefore obliged to make a two-stage argument for their particular god and hope that nobody notices the join between the different parts. The first stage is the science and the second stage is an act of faith on their part, where they claim that it was their god who did it.

But this is an unworkable union between two totally different things.

Science doesn’t employ religious faith; it relies upon evidence. Christianity doesn’t rely on evidence; it relies upon faith. So an apologetic argument that tries to bring together these mutually exclusive things is doomed to fail from the outset.

But no apologist ever mentions this problem. Perhaps they don’t even realize that it is one. A fatal one that sinks their argument even before it leaves the harbour.

Perhaps the second major problem concerning Christian cosmological apologetics is the widespread misunderstanding of how the science of the Big Bang has evolved over the last half century. Many, if not most apologists are stuck in the false belief that the current model of Big Bang cosmology requires an initial singularity as the origin of all of space and time.

This outdated, refuted and discarded scientific model lines up nicely with Genesis 1:1, allowing the apologists to claim that the Bible describes the Big Bang in it’s first verses. But, as I have been at pains to demonstrate, in this thread and in the previous one about Singularity theorem (The Big Bang : A Universe from Nothing?) that is simply not so.

However, this idea still persists in Christian circles, still does the rounds in Christian forums and still crops up when evangelising Christians come to forums like this one, determined to show us that science ‘proves’ that their god is the creator.

Now, I had intended that this be my last posting in this thread, but further thinking has lead me to believe that there are two more items that I should address. The first will be an illustrated explanation of how diagrams illustrating the Big Bang are usually misunderstood, not just Christian by apologists, but also by the public in general.

The second will be how a certain Christian apologist tries invoke a certain scientific theory to justify his claim that, even with Inflation theorem, there must have been a beginning. A beginning into which he can shoehorn the god of the Bible.

I will demonstrate where and how he is wrong and also how, by using this specific theory, his own argument comes back to bite him. Hard.

[Walter]

[Walter]

Above is a typical diagram used in popular level publications to illustrate the evolution of the universe from the Big Bang up until the present day.

But no such diagram would be used among cosmologists. They know full well that it is so simplified and takes so many liberties with the evidence that it is not fit for their purposes. This is an important point. Such diagrams play no role in the actual cosmological science of the Big Bang. Instead, they are simply a convenient means of outreach to the public. A way to convey something of the complex and counter-intuitive physics that underpins our current models of the origin of the universe. Nothing more than that.

But this essential point often goes unnoticed or misunderstood by many Christian apologists, who look at the diagrams and naively believe that they depict the Big Bang accurately. But this is not so. No more than the simplified diagrams of the human brain do full justice to the complexities and subtleties of what actually happens inside the cranium.

Moreover, the flat, two-dimensional surfaces of books, magazines and computer screens where such Big Bang diagrams are seen are ill-suited to the task of effectively communicating what is happening in three-dimensional space. Cartographers and map-makers have a similar problem to overcome. They are trying to show the three-dimensional shape of the land by using contour lines and colour gradients. Handy tools to make up for the vertical dimension of height and depth that has been lost from their flat, two-dimensional maps and charts.

So, all in all, what we see above is NOT the reality that Big Bang cosmology describes. It is NOT what cosmologists declare to have happened. It should NOT be taken as accurate and it should NOT be taken as gospel, pun intended. The diagram above is a kind of visual shorthand, only representing and standing in for the real description itself. That real description of the Big Bang and the evolution of the universe can ONLY be accurately described using the mathematical equations of Quantum Mechanics and General Relativity.

Having covered what the diagram is not, it now falls to me to try and describe what it is.

It should be read from left to right, with the oldest and most ancient events, earliest in the universe’s evolution happening furthest to the left. The arrow of Time points to the right, towards the present day.

One vital point that should be understood and applied to the diagram is that the increase of size seen to happen from left to right is NOT intended to show an increase in the overall size of the ENTIRE universe. The true nature of the overall shape and size of the entire universe is unknown and is probably unknowable.

No. What is being shown here is the increase in size of the OBSERVABLE UNIVERSE. Only that part which we can see. Not the whole, which we cannot see. This is done because the size of the observable universe can be known by… observing it.

Another area of great misunderstanding is on the extreme left of the diagram. What looks like an explosion giving rise to a sharply pointed cone of space that swiftly opens out, increasing greatly in diameter. The naïve Christian apologist will say, “See? That’s the initial singularity. A point of infinite density from which all of space and time originate.” And they will be wrong.

If this diagram only shows the observable universe, then this cone cannot be all of space and time emerging from the initial singularity. Furthermore, this diagram illustrates Inflationary cosmology and in that model of the universe’s origin, there is no initial singularity. So that’s the second count where they are wrong.

Where they are tripping up is that they don’t’ understand that the illustrators CANNOT show what actually happens in inflationary cosmology in a diagram like this. When inflation occurs, every point in space moves away from every other point. What doesn’t happen is every point moving away from a central point, which is what you would see in any normal explosion.

It’s next to impossible to visualise this in the mind’s eye and totally impossible to show it in a diagram. So, the illustrators are obliged to take liberties with the theorem and to simplify what it says, changing it from something that cannot be drawn into something that can. What’s the simplest and easiest way to do this?

Draw an explosion and show the observable universe as a narrow cone that rapidly grows from a point-like source.

This is not accurate, but it does convey the basic message in an easily-understood way. And isn’t that what diagrams are for? Not to give a full, accurate and complete understanding of something but to give a simplified and easily-comprehended summary of it.

So, having outlined the major areas of confusion that catch most people out, the rest of the diagram should be easy to understand. Provided that we remember that what is being shown there applies only to the observable universe and not to the entire universe.

Moving from left to right the universe evolves over time. After a brief interval the narrow cone enlarges abruptly, widening out dramatically as the universe is inflated by the energy field I’ve described earlier in this thread. Then, just as abruptly, this massive surge of growth halts and a more sedate kind of expansion takes over.

The red zone stands for the early epochs when the temperatures were too high for molecules to form. The abrupt change from red to dark purple signals the time when the temperature fell enough for simple molecules like hydrogen and helium could form. The change to pale mauve is meant to show those gases being lit up (ionised) by the light of the first stars. Finally, the universe becomes a uniform deep blue colour. This represents the cold universe where galaxies formed, leading to planetary systems like ours and eventually to us.

The Americas are not shown well on the globe of the Earth, but Africa and Europe are well seen. If we could zoom in deep enough you might be able to see me looking back up at you through a pair of binoculars on a tripod. (Waves!)

But why does the observable universe form a kind of elongated bell-like shape, with its open end flaring out widely like that?

Once again, this is another trick used by the illustrators. To show something about the expansion of the universe that was discovered in 1998. Two separate science teams found that the expansion of the universe, instead of maintaining a steady rate or slowing down, was actually speeding up. This accelerated expansion is shown by dramatically increasing the diameter of the observable universe, far more than it’s steady rate of expansion during the red, purple and mauve phases.

The open end of the universe is left open like this for two reasons. First, because the diagram only covers the past evolution of the universe and stops at today, saying nothing about its future. Second, because it is unknown if the current period of accelerated expansion will continue, fade away or accelerate further.

I hope that this post has covered the purpose and meaning of Big Bang diagrams. Most of them will be much like this one, making much the same simplifications, taking much the same shortcuts and differing largely only in the details. I also hope that I’ve successfully shown how Christian apologists misread and misinterpret diagrams like these.

As usual, if you have any questions about what I’ve written here, please ask them and I’ll do my best to answer them.

Thank you,

Walter.

[Walter]

The Christian apologist William Lane Craig is listened to by many Christians because of his apparent ability to demonstrate that science agrees with scripture, or more specifically, that the science of cosmology validates and justifies the Christian faith, because it agrees with Genesis 1:1.

In my previous thread I demonstrated how Craig failed to do this by trying to argue that the Hawking – Penrose Singularity theorem of 1970 ‘proves’ that all of space and time must have had a beginning. However, it might be worth quickly recapping that thread to put what I have to say in this thread into its proper context. Listed briefly, here are the ways in which Craig failed.

1. The H – P theorem was falsified by new evidence in 1998 and has since been discarded by both scientists and the rest of the scientific community as not applying to our universe.

2. The H – P theorem uses only General Relativity in its equations. But a proper description of the origin of the universe must also factor in Quantum Mechanics. Because the theorem in question doesn’t do this it could only ever be a partial and incomplete description of cosmic origins. Therefore, Craig was premature in claiming that it was a ‘proof’ of how the universe came into being. Proofs must be complete, absolute and final, otherwise they are not proofs in any sense of the word.

3. The initial singularity that resulted from Hawking and Penrose’s equations is not a description of all of time and space emerging from an initial singularity of infinite density. Instead, this singularity marks a breakdown in General Relativity’s ability to describe what is happening. So, a more accurate way of putting it would be to say that the H – P theorem is describing all of time and space emerging from something the General Relativity cannot describe. Yes, the theorem itself is a mathematical proof of this, but once again, a proof must be complete, absolute and final. Because the H – P theorem contains something that its own math cannot describe it cannot be called a proof in the sense that Craig is using the word.

So, confident that he can argue that cosmological science agrees with scripture, Craig continues to tout his argument to this day. Even though he is demonstrably wrong.

With the advent of Inflation theorem in the late 70’s and early 80’s the science of theoretical cosmology changed, requiring Craig to change with it. So, when Arvind Borde, Alan Guth and Alexei Villenkin wrote a paper on Inflation theorem in 2003, Craig seized upon it, because it seemed to show that even an inflationary universe requires a beginning.

https://en.wikipedia.org/wiki/Borde%E2%80%93Guth%E2%80%93Vilenkin_theorem

If the cosmos had a beginning, this was the gap Craig could shoehorn his god into.

However, as I’ve just pointed out in this thread yesterday, science is an agnostic discipline and so can say nothing about any religious or theological issues. Therefore, the Borde – Guth – Villenkin theorem (hereafter, the BGV) can likewise say nothing about religious matters.

Because it does not and cannot identify which god caused Inflation, any creator god could have done it. Not just Allah or Yahweh or Jesus, but any creator god. This problem for Craig now exposes a fatal flaw in his argument.

He is claiming, on the basis of what the BGV says, that is was the god of the Bible who initiated Inflation and created the universe. But because the science he uses to make that claim doesn’t and can’t declare that this is so, Craig’s claim comes not from what the science actually says but what his faith tells him is true.

So his argument is dead from get go. Science doesn’t use faith, it uses evidence. Religious belief doesn’t use evidence, it uses faith. You can’t conjoin these two disparate things in any way shape or form into any kind or workable argument.

Craig himself confirms what I am saying here.

https://www.youtube.com/watch?v=2C3T17aKPCI

In the first half of this short video, he lays out the Christian position on faith versus evidence. According to him faith always trumps evidence and where the evidence appears to contradict faith, a Christian should always go with faith rather than with the evidence.

Now, if that’s true, why do Christian’s need evidence at all? The Bible itself exhorts them to believe without evidence. That being so and there being no need of evidence in Christianity, Craig’s use of cosmology to support Christianity is not only unworkable, its also superfluous.

So superfluous that if he were shown that cosmology doesn’t support Christianity, he’d probably reject it. He’d probably do what he encourages other Christians to do in the video. That is, to ignore the evidence and to listen to the inner witness of the Holy Spirit speaking to his heart, telling him that it does.

This kind of wilful close-mindedness to evidence is the antithesis of the necessary open mindedness required in science. Another indicator of how Craig’s attempt to join faith and science into an apologetic argument cannot work. There is no overlap between faith and science and no amount of hand waving will change that.

Craig’s rejection of evidence over the witness of the Holy Spirit might also explain why he continues to believe that the long-refuted Hawking – Penrose singularity theorem is still a good apologetic argument for the existence of his god. Despite the overwhelming evidence that it isn’t, he knows in his heart that it is.

Anyway, we must now move on to examine the BGV, what it says and what Craig claims it says with regard to cosmic origins. Not here, but in my next posting. This is because the BGV covers an aspect of Inflationary cosmology that up until now, I have left out of this thread. In my next post I will need to start with a quick recap of how Inflation starts, what it does and how it comes to an abrupt halt. Then I will explain how, even though Inflation stopped in our universe long ago, it is theorised to still be inflating other universes… elsewhere.

Thank you,

Walter.

[Walter]

Inflationary cosmology has a trick up its sleeve.

One that I haven’t mentioned before now for fear of over complicating things. Thus far I’ve confined myself to describing only what has happened within the confines of our observable universe. However, while the Inflaton field decayed rapidly in observable universe, the theorem and the maths predict that the field does NOT decay elsewhere. Elsewhere, as in regions far, far beyond the limits of what we can see.

Inflationary theorem posits that once a quantum fluctuation gives rise to the Inflaton field, it then continues to expands a volume of space at a rate many, many times faster than the speed of light. Certain regions of the Inflaton field then become unstable and decay, creating discrete regions that undergo their own hot Big Bang. Our universe is just one of those regions.

Did you see what I’ve done in the paragraph above?

I’ve stopped referring to the decay of the Inflaton field in the singular and started talking about it in the plural. Not ONE hot Big Bang caused by the Inflaton field decaying into thermal energy, but MANY. Not ONE Big Bang, but MANY.

The volume of space inflated by the Inflaton field grows exponentially and never stops growing. Within that volume, many separate regions just like our observable universe are birthed by the spontaneous decay of the Inflaton field, giving rise to an exponentially rising number of such regions.

So, while there was just one quantum event that started the Inflationary process off and its energy creates an ever-growing volume of space, which is the entire universe, within this volume are regions that each undergo their own hot Big Bang, each ending up as it’s own observable universe for whatever observers happen to populate it.

This description of a single universe birthing many regions that each undergo their own hot Big Bang is exactly what is being described in the science paper I mentioned in my last post, the Borde – Guth – Villenkin or BGV.

https://en.wikipedia.org/wiki/Borde%E2%80%93Guth%E2%80%93Vilenkin_theorem

So when Craig uses the theorem in his apologetic arguments he has to be talking, not just about the origin of our observable universe, but also about the origin every observable universe birthed by the Inflationary process. Not just one and not just ours, but ALL of them.

He has no choice in this. That’s what the BGV theorem is all about. As mentioned in its introduction.

Introduction.—Inflationary cosmological models are generically eternal to the future. In these models, the Universe consists of post-inflationary, thermalized regions coexisting with still-inflating ones. In comoving coordinates the thermalized regions grow in time and are joined by new thermalized regions, so the comoving volume of the inflating regions vanishes as t =1. Nonetheless, the inflating regions expand so fast that their physical volume grows exponentially with time. As a result, there is never a time when the Universe is completely thermalized.

Or, in plainer language and in more popular terminology, this theorem is talking about an Inflationary Multiverse. Each post-inflationary thermalized region equates to one of the bubble universes shown in this illustration. Our observable universe is just one of the very many (trillions?) of such regions. Purely theoretical, of course and without any hope of directly detecting these other regions, probably pure speculation too.

Here is an artist’s impression of such an Inflationary Multiverse.

Please note that this image is in no way scientifically accurate. It’s just a guess about what is theorised to exist out there. Also, please don’t go thinking that each bubble corresponds exactly to the volume and size of our observable universe. Being approximately 100 billion light years in diameter. No. Our observable universe would probably be no bigger than a single pixel in one of these bubbles, on the scale of this image.

Anyway, since Craig appeals to the BGV theorem in his apologetic arguments, he has to own what it says. All of it. He can’t just cherry pick what he wants from it and ignore the rest. He can’t just select the part of the theorem that says that the Inflationary process must have a beginning and then deselect everything else. Whatever the BGV says about an ongoing, ever-growing Inflationary Multiverse also applies to Craig’s apologetic argument for god being the cause of the Inflationary process.

To cherry pick from the BGV wouldn’t just be Craig arguing in bad faith it would also be inconsistent of him to do so. In his previous apologetic argument using the earlier Hawking – Penrose Singularity theorem he accepted all of that theorem, even if he didn’t understand the full implications of it, which were left unmentioned by those two scientists. You can’t go all in on one theorem and then cherry pick from another if you want to be taken seriously. That’s inconsistent.

So, by trying to find a beginning in Inflationary cosmology where he can insert his god Craig has no choice but to incorporate the entire Inflationary Multiverse into his arguments.

Oh dear. That’s bad for him. Very bad indeed.

Why? Because if he also uses the Fine-Tuned Universe argument to claim that our observable universe was intelligently designed by the god of the Bible, then he’s making a supernatural claim. Not a natural one. He’s claiming that a supernatural agency finely tuned the constants and conditions within the observable universe to make it life-friendly and possible for us to exist.

That argument might work if he were claiming that one and only one universe exists. Then he could claim that because there is no natural mechanism for fine-tuning it must have been done supernaturally. But, if Craig were to promote a theorem where a natural mechanism for fine-tuning could exist, then he can’t viably claim that it was done supernaturally. There’s no need to invoke the supernatural to explain something if there’s a viable natural explanation for it.

And guess what? There IS such a mechanism in the BGV. The very theorem that Craig uses to claim that Inflation must have had a beginning.

An Inflationary Multiverse, as predicted in the BGV, would contain untold trillions of regions like our observable universe, each one having undergone its own Big Bang. It’s an integral part of the Inflation process that the conditions inside each region are decided randomly. On the basis of pure chance.

Many such regions will be sterile because the physical constants operating within them are not life friendly. But others will be. And as time marches on and the number of such regions increases exponentially, the number of life-friendly regions will increase proportionally too. There will be billions upon billions of life-friendly regions, some with exactly the same physical constants as our observable universe. If you wanted to you could look at the artist’s impression and consider that the different colours of each bubble correspond to the different arrangement of physical constants operating within them.

A vitally important point to remember when considering these crazy numbers is that we cannot know if our region was the very first created in the Inflationary process. It may have been – in which case we will know that the process has been running for at least 13.8 billion years. Or the process may have been up and running for billions of years prior to our region being birthed by it.

Any way you cut this, an Inflationary Multiverse such as the one proposed in the BGV creates more than enough regions to act as a natural mechanism for Fine-Tuning our region. Our observable universe.

That being so, Craig can no longer use the Fine-Tuned universe argument to claim that god finely tuned the unique arrangement of physical constants that we see and that enable us to exist. He’s shot himself in the foot and probably doesn’t even realize it. By embracing the BGV for the beginning it appears to give him he loses more than he gains.

Thus, Inflationary cosmology turns upon him and bites him in the butt. Hard.

Thank you,

Walter.

[mordant]

@Walter

… why do Christians need evidence at all? The Bible itself exhorts them to believe without evidence. That being so and there being no need of evidence in Christianity, Craig’s use of cosmology to support Christianity is not only unworkable, its also superfluous.

Quite so, but of course what he’s doing is trying to deal with the science-curious person whose faith is wavering a bit and would be bucked up by a quasi-plausible argument that science, properly understood, doesn’t or at least needn’t / maybe doesn’t contradict the scriptures. On the other hand, there’s the faith-curious potential convert who doesn’t want to see themselves as an out-and-out luddite, and would get some cover from such arguments.

All he really needs to provide is enough cover to help people adequately manage the cognitive dissonance between science and religious faith of a sufficiently literalist bent. And hope they don’t dig too deeply into either the science, or his arguments.

I’m convinced that last is key: none of this holds up to actual skeptical scrutiny, but it doesn’t really need to, for any given sufficiently faith-motivated believer.

There was this Christian girl who was interested in me right after high school and if I hadn’t fumbled the ball we might have ended up together and my life might have taken a very different path. The gravitational pull of the things that led me out of the faith would have still been there, and at some point depending on how she responded to the implosion of my faith, it’s possible I’d have been faced with the choice between her and unbelief. In that environment, I would at least for a time have found WLC’s “reasoning” a lifeline. It would have postponed the inevitable (which I didn’t know yet WAS inevitable).

I think that’s also why apologists crank out such a Gish gallop of material over time. People are hungry for it and cling to it to avoid the sometimes terrible Hobson’s choices that arise from the loss of faith. In other words their religious faith is most often way more fragile than they let on. They aren’t wrong to see it as under constant assault from multiple directions. The center does not hold.

[Fortunately for me, my prior / late wife that I actually ended up with was somehow not greatly challenged by my budding apostasy despite remaining a believer, so I lucked out there big time. She was concerned for me, yes, but never wavered in her commitment to me or got the notion that she must have fundamentally misjudged my character or improperly assessed who I really was. In other words. she still loved me for who I was rather than for my tribal affiliation. For this, I will always be deeply grateful to her memory.]

[Walter]

Unless there are any questions arising from what I’ve written this post could well be where I draw a line under things and close with a summary.

Inflation theorem appears to offer a coherent and in-depth description of the origin of the Big Bang, but it’s current status is no more than a good best guess about our cosmic origins. What is needed to cement it’s place as our best description of how the universe came into being is a robust body of evidence. We are still awaiting that. Whether we will ever obtain it is unknown.

William Lane Craig’s attempt to create a viable apologetic argument for the existence of the god of the Bible by employing Inflation theorem has failed miserably. On two counts.

1. Inflation theorem identifies a quantum fluctuation in a pre-existing domain as the cause of the Inflationary process. Quantum events like this are considered to happen spontaneously, without the need for any external natural cause. Craig does not accept this, asserting that a supernatural external cause is needed to initiate the Inflationary process. He further asserts that this supernatural cause is the god of the Bible. However, he makes that connection and that assertion, not on the basis of any evidence from Inflation theorem itself, but on the basis of his Christian faith. His argument is therefore an unfeasible mixture of scientific evidence and religious faith. It violates the workings of both science and religion. Science employs evidence and does not use faith. Christianity employs faith and does not use evidence. Thus, both parts of Craig’s argument are in opposition to each other, mutually exclusive to each other and cannot work with each other. They are chalk and cheese. His argument therefore fails.

2. The Borde – Guth – Villenkin theorem of cosmic Inflation (the BGV), which Craig relies upon in his argument, is a theoretical description of, not just one region like our observable universe, but of many. So many that it naturally solves the question of the apparent Fine-Tuning of the physical constants seen in our observable universe. It does so because the physical constants inside each inflated region are decided upon randomly, by the workings of chance as described by quantum mechanics. Therefore, with a sufficiently large number of inflated regions a significant number of them will inherit a life-friendly set of physical constants, just as our region has. So, the Fine-Tuning we see in our region is naturally explained by this entirely physical mechanism without the need to invoke anything supernatural. This means that Craig fails twice. In attempting to use the BGV to make a convincing argument for god being the first cause of the Inflationary process he inadvertently destroys his ability to use the Fine-Tuned Universe argument for the existence of god. A double own goal.

Thank you for your attention.

Walter.

[Get_off_my_lawn]

Thank you for your effort here, @Walter, it is much appreciated . Do not mistake the silence here for lack of interest or lack of attention. I guess it is more because there is not much else to say, and not really anything to oppose against . For the moment, we do not have any creationists in here to use it against, but when one comes along and brings up these topics, I’m quite sure they will be used. Again, thank you for your effort.

[Walter]

Thank you Get_off_my_lawn.

Perhaps my only (slight) regret about creating a thread like this is the complexity of the concepts involved. It sometimes means that there’s a lot of work to do bringing a Christian apologist up to speed on cosmological matters before a proper debate on the issues can ensue.

Thanks again,

Walter.

[Get_off_my_lawn]

@Walter

there’s a lot of work to do bringing a Christian apologist up to speed

It’s the same all over the line, from the naive christian believer, via the more aggressive apologists and pseudoscience promoters (flat earth, creationism, etc.) to conspiracy theorists. They all lack a basic understanding of what they oppose. Thus, it takes a lot of effort to explain basic facts to them. Been there, done that. Some years ago on another forum, I participated in quite lengthy and exhausting threads against flat earthers, creationists, and numerologists. Regarding making information stick, these people seem to be the fact-resistant version of teflon-coated. No matter how many times one correct their provable mistakes, they keep on repeating them like nothing happened. For example, one flat earther kept on cheating by misquoting Michelson/Morley to discredit the experiment. So I found the paper (scanned pdf version of the original paper), found the quote, and pointed out that they left out part of a sentence to make the meaning change. Called him out on it several times, but although he stopped using the actual quote, he kept on using the implication of the quote cheating.

[Sheldon]

@mordant

All he really needs to provide is enough cover to help people adequately manage the cognitive dissonance between science and religious faith

Indeed, and course they never really subject their religious beliefs to anything approaching objectively critical scrutiny, so why wouldn’t they re-imagine science in the same fashion when remotely undermines their core beliefs.

Or as an apologist once said to me, “You don’t understand that god is cleverer than science.”