Talk:Cosmic inflation

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Stopped expansion, what?

What proof do they have that there are regions that are not inflating? How can they say that anything has stopped inflating? They can tell by redshift that there is inflation. To say that parts have stopped inflating goes against all the evidence. --Neptunerover (talk) 02:05, 27 December 2009 (UTC)

Inflation and expansion are two different things. The inflationary period as postulated was very breif and involved remarkably rapid exponential expansion of the universe such that it increased in volume by a factor of at least 10^78 in a tiny fraction of a second. Since then it has gone on expanding but not inflating in an exponential manner. --LiamE (talk) 14:54, 30 January 2010 (UTC)

Thank you greatly for clearing my confusion on that. I was equating the two words. --Neptunerover (talk) 14:58, 30 January 2010 (UTC)

You're welcome. --LiamE (talk) 15:01, 30 January 2010 (UTC)

Looking back over this question I think the first paragraph of the introduction should be rewritten to make the distinction between infaltion and expansion clearer. I think some reference to the very breif time period and vast exponential volumetric increase should both be noted. Anyone fancy having a go? --LiamE (talk) 21:09, 28 May 2010 (UTC)

Maybe? - 2/0 (cont.) 06:56, 29 May 2010 (UTC)

Yep I think that's the sort of intro the article needs. It is easy for editors with prior knowledge of what is being talked about here to miss the need for clear and concise explanation of the theory in the lead. The earlier question by Neptunerover highlighted the previous lead's shortcomings. My only concern now is it is hard for someone with a good scientific grounding let alone a lay man to visualise just how big a 10^78 expansion is and how short a timescale 10^-30ish seconds is but that is not for the lead here. --LiamE (talk) 11:24, 29 May 2010 (UTC)

Big bang?

Certainly there is substantial evidence of cosmic expansion, but what is the evidence restricting this expansion to only empty space? I mean, to say something is not expanding is like saying that it's not a part of the universe. The Earth is expanding underneath us while we all and everything around us expand as well. Considering its size though, the earth expands quickly in relation to us, so gravity, right? It seems they're trying to make this expansion be relative to some fixed point, but that leads back to a big bang which mathematically has been shown not to work. --Neptunerover (talk) 03:48, 27 December 2009 (UTC)

Oops, I was trying to put this section on the science help reference desk. I did that too now, so this may be redundant. --Neptunerover (talk) 03:59, 27 December 2009 (UTC)

The Horizon Problem

In this section, it says "they move apart from each other faster than the speed of light—thus have never come in to causal contact" I believe this is wrong: that the regions are moving apart faster than the speed of light is not the criterion that determines whether or not they have ever been in causal contact. It is that each is beyond the other's particle horizon. (See the article "Cosmological horizon".) If no-one objects, I shall amend this phrase appropriately. Dendropithecus (talk) 00:57, 8 January 2010 (UTC)

Being beyond the horizon is the same as saying "moving apart faster than the speed of light", just less colloquial.Likebox (talk) 04:14, 8 January 2010 (UTC)

Can you explain? I don't get it! Unfortunately, I'm a mathematician, not a cosmologist, though I am now teaching myself cosmology through Wikipedia's pages.

As I see it, the particle horizon depends not on the objects' current relative velocity but on the history of a photon that left one of them some time in the past, as indicated in the article "Cosmological horizon". Depending on the past form of the amplification function a, I deduce that it's theoretically possible for two objects to be moving apart (at the present time) at less than the speed of light, yet still be beyond each other's particle horizons or, on the other hand, for them now to be moving apart at more than the speed of light yet still be able to receive light from each other's past existence.--Dendropithecus (talk) 13:20, 8 January 2010 (UTC)

As briefly as possible, the argument goes like this:

At time t in co-moving coordinates, the velocity of a photon is c/a(t).

In a short time dt, a photon will travel a co-moving distance dx = c*dt/a(t)

The co-moving distance the photon moves from time t=t0 to t=t1 is the integral, between these limits, of the quantity c*dt/a(t).

--Dendropithecus (talk) 14:41, 8 January 2010 (UTC)

You are right--- it depends on what the phrase "current relative velocity" means. To be beyond the horizon means that particle number one currently observes the velocity of particle number two as "greater than the speed of light". It's sort of a heuristic. The notion of now is defined as the past light cone of one of the particles.

The slowing down of particles in normal cosmology means that if you use global time slices to define a global notion of time, then the current velocity of the particle might now be less than the speed of light.

It helps to keep a physical point of view which is horizon-centric. The particles which are in view are those inside the cosmological horizon, and the particles which are out of view are outside the cosmological horizon (or squashed very close to the surface of the cosmological horizon in a pure classical picture). The reason one should focus on horizons is because of the holographic principle--- this is essentially the right way to view general relativity.

Sorry for the terseness--- if you could clarify what is the confusing point I might be able to address it more directly.Likebox (talk) 18:56, 10 January 2010 (UTC)

Thanks for being so patient with me. I'm a bit tied up at the moment & I've only just found time to look at your comments, for which many thanks. I shall come back to you when I've had more time to think about the points you've made. --Dendropithecus (talk) 00:37, 12 January 2010 (UTC)

Please excuse the delay. There are a still a few points I don't understand, as well as some I believe I do.

It seems you are suggesting an observer-centric viewpoint, which is equivalent to an anthropocentric viewpoint with the proviso that an observer situated anywhere else in our global time-slice would see a similar picture. Is this correct?

I also understand that anything we can see at any instant must have been on our light cone at that instant. Any object (if any), that remained on our evolving light cone while appearing to be receding from us at the speed of light, would have a total red-shift, i.e. the incoming photons would have zero frequency, hence zero energy, hence no photons, so the object would be invisible to us (objects just within this limit being barely visible).

I'm not sure what you mean by "a sort of heuristic" (A learning process?), nor of the term "horizon-centric".

I've heard of the holographic principle but I don't appreciate its significance.

As I understand it, general relativity must be (and is) involved in choosing or designing a model for the expansion of the universe that is consistent with Einstein's field equations. Having chosen such a model, I can't see why, on the large scale, we subsequently need anything other than coordinate geometry.

Am I right in thinking that, when you refer to the cosmological horizon, you mean the limiting outer surface of the non-Euclidean 3-space of what we can see, and is this is equivalent to the (evolving) surface in our instantaneous light cone on which we deduce that co-moving objects would appear be moving away from us at the speed of light?

I am troubled by the fact that my maths consistently show that there can be no co-moving point on our evolving light cone that appears to be moving away from us at (or greater than) the speed of light. I presume there is evidence for the existence of such places? If so, then there must be something wrong, if not with my calculations (possible, but unlikely), then with some assumption(s) or hidden assumption(s) I have made. I should be grateful if you could tell me what!

The main two assumptions I am aware of are that the distance of an object on our light cone is c times the time taken for light to traverse the space between us and the apparent velocity of the object is the rate of change of this distance, as seen by us (the observer).

Another problem is that I've read that the red-shift can be explained by the evolution of the metric. I can't, however, see how the metric could evolve so as to reduce the frequency of light to zero. Wouldn't this imply an amplification factor of zero at the source? --Dendropithecus (talk) 23:27, 19 January 2010 (UTC)

Is it not the case that, in the Lambda-CDM model, in terms of real distance and global time, distant objects are currently accelerating away from us, not slowing down? --Dendropithecus (talk) 02:15, 20 January 2010 (UTC)

(On second thoughts, please ignore that last paragraph.--Dendropithecus (talk) 02:16, 24 January 2010 (UTC))

I should be quite grateful if you could point out any errors in anything I've said. I apologise if I sound adversarial - that's not the intention. I'm just trying to find some resolution to the disparity that appears to exist. --Dendropithecus (talk) 01:25, 24 January 2010 (UTC)

(deindent) I read your comments--- you are OK with most things, except for the horizon business. The way to get intuition about infinite red-shifts is to start with a black hole solution--- there you have a metric which has the form (1-2m/r)dt^2 + spatial. The zero at r=2m in the dt component means that a signal is infinitely redshifted from the r=2m horizon to an observer at r=infinity. This means that time seems to stop at the horizon, in external coordinates, and all things as viewed from the outside freeze at the horizon. There is an infinite redshift at a finite distance.

This effect of infinite redshift is observer dependent--- if you fall through the horizon, you don't see anything peculiar happen. The observers that see infinite redshift are those that are outside the black hole. The mushing up of things near the horizon is an artifact of the mathematics--- you don't have an infinite collection of layers of stuff on the surface of a black hole. The cut-off is quantum mechanical, and the principle which governs how to fix the description of horizons so that they don't pile up layers forever is called the holographic principle. The holographic principle is the only known way to make sense of the external description of a black hole. It cuts out the interior, and tells you that the black hole is described just by the stuff outside the horizon, heuristically (meaning not rigorously) you can imagine that there is a planck-scale thin skin around the black hole, and there is nothing going on inside this skin.

Cosmologically, you should start with the DeSitter solution. It's (1-lamda/3 r^2)dt^2 + spatial. This has a zero at a big cosmological distance R. If you trace light rays from r=0, the light rays that reach r=0 come from r<R. Any r greater than R is not in causal contact. This is the example of a metric which has the properties that you want. The form of the metric is on this page, or on the de Sitter space page.

Now imagine adiabatically starting with de Sitter space, and slowly shrinking lamda. Then the cosmlogical horizon distance R slowly gets bigger, and new objects come into view. If lambda drops to zero, the universe begins expanding according to FRW. This process is heuristic, because where are the new objects which come into view as R gets bigger coming from? If you trace back their paths, they come from beyond the horizon. But it's not clear that this is right holographically, because from your point of view there is nothing outside the horizon, just as there is no black hole interior.

When the cosmological constant is negligible (in the early universe, when the matter density is bigger), lambda-CDM looks just like FRW, so you couldn't tell there is a cosmological constant. Later on, when the density of matter falls, the cosmological constant starts to dominate, and the universe starts to inflate again (meaning to expand exponentially at the much slower e-folding rate of the current cosmological constant). I know that the crossover is happening now-ish, and this is how Weinberg predicted the cosmological constant from the anthropic principle. He said, the cosmological constant is only small because we need to be here to observe it. That means it should by just this small, and not much smaller, so that we should be transitioning from cold-matter dominated to lambda dominated just about now, and this is what we see.Likebox (talk) 06:44, 24 January 2010 (UTC)

Many thanks, L. I have read your comments, but they will take some time to digest, especially the de Sitter space. So far I have only two comments:

The fact that we can't see something doesn't imply it doesn't exist.We know a black hole has an interior because we can detect its gravity, & we can deduce some properties of the contents, although we cannot see them.

I've read somewhere that the (apparent) discontinuity at a black hole's event horizon may be smoothed out by a change of co-ordinates. Are you familiar with this? Meanwhile, I shall check the few texts I have. --Dendropithecus (talk) 02:53, 26 January 2010 (UTC)

Am I right in thinking that there's a school of thought that says that anything outside our current light cone doesn't exist yet, so in a sense it doesn't exist at all or, perhaps, since it cannot influence us, we may assume it doesn't exist? --Dendropithecus (talk) 03:17, 26 January 2010 (UTC)

About the existence of the black hole interior--- yes, there are coordinates the continue into the interior, and an observer that falls in will see the interior. The main result of holography is that there are two ways to describe the infalling observer. One way is from the infalling point of view, where the observer crosses the horizon and then something happens when it gets close to the center. The other way is to describe only the exterior, and then the observer is encoded in a complicated way in the vibrations of the black hole horizon.

What I am telling you used to be speculative in the eighties and early nineties. But there is now a model black hole, the d3 brane in type IIB string theory, where we have a good handle on how to describe the objects which are close to the black hole. They are described by an ordinary quantum field theory in 3+1 dimensions. That's the surface oscillations of the black hole. There are six (N by N matrix valued) scalar fields in the theory which have an immediate interpretation as the shaking of the black hole in the remaining 6 dimensions of space (this is string theory), there is a gauge theory which represents the exchange property of the N micro-black holes that make up the full black hole (when it is classical, there are N microscopic black holes right on top of each other with N large, and the gauge group is SU(N)) and there are Fermions which enforce supersymmetry, which is believed to be required so that there are flat moduli which correspond to the black holes sliding around freely.

These black holes are charged, and they are maximally charged, meaning they have just enough charge so that they neither attract nor repel, the gravitational attraction is balanced by the (analog of) electrostatic repulsion. To describe a less extreme black hole, you set the field theory at temperature T. This description is by now folklore, and it is called the AdS/CFT correspondence. Holography and AdS/CFT provide a general framework for understanding all the different forms of string theory, and this principle and its matematical realizations are, in my opinion, the most significant advance in physics since the discovery of quantum mechanics, if not ever.

The question of whether something exists is philosophical. The stuff outside our light cone is invisible to us even in principle, so the question of whether it should be thought of as real does not normally have observational consequences, so you are free to think as you like. I believe, along with many people, that the holographic description of black holes makes it seem likely that there will be an interior-only description of the universe which will not make reference to anything outside the light cone. However, this leads to some paradoxes related to the finite area of the cosmological horizon. Banks points out that the area of the horizon is the number of states in the universe, and the area is growing, and that seems to suggest that the Hilbert space is growing, but that's impossible in a normal quantum theory. There is no good theory of string theory in De Sitter space quite yet.Likebox (talk) 04:00, 26 January 2010 (UTC)

Thanks again! That really does give me something to think about! I've borrowed a copy of "The Road to Reality" from my local library, which gives me even more to think about. It does, however, quote the Eddington-Finkelstein metric, which an example of the metrics mentioned above. I think this shows that the singularity at the event horizon is just an artefact of the observer-based co-ordinates, which is what I think you have said, only in different words.

Whilst looking at the various mappings and embeddings, I can't help thinking that none of these alters the fact that, whatever exotic space the mapping is embedded in, what we end up with is still just a mapping of our 3 space co-ordinates and 1 of time. In other words, all these are just different ways of looking at the same object. Giving the sheet a small non-zero thickness or supposing it to be formed of sintered granules or knitting (as it may be) doesn't change the fact that, on the larger scales, light must find its way through it at the same constant velocity. Put another way, what I'm saying is that, at scales that are large compared to the granularity of space-time (or the folded extra dimensions), but small compared to the radius of curvature, we can always find an inertial frame in which the metric approximates to that of special relativity.

In the article "de Sitter Space", in the section "Static coordinates", the author has written:

" .. In these coordinates the de Sitter metric takes the form:

"$ds^{2}=-\left(1-{\frac {r^{2}}{\alpha ^{2}}}\right)dt^{2}+\left(1-{\frac {r^{2}}{\alpha ^{2}}}\right)^{-1}dr^{2}+r^{2}d\Omega _{n-2}^{2}.$

"Note that there is a cosmological horizon at $r=\alpha$."

But is this right?

If we keep the terms in $d\Omega _{n-2}$ constant, we can see that, as r approaches $\alpha$, small changes in r correspond to increasingly large changes in t. So, although there is a singularity at r= $\alpha$, this corresponds to an infinite value of time. There is, of course, nothing beyond it, but does it make sense to call a singularity at infinite time a cosmological horizon?.

Must go now. Thanks again for your patience. --Dendropithecus (talk) 23:49, 28 January 2010 (UTC)

(The above has been slightly edited -- Dendropithecus (talk) 03:24, 29 January 2010 (UTC))

The discussion of horizons is relatively old, and well understood. To get a clear picture, you should start with flat 2-d Minkowski space as viewed by an accelerating observer. This observers trajectory in space time is t=sinh(tau) x=cosh(tau), and a natural set of coordinates for this observer are the rindler coordinates: x=r cosh(a) t=r sinh(a). In terms of r,a, the metric on spacetime is -r^2 da^2 + dr^2, which is exactly like the polar coordinate metric in flat Euclidean geometry. The one difference is that the coordinates r,a cover one-quarter of the spacetime, the part which is spacelike separated from the origin, and to the right.

You can see from this example that the zero in the da^2 part of the metric, which leads to infinite redshift from the point of view of the eternally accelerating observer, does not mean that there are no other quadrants in spacetime. From this example, whenever a metric locally looks rindler near a zero of the dt^2 part of the metric, then it can be extended past the horizon by "Rindler continuation". people usually call this "analytic continuation", but it has nothing to do with being analytic--- the metric does not have to be analytic for this to work. Rindler continuation says that whenever you have a metric with a zero in the time component, a horizon, you can continue this metric past the horizon by assuming that each point on the horizon is just locally a version of Rindler space, and has three other quadrants which are invisible.

This process produces maximal extensions of solutions of General Relativity. But the current consensus on what these extended solutions mean is murky. For the deSitter example, the solution continues on forever past the cosmological horizon, if you want it to. It is just not clear that this is the correct thing to do from the point of view of holographic physics. This discussion is not directly relevant to cosmology, the same discussion could be had for black holes, or for accelerated observers.Likebox (talk) 06:33, 29 January 2010 (UTC)

I now see I was wrong to suggest that r =$\alpha$ corresponds to an infinite value of time in the "static coordinates" version of de Sitter. This large clanger, for which I apologise, was the result of my having misinterpreted the meaning of the variable r ! More on that later.

I have some problems with your version of the Rindler coordinates, but perhaps I should come back to you when I've had more time to think about them.

Thanks again for your help.--Dendropithecus (talk) 13:07, 30 January 2010 (UTC)

Alternate Theories

Are there any other theorys that explain the expansion of space? For example, is it possible that everything in the universe is uniformly shrinking? If that were so, distant galaxies would appear to be receding as our units of measurement decreased (unknown to us). It would also account for the acceleration of the universe's expansion. The universe would really just be a static size, but as we shrunk, it would appear to grow at an accelerated rate.Broolaf2 (talk) 00:16, 13 January 2010 (UTC)

It would require careful coordination of various physical "constants" if we were shrinking but couldn't notice. And if we can't tell this effect apart from an inflating universe, does it really make a difference?; they would be the same theory. --Michael C. Price ^talk 18:52, 13 January 2010 (UTC)

That makes it sound static. No matter whether inflating or shrinking, it would be the same (static) for an inside observer, but just moving forward in time to get a redshift (maybe). --Neptunerover (talk) 23:40, 19 January 2010 (UTC)

You could just redefine the metre as some fraction of the distance between two suitable co-moving objects. Space, as measured in the new metres, would then always be the same size. This would, however, mean regularly replacing our earthly measuriing instruments. The speed of light would diminish with time, but its frequency would not, unless we also redefined the second. --Dendropithecus (talk) 23:53, 19 January 2010 (UTC)

They don't know what a second is. They might think they know how to measure one, but they don't know what it is. (At least not as far as I can tell). All the cells in our bodies do stuff lightning fast in a second. What's a second to them? How long does a second for us last for them? Is it because of our great mass in comparison to them that our time should be experienced differently? The human measurement of a second should not be universally applied. How many moments are in a moment depends upon how small (or big) you are. The Bible says a day for God is 1000 years for a man. God's a big guy. --Neptunerover (talk) 00:29, 20 January 2010 (UTC)

Earman/Mosterin Nonsense

Earman and Mosterin are philosophers, and their paper is nonsense. The result that deSitter space is unique is supported by perturbation analysis which is so trivial in deSitter space that people don't spend much time on it. The relevant cite is any book on cosmological perturbations, including any modern cosmology textbook.

As far as "fine tuning", it is well known that cosmologists accept that the fine-tuning of initial conditions in the big bang is not ok without inflation, because it sets up the initial conditions so that distant non-connected regions match. With inflation, the conditions become that the inflaton potential should be flat. The second condition is not very restrictive, and is reasonable in many physical models. Earman and Mosterin wrote a bunch of nonsense, which is rejected by all cosmologists. If it is going to be represented here at all, it must be placed side by side with mainstream understanding.Likebox (talk) 05:51, 14 February 2010 (UTC)

If "any book on cosmological perturbations, including any modern cosmology textbook" support your contentions, then it should be effortless for you to include an appropriate citation. Eugene (talk) 19:10, 26 February 2010 (UTC)

Removed non-sense.

Edit: Okay, I'm giving up. I added a detailed explanation here, I added a "statement of purpose" in the end and still Wikipedia moderators are ignoring my edits to the page. I am very disappointed to see some moderators that I cannot even reply to lower the standard of quality of Wikipedia by allowing crackpot material to be inserted in a scientific article.131.215.195.228 (talk) 18:41, 25 May 2010 (UTC)

John Earman hardly qualifies as a crackpot. Eugene (talk) 18:48, 25 May 2010 (UTC)

His statement clearly qualify as such. "I don't believe in a theorem" he does not understand? Moreover, \Omega ~ 1 being a prediction of inflation is exactly part of the solution to the initial conditions problem. The claim quoted in the page that \Omega < 1 being "hard to reconcile with inflation" is a flaw of inflation is illogical. Why wouldn't those claims qualify as crackpot nonsense non-scientific claims? Because he holds a Ph.D.? Well, Kary Mullis claims on HIV are pure crackpot delusions and he is a chemistry Nobel Prize winner. The qualifications (in this case, actually, the lack of them from John Earman who does not have peer-reviewed accepted papers in cosmology journals) do not at any moment disqualify any of the arguments presented below that the claims are not scientific.

It is clear that the claims are not accepted by the scientific community, e.g. of references in which inflation is considered not to be flawed at all but a sensible theory with testable predictions, among several others: Mukhanov V., Physical Foundations of Cosmology; S. Weinberg, Cosmology; D. Lyth & A. Liddle, Primordial Density Perturbation; Padmanabhan, T., Gravitation; S. Dodelson, Modern Cosmology. As another reader already pointed out, basically, any book in cosmology. When WMAP published their results, they compared the data with inflation and found agreement (http://dx.doi.org/10.1086/377228). Inflation is a testable theory and the claims of John Earman that it is "flawed" because he felt offended by the theory are not scientific. A scientific statement is one in which one shows that the theory is flawed because it predicts something which is ruled out experimentally. As such, his claims do not belong in this page or any other science essay or discussion.129.170.84.49 (talk) 19:25, 25 May 2010 (UTC)

If you have RSes that take issue with Earman's specific claims, please add them to the article in refutation of his concerns. Otherwise, you're merely engaged in WP:SYN at best. Eugene (talk) 19:32, 25 May 2010 (UTC)

If we had to accept in every scientific article a crackpot claim and add below or somewhere around it that the claim is crackpot and explain why, we would be doomed. A simple Google search of "Big Bang Theory wrong" produce an enormous amount of similar claims to the ones allowed in these specific sections of this page. I did exactly what you said and added here a clear statement of why the claims written in the page are nonsensical, and the expected approach from an impartial editor would be the remove the content. You asked for a series of references that show that the claims are wrong in the page discussion above, and I gave them to you. Now you came up with an excuse to maintain the propaganda of these claims by saying that I should add why the claims are clearly from a crackpot without any expertise in the subject into the main article so that the propaganda can continue online. I thought this was not an acceptable quality standard for scientific articles in Wikipedia.129.170.84.49 (talk) 20:49, 25 May 2010 (UTC)

As to the "WP:SYN" thing, if you had read what I posted below, in the reference of Mukhanov he *explicitly* states that point a) of the quoted paragraph is wrong. And the statement b) is one that says that a no-hair theorem does not exist and I explicitly showed it to exist below, which also exposes that b) is incorrect. Now, NO ONE is going to publish a paper on a peer-reviewed journal just to combine explicitly these arguments to explain clearly why Earmans assertions are nonsensical, because any grad student in physics can see they are patently wrong. So you will have to conform with the fact that scientists do not spend their time exposing all crackpots of the world. But anyhow, I gave up, no reason will change the mind of anyone trying irrationally to maintain these claims. I can only hope that some Wikipedia moderator with scientific expertise will pay attention to this issue.129.170.84.49 (talk) 20:49, 25 May 2010 (UTC)

I'm sorry but there is little to discuss on the fact that two sections of this Wikipedia article are being removed by me and this action should not be reverted. The sections were:

"CMTU Alternative theory" and "Philosophy of Cosmology".

Let me first address the second. It starts with the following quote:

"(a) results showing that inflation is likely to occur under generic conditions in the universe were not forthcoming (b) cosmic no hair theorems showing that inflation is effective in ironing out generic nonuniformities were not forthcoming (and in our reckoning are probably not true) and (c) in the straightforward version of inflationary cosmology ... the presence of enough inflation... is difficult to reconcile with a low value of Ω0"

For a), please refer to V. Mukhanov, Physical Foundations of Cosmology, Chap. 5. In Sec. 5.1 he explains what the initial condition problems are and translate that into equations of the sizes of particle horizons as functions of redshift, which all depend on the sign of the derivative of the scale factor, which then anyone following the logic can conclude the following, as I quote from the book:

We have seen so far that the same ratio, dot{ai}/dot{a0}, enters both sets of independent initial conditions. The large value of this ratio determines the number of causally disconnected regions and defines the necessary accuracy of the initial velocities. If gravity was always attractive, then ai/a0 is necessarily larger than unity because gravity decelerates an expansion. Therefore, the conclusion ai/a0 ≫ 1 can be avoided only if we assume that during some period of expansion gravity acted as a repulsive force, thus accelerating the expansion. In this case we can have ai/a0 < 1 and the creation of our type of universe from a single causally connected domain may become possible. A period of accelerated expansion is a necessary

condition, but whether is it also sufficient depends on the particular model in which this condition is realized. (V. Mukhanov, Physical Foundations of Cosmology, Cambridge University Press, p.229-230

Regarding b), the "not forthcoming" theorem is known since 1983: R. Wald, Phys. Rev. D 28, 2118–2120 (1983). "I don't believe in a theorem" may be something to be put somewhere up in the blogsphere but certainly not in a scientific essay about a scientific theory. As to c), it makes no sense. \Omega is not small, it is ~ 1, and this is a prediction of inflation. The fact that inflation cannot be reconciled with a small \Omega is the whole point of inflation.

Moreover, in addition to the fact that the claims inserted in this page about such "Philosophy of inflation" are nonsensical, there are several other non-experts like these two out there criticizing inflation or the Big Bang theory, and the insertion of the comment from these two non-experts in this page instead of any one else is a clear sign of propaganda and self-promotion.

Now, to the "CTMU alternative". It started with the quote:

"Thus, conspansive duality relates two complementary views of the universe, one based on the external (relative) states of a set of objects, and one based on the internal structures and dynamics of objects considered as language processors. The former, which depicts the universe as it is usually understood in physics and cosmology, is called ERSU, short for Expanding Rubber Sheet Universe, while the latter is called USRE (ERSU spelled backwards), short for Universe as a Self-Representational Entity"

No equations. Not scientific. Not an alternative model.

It is ONLY an alternative model to inflation if you can calculate the spectral index of CMB with a calculation in quantum field theory. If that is not what you do, it is NOT an alternative. Inflation predicts the shape of the distribution of galaxies in the universe and an alternative *scientific* theory is not a whole bunch of gibberish like the above paragraph but a CLEAR calculation of this function. Since the cited work does not include such a clear mathematical model for the inhomogeneities of the universe it is not an alternative theory, it is not a Cosmological model, it is not science. 131.215.195.228 (talk) 18:41, 25 May 2010 (UTC)

Edit: Now, everyone that has to deal with explaining scientific theories like quantum mechanics, relativity, or cosmological models known that we eventually face crackpots, which is an entirely different category of claims. One thing is if you come up with an alternative model like the ekypirotic model and you submit to a scientific peer-reviewed journal and this is accepted for publication because it contains sound physics and mathematics that can be tested against experiment, even though your model is not the model of choice of most cosmologists. This is not only acceptable, it is extremely important element of scientific research. Another entirely different thing is someone who, not being an expert, not knowing what are the technical difficulties that a theory like inflation solves, comes up with a naive idea that is written in a way to fool non-experts with random use of jargon and that, in the end, is not capable of elaborating a detailed calculation of any observable in the universe that can be compared to an experiment like WMAP or Planck satellite. And we can clearly distinguish this when we see that such claims were not published in scientific peer-reviewed journals. This is the case of the two sections that I removed, and it should be a consensus that an encyclopedic article about science should respect the criteria of what is scientific knowledge and separate that from other things. This is why such sections should not be included in this article. Only peer-reviewed scientific research paper material should be included here. 131.215.195.228 (talk) 18:41, 25 May 2010 (UTC)

1. CMTU get published in intelligent design journals. Eeeeeh.
2. Anyone who doesn't understand that omega~1 is the central prediction of inflation is a crackpot.

Both reverted.--Michael C. Price ^talk 21:54, 25 May 2010 (UTC)

Removal of Philosophy_of_cosmology

{Copied from --> Wikipedia:Editor assistance/Requests#Cosmological Inflation Moxy (talk) 01:41, 26 May 2010 (UTC) } Hi,

I would like to request two sections of the following Wikipedia article to be entirely deleted. The article is

http://en.wikipedia.org/wiki/Cosmological_inflation

the sections are:

1. http://en.wikipedia.org/wiki/Cosmological_inflation#CTMU
2. http://en.wikipedia.org/wiki/Cosmological_inflation#Philosophy_of_cosmology

Brief description of request:

• This article is about a scientific theory. It should contain scientific material.
• The two sections are not of scientific nature. The material was not accepted for publication in a peer-reviewed cosmology journal. The first section is a blog post; the second section was published in a religious newsletter.
• They seem to suggest a controversy which is inexistent in the scientific literature.

Longer explanatory comments:

The section no. 1 (CTMU) consists of a blog posts. It is not a peer-reviewed paper in a journal. It should not be part of an encyclopedic entry on a scientific article. Moreover, it is not comprised of a mathematical model that can be tested against experiment. The theory at hand (inflation), predicts what is called the power spectrum of cosmological perturbations and is consistent with observed anisotropies in the cosmic microwave background and the galaxy distribution observed by Sloan Digital Sky Survey and 2dF (http://dx.doi.org/10.1086/377228 ; for an accessible account to non-experts, see http://map.gsfc.nasa.gov/universe/bb_cosmo_infl.html). An alternative theory to inflation is one that can make these types of predictions, and there are some available in the scientific literature, but we can see from the blog post that it is not a mathematical model to predict cosmological observables. Instead, it is a random combination of jargon that makes little sense.

The same of the above applies to section no. 2. In addition, it was commented in the talk page in detail at least twice, where specific references were given that debunks the paragraph. In fact, the paragraph in question make three claims that: the first one can be seen to be wrong by following a simple textbook reasoning, such as the one of the reference given in the talk section; the second claim is just plain wrong because there are known theorems of the nature the paragraph disputed to exist.

It would be best if this is passed to someone with technical knowledge in Physics and Cosmology.

Thanks 129.170.84.49 (talk) 21:42, 25 May 2010 (UTC)

I'm not particularly familiar with the science involved here so I can't evaluate those arguments that appeal to what-everyone-in-the-biz-already-knows. But I am pretty good at following references and noticing when someone is saying something about a source that just ain't true. CTMU aside, the material on John Earman and Jesús Mosterín is sourced in part with a citation which in turn refers to a book published by the academic publisher Routledge, not a "religious newsletter". Further, the Routledge book itself is only quoting another source, an article that Earman and Mosterin wrote and which was originally published in the peer-reviewed, Univerisity of Chicago published journal Philosophy of Science. It's entirely possible that they are incorrect, and if so it's entirely possible that their specific claims have been addressed. But given the academic positions of both men and the standing of the peer-reviewed academic journal in which their claims were first made, arm-waving denunciations of them as "crackpots" (made, so far, only by Wikipedia editors and not in published work by experts) won't do as a rationale for deleting their material. I'm readding it. Eugene (talk) 03:34, 26 May 2010 (UTC)

Let us put this way: the paper of Earman was not published in a scientific journal peer-reviewed by cosmologists, and should not figure in a page about science. It was instead published in a journal that should not have allowed the paper to be published since the referees could not assess the technical content of it. The academic positions of both men should be a good reason why the material should be excluded, since none of them are cosmologists. At any rate, since it was not published in a scientific journal, we can at best call it a layman's opinion or philosophical prejudice, not a scientific statement. The flaw they argue for is not in the form acceptable for a scientific publication, namely, showing that there is a mathematical inconsistency in the theory or showing that one of the predictions of the theory was ruled out experimentally. Instead, the paragraph quoted tries to convince that the theory is wrong because the authors do not believe in rigorous theorems of General Relativity. Moreover, publishing this content of Earman here makes little sense since there are several other similar claims, some even by a few physicists and astronomers who also hold academic positions, in non-scientific journals and also in some scientific journals. This kind of thing is inevitable. Therefore, it would be best placed in the author's page in Wikipedia, not in the article about the science of inflation, just like other disputes of the Big Bang theory are usually placed in their author's page and not in the Big Bang theory article. The reference of religious newsletter is is still there, ref. 91, which is in fact of the same nature of the ref. that was removed "CTMU". I can add a technical evaluation of the content of this page, and in my professional opinion, the cited work of Earman is incorrect. I understand his claims and they are wrong. What else can we do here? If you don't understand them, then please do not insist in maintaining this material, you are doing a great disservice to education. The addition of the material on an encyclopedic article supports that there is a controversy as to the predictive power or consistency of the theory, which is not true. It is similar to insisting to keep the claims of some renowned person denying that HIV causes AIDS whenever one is to discuss AIDS in a newspaper, talk to the public, or article in encyclopedia. I'm of the opinion that these types of claims do not belong to an encyclopedia. We can address them in a opinion journal like Earman did. And I think that reading the above post should have made clear why the paragraph by Earman is incorrect. I'm the third or forth person to point this out, what else do we need to do here to get this material removed? I can add a ref. that I found, by George Ellis (http://arxiv.org/abs/astro-ph/0602280), who is a physicist, which was written to address among other things the opinions of Earman. Ellis states clearly:

The physical reason for believing in inflation is its explanatory power as regards structure growth in the universe. Inflation predicts the existence of Gaussian scale-free perturbations in the early universe thereby (given the presence of cold dark matter) explaining bottom-up structure formation in a satisfactory way. This theory has been vindicated spectacularly through observations of the CBR and matter power spectra. It is this explanatory power that makes it so acceptable to physicists, even though the underlying physics is neither well-defined nor tested, and its major large-scale observational predictions are untestable. (p.34)

He is not agreeing with the claim that inflation is fundamentally flawed, or that it is hard to make predictions consistent with observations.131.215.7.137 (talk) 06:19, 26 May 2010 (UTC)

Footnote 91 does not cite a "religious newsletter"; it cites an anthology published through the academic publisher Routledge. Your continued inability (or unwillingness) to recognize this point that I can easily verify only increases my unease in defering to your claims in matters I cannot easily check. Eugene (talk) 13:57, 26 May 2010 (UTC)

Yes, it is, it is a unnecessary reference of a book about intelligent design and it is unacceptable in a scientific article. It is unnecessary because only the paper of Earman is being discussed, and still the ID reference is given. If you have any good reason why the material should be kept here, please explain. I have removed the material and I will continue to do so.131.215.7.137 (talk) 15:42, 26 May 2010 (UTC)

From the section under discussion here: "But it is the first point that contains the essential philosophical position—they claim that inflation is no better as a starting point for cosmology than the standard big-bang, except in ways that are not accessible to experimental test." I doubt one can give a single reference where the power spectrum of CMB is predicted in the Big Bang model without inflation or some other additional scheme. It is known that it is impossible to generate the cosmological perturbations in the Big Bang without inflation because of the horizon problem (c.f. http://dx.doi.org/10.1016/0370-1573(92)90044-Z). The CMB power spectra is a prediction of inflation and it can be tested experimentally. See, e.g. http://dx.doi.org/10.1016/j.physrep.2004.08.022, where they explain how WMAP, Planck satellite and future observations can test this specific prediction of inflation.131.215.7.137 (talk) 06:37, 26 May 2010 (UTC)

I agree with 131.215.7.137 - the section should be removed. The content is gibberish; unclear in main, and where it is clear it is incorrect. --Michael C. Price ^talk 16:20, 26 May 2010 (UTC)

So are we in agreement that the material should be deleted? Because Eugene in lack of any reasoning to maintain the material is now appealing to the claim that 4 editors are interested in keeping the material. I don't see that.131.215.195.228 (talk) 04:04, 27 May 2010 (UTC)

Four different editors have reverted the deletions; that's what I've refered to. The material on the philosophy of inflation is relevant to the subject, encyclopedic, verifiable, notable, etc, etc, etc. False claims about the source material being a "religious newletter" have been mooted completely by tracking the material back to it's original peer-reviewed academic journal. Additional information related to the subsection has been added which derives from Alan Guth's own pen. And a supportive comment by Roger Penrose has also been integrated. There is no unbiased reason for its removal. Eugene (talk) 04:11, 27 May 2010 (UTC)

"Four different editors have reverted the deletions; that's what I've refered to."

That is because I tried to remove the content and there is an automatic feature to prevent that. It was not four people who looked at the discussion page and said "No, the material is relevant".

"The material on the philosophy of inflation is relevant to the subject, encyclopedic, verifiable, notable"

It is not relevant because it is not a scientific statement and it is placed in a scientific article. I think also that it hardly qualifies as a real philosophical discussion since it simply states that theory is incorrect. In science this type of assertion must come from an experiment. It is just a personal opinion of the authors . The material is not encyclopedic because it is not the consensus of the scientific community. As such, it violates the neutrality of scientific articles of Wikipedia. Three editors are here in favor of removing the material: myself, Michael Price and Likebox long before. You added your own words to the section now and that present original research in violation of terms of a Wikipedia scientific article.

"Additional information related to the subsection has been added which derives from Alan Guth's own pen"

And this is where your original research comes in. The quote from Guth is correct. It is because of what physicists call a "naturalness problem" that indicates a place where a theory lacks an explanation but it is not necessarily incorrect. The theory of inflation complements the Big Bang theory without inflation because without it one cannot explain the near scale-free inhomogeneities, or what physical process produced them. In the Big Bang theory without inflation these perturbations are inserted "by hand", and no causal physical process can produce them. Inflation is the standard theory of cosmology nowadays because it can add to the Big Bang theory an explanation of these inhomogeneities. The words of the section in question that sustain the theory cannot be tested are incorrect since the theory has already been tested with WMAP (cf. ref given above) and will continue to be tested in future experiments like Planck satellite. It is inadequate to say that the theory does not add anything to the Big Bang theory, and that was the whole point of Guth: it does add because it solves naturalness problems. Guth's words were distorted and removed from context to support a claim that was not what he was referring to. Then a completely unrelated remark from Roger Penrose who is not saying the theory is flawed was added. He was saying that a test of the theory in high energy experiment to detect whatever the inflaton may be is the ultimate test of the theory. Even if he did say the theory is flawed, that would be inappropriate. Science should not be what Penrose or Guth said, but what can be found by following mathematical reasoning and performing experiments. It is not a good practice when someone cannot follow the reasoning takes quotes of famous physicists out of place to support claims that they themselves never really made.

To conclude, there are three editors strongly in favor of removing it. I believe is more appropriate that you let it be, specially since it looks from your posts that you cannot assess the technical content of the arguments in question.131.215.195.228 (talk) 04:39, 27 May 2010 (UTC)

Hello. I was one of the editors who reverted your deletion, and I definitely did it because I read this discussion and decided that the material is relevant. There is no such thing as a "scientific article" in Wikipedia. Yes, there are articles on scientific topicss, but these are subject to exactly the same standards and policies as any other article - there is no walled garden of "scientific articles" with special privileges to isolate themselves from other domains of discourse. Any sourced and NPOV statement that is relevant to the topic of an article is appropriate, provided it does not give undue weight to a minority position. There are precedents for including overviews of relevant philosophical issues in articles on science topics - see quantum mechanics, artificial life and consciousness for examples. I agree that it is important to get the contents of the section right - make sure it gives due weight, does not use quotes our of context etc. But your argument that the section should be removed simply because it is about philosophy is incorrect. Gandalf61 (talk) 09:37, 27 May 2010 (UTC)

(removing a response because it not constructive to the discussion. Author of the response removing it here...)131.215.195.228 (talk) 03:37, 28 May 2010 (UTC)

Gandalf, I'm sorry I wrote the post before It was inadequate. I was too nervous. If it matters I now respond adequately: the problem is not the philosophy part, it is that to get the content right to me it seems the section should be deleted. The section in question says that the theory of inflation is incorrect because it cannot make testable predictions and it does not add to the Big Bang model. But the theory does make testable predictions, such as the shape of the distribution of galaxies in the sky, which has been verified by SDSS and 2dF, or the shape of the anisotropies of the CMB, as seen by WMAP satellite. It does add to the Big Bang because without inflation it is not possible to get the shapes of these inhomogeneities. See, e.g., the above quote and paper by George Ellis. It is not a problem that the section is entitled "philosophy", it is because it says things that are not true. I don't see how saying that inflation is flawed can qualify as a philosophical discussion. Now, it is true that the claims were made by two isolated individuals that are not experts in the field. But this is inevitable; if we are to collect all the statements that the Big Bang theory is incorrect from non-experts out there this page would be 100 times bigger. And also, I fail to understand why the points of these two gentlemen should be included here as a significant dispute of the theory, albeit nonsensical, and not all these other authors with their respective disputes?131.215.7.137 (talk) 05:09, 28 May 2010 (UTC)

Wow, not only a poor mind reader but a poor article reader too. I've never said that I'm a creationist (I'm not, BTW) and the article currently does not cite the book God and Design. As for your claim that I've taken quotations out of context, I've linked the Penrose journal article used in the section and you are of course free to read it. You're very words, however, indicate that this section is meaningful. As you said, inflation is largely an attempt to address the "naturalness problem" associated with standard big bang cosmology; that is, inflationary theory has a distinct philosophical motivation. Given that reality I see no reason why the article shouldn't address the philosophical issues involved so long as it does so with reference to reliable sources. Eugene (talk) 17:55, 27 May 2010 (UTC)

inflation is largely an attempt to address the "naturalness problem" associated with standard big bang cosmology; that is, inflationary theory has a distinct philosophical motivation.

You can call it "philosophical", but the motivation is to answer questions that cannot be answered in the theory without inflation. I would not call that philosophical, but a physics question. You are using a layman's loose definition of philosophy. It is a physics question when someone wants to find a model that explains the value of the mass of the Higgs boson, for instance. There is nothing philosophical about that, it is what in the physics literature is called a naturalness problem.

Given that reality I see no reason why the article shouldn't address the philosophical issues involved so long as it does so with reference to reliable sources.

Your section is not about philosophy, it is saying that the theory is flawed and is using quotes from famous physicists that you don't understand to support a claim that they were not making. All the physicists you quote do believe inflation can be tested experimentally and do believe that the theory adds to the Big Bang theory. I know them personally and they do believe in that. I don't understand why are you insisting on this issue. What do you have to gain to maintain this material here? It is not increasing the public understanding of science; it is making it worse by suggesting that inflation cannot be tested experimentally and it is unnecessary assumption to the BIg Bang. I had already explained that it is impossible to derive the CMB power spectrum without a mechanism like inflation and that WMAP has tested the theory experimentally. This is also explained in the Wikipedia article in the "Observational status" section. Why do you continue to ignore this fact? When you say that the theory cannot add anything, you did not provide a reference where the power spectrum without inflation was predicted. Yes, you did take the quotes out of context because they are not supporting your claim that the theory cannot be tested. Quite the contrary, in the popular science book of Guth he talks about how to test the theory, doesn't he? 131.215.195.228 (talk) 03:34, 28 May 2010 (UTC)

(deindent) No, it is not true that "inflationary theory has a distinct philosophical motivation". Inflation theory arose from the technical realisation that the equations of GR implied that a supercooled vacuum state would lead to exponential expansion of the universe. That this solved many exant cosmological conudrums was a corrolary, not a motivation. --Michael C. Price ^talk 18:13, 27 May 2010 (UTC)

"the historical motivation for inflation ... arose largely on more philosophical grounds"

Cosmological Inflation and Large-Scale Structure, Andrew R. Liddle & David Hilary Lyth

"Indeed, the primary motivation for the inflationary paradigm was to solve the naturalness problems"

"Pre-Big-Bang Inflation Requires Fine-Tuning", Physics Review D, Michael S. Turner & Erick J. Weinberg

"A principal motivation of any inflationary model is to get rid of the fine tuning of the initial conditions of standard cosmology."

"The fine tuning problem in pre-big-bang inflation", Physics Letters В, Maggiorea, Michele & Riccardo Sturanib

Eugene (talk) 19:40, 27 May 2010 (UTC)

You've got the Guth book. Read it. Guth found out about the horizon problem after his realisation. --Michael C. Price ^talk 20:18, 27 May 2010 (UTC)

Actually, don't bother. Remain ignorant, I don't care any more. This nicely illustrates how ignorant quote farming can destroy content. Stuff you all. --Michael C. Price ^talk 20:22, 27 May 2010 (UTC)

Classy. Eugene (talk) 20:38, 27 May 2010 (UTC)

The section is total crap. The paper first quoted makes it clear that they are talking about pre big bang inflationary theory, but this article begins with the definition that it covers post big bang inflation. Michael is completely right - it is quote farming by someone who is so out of his depth it is not even funny. Sophia ♫ 22:11, 27 May 2010 (UTC)

Thanks for restoring my faith in WP and/or the human race. Section removed. --Michael C. Price ^talk 22:26, 27 May 2010 (UTC)

Well hello Sophia. Never fear sweetie; I haven't misrepresented the sources.

I'm not entirely sure if you're refering to the first article cited in the short list above or the first article cited in the actual article's section on this matter. In any event I'll address them both so you don't lose sleep over it.

The first article cited in the section in question is by Maggiorea & Sturanib. While their paper is certainly titled "The fine tuning problem in pre-big-bang inflation", their relevant comments are directed at "any inflationary model", of which pre-big bang is merely one variety. As for the first article cited in the above list, the one by Turner and Weinberg, their relevant comments are likewise directed at the entire "inflationary paradigm", of which, again, pre-big bang inflation is merely one example. Nice try though. Section back in. Eugene (talk) 22:47, 27 May 2010 (UTC)

Read Guth's book yet, Eugene? Try reading pg 184 (which you've already quoted from) and tell me if he was motivated by the horizon problem before he discovered inflation. --Michael C. Price ^talk 00:19, 28 May 2010 (UTC)

I got so upset with the fact that I found this section in this article that I posted a detailed explanation of why the section was incorrect. (You know, when you see something like that, you get emotional...) I have to admit it was kind of inflammatory. I also admit that I was emotional and I should have said the same content in a way less aggressive. I apologize for that. It was really, really frustrating to see that after I had written my explanation for deletion with some care and deleted the section, editors reverted the deletion "because it was not constructive". At first I thought it was a bot, so I tried it again. Anyway, when it became clear from the above post that real editors were reverting the deletion I got very upset again. It is frustrating because no editor cared to come here read my explanation of why the section was saying 2+2=5 before reverting. I have provided detailed literature debunking each of the points already. This section is certainly not promoting education of inflation to the public. There is no consensus that the section is relevant and several editors are against it and have explained why the section is wrong, this should be a sign of problem. There does not seem to me that anyone presented a substantial explanation of why the section should be kept online. The only thing provided was "the authors are famous". I apologize again for my very agressive words in my previous post. However, I stand by my opinion that the material is not encyclopedic I think the case for deletion has been made above to exhaustion. It is now only to ask help from some admin or something.131.215.195.228 (talk) 02:40, 28 May 2010 (UTC)

Disruptive editing

Editors, please do not give up on this article. Do not despair. Wikipedia's mechanisms for overcoming a disruptive editor are frustrating and inefficient, but one day they will succeed. Please be patient. This article is not going to be of interest to many, and the article is not about a subject which may bring harm to anyone. Nothing bad is going to happen if we need to take a few months to undo the mischief of User:Eugeneacurry. Please do not let User:Eugeneacurry rile you. Remain calm and carry on. At the moment, User:Eugeneacurry is showing contempt for the entire Wikipedia community by refusing to learn from the result of his experience at WP:Administrators'_noticeboard/Edit_warring. Do not be moved by his contempt; it is of no consequence. Please do not call User:Eugeneacurry "stubborn" or anything else. Calling him names is not going to change anything. The outcome, if User:Eugeneacurry persists in opposing the community, is inevitable and gratifying. For the time being, please revert everything by User:Eugeneacurry. I will collect diffs of User:Eugeneacurry editing against consensus. We need those diffs to help an administrator help us. All will be well in the end. PYRRHON  talk   04:02, 28 May 2010 (UTC)

Hopefully there's no need to be so hard on Eugene. Perhaps we can reach a compromise that might actually improve the article. Whilst there is no merit in some of the new material, it raises a topic that should be clarified to save future heated discussion, namely that of the "motivation" for inflation. Guth didn't know about the horizon problem when he invented/discovered inflation, yet many sources state that this is a motivation for inflation. I think this is because the term "motivation" is used in two different senses; one is historical, and one is retrospective. Historically inflation developed from investigations into the magnetic monopole problem, which uncovered the strange, expansive behaviour of space implied by general relativity and which had lain undiscovered for some 60+ years. Retrospectively, though, once invented everyone realised that this solved sooooo many cosmological puzzles that this became the motivation for inflation's widespread and enthusiastic adoption by astrophysicists in general. Remove those retrospective reasons though, and inflation would still be motivated by the original reason; namely it being implied by general relativity in the presence of a false vacuum.

It's unfortunate that many commentators lose sight of the original historical motivation, concluding that inflation is just a concoction to plaster over cosmological lacunae.

If this makes sense, then I suggest:

1. Forget about Earman et al (i.e. remove from article), they just doesn't cut the mustard; they clearly don't understand the technical side of inflation.
2. Stop asking for sources for statements accepted by all experts in the field.
3. Add a "motivations" section.

--Michael C. Price ^talk 13:39, 28 May 2010 (UTC)

Part of my intractability on this matter stems from the simple falsehoods found in the posts of those advocating for the material's deletion. The IP editor said that a book published by an academic publisher (which was only being used as a pass-through source to a peer-reviewed academic journal anyway) was a "religious newsletter"; Sophia said that the comments from the "first article" cited were directed only at one particular kind of inflation (which statement was shown to be incorrect); Georgewilliamherbert said I was the only one advocating for the material's retention even though Gandalf was arguing for the same thing; Michael C. Price has said I'm misrepresenting Guth's position on the horizon problem as a motivation when I've only included a quote indicating that Guth agrees that the horizon problem is not a failure (strictly speaking) of the SBB model.

But I don't want to be a jerk. As I've said, I'm not qualified to evaluate claims of what-everyone-in-the-biz-already-knows. And if the IP really is BFFs with the cosmologists I've cited--and they've said my edits misrepresent them--then I may really be sunk. Still, the material in question is well sourced, particularly attributed when controversial, and notable (I think). I'm going to put a RfC in on this and, if it goes against me, then I'll drop it. I'm posting to the science board and the philosphy one as well--given the topic in question (I.e. philosophical issues regarding a scientific theory) this seems appropriate. Eugene (talk) 15:21, 28 May 2010 (UTC)

Addressing the complaint against me: Eugene misunderstands the problem. Yes, I deleted Eugene's statement that Guth was motivated by the horizon problem: he wasn't, as his bio' shows. --Michael C. Price ^talk 17:40, 28 May 2010 (UTC)

Not to be nit-picky, but I never actual said that Guth was himself motivated by the horizon problem: "Alan Guth has written that, while the 'horizon problem' has been one of the driving forces behind inflationary theorizing, the 'horizon problem is not a failure of the standard big bang theory in the strict sense...'"[1] Eugene (talk) 18:01, 28 May 2010 (UTC)

And where, precisely, does Guth say that "the 'horizon problem' has been one of the driving forces behind inflationary theorizing"? (Note he says, page 180/1, that he was "totally unaware" of it.) --Michael C. Price ^talk 18:21, 28 May 2010 (UTC)

And correcting the charge against me - I said that the first paper quoted (and by that I meant in the section under dispute) was about pre big bang inflation and it is. They obviously try to use this model to explain the observed features of the universe because that is the point of cosmology! Sophia ♫ 19:08, 28 May 2010 (UTC)

Eugene, yes, you are right, I was initially inclined to think that it was a newsletter, but a fact checking shows that it is not, it is a religious book on creationism with collected material. Are you now ready to understand also that the claims you are making are completely inadequate, since simple fact-checking shows that? Experiments on CMB and large scale structure have already tested inflation and more tests are underway, predicting adiabatic initial conditions and the scalar and tensor spectral indices and the non-gaussianites amplitudes cannot be done without inflation and hence the theory does add testable predictions to the Big Bang theory in a very fundamental way. Naturalness problem is one in which it is asked something that goes beyond a given theory, like when it is said that asking for a model that predicts the ratio of the cosmological constant to the Planck mass, or the ratio of the Higgs mass to the Planck mass are both naturalness problems, and these qualify as physics questions -- I can't see a more physical question than that, like asking why is k ~ 0 or \Omega ~ 1 in the universe. These shows that the section we are discussing here is misleading. Because it is misleading in such important ways, I find it hard to think that this section can improve general public understanding of the Big Bang theory. It leads people to think that most professional cosmologists in the world are saying that they believe the universe had an inflationary epoch without being able to test this idea experimentally, somehow forgot what Galileo taught us. Or that there is a controversy in academia wether or not inflation is a theory with testable predictions, which is also untrue. A single paper of WMAP with the measured scalar spectral index < 1 with tests of inflation have more than 4,000 citations in peer-reviewed journals; in total, WMAP all papers have something of the order of 10,000 citations while the Earman paper shows only 29. So even your "notability" argument seems to be against you.131.215.195.228 (talk) 01:34, 29 May 2010 (UTC)

I still think that you're misrepresenting the book; to call it a "religious book" is a bit of a streach given that sections of it were written by Michael Ruse, Martin Rees, and other notable non-theists. But that's neither here nor there since the book is no longer cited in the material in question.

I'm unfamiliar with a lot of the technical verbage you've used in your last reply so I can't speak to those issues (cynically, I wonder if that was the point). But I do find your comparison of the one article with 3000+ others citing it contrasted against the 29 articles which cite Earman's paper to be a powerful one. This does give a clear prima face impression that the inclusion of the Earman paper may be WP:UNDUE. Before I concede though and limp away to lick my wounds, one question: Is the article on the WMAP by Spergel et al. a "normal" physics article, or does it contain a lot of hard data that isn't available elsewhere--effectively making it a reference work? After all, it would hardly be far to compare the number of academic journal articles on the Kennedy assassination which cite some other such article against the number which cite the Zapruder film. Eugene (talk) 03:06, 29 May 2010 (UTC)

The paper I linked above is the one where the result of the experiment after its third year was given, their discovery paper. It presents the final analyzed data and their fits to it using the standard big bang model and using inflation to tell them how the deviations of the temperature from different patches of the sky depends on the size of the patches one uses (this is the information encoded in what is called "power spectrum"). The data itself is freely available from the NASA website. You can read the main article of Wikipedia on inflation where this is explained. To put most of what I said into perspective, follow the citations link above and go to the "PDF from arXiv", it is free; look at their Fig. 2. The "adiabatic initial conditions" from inflation is what tell us that after following the equations of General Relativity, we have those peaks and valleys in the picture.There are seven different solutions to the shape of this picture in the Big Bang theory without inflation; with inflation, there is the one we see in the picture. If they had obtained any one of the other six possibilities, single-field inflation would have been ruled out by experiment.They quote their spectral index which slow-roll inflation predicts to be close and less than 1, and that is what they observe. This results have significantly improved this year: http://arxiv.org/abs/1001.4538 .131.215.195.228 (talk) 04:10, 29 May 2010 (UTC)

Well, you didn't exactly answer my question. But, from what you have said, it seems like the paper you have mentioned is more of a reference work. And, we would expect it to be quoted much more often than an analysis paper. I think I will wait out the RfC. Eugene (talk) 04:18, 29 May 2010 (UTC)

That is because I don't really know how to answer your question and I want to be honest. I think it is what you would call a "normal" physics paper, say like the paper where Rutherford published with his results that showed evidence for the Rutherford model in place of the Thomson model. Or like the paper that discovered the Z boson at CERN. These kind of paper. These types of papers are highly cited because they have made breakthroughs. I don't know if that is "normal" or "reference".131.215.7.137 (talk) 05:10, 29 May 2010 (UTC)

RfC: Philosophical issues pertaining to cosmological inflation

There is a dispute at inflation (cosmology) as to whether the following section should be included:

Philosophical issues

Inflationary theory has historically been advanced for largely philosophical reasons. Specifically, all inflationary theories attempt to minimize the fine-tuning of initial conditions required by standard big bang cosmology, sometimes called the "naturalness problem". As Andreas Albrecht (a proponent of inflationary theory) has written concerning the theoretical success of the standard big bang model,

"It turns out that most of the cosmological 'problems' that are usually introduced as a motivation for inflation are actually only 'problems' if you take a very special perspective. ... The Flatness and Homogeneity features describe the need to give the SBB [I.e. standard big bang] very special initial conditions in order to match current data. Who cares? If you look at the typical laboratory comparison between theory and experiment, success is usually measured by whether or not theoretical equations of motion correctly describe the evolution of the system. The choice of initial conditions is usually made only in order to facilitate the comparison. By these standards, the SBB does not have any problems. The equations, with suitably chosen initial conditions, do a perfectly good job of describing the evolution of the Universe."

Alan Guth agrees, having written that the "horizon problem is not a failure of the standard big bang theory in the strict sense, since it is neither an internal contradiction nor an inconsistency between observation and theory."

Philosophers of science such as John Earman and Jesús Mosterín have therefore argued that inflationary cosmology is flawed since inflation is no better as a starting point for cosmology than the standard big bang, except in ways that are not accessible to experimental test. Since a scalar inflatonary model of cosmology can only be fixed to match observations by a certain amount of initial fine-tuning, Earman and Mosterin reckon that this type of fine-tuning is no better as an explanation of experimental results than the initial fine-tuning required by the standard big-bang model. Roger Penrose has argued along similar lines, stating that "[t]he case for inflation must come, not from cosmology, but from high energy physics–though ... this case is 'shaky, indeed.'"

The references used in the section are as follows:

There are two issues: (1) Should this material appear in the article, and, if so, (2) should the material be presented as is, in a single section, or should it be distributed throughout the article? Eugene (talk) 15:21, 28 May 2010 (UTC)

• (1) Include, (2) Single Section The material is well sourced, particularly attributed where contentious, and notable. Eugene (talk) 15:21, 28 May 2010 (UTC)

• (1) Exclude, (2) N/A Looks like WP:Bollocks to me. --LiamE (talk) 21:01, 28 May 2010 (UTC)

• (1) Exclude, (2) N/A I believe the material is inaccurate and misleading and should not be included. Inclusion in the middle of the article would just look silly, since the article contains statements all contradictory of the above section (e.g. the article presents the tested predictions of the theory with scientific references but the section claims that the theory makes no predictions that can be tested experimentally). I also believe the section is poor as it is with a collection of quotes out of place to sustain an idea that was not present in the sources given. For example, the given quote from Guth is displaced out of context since even in the book quoted Guth explains how to test the theory on Chap. 14, cf. page 239 and beyond. The "well-sourced" is therefore being used as a disguise to insert incorrect material into the page.131.215.195.228 (talk) 01:44, 29 May 2010 (UTC)

• Exclude per WP:SCIRS. - 2/0

(cont.) 04:45, 29 May 2010 (UTC)

• Exclude. The content that User:Eugeneacurry wants to include does not make the article better. PYRRHON  talk   01:34, 1 June 2010 (UTC)

• (1)Include The philosophical implications of scientific theories are of interest to many, even if others regard such discussions as Bollocks. (2)Keep as separate section DaveApter (talk) 20:51, 7 June 2010 (UTC)

What sizes are we talking about?

If there are any estimates or assumptions on the volume of the universe before and/or after inflation, they should be stated in the article. Currently it gives only the relative increase in size, but no absolute numbers. Or are these completely unknown? -- 77.7.146.3 (talk) 02:47, 28 September 2010 (UTC)

Inflation only gives relative size increases. Consequently the absolute figures are completely unlnown. --Michael C. Price ^talk 03:11, 28 September 2010 (UTC)

Also, the common assumption is that the volume of the universe is infinite both before and after inflation. (and if its not it, it is infinite for all intents and purposes.) The thing that is growing is the scale factor, which does not have a meaning full absolute size.TimothyRias (talk) 05:41, 28 September 2010 (UTC)

A common assumption before inflation? Where did you read that? It only has to be big enough for a "smooth" patch. --Michael C. Price ^talk 08:00, 28 September 2010 (UTC)

A common assumption in the sense that people seldom explicitly assume a finite size, and just work with an infinite universe. (Of course there are notable exceptions to this, for example in chaotic inflation, and even there the universe itself is usually considered infinite just the inflating patch is a finite piece.) It clearly is not a necessary assumption, just one of convenience.TimothyRias (talk) 08:29, 28 September 2010 (UTC)

Hawkings gives the relative expansion in lay man's terms as "smaller than an atom to the size of an orange in less than a trillionth of a second, almost no time at all" (quoting from memory there so dont use that as gospel but its close). I am pretty sure he is talking about the observable universe there, ie everything we can see now was in something thr size of an orange at the end of inflation. The actual universe is bigger and was infact bigger than than the orange, but as yet we dont know by how much. --LiamE (talk) 18:23, 2 October 2010 (UTC)

Is there a Big Bang before inflation or not?

Hi everybody! I am a physicist. I even did my Master's thesis on Cosmology, but that was 35 years ago and I completely changed topics since then so I am not up to date. But still, I have a pretty clear picture of non-inflationist Big Bang scenarios, and I'd like someone to help me clarify what goes on with inflation. So this is how I see the history of the Universe, backwards in time. Please do tell me if this is correct.

Future: As everything else will get diluted, ‘’dark energy‘’, which is same as cosmological constant, takes over and accelerated, exponential, expansion will go on indefinitely, albeit with a very long characteristic time-scale, of the order of tens of billions of years. Technically this should be called "inflation", since it is exactly the same mechanism, really, but extremely slow.

Right now: ‘’dark energy‘’ is roughly of the same order of magnitude as the remainder (‘’dark matter‘’, ordinary matter), and we are in a transition situation. This is an atypical situation. Has it to do with some “anthropic principle” that this is what we see?

Not so long ago: (I mean in terms of the logarithm of the expansion factor: less than one unit of decimal log, since a factor 1/10 in length, 1/1000 in volume and thus 1000 in matter density×c squared would dwarf the ‘’dark energy‘’ density; timewise this is still a large fraction of the time elapsed since the Big Bang): matter dominated expansion, decelerated evolution of the scale factor as time^(2/3). During this era galaxy and stars are born, supernovae enrich the interstellar gas in heavy atoms, etc. Early in this era there was only a hydrogen-helium fully ionized plasma. This lasted about 10 units of decimal log.

Indeed, 10 units of decimal log before, the total energy density of photons exceeded that of everything else. That happened when the typical energy of a photon was only of about one electronvolt. So the physics was not “exotic” at that time. During this “radiation dominated period”, the scale factor behaved as the square root of time.

In the old, non-inflation picture, the only one I knew at the time of my Master's Thesis, going back in time the energy density grew indefinitely higher and higher, in a finite time, hitting a singularity at time 0: the Big Bang. Nothing can prevent this singularity, not even Quantum Mechanics though QM changes the “instantaneous” character of the singularity and makes it more “fuzzy”, but still there is an origin, albeit a bit fuzzy, of time (this is how I understand Hawkings, anyway).

But inflation changes all this. The energy density that was present during the “radiation dominated period” came from reheating at the transition between ‘’false vacuum‘’ and ‘’true vacuum‘’ that marks the end of inflation. Just before the transition, whatever existed before inflation was diluted to almost nothingness, and nothing effective has been transmitted to us (in particular, the magnetic monopoles are now far, far between) except the ‘’false vacuum‘’ energy that was thermalized and caused the reheating. But before that? What is the accepted scenario, the ‘’standard wisdom‘’?

If there is absolutely nothing but ‘’false vacuum‘’, exponential inflation should have lasted indefinitely in the past, as it will last indefinitely in the future (though with an considerably smaller rate) since it would be a pure de Sitter Universe.

But if there is something at all, however enormously diluted by inflation itself, going backwards in time, backward the huge inflation factor, this “something” would have had a huge energy density, up to a point that this energy density becomes comparable to the cosmological constant of the ‘’false vacuum‘’ (just as now the mass density ×c squared is comparable to the much much smaller residual energy density of the ‘’true vacuum‘’ , the present-day cosmological constant). At that point back in time, the exponential growth should no longer be valid, and earlier than that, one should have again a “radiation dominated period” behavior, scale factor as the square root of time, down to an ‘’origin of time‘’, a Big Bang before inflation in a finite time. And moreover, isn't the very rationale for the ‘’false vacuum‘’ to exist the fact that at hugely high temperature, such as what prevailed when the energy density is much higher than its ‘’dark energy‘’ (= cosmological constant) it is stable, and that if it exists at all after diluting this huge energy density to almost nothing through inflation, it is because it takes some time for it to “cascade down” to the ‘’true vacuum‘’ ? Can anyone comment on this, please, and tell me what the ‘’standard wisdom‘’ is regarding what happened before inflation, if there is such a ‘’before‘’?87.88.114.80 (talk) 18:02, 24 November 2010 (UTC) Sorry, I forgot to log in before typing this. I wanted to sign it so I do it now Alfredr (talk) 18:06, 24 November 2010 (UTC)

BTW, Gandalf61: thanks for rewriting my edit to the main article. We do agree, from the local point of view, things are disappearing beyond the horizon, and “moving beyond” is clearer than “falling out of”. I had just made the minimal change. Alfredr (talk) 18:16, 24 November 2010 (UTC)

I think that the standard wisdom is, that pretty much nothing can be said about what happend before inflation. (Or even if there was a "before".) Various models for mechanisms that could cause inflation might say something about how inflation started, but nothing that is generally agree upon. (PS. talk pages are not the place to discuss the topic of the article. They are meant to discuss changes/improvements to the current article.)TimothyRias (talk) 12:22, 25 November 2010 (UTC)

Well, where then should the topic be discussed? From what I saw above, though some talks were about removing irelevant “philosophical” material (thus improving the page), other discussions were about the topic itself. The mechanisms you refer to, don't they usually involve temperatures corresponding to energy densities much higher then the “dark energy”, implying an initial singularity?Alfredr (talk) 13:02, 25 November 2010 (UTC)

As to why not to discuss the topic on the talk page see WP:TALK and WP:NOTFORUM. If you want have a general discussion about inflation Wikipedia is in general not the place to. If you have a question you want answer then there is the WP:Reference Desk. Sometimes, discussions on a talk page do derail, but this something to try to prevent.

As to your question, there are more models for inflation on the market than I care to count. Each with its own mechanism. In general they do not need "high temperature" (although some obviously do). BTW, most cosmologists I know, speak about the big bang as the reheating phase after inflation. TimothyRias (talk) 13:29, 25 November 2010 (UTC)

SOMEBODY DO SOMETHING!

This is one of the worst articles I've come across on Wikipedia. I know there is lots of discussion concerning the quality of this article, but I feel I have to make an additional plea for an experienced and knowledgeable editor to revise it. Especially the "overview" section. At the very least the numerous unaccepted theories described should be presented as alternative. —Preceding unsigned comment added by 71.65.217.167 (talk) 04:06, 28 December 2010 (UTC)

What?

Citation: "While special relativity constrains objects in the universe from moving faster than the speed of light with respect to each other, there is no such constraint in general relativity. For example, an object which crosses the event horizon and falls into a black hole can be thought of as moving faster than light from the point of view of an outside observer."

A cosmic humbug. Speed of light is preserved in general relativity as well. And if crossing of the event horizon were an equivalent of approaching speed larger than c, then any object just on the horizon would have to be travelling just at the speed of light. As some of them were massive, their energy would be infinite, and therefore would produce infinite gravitation. I remove this nonsense. I hope it is not needed for the rest of the article.

Please, do something with this article it's not the C class, it should be speedy deleted in case somebody takes it for granted. Olaf (talk) 17:51, 4 January 2011 (UTC)

In what sense can an "object which crosses the event horizon and falls into a black hole" be thought of as moving faster than light from the PoV of an external observer? Could somebody elaborate? Michael? (Since you decided to put this back)

This doesn't seem to make sense, since from the PoV of an external observer any object (including light) will take an infinite amount of time to fall across the horizon. In that sense the external observer will think that the object comes to a halt. There might be some otherw ay of viewing this in which it does makes sense, but for the moment I'm not seeing it.TimothyRias (talk) 16:36, 6 January 2011 (UTC)

Heh, perhaps it should say be thought of as moving slower than light from the point of view of an outside observer. -- cheers, Michael C. Price ^talk 00:33, 25 January 2011 (UTC)

Another speed of light issue

Citation:

In a big bang with only the matter and radiation known in the Standard Model, two widely separated regions of the observable universe cannot have equilibrated because they move apart from each other faster than the speed of light

Well, it's Newtonian thinking. If object A is going left at the speed 0.999c, and object B is going right at the speed 0.999c, then in the frame of the object A object B is moving at the speed $s={0.999c+0.999c \over 1+((0.999c)^{2}/c^{2})}=0.999999499c$ (see velocity-addition formula). It's still possible to send a photon from A to B. There may be not enough time for it, but it's not a superluminal travel.
I didn't fixed it, an expert is needed to rebuild the article. — Preceding unsigned comment added by Olaf (talk • contribs) 06:36, 5 January 2011 (UTC)

There is nothing (factually) wrong that quote. In an expanding universe the distance between to regions can become bigger at a rate faster than the speed of light. The distance at which this happens is called the Hubble sphere.TimothyRias (talk) 06:50, 5 January 2011 (UTC)

All right, I was wrong, it is possible if the timespace expands, but according to this paper it doesn't mean that the communication is broken:

We show that we can observe galaxies that have, and always have had, recession velocities greater than the speed of light.

An observer can still receive light from these faster-than-light objects, so the next sentence of the Wikipedia article seems to be wrong:

An expanding universe generally has a cosmological horizon, and like a black hole event horizon, this marks the boundary to the part of the universe that an observer can see

Olaf (talk) 20:21, 24 January 2011 (UTC)

Paul Steinhardt's critique in Scientific American

I'm not qualified to make edits to this page, but it is clear to me that Paul Steinhardt is a competent expert and that he has significant concerns about inflation. The critique seems twofold: 1) The initial conditions for inflation are highly improbable, and 2) perhaps more problematic, inflation implies so many different possible universes that it may not be falsifiable and thus the evidence in support of inflation may not add much, if anything, to our reasons to believe that it accurately reflects reality. See The Inflation Debate in the April 2011 edition of Scientific American. This page needs more balance to reflect the doubts about inflation among scientists. It need not be reflected throughout the entire article, but a criticism section is justified.Natty1803 (talk) 17:18, 10 April 2011 (UTC)

Section: Criticisms of inflationary cosmology

I just removed the following text from the article:

text for discussion

Since its introduction by Alan Guth in 1981, the inflationary paradigm has being very fashionable in the community of cosmologists. It has been hailed as the only game in town and has been presented as established science in the popular science literature and even in cosmology textbooks. Nevertheless, several physicists, mathematicians and philosophers of science have pointed to its shortcomings, unfulfilled promises and lack of serious empirical support. In 1999, John Earman and Jesús Mosterín published a thorough critical review of inflationary cosmology, concluding that “we do not think that there are, as yet, good grounds for admitting any of the models of inflation into the standard core of cosmology”. It has been questioned whether the alleged problems that inflation was called to solve (from the lack of magnetic monopoles to the uniformity and flatness of the observable universe) are not pseudoproblems, as the magnetic monopoles have nothing to do with the big bang model and the acceptance of initial or boundary conditions is standard practice in the construction of physical models. In any case, in order to work, and as pointed out by Roger Penrose from 1986 on, inflation requires extremely specific initial conditions of its own, so that the problem (or pseudoproblem) of initial conditions is not solved: “There is something fundamentally misconceived about trying to explain the uniformity of the early universe as resulting from a thermalization process. […] For, if the thermalization is actually doing anything […] then it represents a definite increasing of the entropy. Thus, the universe would have been even more special before the thermalization than after.” The problem of specific or “fine-tuned” initial conditions would not have been solved; it would have got worse. A recurrent criticism of inflation is that the invoked inflaton field does not correspond to any known physical field, and that its potential energy curve seems to be an ad hoc contrivance to accommodate almost any data we could get. It is significant that Paul J. Steinhardt, one of the founding fathers of inflationary cosmology, has recently become one of its sharpest critics. He calls ‘bad inflation’ a period of accelerated expansion whose outcome conflicts with observations, and ‘good inflation’ one compatible with them: “Not only is bad inflation more likely than good inflation, but no inflation is more likely than either. … Roger Penrose considered all the possible configurations of the inflaton and gravitational fields. Some of these configurations lead to inflation … Other configurations lead to a uniform, flat universe directly –without inflation. Obtaining a flat universe is unlikely overall. Penrose’s shocking a conclusion, though, was that obtaining a flat universe without inflation is much more likely than with inflation –by a factor of 10 to the googol (10 to the 100) power!” References

Criticism sections are in general deprecated, particularly when the sources presented are not particularly important to the topic of this article. A lot of this material is undue weight, weasel worded, and unclear and unencyclopedic in its presentation. Some of it could probably be used in discussion of alternatives and history, though. - 2/0 (cont.) 00:17, 10 May 2011 (UTC)

The removal is unjustified IMO. (& Criticism sections are NOT in general deprecated). -- cheers, Michael C. Price ^talk 09:33, 10 May 2011 (UTC)

I'm fine with not having a specific Criticism section if there was a reference to the critique in the intro which was then fleshed out in the History section. Perhaps something along the lines of the String theory page? Natty1803 (talk) 22:42, 10 May 2011 (UTC)

This is a good approach. Of the sources presented above, I am leery of using the and 1999 earlier for discussing a developing field of science. They may be necessary for fleshing out the History section, but a modern retrospective critique would be preferred. I am not aware of any issues with the Penrose (2004), but as always, we should be careful of generalizing the views of a single source (disclosure: I prefer LQG to String Theory). The Scientific American 2011 looks like on of their periodic 'stirring up controversy without giving proper caveats' articles; it should be usable, but only with attribution to the author and context. I have not checked Steinhardt (2007), but see no obvious reason not to use it. - 2/0 (cont.) 01:53, 11 May 2011 (UTC)

Censorship of serious criticism should not take place

The inflationary scenario is an important but controversial scientific theory. It should not be treated as the dogma of a religious sect. The dogmatic presentation of the article of Wikipedia and the systematic censorship of any serious criticism of this hypothesis is regrettable. Prestigious mathematicians, physicists and philosophers of science have expressed well-articulated criticisms and doubts about the theory of inflation and its empirical credentials. A balanced and fair encyclopedic article on inflation should not just ignore them. It is only natural that the main body of the article is devoted to the point of view of the proponents of the theory, but dissenting academic voices need not be suppressed. Readers have a right to know that certain theories (even important ones) are more speculative than others, and that not everyone is impressed by their empirical support. References to these doubts and criticisms should not be censored and cut out. This way of proceeding is incompatible with the open spirit of Wikipedia and with the free spirit of the scientific method. Pisto 17:15, 23 May 2011 (UTC)