What's Wrong With Dark Energy?
    By Johannes Koelman | August 19th 2010 07:29 PM | 31 comments | Print | E-mail | Track Comments
    About Johannes

    I am a Dutchman, currently living in India. Following a PhD in theoretical physics (spin-polarized quantum systems*) I entered a Global Fortune


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    A young fisherman in a distant past looks across the sea and ponders: "What an unimaginably big stretch of water!" He has no idea where it ends or even if it ends. But he knows one thing: over time spans of many years the rainfall into the sea adds up to a lot of water, and therefore the sea must be rising. This means that in a number of generations the sea will inevitably flood the lands, making the world an inhabitable place. But it also means that in the past the sea must have been much shallower. Too shallow for fish to thrive in. An inevitable conclusion forces itself upon our young fisherman. His generation is a very privileged one. A generation that lives late enough to find fish to feed on, and early enough to find land to live on. A remarkable coincidence.

    Obviously, the young fisherman interprets the data in the context of a flawed model. A model that ignores the importance of evaporation. When evaporation is taken into account, the coincidence disappears altogether. Future generations will also be able to live on land, and past generations did have the opportunity to fish. The fisherman's generation is not special in any way.

    Copernican enlightenment

    At a dark cloudless night, when we look up at a sea of stars, we tend to ponder as well. But we know better than the young fisherman. Right? We are enlightened. Copernicus taught us something profound: if you think your situation is special, you should probably think deeper.

    So we are deeply aware of the fact that we are situation is not special. Our planet is an average planet orbiting a mediocre star whirling with many billions similar stars in a giant vortex. A vortex of stars that is most ordinary amongst many billions of similar vortices that make up the cosmic sea we live in. There is absolutely nothing special about our position in the universe.

    Where is our sun? Don't be bothered. The Copernican principle tells us you might as well try to spot your particular piece of hay in a haystack! (Image: Jon Lomberg -- Portrait of the Milky Way)

    Cosmologists have elevated this idea to a fundamental principle rather unimaginatively named the cosmological principle. Simply put this principle says: on a cosmic scale there is no special place. The distant sky looks the same from each position in the universe. The immediate consequence of this is that if your theory requires observers on earth to occupy a special or privileged position within the universe, your theory is deemed to be wrong.

    This cosmological principle forces us to adopt a non-anthropocentric view that immensely simplifies our description of the universe. It is at the very foundation of modern cosmology and integral part of the standard model of cosmology that describes the big bang and the cosmic expansion.

    But there is a snag.

    Since Einstein we know that we can not consider space as a entity separate from time. Space and time are inseparable. Or as Hermann Minkowski put it most eloquently a century ago:
    "Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality."
    How does the cosmological principle gel with the Minkowskian principle of unified spacetime?

    It doesn't.

    The cosmological principle separates space from time. It dictates our position in space to be mediocre, whilst allowing our position in time to be very special. Cosmologists tell us we are a very special generation privileged to live in a highly unique window of time.

    Sound familiar?

    The standard model

    Deep space observations have profoundly changed our view on the universe. This has resulted in what is referred to as the standard model of cosmology, the Lambda-CDM model. According to this model current times are absolutely unique. It tells us that the recently observed acceleration of the cosmic expansion just kicked in, and that it is only around the current age of the universe that this acceleration can be observed. At earlier times the acceleration would have been too small to be observable, and at later times distant galaxies will have accelerated out of view and thereby rendering the cosmic acceleration again unobservable. The cosmic acceleration happens to be observable around the time cosmologists populate planet earth.

    What is the ingredient in the Lambda-CDM model that is responsible for this coincidental acceleration?

    To answer that question, we need to wind back almost a century, to the time when Einstein was trying to get his newly derived theory of gravitation to describe the cosmos. In a misguided attempt to get a description for a static universe, Einstein introduced a cosmic tension in his theory in the hope that this tension could balance the gravitational attraction so as to render a static universe. When a decade later Edwin Hubble observed the universe not to be static but rather to expand, Einstein realized he could have predicted such a non-static universe, would he not have introduced the cosmic tension fudge factor into his theory of gravity. Einstein henceforth referred to the introduction of this cosmic tension as 'his biggest blunder'.

    Hubble watching Einstein being confronted with his 'biggest blunder'

    At the very end of the twentieth century, decades after Einstein's death, cosmologists found themselves with their backs against the wall. Faced with the unexpected observation of the cosmic acceleration they saw no other way out than to re-introduce Einstein's biggest blunder. Driven by further observational evidence, a slightly more generic form of cosmic tension, referred to these as 'dark energy', quickly gained prominence in mainstream cosmology. By tuning the dark energy tension such that at cosmic scales it overpowers gravity, a description of the cosmic acceleration results. The resulting model is referred to as the Lambda-CDM* model, a remarkably successful description of the universe. But also a description that leads to a weird coincidence.

    Amongst other feats, the Lambda-CDM model (purple curve) is highly successful in describing the 'echo of the big bang': the cosmic microwave background (the symbols denote measurements on the statistics of its anisotropy). 

    Quantifying the Coincidence

    So we have a highly successful cosmological model hampered by a bizarre coincidence. But how bizarre is this coincidence really?

    Let us put some numbers in. What is the current age of the universe? Expressed in natural units, about 1061 ticks have passed since the big bang. It is around this very time that we can observe the accelerated expansion of the universe. But only marginally so. It took us four centuries of telescope technology improvement before we managed to observe the cosmic acceleration. Observing cosmic acceleration is challenging, as one needs to look very, very deep into space to see any effect. This is because dark energy represents a cumulative effect. In a rough analogy, one can think of dark energy as a negative mass that increases proportional to volume. For a volume the size of our earth, the dark energy adds up to a negative mass corresponding to removing a single grain of sand from the entire earth.

    Tiny as it might be from our earthly perspective, the dark energy effect does grow proportional to volume. It keeps growing with increasing size until we reach the size of the whole observable universe. At that size, the effect has grown from taking away a grain of sand into an effect that overpowers the total mass in the universe. At the scale of the universe, dark energy beats the deceleration due to gravitational attraction, and the result is a cosmic acceleration.

    All of this applies to a cosmic age of around 1061 ticks. Earlier on (any time till about 1060 ticks since the big bang) the size of the universe was so much smaller that the total dark energy effect got dwarfed by the forces of gravity. Would we have lived around 1060 ticks after the big bang, we surely would not have observed a cosmic acceleration. Later on (any time around 1062 ticks or later) the acceleration will again be undetectable. This is not due to the relative weakness of the dark energy, but rather due to the distant objects in the universe that currently allow us to observe cosmic acceleration having accelerated out of view.

    It is important to realize that we are not just talking practical issues here. Accelerated expansion does not just make late deep space observations impracticable, but rather poses strict fundamental limits. According to the Lambda-CDM model, ultimately all distant galaxies will permanently accelerate out of sight beyond a cosmic horizon that can effectively be considered 'the edge of the observable universe'. It doesn't matter how big a telescope future generations will be able to construct, if all distant galaxies have accelerated out of the observable universe, those future generations will not be able to even get a hint of the cosmic acceleration.

    The net effect of all of this is that we are here just at the right time. Neither earlier astronomers nor later astronomers would be able to correctly predict the dynamics and ultimate fate of the universe. It is only us who can accomplish this feat.

    Amongst those interested in science, many hold a clear aversion against the concept of dark energy. Not seldomly, this aversion seems fueled solely by the very term 'dark energy' which carries the connotation of 'ill understood' and 'mysterious'. However, would those dark energy critics become familiar with the feats accomplished by Lambda-CDM, the cosmological model firmly build on a dark energy foundation, I am sure many of them would embrace the model.

    But one doubt should stays: how come we, scientific heirs of Copernicus, end up with such a strangely anti-Copernican standard model of cosmology? Are we really living at the very right moment in a mediocre location? Or is Lambda-CDM ready for revision? Should we eliminate Lambda, the dark energy component, from the model?

    One thing is sure: any model claimed to be capable of replace Lambda-CDM will face some tough challenges in describing a wealth of highly accurate cosmological data.

    * Lambda is the symbol for the cosmological tension Einstein introduced into his equation and stands for the dark energy component that drives the cosmic acceleration.


    Are you saying you believe in a steady state? Astronomers before and after us would have difficulty detecting accelerated cosmic expansion, but physicists would find it anyways, say via advanced experiments in the local universe or by finding a consistent theory of quantum gravity. The cosmological principle, in my book, says that the spatial hyper-surface is so uniform that you can infer (“construct”) a cosmic time t from the observed temperature T. Quantum physics still needs absolute time, and quantum physics is something rather fundamental (how the observer interacts with the observed, what can be consistently conscious at all, …). Gravity and relativity on the other hand are only emergent (are the thermodynamics of an underlying, maybe absolute layer that may only in a further step be relationally reducible). The ether may be hidden, but hidden quantum variables are inconsistent. I would be very careful to elevate space-time relativity, and effective, emergent symmetry, to such an important status.
    Johannes Koelman
    Absolutely not, no Hoylian scenarios for me. I do not want to propose a perfect cosmological principle, but on the other hand I can not accept this weird coincidence that can be traced back to the introduction of the dark energy component in the model. The coincidence mentioned in my opinion forces us to consider the question "have we introduced a model with too many parameters?"

    If humans would have evolved 10^62 ticks or later after the big bang, I really see no way physicists could have ever come up with a credible theory containing dark energy. And if nature is so effective in wiping out its traces at any time different from ours, then I would feel forced to conclude it is also doing it now. This would be a too negative view for me to accept.
    Amateur Astronomer

    "Have we introduced a model with too many parameters?"

    I would guess that we have introduced too many parameters, but not enough dimensions. Already General Relativity needs 6 dimensions near light speed to avoid coordinate transformations between space and time like frames.

    Lambda-CDM has some serious problems. Remember the Ptolemaic system survived a long time with serious problems, and was replacing only after improved observations supported better theories.

    It is obvious that Lambda-CDM ignores quantum mechanics, so half of the readers should realize already that Lambda-CDM will be replaced by a better theory. Quantum Field Theory is my preference for a contender. QFT had a few problems too, but now it appears they can be resolved. Gravity was not described in QFT, but now gravity appears to be emergent from entropic energy and information. Curvature was not correctly described, but now it appears that equal partition of energy in the vacuum will resolve that. The obvious remedy would be to add the two corrections, but the preferred method now is to rewrite the theories from fundamental principles and let the corrections emerge as a consequence of the correct theory.

    The biggest problem in Lambda-CDM and the one most relevant to Johannes’ articles is the way electromagnetic fields are handled or sometimes simply ignored in the stress energy tensor of Friedmann–Lemaître–Robertson–Walker metric (FLRW).  One remedy would be to put the electromagnetic terms into the stress energy tensor, but the preferred remedy now is to increase the number of dimensions and let the Maxwell equations emerge from the fundamentals as they do in Kaluza Klein theory. Either way Lambda-CDM is due for some serious updating.

    Lambda-CDM has a fundamental weakness dating from the 1934 book by Richard Tolman. First he treated a static DC electromagnetic field by the method of Reissner Nordström where the field counteracts gravity and bends space backward, causing time to pass more quickly, and masses to repel each other. It led in later times to theories of accelerating galaxies driven by faint electromagnetic fields instead of dark energy. Then in the nest paragraph, Tolman treated alternating AC electromagnetic fields as contributors to positive curvature, increasing the strength of gravity, because of the deflection of star light passing near the sun.

    It seems a bit irrational to have two different curvatures resulting from electromagnetic fields. Dark energy could be eliminated from Lambda-CDM If the bending of light near the sun could be attributed to a tiny decrease of light speed in a gravitational field. The difference would be 150 parts per billion change in the speed of star light passing near the sun.  An equation would look something like this for nearly flat space with g local gravity.

    d(c^2) /dr  =  g

    That is a change of about 10 parts in 10^17 in the vertical direction on Earth, or too small for Michelson and Morley to measure.

    For strongly curved space there is a correction from the same partition function that was applied to QFT above.

    d(c^2) /dr  =  2 (1-Z) g

    In flat space Z is exactly one half.  To give some idea of how little is needed to get rid of Dark Energy, the negative curvature that is needed in deep space to account for accelerating galaxies only requires a tiny change in Z.

    ΔZ = 3* 10^-24

    Friedmann–Lemaître–Robertson–Walker metric treats all of the radiant energy just like Tolman treated AC fields in his book. It ignores the static electromagnetic fields completely, which compared to ΔZ, makes Lambda-CDM look like it has a fatal flaw. That doesn’t mean the improved model will interpret astronomical data differently. It means the conclusions about Dark Energy will be different from those in Lambda-CDM.

    In conclusion Lambda-CDM has problems, and there are proposed remedies. The remedies are not rejected by the strength of Lambda-CDM. The remedies are ignored in favor of completely new theories derived from fundamental principles. In new theories the remedies emerge from fewer parameters, but larger numbers of dimensions. Lambda-CDM is not a fortress that is impossible to destroy. It is a museum piece to be preserved, visited, and admired.

    Earth scientists have been through the same struggle. Pre-scientific "geologists" explained the earths features with all kinds of catastrophes. The science kicked in in the 19th century and all catastrophes were banned: Everything had to be explained from gradual processes.

    But in the latter half of the 20th century it became clear that sometimes catastrophes do happen. Science had to live with the fact that sometimes a piece of rock hits the earth that is sufficiently large to wipe out most life forms. Or that a super-volcanic eruption can change the atmosphere enough to do the same.

    Special times and places are very suspect, I agree. But it takes time to develop galaxies, stars and planets and to burn enough hydrogen and helium into heavier elements to sustain life. At an age of 2 Billion years (10^60), life probably could not have emerged. After 10 Billion years, it could have. After 200 Billion years (10^62), life maybe has become impossible anyway, eg, because too much of the hydrogen has burned up or black holes gobbled up too starts etc.

    So, in that sense, life itself might be in this special place in time.

    I rather believe not, but the universe might not care about what I want.

    Johannes Koelman
    Rob -- I would put it much stronger: the universe does not care what you or I want, and it does not care whether it took life on some pale blue dot 10^60 ticks to develop. Why would the universe be so kind to us to make dark energy observable just at the very time we are capable of noticing it?

    And yes, catastrophes are relevant to geology and our evolution. But the point is, they happen all the time. There is no *special impact*. The K/T event happens to be the last major event currently, but others have taken place and more will follow.
    Perhaps cosmic acceleration just isn't that important and invariant. Maybe at 10^64 ticks we'd start observing a deflating universe. Or maybe at 10^58 there wasn't much acceleration, but cosmic torsion was going on. Geological and evolutionary catastrophe's happen all the time on the time scale of geology/life, cosmic catastrophe's would operate on a cosmic scale that might preclude us ever observing the evidence of more than one.

    We're still bound by observing the universe from a rounding error away from a single point in spacetime, and we're stuck trying to extrapolate an understanding of the whole universe from that. Copernicus's ideals are helpful in that you are better off assuming one point is reflective of the rest than that one point is privileged, but any extrapolation from a single point is likely to be wrong in some ways.

    Johannes Koelman
    "Perhaps cosmic acceleration just isn't that important [..]"

    Paul -- that could be true, but it is a perspective difficult to maintain if the explanation of this acceleration requires an amount of energy about 2.5 times as big as the total (luminous and dark) mass content of the universe.
    Quentin Rowe
    And why would the universe be so kind to have provided a whole universe, just for us?

    We are steeped in centralism, and despite Copernicus's teaching, we haven't really changed our thinking at all. With this in mind, why don't we just surrender, and consider that we may be central to the universe?  To be or not to be, this is the question...   ;-)
    If we want to follow the idea of non-static Universe and simultaneously deny the idea of "coincidence", the only remaining logical option would be that observabily of expanding Universe and development of Intelligent life are interconnected events...
    I don't know of anything that could link those two events, but somehow it still seems a possibility. Probably, the relationship might derive from some of the Quantum laws of interaction between the Observer and the System... (I don't want to meditate on the subject any further, since I don't feel qualified - I'm just a pop-science junkie, after all, not a scientist... :))

    Quentin Rowe
    If we want to follow the idea of non-static Universe and simultaneously
    deny the idea of "coincidence", the only remaining logical option would
    be that observabily of expanding Universe and development of Intelligent
    life are interconnected events...

    I've considered this idea before, although I don't believe inteligence is a requirement. I would prefer conscienceness instead. I think the key is to not separate consciencness and physicality in the first place. Keep them united, which is more a more natural way to approach the problem.

    First, I'm going to invoke the first law of thermo to suggest non-volumetric energy expression as a real possibility. We live in a volumetric universe, but first law requires that energy cannot be destroyed,  just rearranged, converted or expressed as some other arrangement.

    A singularity is non-volumetric, and therefore appears infinite in many ways, particularly it's density. In other words, there's a whole lot going on inside a singularity.

    If it were possible for a conscious entity to reside in such a singularity, an entity whose energy states were non-volumetric, then imagine that being decided to take a peek into a volumetric universe.

    It might go something like this:

    First peek: "Hmmm, what we got here?" (senses wide-open spaces, lots of ROOM!)
    Realisation: "Whoa, man this place has so much POTENTIAL!
    Massive and rapid expansion:  (realisation blows mind, inflation ensues)
    Interesting and multiple phenomena emerge:
    "Wait up, I never woud've guessed it would be like this... I think I'll back off with the real-estate aquisition and check out the neighbourhood. This is fascinating!"
    Further down the ages: "I think I'm coming to grips with this space-time thing. I'm feeling right at home here. I've had a lot of fun, but I'd like to see what hppens if I carry on with the expansion."
    An eternity later: "far out, I'm back to where I started: a singularity, but an inverted version of where I began. An infinitely flat singularity of pure volume, with zero density and zero tempurature."
    Goes back home: "Man, what  trip! I've got to tell my friends, but they will never believe me"

    Of course, this is all just rabid imagination at work here. No science, just a bit of fun. ;-)

    I would agree with the idea of consciousness. But then - either consciousness, or intellect are not fully defined, to my knowledge... And what defines the Observer then? An ability to comprehend and react to the changes in the System observed?

    Indeed, I see three logically possible options:

    1) the dark energy being observable now seems all too convenient, but is actually a true coincidence

    2) there is some deep (yet undiscovered) connection between dark energy becoming dominant at cosmological scales and the evolution of life

    3) the big bang theory that incorporates dark energy is flawed.

    Current consensus seems to favor 1). The author suggests 3) might be the case. I would love 2) being the right answer.

    In the future won't there be new most-distant objects the will allow the observation of dark-energy (red shift?)? Objects which are next most distant presently.

    Johannes Koelman
    Anon -- good question. The answer is "no". At some stage the only objects (galaxies) remaining will be those gravitationally bound to the galaxy cluster our Milky Way belongs to. The gravitational attraction between objects in his cluster prevents them from expanding according to Hubble's law.
    > ultimately all distant galaxies will permanently accelerate out of sight beyond a cosmic horizon

    How distant is "distant"? Assuming the distance of the horizon can change (I assume reduce) over an interval; how long would the interval be while the observation can be made?

    Although my degrees are in the biological sciences and electronics, this article moved some information I'd learned in college physics decades ago to the forefront, and has caused me to consider an allegory between the observations of the universe and the difficulty in "observing" quarks. If I remember my old lessons correctly, attempting to observe the charm of a quark changes the state of the quark, so it has to be observed indirectly to come to a conclusion on its charm state. I would suppose the same may be true of dark matter/energy. It may require setting up a space probe to observe the universe from a significant distance away from Earth, and transmit its observations for comparisons. Using the ocean analogy you opened your article with, it would be akin to observing a wave on the horizon from sea level at two locations along the coast - the bend of the wave may be noticeable from one location but not the other. The trick would be finding what is the significant distance required to make such a comparative observation? Anyway, just thought I'd share my thoughts - interesting article!
    Chris Qualls

    You're still speaking of factors of ten for the coïncidences. It's not nice, no, but it's not like we're only one or two billion years off.

    Would life have been possible as early as 1.5E9 years after the Big Bang? If Dark Energy is 'observable' for some 140E9, I'd say we're in on the ground floor. We've found it almost as soon as we've come into existence.

    Johannes Koelman
    Sili -- thanks for asking this question! It is a very good question that gives me an opportunity to stress a key point:
    to determine whether or not there is a coincidence, we should avoid an anthropocentric bias. To use a linear timescale of around 10^61 ticks (some 15 billion years) would introduce such an anthropocentric bias. This bias is avoided by considering time in terms of the number of 10-foldings. Only when viewed from this 'logarithmic perspective', it is that the coincidence stares us in the face.
    The theory is not anti-Copernican at all. It simply requires that there are many other sentient worlds that developed to our level in the past, or will develop to our level in the future, and many other worlds that are at our level right now. We are not in a special place, but one of a multitude that happens to be able to make these particular observations now, but also happens to not be able to make an untold number of other observations that other worlds were able to make.

    If I leave my office building just before it collapses in an earthquake am I especially lucky? Or am I more lucky if I were on my normal travels and safely at a client's office building all the way across town? Or if I stayed home? Applied to the population of the city, the luck is randomly applied but to each subjectively evaluated. On a cosmic scale, the witnesses to an event are in no way special, but just part of a distributions of uncounted observers and untold numbers of events.

    And that makes sense, too... The outcome of the event depends on the Observer's vantage point, why not?

    Johannes Koelman
    "We are [..] able to make these particular observations now, but also happens to not be able to make an untold number of other observations [..]"

    Absolutely. That is a perfectly valid point of view. But a view with dark consequences: it tells us we will never be able to fully comprehend the universe. As I remarked in one of the reactions above: this for me is a too negative perspective.
    Bonny Bonobo alias Brat
    Couldn't all of this, including the coincidence regarding man's current evolutionary observational abilities, be explained more simply by the cyclic model of the universe, and any one of the cosmological models that it contains, in which the universe follows infinite, self-sustaining cycles?
    For example, Einstein's oscillating universe theory theorized a universe "following an eternal series of oscillations, each beginning with a big bang and ending with a big crunch; in the interim, the universe would expand for a period of time before the gravitational attraction of matter causes it to collapse back in and undergo a bounce". See
    My article about researchers identifying a potential blue green algae cause & L-Serine treatment for Lou Gehrig's ALS, MND, Parkinsons & Alzheimers is at
    Bonny Bonobo alias Brat
    Except I should add that I think there are probably multiple big bangs, like a firework display throughout the universe, and each big bang has its own multiverse around it, which is either expanding or contracting against either a resistance or a concordance with whatever is happening in its adjacent multiverses. 

    Visually it would be a bit like the bubbles in a glass of champagne but on a much larger and slower scale, and there would be no glass to contain the champagne. Just a universe of infinite champagne in every direction. This is the Bonobo Champage Universe theory.
    My article about researchers identifying a potential blue green algae cause & L-Serine treatment for Lou Gehrig's ALS, MND, Parkinsons & Alzheimers is at
    Quentin Rowe
    Actually, I don't think it matters much how the universe continues to be a universe, whether the cyclic, multiverse, constant-state, or continuous inflation models are invoked. The issue at stake here is "does existence have a beginning and an end, or is it eternal?"

    To make the question even trickier, we can ask "does physical existence have a beginning and an end, or is it eternal? This version allows the possibility of non-volumetric (non-space-time) expressions of energy.

    From the point of view of life, or a conscious observer, what matters is how many possible configurations of state-space are available to express all possible outcomes. From this emerge the laws of physics, us, and the multitude of discovered and undiscovered phenomena in between. A playground really!

    As observations make it clear that the universe will not collapse, we need to consider more the implications of what it means for the future of the physical universe, and why we would even care if it will eventually stretch out to a flat 'empty' space.

    Johannes articles of late have succeeded in getting us to explore these important issues, and I'm really enjoying the discussions and comments.
    Amateur Astronomer
    “Actually, I don't think it matters much how the universe continues to be a universe, whether the cyclic, multiverse, constant-state, or continuous inflation models are invoked. The issue at stake here is "does existence have a beginning and an end, or is it eternal?" Quentin, from the photon point of view the cosmos probably does have a beginning and an end, separated by no distance and no time, or in quantum terms, not more than one Planck length in one Planck time. That is the model produced by the uncertainty principle for cosmic beginnings. Fortunately we have the Lorentz transformations to give us some space and time from the same physical event. If there really was no mass involved in the cosmic creation, then the Lorentz transformations from light speed give us an indeterminate number of observers, energy densities, physical sizes, and expected cosmic life times. It is possible to make some estimates from parts of existing science combined together in unusual ways, and slightly extended with new ideas. Best thinking about entropy and energy in cosmic creation is that the focusing of radiant energy causes a slow accumulation of total energy. Here focusing represents a non random component in an otherwise random process. Where the nonrandom processing occurs there is a local decrease in total entropy as described by Schrödinger in the third law. Cosmic creation then represents a non random selection combined with the creative potential of uncertainty. It is a bit more complicated than that, because in cosmic time all of the physical constants are probably changing slowly. When the estimates are made with the vacuum potential created by radiant focusing, the conclusion is a very old cosmos, much larger and older than the universe. Also in this version the cosmos contains an indeterminate number of universes. The cosmic time and space is estimated to be large enough to contain as many universes as there are grains of sand in the oceans and specks of dust in the deserts. Creation of the universe in an old cosmos does not necessarily have to be a quantum event occurring by chance. The best ideas about that say the slow accumulation of vacuum potential reaches a limit. In holographic terms, the information storage requirements exceed the available storage space. Condensed energy of rest mass is the likely response to a shortage of storage space. Some scientists believe a big bang occurs too create a universe when the fine structure drifts out of the stable range. Will it end? I guess the cosmos will not end. There is no way to predict the cosmic duration, or even a decline of the cosmic potential. Lorentz transformations of the photonic event can contain any conceivable cosmic duration, even infinite time. With the presently prevailing science there are guesses that the universe might end or it might not. Ten years ago most scientists were sure it would end one way or another. It was a rather dull view of science, before galactic acceleration was discovered. If the universe did end, there is really no way to predict the end of the cosmos. There are ways to predict the creation of new universes and the interaction of one universe and another. Some scientists claim to have discovered a mature galaxy near the visible horizon, where everything should be very young at an early stage in our universe. Lambda-CDM is not able to handle multiple universes and light speed with its 4 dimensions. To go that far a six dimensional model is required. I prefer QFT, but here is a link to a rather good competing theory that predicts emergent gravity from 6 dimensional space time applied to general relativity. Even in 4 dimensions there are three dimensions of time like coordinates near light speed. That requires a transformation of coordinates during acceleration. Six dimensions eliminate the need for coordinate transformation during acceleration. The 6 dimensional frame is the probably not the final theory. It is just the largest coordinate system that can be measured with current technology. Three dimensions of time give a new meaning to your question. There could be an end in one variety of time, but not the other varieties of time. The end in one time line might only be represented as a change of direction in the other time lines. The bottom line is that existence probably did have a beginning, but it is not likely to end, although there will be changes that look like an end from some view points.
    I cant see how eliminating the dark energy solves the problem, actually....

    ...the acceleration that would put galaxies out of our visible horizon in the future would still be there.

    or maybe I am deeply confused :-)

    Some time ago Johannes introduced the idea here that entropic acceleration could explain the observed cosmic acceleration. To some extend the idea caught on (several groups including one headed by Nobel laureate Smoot have done follow-up research. More recently, Johannes has written a dumbed-down version of the theory here entitled 'It From Bit - The Whole Shebang'.
    This novel description of the cosmic acceleration makes dramatically different predictions than the standard model. In particular galaxies would not accelerate out of view.

    Johannes Koelman
    AnonMax and AstroMonkey -- good question and comment. The cosmic acceleration predicted by the entropic gravity approach indeed does not lead to the coincidence described above. In a future blogpost I plan to describe the behavior of this cosmological model in more detail. One word of warning: despite the follow-up work, the model has not been tested against the various CMB measurements. So I don't want to put it forward at this stage as the solution to the coincidence problem.
    thanks! in the past I had seen a piece of speech given by DeGrasse Tyson about the subject of how "special" it is this moment in universe-time where we appeared as a species.

    I had found it awe-inspiring BUT troublesome, for the obvious anthropocentric issue.

    I look forward more insights from the entropic gravity approach.

    Amateur Astronomer
    “Explicit calculation of partition functions for a constant vacuum gauge potential” was published in 1983 by Alfred Actor, a leader in vacuum partition theory. URL: DOI: 10.1103/PhysRevD.27.2548 It was published in a peer reviewed magazine of The American Physical Society while he was working in the Department of Physics at Pennsylvania State University. “The partition function and thermodynamic potential are calculated in arbitrary space-time dimension d for scalar and spinor fields coupled to a constant vacuum gauge potential gA0 at finite temperature T. For d=2, 4, 6, _ _ _, closed expressions in terms of Bernoulli polynomials are obtained. This generalizes known results for d=4.” Three important items are found in the paper. Two are from the partition function and the statistical thermodynamic potential applied to the vacuum with a finite temperature. The other interesting part is that Alfred Actor generalized his vacuum partition solutions to 6 dimensions, which is also now proposed as the coordinate system for general relativity near light speed. Alfred Actor was 20 years ahead of his time in some of his topics, but now nearly forgotten in the age of internet. My greatest difficulty with Lambda-CDM is the absence of a partition of the vacuum with statistical thermodynamics in 6 dimensions. These things predate Lambda-CDM, making the omission a serious flaw.

    I'm not a scientist or a journalist, I'm actually a web developer that takes an interest in cosmology.
    Thought I'd add my 2 cents and maybe you intellectual people can enlighten me.

    I'm basing what I say on personal opinion:

    Could it not be so that the universe just 'is' there is no time-line no beginning or end, almost the same concept humans have of God. Human's like to label things, put them in boxes so we think we understand them.

    How could we possibly start to put the universe in a box when there's so much about our own planet that we aren't unaware of?

    I believe that the universe is constant, it recycles itself the same way our planet does, I would prefer to be optimistic and say that this expansion of space isn't true but say it is and everything expands to a state where it becomes the Big rip and atom's can't even hold themselves together maybe there is some kind of recycling process and it will reach a point where it contracts back to a singularity then explodes again or there's a glitch in the quantum world (with an infinite amount of time anything is possible).

    I just can't believe that once there is nothing but the emptiness of space there will never be anything else....
    If time and space is infinite then how are we here now? :)