New theory eliminates need for dark energy


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The uncertainty of science: A new theory now shows that dark energy, the apparent acceleration of the universe’s expansion rate on large scales, does not need to exist in order to explain the data that astronomers have obtained.

In the new work, the researchers, led by Phd student Gábor Rácz of Eötvös Loránd University in Hungary, question the existence of dark energy and suggest an alternative explanation. They argue that conventional models of cosmology (the study of the origin and evolution of the universe), rely on approximations that ignore its structure, and where matter is assumed to have a uniform density. “Einstein’s equations of general relativity that describe the expansion of the universe are so complex mathematically, that for a hundred years no solutions accounting for the effect of cosmic structures have been found. We know from very precise supernova observations that the universe is accelerating, but at the same time we rely on coarse approximations to Einstein’s equations which may introduce serious side-effects, such as the need for dark energy, in the models designed to fit the observational data.” explains Dr László Dobos, co-author of the paper, also at Eötvös Loránd University.

In practice, normal and dark matter appear to fill the universe with a foam-like structure, where galaxies are located on the thin walls between bubbles, and are grouped into superclusters. The insides of the bubbles are in contrast almost empty of both kinds of matter. Using a computer simulation to model the effect of gravity on the distribution of millions of particles of dark matter, the scientists reconstructed the evolution of the universe, including the early clumping of matter, and the formation of large scale structure.

Unlike conventional simulations with a smoothly expanding universe, taking the structure into account led to a model where different regions of the cosmos expand at different rate. The average expansion rate though is consistent with present observations, which suggest an overall acceleration.

In other words, the uneven structure of the universe has never been considered in previous models, and once included in the equations the need for dark energy disappears.

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8 comments

  • pzatchok

    Someone just slayed the dragon.

    I wonder if this new model eventually allows for a closed universe instead of an ever expanding one?

  • wayne

    pzatchok-
    good stuff.
    Dr. Susskind has been consistently preaching we are in a paradigm shifting zone, and maybe this is it.
    Haven’t delved into this development yet, but just quickly referencing your open vs. closed thought; even if the universe is open, Dr. Penrose’s cyclic-theory handles that quite well, if one is partial to that, as I am. (given I only play a cosmologist on the interweb.)
    This gets into the isotropic vs. orthotropic perspective as well.

    Conformal Cyclic Cosmology
    Roger Penrose
    https://youtu.be/TIZCkg0Zs8Y
    (the quick 3:31 version)

  • LocalFluff

    Inter-clustural structure is only one of several independent proofs of dark mass. There’s also the rotation rate of galaxies, galaxy clusters as gravitational lenses and bullet galaxies. No one alternative theory fits them all. There might be more than one phenomena involved here. It’s anyway promising that they find ways to try to juggle with this invisible giant.
    -Mirror mirror in the sky, tell me why most mass’ so shy!

  • Diane Wilson

    And the one thing that we know about dark matter is that “dark matter” is short-hand for “there’s something going on here, but we have no idea what it is.”

    Paradigm changes, indeed. So if multiple paradigms change at once, is that a paradigm quake, or is it quantum paradigmatics?

  • wayne

    Diane–
    Totally agree the “dark-anything” moniker is unproductive and just smacks of “insert unknown term here.”
    (Not a fan of the concept of “inflation” either, but it does now strike me as possibly fitting in with this new idea, and with a less magical-bent to it.)
    –I’m an old Behavorist from the late 70’s, and we were big on paradigm shifts in psychology. I have no clue how that works in Physics/Cosmology.
    Just as an interested amateur, I tend to think the success of the whole Lamda CDM theories have inadvertently blinded us to some Fundamental Thing we are missing in all this.

    Not a string theory guy, but a lot of the Math is intriguing and solves other/different problems, and I’m partial to Dr. Penrose, in that he handles Entropy & Infinity, & some other pesky issues.

    (fascinating topic)

  • Diane Wilson

    Wayne,

    I think that physics and cosmology are oblivious to our paradigms, but our paradigms can surely blind us to reality. Even Einstein had trouble accepting some of the implications of relativity. That was pretty much the end of his career as a physicist, so he made a career change into being Einstein.

    I’m reminded of an old joke about a mathematician and a statistician facing off in court. The statistician says that the mathematician is insane. The mathematician says that a statistician can never be sure.

  • wayne

    Diane–
    …oh yeah– humans are masterful at overlaying our constructs onto Reality. For my money, it’s going to be some manifestation of entanglement.

    The paper is here–
    “Concordance cosmology without dark energy”
    http://www.ras.org.uk/images/stories/press/Cosmology/slx012.pdf
    (But I have not yet had a chance to ponder it.)

    At this point I would shill for Dr. Penrose’ new book, and this fresh lecture:

    Fashion, Faith and Fantasy in the new Physics of Reality
    Roger Penrose at the Royal Institution
    March 2017
    https://youtu.be/iH4XJHJ8AOw

  • Max

    Just to put it all in perspective.

    http://flip.it/ei03Ns

    Reminds me of the final “zoom out scene” in “men in black”

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