Dark energy might not exist


Please consider donating to Behind the Black, by giving either a one-time contribution or a regular subscription, as outlined in the tip jar to the right. Your support will allow me to continue covering science and culture as I have for the past twenty years, independent and free from any outside influence.

The uncertainty of science: A new model for the universe that omits dark energy produces a better fit to what is know than previous theories that included it.

The new theory, dubbed timescape cosmology, includes the known lumpiness of the universe, while the older traditional models that require dark energy do not.

Timescape cosmology has no dark energy. Instead, it includes variations in the effects of gravity caused by the lumpiness in the structure in the universe. Clocks carried by observers in galaxies differ from the clock that best describes average expansion once variations within the universe (known as “inhomogeneity” in the trade) becomes significant. Whether or not one infers accelerating expansion then depends crucially on the clock used. “Timescape cosmology gives a slightly better fit to the largest supernova data catalogue than Lambda Cold Dark Matter cosmology,” says Wiltshire.

He admits the statistical evidence is not yet strong enough to definitively rule in favour of one model over the other, and adds that future missions such as the European Space Agency’s Euclid spacecraft will have the power to distinguish between differing cosmology models.

Both models rely on a very weak data set, based on assumptions about Type 1a supernovae that are likely wrong. It is thus likely that neither explains anything, as neither really has a good picture of the actual universe.

Share

5 comments

  • Cotour

    Irony:

    The Anarchestra is made of junk and is real, and the existence of dark Matter may be “junk” science and may not in fact exist at all.

    The lowest and most base thinking is real and the highest and most sophisticated thinking may be incorrect and not exist. This reminds me of other things where some “sophisticated” thinking assumes one thing and it turns out to be exactly the other.

    What other examples in history of this are there?

    I am certain that this has happened all the time throughout history.

  • wayne

    yarrr, this paper is behind a paywall.

    Cotour–
    The whole History of Science, is an example of things like this. (assuming it does more accurately describes reality it will be adopted, if it doesn’t, it won’t.)

    For the Cosmological principle, it is assumed that, on large enough scales, the Universe is isotropic (looks essentially the same in all directions) & homogeneous (any given large space is essentially equal to any other given large space.) If it’s not, depending on what galaxy you are in, you might see the Universe accelerate or decelerate from your reference frame.

    As Mr. Z touched upon, we have trouble determining accurate distances to far away things. It’s the “extra-galactic distance-ladder” ‘thing. And while there are good reasons for accepting what we think we know about distance, it inevitably leads to boxing you in to some degree, for a whole lot of other situations in Cosmology that have to be explained within the theory.

    Love me some Cosmology threads!
    Great Topic, Interesting development.
    Too late for me to ponder effectively!

    (Tangentially– Dr. Roger Penrose and his Conformal Cyclical Cosmology, doesn’t rely on dark-matter, nor inflation., and he tackles the 2nd law of thermodynamics, which a lot of other theories gloss over.)

  • My opinion on dark energy/matter is known, so I won’t rehash it. I will say that when doing proofs I was taught to strive for the elegant solution. Dark energy/matter isn’t elegant.

  • wayne

    Blair–
    good point.
    (I would maintain, Penrose is very elegant.)

    whoops– I do need to restate my characterization of Penrose’s Model and dark-matter.
    This is new:

    “Dark Matter Decay?”
    Roger Penrose
    Quantum Physics and Gravity workshop
    Vienna June 20, 2017
    https://youtu.be/0DMlzJ7da3s
    1:01:36

    “In the cosmological scheme of conformal cyclic cosmology (CCC), the equations governing the crossover form each aeon to the next demand the creation of a dominant new scalar material that is postulated to be dark matter. In order that this material does not build up from aeon to aeon, it is taken to decay away completely over the history of the aeon. The dark matter particles (erebons) would be expected to behave as essentially classical particles of around a Planck mass, interacting only gravitationally, and their decay would be mainly responsible for the (~scale invariant) temperature fluctuations in the CMB of the succeeding aeon. In our own aeon, erebon decay ought to be detectable as impulsive events observable by gravitational wave detectors.”
    -For this, he goes through his CCC relatively fast then jumps right into the craziness.

    Ever since Penrose came up with his Model, he’s been trying to flesh out aspects that might be experimentally confirmed/refuted. (His previous venture into analyzing the CMB was not fruitful.)

    Again, great Topic!

  • LocalFluff

    I think they have conveniently bunched together all the problems into that Dark Energy and Inflation thingy, so that they can more easily move on with what can be investigated now. When I watch conferences such as those of the Space Telescope Science Institute, things like dark Energy are never questioned. It is accepted as the working hypothesis. More, I think, for practical reasons than as the truly believed description of reality.

    While not much questioned by professional astrophysicists, Dark Energy and Inflation are also not at all as celebrated like Relativity is. Einstein remains the foundation of astrophysics. Every astronomer points at Relativity and proudly exclaims that here we’ve got a theory that works! DE&I they rather not mention, just silently assume for the time being.

Leave a Reply

Your email address will not be published. Required fields are marked *