Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 


Forgot your password?
Close
typodupeerror
×
Space Science

Simulation Suggests 68 Percent of the Universe May Not Actually Exist (newatlas.com) 106

Posted by BeauHD from the figment-of-your-imagination dept.
boley1 quotes a report from New Atlas: According to the Lambda Cold Dark Matter (Lambda-CDM) model, which is the current accepted standard for how the universe began and evolved, the ordinary matter we encounter every day only makes up around five percent of the universe's density, with dark matter comprising 27 percent, and the remaining 68 percent made up of dark energy, a so-far theoretical force driving the expansion of the universe. A new study has questioned whether dark energy exists at all, citing computer simulations that found that by accounting for the changing structure of the cosmos, the gap in the theory, which dark energy was proposed to fill, vanishes. According to the new study from Eotvos Lorand University in Hungary and the University of Hawaii, the discrepancy that dark energy was "invented" to fill might have arisen from the parts of the theory that were glossed over for the sake of simplicity. The researchers set up a computer simulation of how the universe formed, based on its large-scale structure. That structure apparently takes the form of "foam," where galaxies are found on the thin walls of each bubble, but large pockets in the middle are mostly devoid of both normal and dark matter. The team simulated how gravity would affect matter in this structure and found that, rather than the universe expanding in a smooth, uniform manner, different parts of it would expand at different rates. Importantly, though, the overall average rate of expansion is still consistent with observations, and points to accelerated expansion. The end result is what the team calls the Avera model. If the research stands up to scrutiny, it could change the direction of the study of physics away from chasing the ghost of dark energy. "The theory of general relativity is fundamental in understanding the way the universe evolves," says Dr Laszlo Dobos, co-author of the new paper. "We do not question its validity; we question the validity of the approximate solutions. Our findings rely on a mathematical conjecture which permits the differential expansion of space, consistent with general relativity, and they show how the formation of complex structures of matter affects the expansion. These issues were previously swept under the rug but taking them into account can explain the acceleration without the need for dark energy." The study has been published in the Monthly Notices of the Royal Astronomical Society. You can view an animation that compares the different models here.
This discussion has been archived. No new comments can be posted.

Simulation Suggests 68 Percent of the Universe May Not Actually Exist More

Simulation Suggests 68 Percent of the Universe May Not Actually Exist

Comments Filter:

  • That is new for an April Fool's prank :D

    • Re: (Score:2)

      by Zumbs ( 1241138 )
      The date on the linked article is March 30th, so even taking different time zones and daylight savings etc into account, it was not published on April 1st. Unless they modified the date stamp to fool us.

      • The date on the linked article is March 30th, so even taking different time zones and daylight savings etc into account, it was not published on April 1st. Unless they modified the date stamp to fool us.

        It is a well-known pseudo-scientific trope, I think even xkcd has made fun of this "theory". I am guessing slashdot included it today to troll physicists, since this tends to piss them off.

      • Spacetime was compressed so that this prank is actually on Apr 1.
    • What they meant to say is that 68% of the universe consists of physicists' simplifying assumptions, i.e.: space is uniformly flat everywhere and everywhen, the gravitational constant is the same everywhere and everywhen, etc.

  • It seems the sims are running simulations in my simulated universe.
    - The creator.

    • bs (Score:1)

      by Anonymous Coward

      Nah, it is the Zigerions. They nest 3 simulations just to be extra safe. And still fail.

    • Heard a good one this week:

      "Maybe nothing can go faster than the speed of light because that's the tick-rate of the server our simulation is running in."

  • More accurately: dark matter/energy is gone. (Score:5, Funny)

    by Gravis Zero ( 934156 ) on Saturday April 01, 2017 @06:07AM (#54157035)

    This was published March 30, 2017 so it's not a April fools joke.

    Suck it, dark matter! You ain't real, bro! *High-fives girlfriend* Aww, she's not real either. ;(

    • No, just the dark energy

      • I was at a Carnegie Institute open house a year ago and was chatting with the lead scientist, and I asked him to describe Dark Energy in terms that my 10 year old son could grasp. He said "it's a correction to our equations so that our math agrees with our observations."

        That's when I stopped believing in dark energy. They just haven't made enough observations.

        • Replying to myself is bad style, I know, but I just want to add:

          They'll figure it out eventually. Those people are NOT idiots.

          • They'll figure it out eventually. Those people are NOT idiots.

            Many of them are not. Many of them realize that when they have a correction factor, like Einstein's Cosmological Constant, that those numbers represent "future work required to determine the cause of the need for this adjustment".

            But enough of them start to believe that the mathematical adjustment is a real phenomena that a significant group of people starts to go off the rails. We see a new phlogiston crop up every few decades and then it goes

        • "That's when I stopped believing in dark energy. They just haven't made enough observations."

          Dammit! Just when I was hoping to unload my leftover luminiferous aether.

        • The Cosmological Constant, which is the part of the equation that requires dark energy, is a fundamental part of the Einstein field equation. It is as real as a constant of integration is. There is no question mathematically that this term is required. The real question is what is its value, because theory does not predict that. Scientists tend to think it is one of 0, ~10^35, or ~10^88, but the question is very much open. The big range in predicted values is the problem, not the fact that there the fi

        • That is one of the dumbest things I've read. If that's literally all the research you've bothered to do into the phenomenon, you're a complete retard to even begin to have an opinion on it. Your "lead scientist" was clearly has also not done any astrophysics.

  • More accurately: dark matter/energy isn't. (Score:3, Funny)

    by Gravis Zero ( 934156 ) on Saturday April 01, 2017 @06:09AM (#54157039)

    This was published March 30, 2017 so it's not a April fools joke.

    In your face, dark matter! You ain't real, bro! *High-fives girlfriend* Aww, she's not real either. ;(

  • So this means my bitch of an ex-wife... (Score:1)

    by Anonymous Coward

    ...really doesn't have a heart, just like I suspected? Not that I'm bitter or anything.

  • Google (Score:1)

    by Anonymous Coward

    Why does everyone think it is hilarious to post bullshit on April Fools Day?

    I was frantically trying to get my young daughter to a Hospital and accidentally hit the "Game" icon in Google Maps.

    Anyway, it worked out well, my daughter died, and I am saving at least $5,000 to $10,000 a year!

    Thanks Google!

  • Don't DownVote Me, Bro (Score:5, Funny)

    by cellocgw ( 617879 ) <cellocgw&gmail,com> on Saturday April 01, 2017 @07:00AM (#54157103) Journal

    INB4:

    Black Matter Lives!

  • Can you make it brighter, so it makes my eyeballs bleed?

    • Re: (Score:2)

      by khchung ( 462899 )

      Is this the new beta? Guess /. hired too many programmers and web "designers" who have nothing better to do, and got to keep redesigning over and over to justify their pay.

      Oh, yeah, the new look SUCKS, I guess everyone already knew that.

  • thank goodness its april 1st, I was just heading back to soylentnews.org

  • If the expansion of the universe is not consistent, what causes the variation?

    • If the expansion of the universe is not consistent, what causes the variation?

      Its the inconsistency in the acoustic whooshing of the matter that causes it to be expansive.

    • Re:Not a physicist, but curious (Score:5, Interesting)

      by ByteSlicer ( 735276 ) on Saturday April 01, 2017 @08:34AM (#54157255)

      If the expansion of the universe is not consistent, what causes the variation?

      Einstein's equations are non-linear. The metric expansion of space-time depends on how much matter and energy there is inside that portion of space-time.

      Also, quantum fluctuations in the hot dense "quantum soup" before the big bang grew into large scale structures: mass seems to be concentrated in the walls of huge bubbles, as super-clusters of galaxies, with very little mass/energy inside.

      At the largest scales, the universe is still homogeneous, so on average, the expansion rate should be constant. But on the scale of the "bubbles", the differences in mass/energy density cause differences in the metric expansion of space-time.

      Until recently, this was ignored in simulations, because Einstein's equations are currently impossible to solve exactly at that scale. So now they used better approximations than before, that include this varying metric expansion, and found they don't need dark energy flows to explain some observations. Instead, differences in expansion rates make it appear that some regions "flow" towards other regions, despite everything expanding.

      From our point of view expansion appears to be accelerating because of this, causing us to believe that the cosmological constant Lambda (a.k.a. Dark Energy) is not zero. So now it seems they can explain a seemingly accelerating expansion with Lambda=0 using normal metric expansion.

      • You had me until the last paragraph. Gravity is only attractive, we would not see any acceleration in expansion, only uneven deceleration. This is why it was a complete surprise until the groundbreaking type 1a supernova study revealed it. When I was in school the three options were the Big Crunch, expansion that halts after an infinite time, or expansion that continues to slow down but never stop. Acceleration wasnt even considered mainstream.

    • Attempt at serious reply... (Score:4, Informative)

      by Richard Kirk ( 535523 ) on Saturday April 01, 2017 @09:58AM (#54157527)

      ...it's also a bit of a dull reply, as it is mostly about finding names for things...

      There didn't seem to be enough matter to explain the evolution of the universe, so scientists guessed at what might be causing it. It looked like there was more matter that we couldn't see, so they invented the idea of 'dark matter', which was something that had mass but was otherwise pretty inert so we didn't see it. BTW: 'dark' here is an old use meaning 'unable to be seen', such as 'the dark side of the moon' being the side that faces away from earth, not the side that is not lit by the sun. The other possibility was that gravity was somehow slightly different when operating over very large distances and times. This was settled because astronomers got better at calculating the distributions of mass in the universe when they thought there was something interesting to find, and found there were cases, such as the 'bullet nebula' where there were very significant amounts of mass in different places to the star-like matter we could see. This gives credence to the idea that 'dark matter' is a real sort of 'stuff', our can be treated as a sort of stuff, rather than just an systematic difference in the equations.

      Okay, suppose we assume for now there is lots of invisible stuff that has mass and momentum, but otherwise does not interact with anything else much (think of neutrinos, but more so). If we take our best assumptions as to the right amount of dark matter, then there is a slight error which means something else is pushing the universe apart. If it looks like extra energy, we call it 'dark energy' and astronomers start looking for ways to detect it. In the meanwhile, other people look for a rival model where there is a systematic error in the equations for very large distances and times. That's pretty much where we are now. Indeed, the two explanations are not different - one just describes the error as 'extra energy' and the other one does not - until we get some new experimental evidence that shows which explanation is more useful.

      Dark energy is a small correction term to our universe. If you want something we really don't understand, try the inflationary period of the early universe. We know it got really big, really fast, but really evenly; but we don't have any of the details.

  • Dark energy (Score:1)

    by Anonymous Coward

    Anybody who understands science and the scientific method, and isn't just an acolyte of the One True Religion of Science, must have surely seen something like this coming. Think about the reasoning:

    1. Our mathematical models of the vast and ancient universe, invented by us bald apes that are lucky to live a century, do not fully agree with observation.

    2. Therefore, to account for this discrepancy, the universe must consist primarily of unknown, invisible substances whose only interaction with our visible un

    • This is an intrinsic problem in observational sciences such as medicine and astronomy, where experiments cannot be performed: all of the postulated mechanisms are plausible hypotheses, rather than theories. The only way to falsify an hypothesis is to happen to make an observation that is at variance with the hypothesis. In experimental science, one can typically designs experiments that either provide or fail to provide such observations; in observational science, all one can do is watch and wait.

  • Or to be very specific, 68% of the researchers doing This Particular Study do not exist. That means the ones that DO just got a raise!

    Sounds like fraud to me. Call the Science Police!
  • The study showed that the "Dark" energy is not necessary to explain the expansion of the universe. Since they have never "proved" it existed, how can it "disappear"?
  • If this is true, then I just lost 145 pounds. Yipee!!!

    • Re: (Score:1)

      by Tablizer ( 95088 )

      If this is true, then I just lost 145 pounds. Yipee!!!

      Being married to a physicist:

      Wife: "Does this universe simulation make my ass look fat?"

      Husband: "Mind if I tweak a few sim parameters before I answer?"

      Wife: "Sounds like a waffly 'yes'. You can tweak your own parameter tonight!"

  • Regardless of conflicting theories, Dark Energy will live on. This is for two reasons: 1- Dark Energy is rather essential to some science fiction fantasy; and 2- Dark Energy is not copyrighted by Disney or any other litigious entity. Try using 'the Force', 'the Spice Melange', 'Sonic Screwdriver' or 'the One Ring' to explain your scifi miracles and legal problems arise.

    And, hey, It's Dark, and it's Energy; what's not to like?

    • Re: (Score:2)

      by mentil ( 1748130 )

      Look at how much Freud and Jung live on in pop psychology. Dark Matter/Energy aren't going anywhere in the public consciousness, even if they are fully debunked tomorrow. That said, they don't have much presence in the public consciousness, and there's always the good-old fallback explanation: aliens.

  • If it doesn't exist, then by definition it's not part of the universe.

    Better title. Researchers estimate the mass of the Universe be be 32% of the previous consensus models.

  • Musk is apparently convinced everything is just a simulation. He seems to be right about sooooo much... he could be right. I'm just a figment of his imagination.

  • Even God has deficit problems.

  • ...the discrepancy that dark energy was "invented" to fill might have arisen from the parts of the theory that were glossed over for the sake of simplicity. The researchers set up a computer simulation of how the universe formed, based on its large-scale structure. [Matter grew lumpy in simulations]...The team simulated how gravity would affect matter in this [lumpy] structure and found that, rather than the universe expanding in a smooth, uniform manner, different parts of it would expand at different rate

  • Wait until they find out that Dark Matter is is a similar aberration!

Slashdot Top Deals

Technology is dominated by those who manage what they do not understand.

Close