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Gravity Error Detected? (independent.co.uk) 276

jd (Slashdot reader #1,658) writes: The large scale maps of the universe show something is seriously wrong with current models of gravity and dark matter. The universe simply isn't clumping right and, no, it's not the new improved formula. As you go from the early universe to the present day, gravity should cause things to clump in specific ways.

It isn't. Which means dark matter can't be cold and general relativity may have a problem.

They need more data to prove it's not just a freaky part of the universe they're looking at, which is being collected.

"The new results come from the Kilo-Degree Survey, or KiDS, which uses the European Southern Observatory's Very Large Telescope to map the distribution of matter across our universe," according to the Independent: So far, it has charted roughly 5% of the extragalactic sky, from an analysis of 31 million galaxies that are as much as 10 billion light years away... That allows researchers to build up a picture of all matter in the universe, of which some 90 per cent is invisible, made up of dark matter and tenuous gas.
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Gravity Error Detected?

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  • No Dark Matter (Score:5, Interesting)

    by crow ( 16139 ) on Sunday August 02, 2020 @11:52AM (#60357655) Homepage Journal

    I've long believed that there is no such thing as dark matter. Yes, the mathematics of the current models show that it must be there, but I prefer the other option that we're missing something fundamental in the current models. This latest information suggests that I might be right.

    Of course, I'm not a physicist, and I appreciate scientists exploring all the options, including new theories as well as finding ways of detecting dark matter.

    • Re:No Dark Matter (Score:5, Interesting)

      by ClickOnThis ( 137803 ) on Sunday August 02, 2020 @12:04PM (#60357701) Journal

      I've long believed that there is no such thing as dark matter. Yes, the mathematics of the current models show that it must be there, but I prefer the other option that we're missing something fundamental in the current models. This latest information suggests that I might be right.

      Of course, I'm not a physicist, and I appreciate scientists exploring all the options, including new theories as well as finding ways of detecting dark matter.

      IAAP, although I am not an expert in dark matter/energy.

      I have wondered the same thing as you. However, scientists tend towards parsimony when they try to explain new phenomena. In other words, they apply Occam's Razor. Proposing an unseen dark matter/energy model is the current simplest explanation for observations. If this new observation demands the model be revised, well then, to borrow Arthur Eddington's words, so much the worse for dark matter/energy.

      • Re: (Score:2, Interesting)

        by crow ( 16139 )

        I disagree in that I think Occam's Razor says that the simplest solution is that we haven't figured out the model correctly, especially given our failures to detect, explain, or define dark matter (though it may be that I've missed some of that). However, it's one thing to say that our current model is wrong, and it's a whole nother thing to define a new model with working mathematics that explains everything we've observed without requiring dark matter. So until someone comes up with a better model, the

        • We've only failed to DIRECTLY detect dark matter. It is, by definition, hard to detect. We haven't searched the entire possible energy spectrum. This is like saying horses must not exist after searching the shoe store. We haven't finished looking at all the possible candidates. Remember the Higgs Boson? First predicted in 1964, first detected in 2012. However, with dark matter there is plenty of indirect evidence, just search Google for 5 minutes(Wikipedia is a good starting point). So, when the physicists
          • I'm pretty sure that it's not that we've "only failed to DIRECTLY detect dark matter". We can't detect dark matter - except by making the assumption that it's there, and looking for places it would be if it does exist. My understanding of dark matter is that it may be undetectable, even in principle, except by its gravitational effects (I'd be happy to be wrong). To me, that's unsatisfying. When we've got a new theory - just about any new theory - I'm probably going to lean toward it.
            • My understanding of dark matter is that it may be undetectable, even in principle, except by its gravitational effects

              and we can detect evidence of those gravitational effects. That sounds like a pretty good indirect detection. We detect other things by their effects on other forces, like light (electromagnetic forces)

              • Re: No Dark Matter (Score:5, Insightful)

                by apoc.famine ( 621563 ) <<apoc.famine> <at> <gmail.com>> on Sunday August 02, 2020 @06:49PM (#60358805) Journal

                We can detect evidence of those gravitational effects if and only if our current model of gravity is correct. That's the point that's being made here. If our current model of gravity is incomplete, than we need to go back and recalculate a whole lot of stuff, and that may or may not exclude dark matter.

                It's only a pretty good indirect detection if the model is correct, and we don't know that for sure.

                There's a nice bit of evidence that it is incomplete: The lack of connection between relativity and quantum. One would expect that two models of the physics of the universe with solid observational confirmation wouldn't be incompatible, and yet they are. That suggests to me that at least one of them is incomplete, and of the two, quantum effects are the only ones we can really experiment on. That makes me instantly suspicious of relativity, because we can't easily do experiments on it.

                IWAPALTA

          • Re: No Dark Matter (Score:4, Interesting)

            by MrL0G1C ( 867445 ) on Sunday August 02, 2020 @02:54PM (#60358235) Journal

            We've only failed to DIRECTLY detect dark matter.

            That would be because scientists have no idea what dark matter is so far as I'm aware. As a layman dark matter just looks like scientists fudging the numbers because gravity doesn't seem to be working right on larger scales.

            Dark matter strikes me as being the modern Aether, a stop gap until something better comes along. https://en.wikipedia.org/wiki/... [wikipedia.org]

            • Dark matter strikes me as being the modern Aether, a stop gap until something better comes along.

              Or it could be the modern neutrino, fixing serious problems with physics theory, but undetectable for decades after it was proposed.

            • Re: No Dark Matter (Score:5, Informative)

              by dryeo ( 100693 ) on Sunday August 02, 2020 @03:26PM (#60358327)

              Aether wasn't a stopgap, it was based on serious reasoning and made perfect sense in its time. Waves need a medium to move in and light has the properties of waves.
              When instruments got sensitive enough to measure the Aether, the results disagreed with theory. After a bunch of re-measurements and double checking, science moved on. That's how science works.
              The neutrino, a type of dark matter, was a fix to make some equations work. Eventually they were detected though we're still learning about them.
              A lot of people also get confused by the term "dark", which can mean unknown. Darkest Africa, the dark side of the Moon, dark matter, all unknowns at the time the terms were invented.

              • by ras ( 84108 )

                Aether didn't disappear. It just got renamed to Quantum Field Theory.

                • I don't think that space is filled with QFT and that's the medium that EM waves propagate through.

                  You were successfully executing a point, but botched the landing.

      • Phlogiston, Ether, Dark Matter

        What they have in common is that nobody detected any of them, but they are/were all convenient excuses.

        "Magic happens here" is not a hypothesis.

        • Re:No Dark Matter (Score:5, Insightful)

          by ClickOnThis ( 137803 ) on Sunday August 02, 2020 @02:58PM (#60358247) Journal

          Phlogiston and the ether were neither "convenient excuses" nor "magic" in their time. They were reasonable conclusions given the knowledge in their day.

          Phlogiston seemed a reasonable explanation for the way fire behaved -- as though something was "coming out" of the fuel. But it was disproved after careful experiments showed that burning something caused it to get heavier, not lighter.

          The ether seemed a reasonable explanation for the observed behavior of non-EM waves requiring a medium to propagate. It was disproved by the Michelson-Morley experiment.

          Science does not move in a stately fashion from one truth to another. It is messy. It progresses by making assumptions that seem to fit observations, and then testing them further. Even wrong assumptions can be useful, because they identify something that can be tested.

          Dark matter may very well go the way of phlogiston and the ether. But for now, it's a useful assumption, not a convenient excuse or magic.

          • Sorry, I mangled the ether part. Here's the correction:

            The ether seemed a reasonable explanation for the observed behavior of EM waves, because non-EM waves required a medium to propagate.

        • Re:No Dark Matter (Score:5, Interesting)

          by dryeo ( 100693 ) on Sunday August 02, 2020 @03:44PM (#60358381)

          Ether was indirectly detected, it was the medium that light waves traveled in at a time when all waves had been observed moving through a medium, and light had the properties of a wave. Made perfect sense in early 19th century physics.
          Note that when the instruments became sensitive enough to directly measure the ether and it was found not to be there, after a bunch of double checking, science moved on.
          The first type of dark matter was postulated to balance an equation. After a few decades, it was detected and became known matter instead of unknown (dark) matter. Originally called the neutron, as was considered so neutral to be close to undetectable, it eventually was renamed to the neutrino (little neutron) as a different particle had been postulated then found and given the name neutron.
          The positron was another example of a particle existing as an equation, or magic as you say. Eventually one was detected.
          Science, you make predictions, sometimes they come true, and sometimes they don't and you go back to the drawing board. Many of the predictions of dark matter have been detected, others need better instruments.

    • That is the thing: We never really said there is.
      We just observed something in the universe, that does not match our current models. And we gave that a name. "Dark matter".

      We know almost nothing else about it. None of our measurements up to now detected it. Which interestingly already tells us a lot about its properties. As in: How it does not interact.
      But it might not be matter at all. Even by the generic quantum field theory definition, where every type of "particle" is just a wavefunction in an all-encom

      • Re: No Dark Matter (Score:5, Informative)

        by lgw ( 121541 ) on Sunday August 02, 2020 @01:07PM (#60357909) Journal

        We know almost nothing else about it. None of our measurements up to now detected it.

        That's just not true. We haven't made a dark matter particle in the LHC (or, very likely, we make them constantly and can't detect them), or found one in early experiments that are basically repurposed neutrino observatories. But there's a world of difference between detecting a specific dark matter particle, and detecting dark matter,

        There are 3 sets of evidence for dark matter, and the last isn't usually discussed because it's technical, but it's the most direct and important:

        * Galaxy rotation rates (there were a great many theories for this early on)
        * Galaxy-sized masses causing gravitational lensing where there's no galaxy (rules out modified gravity theories at the galaxy scale),
        * Matter ratios detected in the WMAP CMBR data [wikipedia.org]

        That curve in the top half of that link, the anisotropy curve, tells us all sorts of things about the universe when it was about 300k years old. The curve is famous, because the first 2 peaks exactly matched predictions. Thinkgeek used to sell "Science Works, Bitches" shirts with that curve on it. But the 3rd and 4th peaks were somewhat new data.

        Why does that matter? It tells us through direct observation the ratio familiar matter to cold dark matter in the universe. And guess what - it's exactly the ratio to explain galaxy rotation rates. That's pretty much the end of other explanations for dark matter. It can't be neutrinos, or black holes, or modified gravity. Cold dark matter directly confirmed by measurements with multiple significant figures.

        And that in turn tells us a bit more about dark matter beyond "cold" (which just means "moves much slower than light"). It tells us that dark matter doesn't clump. There's no sort of "dark electron" or "dark photon" that can cause friction or otherwise radiate energy away from a collision, even in a form we can't see. We know this because that would give dark matter in galaxies the same sorts of shapes as regular matter, which is known not to be the case.

        We also know it doesn't interact via the strong force, or we'd have found it by now (not that that was theorized, but you never know until you look). Evidence is growing against it interacting via the weak force, unless the particle mass is many orders or magnitude away from protons and electron, e.g. axions are still viable.

        We just don't know its quantum mechanical properties. We know rather a lot about its properties at the scale of cosmology. The data in TFS is an interesting twist on dark energy, which is a whole different topic, and while minor even at the scale of galaxies is the most powerful thing happening at the scale of the visible universe. It's still very early days for dark energy, but we do know quite a bit about dark matter.

        • No, it tells us that IF we have got gravity right, then an additional explanation can match the curve (with another additional explanation to fuzz out the errors, dark energy). We should be starting from nothing and working forward.

          While dark matter and energy may indeed be the answer, they are certainly not proven, or even conclusive. Presenting them as "the answer" rather than "the current best answer that still has issues" is problematic. Keeping Dark Matter as the only solution slows research for other

          • by Demena ( 966987 )
            Dark matter is simply not the answer to galactic rotations as the same issues occur with widely separated binary stars. Dark matter works for one and NOT the other. Quantified Inertia works for both as well as million other things (including the output od an EM drive). QI is currently the best theory we have.
    • Re: (Score:2, Insightful)

      by Dread_ed ( 260158 )

      You and me both. The addition of dark matter and energy reeks of the same kind of thought that gave us the "cosmological constant."

      "Hey Einstein, what does this number here do?"

      "It keeps the universe from expanding."

      Looks a lot like:

      "Hey Fritz and Vera, whats does this dark stuff do?"

      "It keeps the galaxies from expanding."

      Not that these things are equivalent, galaxies expanding is the opposite of what we observe, and the universe expanding is what we observe. That said, what is behind each pronouncement i

      • Re:No Dark Matter (Score:5, Informative)

        by gtall ( 79522 ) on Sunday August 02, 2020 @02:49PM (#60358209)

        I see you don't understand dark matter or dark energy. Think of them as placeholders. Whatever we measure those placeholders must have in order for the universe to conform to a theory and observations means nothing more than that...and nothing less. They could have called them green eggs and ham for all the difference it makes. But people like you fixate on the names as though the names were somehow predicting what the phenomenon actually is.

      • by dryeo ( 100693 )

        Looks to me like how the neutrino came about. Hey, we need a magical particle to make this equation describing fusion to explain how the Sun shines balance. We'll call it the neutron as it is a neutral particle that might be undetectable.
        Decades later, after the name was used for another magical particle, the neutrino was detected.
        The positron was another magical particle that made some equations balance.

    • by gweihir ( 88907 )

      Well, we know we are missing something fundamental in the current models: No Quantum-Gravity. An inconsistent theory can, of course, have numerous other flaws. The only thing we have which is (probably) reliable are the observations. The rest is broken at this time.

    • Re:No Dark Matter (Score:4, Informative)

      by sg_oneill ( 159032 ) on Sunday August 02, 2020 @12:31PM (#60357803)

      but I prefer the other option that we're missing something fundamental in the current models, but I prefer the other option that we're missing something fundamental in the current models.

      Thats literally all "dark matter" and "dark energy" is. Placeholders in the math that say "Somethings missing in our model which we dont understand yet".

      Of course there are theories some more popular than others as to what that missing thing is. Thats whats being refered to here, evidence that the most popular theory, a massive particle that doesnt interact with most forces except gravity, might well be wrong, but that doesnt "disprove" dark matter, it just narrows down the possibilities as to what that question mark actually refers to.

        You *DO* believe in Dark Matter, you just didnt know what "Dark Matter" refers to. Now you do.

    • Re: (Score:2, Informative)

      by Anonymous Coward

      I've long believed that there is no such thing as dark matter.

      Cool. On what grounds, precisely? How do you explain the great many observations without gravitating matter which [at least so far] eludes direct observation?

      Yes, the mathematics of the current models show that it must be there

      Indeed.

      I prefer the other option that we're missing something fundamental in the current models.

      That's fine. People are entitled to their opinions. That said, what would that fundamental thing be? And how would it explain the observations? Do you have a falsifiable model, which fits the observations yet provide an alternative explanation compared to the current models?

      This latest information suggests that I might be right.

      Highly unlikely, unless you have an advanced physics degree of relevance

    • I've long believed that there is no such thing as dark matter. Yes, the mathematics of the current models show that it must be there, but I prefer the other option that we're missing something fundamental in the current models.

      Yes, many assumptions are being made that may be proved false. Right now there are many assumed "constants" that we use to define that the behavior of the universe but they may be less constant than we believe.

      Then we have bigger questions like: What is gravity? If we can get a better grasp on gravity then we may find that it can be altered.

      We must test all the possibilities we can so that we can fill in more missing gaps in our knowledge to discover the true nature of dark matter. It could simply be a m

    • The Administration Building at Fermilab is open to visitors, and I was riding the elevator to the observation level where you can see the extent of the Tevatron and the Fermilab grounds. The signs around the Lab telling what they do for the benefit of us tourists explained that the Tevatron has been retired but that the Lab was conducting experiments on Dark Matter.

      With family members in the elevator, in a Homer Simpson as a scientifically naive tourist voice, I told them, "I really don't believe in all

    • by dryeo ( 100693 )

      We've already found one type of "dark" matter, they're called neutrinos and were postulated to make some equations balance, and as we now know about them, they're no longer "dark". Dark can mean unknown, the dark side of the Moon meant the unknown side of the Moon until we launched a space craft to look at it and now it is the far side of the Moon.

    • I've long believed that there is no such thing as dark matter.

      If not dark matter, what do you think of the RelMOND [theatlantic.com] theory then?

    • by shanen ( 462549 )

      But you brought math into it, so I have an excuse to ask my latest crazy math question.

      There are almost no leptons in the interstellar vacuum. Even fewer in the intergalactic vacuum. But there are lots of photons in every cubic centimeter. The photons have energy, but I can't find out what is the rest mass equivalent to the energy of the photons in the vacuum. Or is the big question why that mass equivalent doesn't matter?

      Is there a doctor of astrophysics in the house?

      • by habig ( 12787 )

        Is there a doctor of astrophysics in the house?

        Yep! Way better than when I'm on an airplane and the fight attendants see "Dr." on the ticket and ask me to help some poor passenger. "Not that kind of Dr!", I'm forced to answer.

        But you brought math into it, so I have an excuse to ask my latest crazy math question.

        There are almost no leptons in the interstellar vacuum. Even fewer in the intergalactic vacuum. But there are lots of photons in every cubic centimeter. The photons have energy, but I can't find out what is the rest mass equivalent to the energy of the photons in the vacuum. Or is the big question why that mass equivalent doesn't matter?

        Turns out that the starlight mc^2 equivalent out there in empty space is order of magnitude not so different than the random matter bits in pick your favorite nearly empty cm^3 of space. Throw in the occasional really dense thing like stars, gas clouds or whatnot and the universe is more dominated by matter than by radiation tho

    • So you favour MOND or Emergent Gravity? Both are perfectly good theories, both explain things Dark Matter does not, although neither explain everything Dark Matter does.

      They would not be up for debate if physicists were confident they were wrong.

      A correction to a model is certainly simpler than adding new particles (you won't have a particle in isolation, it's always in a family, plus twinned with an opposite) but you can have uneven distributions of particles, the model has to be universal.

  • by Rosco P. Coltrane ( 209368 ) on Sunday August 02, 2020 @11:54AM (#60357661)

    I thought the biggest one was casting Sandra Bullock. But apparently it's even worse than that.

  • by nospam007 ( 722110 ) * on Sunday August 02, 2020 @11:56AM (#60357669)

    I find gravity errors usually after a dozen beers or so.

  • by kipsate ( 314423 ) on Sunday August 02, 2020 @12:00PM (#60357679)
    Ad bomb alert! The linked website will ask you to turn off your ad blocker and subsequently bombs you with auto-playing videos and tasteless clickbait ads. Instead, use one of these:

    The universe is nearly 10 percent more homogeneous than expected [techexplorist.com]
    Universe Is More Homogeneous Than Expected [spacedaily.com]
    New KiDS result: Universe 10 percent more homogeneous than assumed [miragenews.com]
    • Simple solution; if they ask you to turn off the ad-blocker, don't do it.

      Often you can use the ad-blocker's eye-dropper tool to block their anti-blocker overlays. They can't block your blocker by force without blocking accessible browsers, so usually it is a soft-block popup.

      • If you stumble across one of those site that surreptitiously redirects you to an anti-adblock landing page after disabling said blocker, hitting escape a few times will often prevent this from happening. Also firefox's reader mode is handy, where it works.
        • I use uMatrix, and I think 100% of the sites that do that use cross-site JS for it, so I don't even get redirected.

    • I just read the article and didn't get any notices about my ad blocker. The article loaded and I read it with no fuss at all.

      Are you running Javascript on random websites? That's the only reason I can think of offhand for why you would get that notice and all of the crap when I didn't.

  • by BAReFO0t ( 6240524 ) on Sunday August 02, 2020 @12:02PM (#60357687)

    Let's see how they justify this one. :)

    I hope they don't go full string theory.
    Never go full string theory.

  • by Arethan ( 223197 ) on Sunday August 02, 2020 @12:14PM (#60357749) Journal

    What they see is clearly just a very slight wobble to our bubble as it continues its ride up the continuum. This is almost certainly due to the population density imbalance across the disc. If we donâ(TM)t fix it soon, we may risk flipping the disc!

    Donâ(TM)t worry though, Iâ(TM)m sure our experts are recalibrating the stabilizers at this very moment.

  • "I toldja it was all rigged! The scientists were wrong wrong wrong! Everybody knows now, believe me! God doesn't play dice with the universe and he doesn't wear a mask. Ever see him in a painting with a mask? Not! I did see him playing cards at Mar-a-Lago; he loved the place! I'll ask him about gravity next time so you don't have to get your fake news from Al Gore and his gravitational warming shtick."

  • If your theory starts with "Maybe Einstein was wrong" you need a new theory.

  • Less likely to make a complete bollocks of it.
    A pity more are not still alive.

  • Absurd, gravity doesn't make mistakes.

  • The linked article doesn't contain any references. It may be correct, or it may be fabrication, and there's no way to tell.

    For all I can tell, it's somebody's spin-off on https://www.quantamagazine.org... [quantamagazine.org] though they do cite a different instrument. (KiDS : Kilo-Degree Survey) and one can read into the article that Hendrik Hildebrandt was an astronomer involved with whatever study it is. (This *is* a guess based on the linked article. They quoted him, but they don't say why.)

  • Obsessive compulsive wracked professors were seen jumping from high rise buildings.

  • There has never been direct evidence of dark matter other than "this math doesn't add up, let's stick in a filler." Scientists never want to admit when they're wrong or confused or have incomplete knowledge. You want to talk about evidence? All evidence points to us not knowing how space expansion, compression, bending, and gravity really work.

Were there fewer fools, knaves would starve. - Anonymous

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