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posted by martyb on Friday May 29 2020, @07:41AM   Printer-friendly
from the so-THERE-you-are! dept.

Half the matter in the universe was missing—we found it hiding in the cosmos:

In the late 1990s, cosmologists made a prediction about how much ordinary matter there should be in the universe. About 5%, they estimated, should be regular stuff with the rest a mixture of dark matter and dark energy. But when cosmologists counted up everything they could see or measure at the time, they came up short. By a lot.

The sum of all the ordinary matter that cosmologists measured only added up to about half of the 5% what was supposed to be in the universe.

This is known as the "missing baryon problem" and for over 20 years, cosmologists like us looked hard for this matter without success.

It took the discovery of a new celestial phenomenon and entirely new telescope technology, but earlier this year, our team finally found the missing matter.

[...] But when radio waves pass through matter, they are briefly slowed down. The longer the wavelength, the more a radio wave "feels" the matter. Think of it like wind resistance. A bigger car feels more wind resistance than a smaller car.

The "wind resistance" effect on radio waves is incredibly small, but space is big. By the time an FRB ["Fast Radio Burst"] has traveled millions or billions of light-years to reach Earth, dispersion has slowed the longer wavelengths so much that they arrive nearly a second later than the shorter wavelengths.

[...] We were overcome by both amazement and reassurance the moment we saw the data fall right on the curve predicted by the 5% estimate. We had detected the missing baryons in full, solving this cosmological riddle and putting to rest two decades of searching.

Journal Reference:
J.-P. Macquart, J. X. Prochaska, M. McQuinn, et al. A census of baryons in the Universe from localized fast radio bursts, Nature (DOI: 10.1038/s41586-020-2300-2)

The initial results are based on six data points, FRBs; the researchers will continue to look for others.


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  • (Score: 2) by MostCynical on Friday May 29 2020, @07:48AM

    by MostCynical (2589) on Friday May 29 2020, @07:48AM (#1000448) Journal
    --
    "I guess once you start doubting, there's no end to it." -Batou, Ghost in the Shell: Stand Alone Complex
  • (Score: 4, Interesting) by bradley13 on Friday May 29 2020, @12:12PM (20 children)

    by bradley13 (3053) on Friday May 29 2020, @12:12PM (#1000493) Homepage Journal

    Dark matter is already a kludge. There's a gravitational effect that we don't understand, let's just invent some form of utterly undetectable matter that magically provides the needed gravitation. So now, some other prediction is off, and we're inventing even more matter, which (as baryons) absolutely ought to be detectable through ordinary particle interactions. But the only verification of its existence is this incredibly indirect effect that could be more satisfactorily explained other ways. As a layman with an interest in cosmology, this all looks like band-aids on band-aids, trying to keep a broken theory from falling apart.

    On the other hand, Heisenberg once said, “Not only is the Universe stranger than we think, it is stranger than we can think.”

    --
    Everyone is somebody else's weirdo.
    • (Score: 1, Touché) by Anonymous Coward on Friday May 29 2020, @01:06PM (2 children)

      by Anonymous Coward on Friday May 29 2020, @01:06PM (#1000505)

      this incredibly indirect effect that could be more satisfactorily explained other ways

      So, explain them? Without violating other established and well-proven theories, of course.

      • (Score: 1, Insightful) by Anonymous Coward on Friday May 29 2020, @02:57PM (1 child)

        by Anonymous Coward on Friday May 29 2020, @02:57PM (#1000547)

        I think what bradley is getting at is that what is needed at this point is not another kludge to fit the data but a paradigm shift. No one yet knows what that paradigm shift will be.

        • (Score: 1, Touché) by Anonymous Coward on Saturday May 30 2020, @05:03AM

          by Anonymous Coward on Saturday May 30 2020, @05:03AM (#1000927)

          Ah, so we explain the mysterious dark matter with the unknown paradigm shift. That clears it all up - thanks Bradley et al.

    • (Score: 2) by PiMuNu on Friday May 29 2020, @02:13PM (7 children)

      by PiMuNu (3823) on Friday May 29 2020, @02:13PM (#1000529)

      > let's just invent some form of utterly undetectable matter

      You are starting with a strange bias - that matter should be detectable. Why?

      • (Score: 0) by Anonymous Coward on Friday May 29 2020, @03:05PM (5 children)

        by Anonymous Coward on Friday May 29 2020, @03:05PM (#1000553)

        I suggest we posit that ghosts are responsible. Perfect explanation as they will be undetectable. Or maybe just declare that God did it. Problem solved. You're welcome.

        • (Score: 2) by PiMuNu on Friday May 29 2020, @04:14PM (3 children)

          by PiMuNu (3823) on Friday May 29 2020, @04:14PM (#1000585)

          > ghosts are responsible
          > God did it.

          But ghosts and God do not obey the laws of physics; for example God enables transport of information at faster than speed of light ("omniscient") and ghosts break energy/momentum conservation (telekinesis). Try again, but now give me a theory that obeys the laws of physics - or a very good explanation for why they are wrong!

          • (Score: 2) by Bot on Sunday May 31 2020, @12:29PM (2 children)

            by Bot (3902) on Sunday May 31 2020, @12:29PM (#1001328) Journal

            >for example God enables transport of information at faster than speed of light

            this is like saying that a host spies on a 100% simulated VM by placing a backdoor on it. No, you don't need to alter any rule, you are the host, the dreamer of the dream, you can roll back or forward and inspect all VM state, as the VM exists only as an abstraction in you.

            --
            Account abandoned.
            • (Score: 2) by PiMuNu on Sunday May 31 2020, @01:43PM (1 child)

              by PiMuNu (3823) on Sunday May 31 2020, @01:43PM (#1001350)

              > No, you don't need to alter any rule, you are the host

              I agree religion exists outside physics. But GP was trying to use God instead of dark matter, so I was explaining why religion is logically different to dark matter.

              • (Score: 2) by Bot on Sunday May 31 2020, @02:23PM

                by Bot (3902) on Sunday May 31 2020, @02:23PM (#1001369) Journal

                Religion is logically different to dark matter because dark matter is just a way for the scientist to escape the fear of the unknown.

                --
                Account abandoned.
        • (Score: 2) by PiMuNu on Friday May 29 2020, @04:18PM

          by PiMuNu (3823) on Friday May 29 2020, @04:18PM (#1000586)

          Gah, I missed my point in GP post.

          The point is, you are rejecting a perfectly reasonable theory on the basis that "we humans can't directly measure DM, apart from through these many gravitational anomalies, therefore DM *must* be wrong". That's a very anthropic view point, and one that the universe may not agree with.

      • (Score: 0) by Anonymous Coward on Saturday May 30 2020, @05:06AM

        by Anonymous Coward on Saturday May 30 2020, @05:06AM (#1000929)

        > utterly undetectable matter

        Utterly undetectable except for its gravitational effects, of course, which is the way we know there's a discrepancy. Dipshit.

    • (Score: 2) by meustrus on Friday May 29 2020, @02:22PM (2 children)

      by meustrus (4961) on Friday May 29 2020, @02:22PM (#1000532)

      Band-aids on band-aids are what you get when the theories become too complex for one person to understand all of them. New stuff can't be comprehensive enough to apply everywhere.

      I'm reminded of Stephen Wolfram's new physics project [stephenwolfram.com]. But he's been dismissed around here as a kook. Clearly this problem is just too hard to solve, so we should give up on finding an elegant solution.

      --
      If there isn't at least one reference or primary source, it's not +1 Informative. Maybe the underused +1 Interesting?
      • (Score: 3, Funny) by takyon on Friday May 29 2020, @02:38PM

        by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Friday May 29 2020, @02:38PM (#1000539) Journal

        This story is like a band-aid was peeled off, leaving only one or two band-aids.

        --
        [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
      • (Score: 0) by Anonymous Coward on Saturday May 30 2020, @05:12AM

        by Anonymous Coward on Saturday May 30 2020, @05:12AM (#1000932)

        As a physicist... I would say band-aids appear whenever the person explaining something to you doesn't have a clear-as-day understanding of it themselves. You've all seen the bluff and bullshit maneuver. Confidence tricks. Watch Boris Johnson or any self-respectiing politician. Half bluff, half privilege / benefit of the doubt, even half right some of the time.

    • (Score: 0) by Anonymous Coward on Friday May 29 2020, @03:24PM

      by Anonymous Coward on Friday May 29 2020, @03:24PM (#1000564)

      Dark matter is like Camelot. It's just a model.

    • (Score: 1) by khallow on Friday May 29 2020, @04:00PM (2 children)

      by khallow (3766) Subscriber Badge on Friday May 29 2020, @04:00PM (#1000576) Journal

      But the only verification of its existence is this incredibly indirect effect that could be more satisfactorily explained other ways.

      Like what? Sorry, MOND and quantum inertia are kludges too. Presently, there is no more satisfactorily explained way to explain gravitation anomalies.

      As to the differential lag in EM spectrum, what is the more satisfactory explanation?

      • (Score: 1, Insightful) by Anonymous Coward on Friday May 29 2020, @07:53PM (1 child)

        by Anonymous Coward on Friday May 29 2020, @07:53PM (#1000713)

        I do prefer when two anomalies cancel out rather than add up.

        • (Score: 0) by Anonymous Coward on Saturday May 30 2020, @05:15AM

          by Anonymous Coward on Saturday May 30 2020, @05:15AM (#1000934)

          That's what we in the business call a lose-lose-win? OMG WIN!

    • (Score: 1, Informative) by Anonymous Coward on Friday May 29 2020, @10:33PM

      by Anonymous Coward on Friday May 29 2020, @10:33PM (#1000817)

      These are ordinary particle interactions! They are not inventing any physics here, it is all straight EM-particle stuff. The difference is that now we have these FRBs and ways to easily detect them, so now we can look in detail at frequency dispersion through a medium. If we know what the spectrum is as it leave the source, and we know what it is when it gets to us, and we know the distance between the two, we can back out information about what is in between to make the frequencies change the way they do. Any experimental scientist over the last several hundred years would be fine with this.

    • (Score: 0) by Anonymous Coward on Sunday May 31 2020, @07:07PM

      by Anonymous Coward on Sunday May 31 2020, @07:07PM (#1001466)

      There's no dark matter etc, it's love that's pulling stuff together... ;)

  • (Score: 2) by bzipitidoo on Friday May 29 2020, @09:38PM (4 children)

    by bzipitidoo (4388) on Friday May 29 2020, @09:38PM (#1000786) Journal

    And tt has a light side and a dark side.

    • (Score: 0) by Anonymous Coward on Friday May 29 2020, @10:38PM (3 children)

      by Anonymous Coward on Friday May 29 2020, @10:38PM (#1000819)

      Teletype?

      Texas Tech?

      TurboTax?

      Teen Titans?

      Taco Tuesday?

      Trinidad and Tobago dollar?

      • (Score: 2) by bzipitidoo on Friday May 29 2020, @11:17PM

        by bzipitidoo (4388) on Friday May 29 2020, @11:17PM (#1000827) Journal

        Two Types, though those ignorant of the true binary nature of the universe think it's Ten Types.

        It's all good. And evil.

      • (Score: 0) by Anonymous Coward on Saturday May 30 2020, @05:17AM

        by Anonymous Coward on Saturday May 30 2020, @05:17AM (#1000937)

        T**** 2020

      • (Score: 2) by Bot on Sunday May 31 2020, @12:33PM

        by Bot (3902) on Sunday May 31 2020, @12:33PM (#1001330) Journal

        typo

        --
        Account abandoned.
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