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posted by martyb on Thursday January 02 2020, @07:06PM   Printer-friendly
from the wibbly-wobbly-spacetimey-jets dept.

Submitted via IRC for chromas

A Strange Black Hole Is Shooting Out Wobbly Jets Because It's Dragging Spacetime:

Some 7,800 light-years away, in the constellation of Cygnus, lies a most peculiar black hole. It's called V404 Cygni, and in 2015, telescopes around the world stared in wonder as it woke from dormancy to devour material from a star over the course of a week.

That one event provided such a wealth of information that astronomers are still analysing it. And they have just discovered an amazing occurrence: relativistic jets wobbling so fast their change in direction can be seen in mere minutes.

[...] V404 Cygni is a binary microquasar system consisting of a black hole about nine times the mass of the Sun and a companion star, an early red giant slightly smaller than the Sun.

The black hole is slowly devouring the red giant; the material siphoned away from the star is orbiting the black hole in the form of an accretion disc, a bit like water circling a drain. The closest regions of the disc are incredibly dense and hot, and extremely radiant; and, as the black hole feeds, it shoots out powerful jets of plasma, presumably from its poles.

[...] "We think the disc of material and the black hole are misaligned," [astrophysicist James] Miller-Jones said. "This appears to be causing the inner part of the disc to wobble like a spinning top and fire jets out in different directions as it changes orientation."

[...] It's a bit like a spinning top that starts to wobble as it's slowing down, the researchers said. This change in the rotational axis of a spinning body is called precession. In this particular instance, we have a handy explanation for it courtesy of Albert Einstein.

In his theory of general relativity, Einstein predicted an effect called frame-dragging. As it spins, a rotating black hole's gravitational field is so intense that it essentially drags spacetime with it. (This is one of the effects scientists hoped to observe when they took a picture of Pōwehi.)

In the case of V404 Cygni, the accretion disc is about 10 million kilometres (6.2 million miles) across. The misalignment of the black hole's rotational axis with the accretion disc has warped the inner few thousand kilometres of said disc.

The frame-dragging effect then pulls the warped part of the disc along with the black hole's rotation, which sends the jet careening off in all directions. In addition, that inner section of the accretion disc is puffed up like a solid doughnut that also precesses.

"This is the only mechanism we can think of that can explain the rapid precession we see in V404 Cygni," Miller-Jones said.

[...] the team had to [take] 103 separate images with exposure times of just 70 seconds and [stitch] them together to create a movie - and sure enough, there were the wibbly wobbly spacetimey jets.

A video explaining the activity is available on Vimeo.

A rapidly changing jet orientation in the stellar-mass black-hole system V404 Cygni, Nature (DOI: doi:10.1038/s41586-019-1152-0)


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  • (Score: 3, Insightful) by stormwyrm on Friday January 03 2020, @12:59AM (16 children)

    by stormwyrm (717) on Friday January 03 2020, @12:59AM (#938894) Journal

    Dark matter can actually be compared to the old Ptolemaic system of epicycles. You know, ancient astronomers didn't come up with the system of epicycles out of nothing: it actually did agree with the crude astronomical observations possible with naked eye astronomy, which is why it persisted as the dominant theory of the universe for nearly two thousand years. The Ptolemaic system was eventually superseded when the telescope was invented and better observations became possible, and a theoretical framework for the motions of the planets could be developed culminating in the work of Kepler and Newton. So too with dark matter: it actually does agree with the astronomical observations we can make today, from the scales of planets and stars, to the scales of galaxies, all the way to the large-scale structure of the universe itself. Someday we might think up a better way of looking at the universe and there will be a new theory that ties it all together. But until then, dark matter is the best explanation we have for much of what we can see.

    A galaxy with no dark matter can actually be proof that dark matter is real, being an exception that proves the rule. The galaxy formation theories involving dark matter do predict that young galaxies at high red shifts should not yet have much dark matter, which is supposed to accumulate in later stages of formation, and as such they should rotate with Newtonian motion. That was what they thought they saw at first, but making observations of the rotation of very distant galaxies is obviously very difficult, and mistakes can be made, so now the prediction is still up in the air. That is of course how the process of science works. Science is always wrong, it just gets less wrong over time. Someday, with better telescopes and such, it might be possible to confirm or refute dark matter in this way. If they look at a very distant galaxy that dark matter theory predicts should not yet have a lot of dark matter in it and find that it's still rotating as though it had dark matter, that would be a serious blow to dark matter and a very strong boost to modified gravity theories. But if observations do find such young galaxies behaving exactly the way dark matter theory predicts, well, that would be another nail in the coffin for alternatives. Many of the other predictions dark matter made were later borne out by observations though. These dark matter-free young galaxies are one prediction that isn't yet resolved.

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  • (Score: 2) by Gaaark on Friday January 03 2020, @01:44AM (4 children)

    by Gaaark (41) on Friday January 03 2020, @01:44AM (#938907) Journal

    Yes, DM is VERY epicyclic: one day we'll look back and have a good laugh.

    "But until then, dark matter is the best explanation we have for much of what we can see."
    But it also fails in so many areas, such as wide binaries, the existence of which NULLIFIES dark matter!

    "A galaxy with no dark matter can actually be proof that dark matter is real"
    My house doesn't have a unicorn in it: EVIDENCE UNICORNS ARE REAL!

    MOND works as well as DM: BOTH have an arbitrariness to them (MOND has it's adjustable formula, DM has NO formula, just arbitrary addition of DM to each galaxy you look at)

    I prefer QI because, for one, it has a non-adjustable formula that is predictive and works in so many ways.

    --
    --- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
    • (Score: 3, Informative) by stormwyrm on Friday January 03 2020, @02:13AM (3 children)

      by stormwyrm (717) on Friday January 03 2020, @02:13AM (#938913) Journal

      "A galaxy with no dark matter can actually be proof that dark matter is real"
      My house doesn't have a unicorn in it: EVIDENCE UNICORNS ARE REAL!

      Absence of unicorns could be evidence of their existence if the theory of unicorns gave conditions for where you shouldn't find them, so if you went to a place that satisfies those conditions, and didn't find them, then that's evidence in favour of their existence and that the theory of unicorns is correct. Conversely, that implies that a place that doesn't satisfy those conditions should have unicorns, and as such you should be able to observe them in such places somehow. Dark matter is that way: we have observations that it potentially explains, e.g. the rotation of galaxies, and that is how its presence is inferred. Theories of galaxy formation based on its hypothesised properties predict that at earlier stages dark matter should not yet be present. We can't yet observe galaxies at that stage of formation clearly enough to determine how they rotate though. That is one impetus for better telescopes and other observational instruments.

      --
      Numquam ponenda est pluralitas sine necessitate.
      • (Score: 2) by Gaaark on Friday January 03 2020, @02:29AM (2 children)

        by Gaaark (41) on Friday January 03 2020, @02:29AM (#938918) Journal

        But to me, after, what, 40 years and millions of dollars and research hours, we have nothing more than unicorns: we have no formula, no way of non-arbitrarily knowing how much DM goes into each different galaxy, no predictive qualities. It is all "Dark matter as we know it cannot solve this, so we will make up a new 'quality' for DM to posess!"

        It is all non-scientific.

        At least QI is predictive, has a non-arbitrary formula and works in so many areas: a scientific mind says "Let's put our money into something like this". Instead we have DM that keeps getting new qualities every time it hits up against something it can't solve, just like Superman did when it wasn't enough that he could just jump high and far quickly because he was used to a higher gravity.

        Not scientific and very much like magic: instead of DM, you might as well say it's cow farts: cow farts are just as predictive and have as much of a scientific formula (actually, it probably has more formulae than DM).

        And DM can't explain wide binaries at ALL... unless it gains some new Superman quality....

        I can't say QI IS the answer, but it's, to me, a better answer than DM.

        --
        --- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
  • (Score: 2) by FatPhil on Friday January 03 2020, @11:12PM (10 children)

    by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Friday January 03 2020, @11:12PM (#939274) Homepage
    > Dark matter can actually be compared to the old Ptolemaic system of epicycles.

    Quite the opposite. It simplifies the theories, as it explains a whole bunch of seemingly-unrelated other things that seem to be going wrong with what we see in the universe.

    Introducing dark matter is literally like sticking the sun in the middle - all the planets now rotate happily about it - it's just a sun we can't directly see yet. It has the annoying property that it's going to be very hard to ever see it, but it took half a century to find evidence for just one higgs boson, we shouldn't get too stressed yet.

    When two galaxies look identical (in terms of mass distribution) at all wavelengths of the electromagnetic spectrum but behave differently (in terms of rotation curves), is "something that does not strongly interact with the electromagnetic field is affecting things" not the absolute simplest explanation?
    --
    Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
    • (Score: 2) by Gaaark on Saturday January 04 2020, @01:39AM (9 children)

      by Gaaark (41) on Saturday January 04 2020, @01:39AM (#939318) Journal

      Except DM is basically nullified by wide binaries because it cant explain them at all

      https://physicsfromtheedge.blogspot.com/2017/10/dark-matter-does-not-exist.html [blogspot.com]

      "When two galaxies look identical (in terms of mass distribution) at all wavelengths of the electromagnetic spectrum but behave differently (in terms of rotation curves), is "something that does not strongly interact with the electromagnetic field is affecting things" not the absolute simplest explanation? "

      Not when that solution is not scientific. The way I see it is we got something wrong somewhere along the way and we're just barreling ahead.

      For example, Einstein originally thought space and time were separate (as did Mach), but the math was too hard for him so he combined them and now we have space-time problems: paradoxes, worm holes, etc that would disappear if Einstein had stuck with his first thought.
      I don't believe in time travel or worm holes and would love to see more exploration in that area of space and time being separate.

      But I am not a physicist, so let's just blindly go along getting things 'wronger and wronger'.....

      I just like science.

      --
      --- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
      • (Score: 2) by FatPhil on Saturday January 04 2020, @03:13AM (8 children)

        by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Saturday January 04 2020, @03:13AM (#939348) Homepage
        > Except DM is basically nullified by wide binaries because it cant explain them at all

        Erm, you seem to be making assumptions about the mass distribution of the dark matter you're presuming doesn't exist, in order to conclude that its presence doesn't explain things.

        Did you ever stop to think that maybe it might be absent in places?

        Its proponents did.

        You're yet again 4 steps behind them.
        --
        Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
        • (Score: 2) by Gaaark on Saturday January 04 2020, @03:43AM (7 children)

          by Gaaark (41) on Saturday January 04 2020, @03:43AM (#939358) Journal

          I guess I'm 4 steps behind.

          But tell me, how does DM keep wide binaries from separating? They are spaced too far apart for DM to keep them circling each other. Show me the formula for DM to keep them circling...

          And yet QI has an answer, a formula for it and even is predictive of it.

          I'll stay 4 steps behind, thank you.

          --
          --- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
          • (Score: 2) by FatPhil on Saturday January 04 2020, @03:48AM (6 children)

            by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Saturday January 04 2020, @03:48AM (#939361) Homepage
            Reread my previous post.

            Handy hint: Task made simpler by removing head from arse.
            --
            Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
            • (Score: 2) by Gaaark on Saturday January 04 2020, @04:18AM (5 children)

              by Gaaark (41) on Saturday January 04 2020, @04:18AM (#939376) Journal

              You should take your own advice: DM is needed, according to DM supporters, to keep galaxies from flying apart/keep the stars from flying away from each other.
              But it's not needed to keep wide binaries (which are basically just galaxies not flying away from each other) from flying apart???

              If you don't need DM to keep wide binaries together, why do you need DM to keep galaxies together?

              And...do you always revert to rudeness when losing an argument?

              --
              --- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
              • (Score: 2) by FatPhil on Saturday January 04 2020, @01:28PM (4 children)

                by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Saturday January 04 2020, @01:28PM (#939475) Homepage
                No, I resort to rudeness when faced with abject stupidity. You're hysterical, and you need a slap.

                Why do you think the existence of DM at all implies there's significant levels of DM everywhere. Your previous 3 posts have had that implicit assumption in them. No scientist asserts that at all, no scientist would aggree with at all. You, however then assert that because there seem to be regions with no DM, that DM cannot exist anywhere.

                You've created a misrepresentation of DM, proved it false, and concluded that the actual experimentally-validated (we've seen the lensing it performs) models we have are false.

                That's pure straw man. And you are an idiot for repeatedly resorting to it.
                --
                Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
                • (Score: 2) by Gaaark on Saturday January 04 2020, @02:34PM (3 children)

                  by Gaaark (41) on Saturday January 04 2020, @02:34PM (#939490) Journal

                  Sigh: let's do it again.

                  Galaxies need DM to stay together: there is not enough visual mass to keep them from flying apart, right?

                  Wide binaries. What keeps them orbiting each other when there is not enough visual mass to keep them from orbiting. DM, right?

                  But DM can't work that magic. QI can. Therefore, QI is the better theory, no?

                  No?

                  But I am done with your rudeness. You can't prove to me that DM is a better theory, so you just continue being ruder and ruder. Maybe YOU are the idiot?

                  Bye.

                  --
                  --- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
                  • (Score: 2) by FatPhil on Saturday January 04 2020, @04:45PM (2 children)

                    by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Saturday January 04 2020, @04:45PM (#939532) Homepage
                    Why do you presume that a theory has to explain everything in order to be an improvement on what came before?
                    Nobody is saying that DM is fully understood, or that various DM-based models have solved every problem.

                    DM, with very simple properties, solves a lot of seemingly unconnected problems that non-DM models had. It solves problems it wasn't even invented to solve - that makes it very powerful.
                    --
                    Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
                    • (Score: 2) by Gaaark on Saturday January 04 2020, @08:46PM (1 child)

                      by Gaaark (41) on Saturday January 04 2020, @08:46PM (#939617) Journal

                      Okay. For ME, QI solves more problems than DM.

                      It's different for you.

                      We'll have to agree to disagree.

                      Thanks.

                      --
                      --- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
                      • (Score: 2) by FatPhil on Saturday January 04 2020, @11:35PM

                        by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Saturday January 04 2020, @11:35PM (#939686) Homepage
                        Yeah, if you hadn't noticed, I'm still well up for more investigation into QI. It's closer to being testable than things like supersymmetry and infinitesimal additional dimensions, and does have analogues that are almost certainly true (e.g. Unruh radiation). The absolute presumption that DM is the correct model is an arrogance that shows almost as poor respect for how science advances as the flat out rejection of DM.
                        --
                        Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves