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posted by martyb on Friday June 06 2014, @03:05PM   Printer-friendly
from the swirls-are-swell dept.

We started this month with a story about how Black Holes at Center of Galaxies Might Instead be Wormholes. Now, an article out on Phys.org proposes Gravitational Fields Around Black Holes Might Eddy and Swirl.

From the article:

The team decided to study fast-spinning black holes, because a fluid-dynamics description of such holes hints that the spacetime around them is less viscous than the spacetime around other kinds of black holes. Low viscosity increases the chance of turbulence -- think of the way water is more swirly than molasses.

The team also decided to study non-linear perturbations of the black holes. Gravitational systems are rarely analyzed at this level of detail, as the equations are fiendishly complex. But, knowing that turbulence is fundamentally non-linear, the team decided a non-linear perturbation analysis was exactly what was called for.

They were stunned when their analysis showed that spacetime did become turbulent.

There is a related article, also on Phys.org, spacetime could be like a very slippery superfluid which notes:

In this sense, general relativity would be the analogue to fluid hydrodynamics, which describes the behaviour of fluids at a macroscopic level but tells us nothing about the atoms/molecules that compose them. Likewise, according to some models, general relativity says nothing about the "atoms" that make up spacetime but describes the dynamics of spacetime as if it were a "classical" object. Spacetime would therefore be a phenomenon "emerging" from more fundamental constituents, just as water is what we perceive of the mass of H2O molecules that form it.

 
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  • (Score: 3, Insightful) by kaszz on Friday June 06 2014, @04:30PM

    by kaszz (4211) on Friday June 06 2014, @04:30PM (#52303) Journal

    If this turns out to be true then it's a fundamental change in the understanding of universe.

    (and if it's a "fluid" perhaps one can make some artificial waves or manipulations..)

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  • (Score: 3, Interesting) by RaffArundel on Friday June 06 2014, @06:11PM

    by RaffArundel (3108) on Friday June 06 2014, @06:11PM (#52331) Homepage

    Why? I'm not really seeing anything mind-blowing here.

    The first article states the following:
    1. Gravity may be able to be described using field theory
    2. At high energies field theory can be described with fluid equations
    3. Low viscosity fluids exhibit turbulence
    4. (ignoring obvious meme here) When you put all three of those together - spacetime can be warped by turbulent gravity!

    Item #3 is true of fluids because of the interactions of the individual particles, if no such "gravity particle" exists then you are just playing a shell game with no ball under the cup at all. Perhaps it bolsters some other claim about gravitational modeling, probably trying to bridge QFT and Relativity, and the article goes so far as to say it will have more impact on refining turbulence models for real turbulence events like wing vortices. Sorry, to be a downer here, but it reads like "someone uses a fluid model that predicts turbulence and it does in that model!"

    The second article is a great companion to the first. It tells us that there is no apparent dissipative effects that are predicted by fluid models, therefore one of two things are likely true:
    1. Space-time has a viscosity approaching zero and if it is non-zero, it is because we lack the tools to detect the dissipation effect.
    2. It's the wrong model to use.

    Hopefully, someone with a little more background in theoretical physics will come along and delve into the implications. I will point out that calling another scientist's dissenting beliefs "folklore" is a little bold from someone who just ran a computer model. How about you save the smack talk for when you actually see some indication your model is valid?