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posted by Fnord666 on Tuesday July 09 2019, @04:51AM   Printer-friendly
from the things-fall-up? dept.

Supercomputer Shows 'Chameleon Theory' Could Change how We Think About Gravity:

Supercomputer simulations of galaxies have shown that Einstein's theory of General Relativity might not be the only way to explain how gravity works or how galaxies form.

Physicists at Durham University, UK, simulated the cosmos using an alternative model for gravity -- f(R)-gravity, a so called Chameleon Theory.

The resulting images produced by the simulation show that galaxies like our Milky Way could still form in the universe even with different laws of gravity.

The findings show the viability of Chameleon Theory -- so called because it changes behaviour according to the environment -- as an alternative to General Relativity in explaining the formation of structures in the universe.

[...] General Relativity was developed by Albert Einstein in the early 1900s to explain the gravitational effect of large objects in space, for example to explain the orbit of Mercury in the solar system.

[...] Scientists already know from theoretical calculations that Chameleon Theory can reproduce the success of General Relativity in the solar system.

[...] The Durham researchers expect their findings can be tested through observations using the Square Kilometre Array (SKA) telescope, based in Australia and South Africa, which is due to begin observations in 2020.

SKA will be the world's largest radio telescope and aims to challenge Einstein's theory of General Relativity, look at how the first stars and galaxies formed after the Big Bang, and help scientists to understand the nature or dark energy.

Journal Reference:
Christian Arnold, Matteo Leo, Baojiu Li. Realistic simulations of galaxy formation in f(R) modified gravity. Nature Astronomy, 2019; DOI: 10.1038/s41550-019-0823-y


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  • (Score: 2) by mhajicek on Tuesday July 09 2019, @06:39AM (2 children)

    by mhajicek (51) on Tuesday July 09 2019, @06:39AM (#864886)

    Does it solve "dark matter"?

    --
    The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
    • (Score: 0) by Anonymous Coward on Tuesday July 09 2019, @08:17AM

      by Anonymous Coward on Tuesday July 09 2019, @08:17AM (#864900)

      Nope, the paper presumes the existence of dark matter.

    • (Score: 3, Insightful) by c0lo on Tuesday July 09 2019, @09:17AM

      by c0lo (156) Subscriber Badge on Tuesday July 09 2019, @09:17AM (#864911) Journal

      With enough parameters added to a model, anything and everything can be matched.

      --
      https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
  • (Score: 5, Interesting) by bradley13 on Tuesday July 09 2019, @08:56AM (1 child)

    by bradley13 (3053) on Tuesday July 09 2019, @08:56AM (#864906) Homepage Journal

    Gads, it's been too long since I studied this stuff. Nonetheless, the Wikipedia article about f(R) gravity" [wikipedia.org] comes to the rescue...

    Basically, one is replacing the term R in Einstein's equations with a function f(R). In the simplest case, f could be the identity function, i.e., there is no change. So there is not surprise that f(R) gravity can be consistent with general relativity.

    However, f could also vary. If it includes an additional constant so f(R) = c + R that would be the famous "cosmological constant". It could also include higher order terms, for example, f(R) = R + aR2 + bR3 + ... In this case, the coefficients a, b, etc. have to be relatively small, in order to be consistent with observations. But small does not mean zero.

    Personally, I have always found the argument that laws of physics may vary over time to be compelling. Could it be, for example, that the cosmological constant was once substantially higher than we see today? Could this not remove the need for dark matter? All of the galaxies that we observe, we are observing in the past - a temporally changing f(R) function could explain much.

    --
    Everyone is somebody else's weirdo.
    • (Score: 2) by hendrikboom on Tuesday July 09 2019, @06:38PM

      by hendrikboom (1125) Subscriber Badge on Tuesday July 09 2019, @06:38PM (#865094) Homepage Journal

      The wikipedia page about the fine structure constant has an interesting section on attempts to determine whether it has changed over the last ten billion years. Perhaps it has.

  • (Score: 2) by Gaaark on Tuesday July 09 2019, @07:30PM

    by Gaaark (41) on Tuesday July 09 2019, @07:30PM (#865116) Journal

    Using QI, gravity becomes a push, and there is no need to 'warp space and time', eliminating time travel problems and worm hole problems.

    Problems solved.

    --
    --- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
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