Einstein's theory of general relativity holds up; Still....

Discussion in 'Astronomy, Exobiology, & Cosmology' started by paddoboy, Jul 25, 2019.

  1. paddoboy Valued Senior Member

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    27,543
    https://phys.org/news/2019-07-einstein-relativity-theory.html

    Einstein's general relativity theory is questioned but still stands for now:

    More than 100 years after Albert Einstein published his iconic theory of general relativity, it is beginning to fray at the edges, said Andrea Ghez, UCLA professor of physics and astronomy. Now, in the most comprehensive test of general relativity near the monstrous black hole at the center of our galaxy, Ghez and her research team report July 25 in the journal Science that Einstein's theory of general relativity holds up.

    "Einstein's right, at least for now," said Ghez, a co-lead author of the research. "We can absolutely rule out Newton's law of gravity. Our observations are consistent with Einstein's theory of general relativity. However, his theory is definitely showing vulnerability. It cannot fully explain gravity inside a black hole, and at some point we will need to move beyond Einstein's theory to a more comprehensive theory of gravity that explains what a black hole is."

    more at link.....

    the paper:

    https://science.sciencemag.org/content/early/2019/07/24/science.aav8137


    Relativistic redshift of the star S0-2 orbiting the Galactic center supermassive black hole:


    Abstract:
    General Relativity predicts that a star passing close to a supermassive black hole should exhibit a relativistic redshift. We test this using observations of the Galactic center star S0-2. We combine existing spectroscopic and astrometric measurements from 1995-2017, which cover S0-2’s 16-year orbit, with measurements in 2018 March to September which cover three events during its closest approach to the black hole. We detect the combination of special relativistic- and gravitational-redshift, quantified using a redshift parameter, ϒ. Our result, ϒ = 0.88 ± 0.17, is consistent with General Relativity (ϒ = 1) and excludes a Newtonian model (ϒ = 0) with a statistical significance of 5σ.
     
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  3. paddoboy Valued Senior Member

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    OK, A question....Concerning the sentence I have highlighted in the article thus..." It cannot fully explain gravity inside a black hole"
    Are they referring to the Singularity as defined where GR breaks down? That is the quantum/Planck level. GR tells us that once the Schwarzchild radius is reached, further collapse is compulsory, and as I see it, that means at least up to where GR fails us.
    The spacetime curvature as predicted by GR, tells us that once the Schwarzchild radius/EH is reached, all paths lead to the singularity. So what is there to explain about the gravity and the spacetime curvature? [other then at the quantum/Planck level]
     
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  5. river

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    Physically .

    Upon what is this singularity based ?
     
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  7. paddoboy Valued Senior Member

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    Answering my own question, I see it simply as some questionable or careless journalism. It's not the gravity per se that can't be explained [GR tells us that once the Schwarzchild radius is reached, further collapse is compulsory] Its questioning, rightly, where GR breaks down and the nature of matter/energy there...that is at the quantum/Planck level.
     
  8. river

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    17,307
    Upon what physical form is this based ?

    All mathematical theories break down when energy and matter are considered . Because the mathematics isn't based on energy and matter .
     
  9. paddoboy Valued Senior Member

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    Just to add, that most astronomers today reject any "physical" singularity as defined by infinite spacetime curvature and density. Nothing so bizarre, rather the more logical singularity as defined by where our laws of physics and GR, fail us...that is the quantum/Planck level.
     

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