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PBS asks, must we rewrite general relativity?

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File:Spacetime curvature.png
spacetime curvature according to general relativity/Johnstone

Because we just haven’t found the dark matter that the theory seems to require.

Further to Human languages must be irreducibly complex (Can someone help us understand what this translation from German means?)—maybe it was something about how cosmology needs to change, which Neil Turok of the Perimeter Institute in Canada said plainly earlier this year. Something like: Hi, Nonsense, meet Budget:

From PBS:

Do We Need to Rewrite General Relativity?

Astronomical observations show that there isn’t enough ordinary matter to account for the behavior of galaxies and other objects. The fix is dark matter, particles invisible to light but endowed with gravity. However, none of our detectors or experiments have ever seen a dark matter particle directly, leading some to doubt that dark matter actually exists. Just as Newton’s theory of gravity is “good enough” for most familiar situations and reveals its limitations only in extreme situations or upon the most detailed examination, maybe what we call dark matter is actually a breakdown of general relativity.

It’s a tantalizing thought, but as Perimeter Institute physicist John Moffat points out, “It’s not easy to modify Einstein’s theory!” The problem is that general relativity (“GR”) is too good: its predictions match observations so closely that, in changing it, physicists seem likely to fall short. The “classic tests” of GR—the small shifts in the orbit of Mercury, the bending of the paths of light around the Sun, and the change in light properties when moving in and out of gravitational fields—are precise enough that they can be used to judge any alternative idea.

That hasn’t stopped maverick scientists like Moffat from looking at alternatives to GR. The rotation of spiral galaxies inspired a particular modification to gravity that lingers like a fungus in the basement of astronomy: “modified Newtonian dynamics,” or MOND. As the name suggests, it’s a change to Newton’s law of gravity rather than general relativity, and it does very well at describing the motion of stars and gas in spiral galaxies without the need for dark matter. However, MOND fails for some other types of galaxies, galaxy clusters, and—because it isn’t compatible with relativity—it cannot explain the “classic tests” of GR, much less the evolution of the universe as a whole.

Nevertheless, MOND is successful enough in galaxies to inspire some theorists to try to modify it, in hopes of making predictions that more closely match nature. More.

For more re quest for dark matter, see

MOND: Is Discover mag’s “blasphemy” about dark matter really about fine tuning?


New Scientist asks the same question as Barry Arrington re dark matter

For more re PBS, see Public Broadcasting joins the popular demand for a multiverse

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3 Replies to “PBS asks, must we rewrite general relativity?

  1. 1
    bornagain77 says:

    as to: “Astronomical observations show that there isn’t enough ordinary matter to account for the behavior of galaxies and other objects.”

    I notice that this failure of materialistic theories to account for large scale structure of, and in, the universe, or more precisely, the failure to account for ‘form/shape’, is a persistent problem for materialists.

    Most notable of these failures is the recent failure of inflation theory to account for why the universe is as flat and round as it is:

    Inflation theory was proposed to solve two fine-tuning problems of the initial conditions of the early universe known as the “flatness problem”[1] and the “horizon problem”[2].

    Why converge? – Jun 22, 2015
    Excerpt: “The biggest thing that helped was the BICEP measurement,” he says. “Inflationists came out of the woodwork and said, yay, we were right…then they realised they’d forgotten about dust.” This led people to the realisation, he says, that even though hundreds or thousands of people are working on an idea, it may still be wrong. This episode “made people aware we need to be more objective about what we’re doing,”

    Around the 13:20 minute mark of the following video Pastor Joe Boot comments on the self-defeating nature of the atheistic/materialistic worldview in regards to ever providing a coherent overarching ‘design plan’ for the universe:

    “If you have no God, then you have no design plan for the universe. You have no preexisting structure to the universe.,, As the ancient Greeks held, like Democritus and others, the universe is flux. It’s just matter in motion. Now on that basis all you are confronted with is innumerable brute facts that are unrelated pieces of data. They have no meaningful connection to each other because there is no overall structure. There’s no design plan. It’s like my kids do ‘join the dots’ puzzles. It’s just dots, but when you join the dots there is a structure, and a picture emerges. Well, the atheists is without that (final picture). There is no preestablished pattern (to connect the facts given atheism).”
    Pastor Joe Boot – Defending the Christian Faith – video (13:20 minute mark)

    Whereas inflation fails miserably to account for why the universe is as round and flat as it is, it is interesting to note that the Holy Bible said that the universe is round and flat thousands of years before scientists discovered the universe actually is round and flat:

    Proverbs 8:26-27
    While as yet He had not made the earth or the fields, or the primeval dust of the world. When He prepared the heavens, I was there, when He drew a circle on the face of the deep,

    Job 26:10
    He has inscribed a circle on the face of the waters at the boundary between light and darkness.

    Job 38:4-5
    “Where were you when I laid the earth’s foundation?
    Tell me, if you understand.
    Who marked off its dimensions? Surely you know!
    Who stretched a measuring line across it?

    The ’roundness’ of the universe is visualized in the following video:

    The Known Universe by AMNH – video – (please note the ‘centrality’ of the Earth in the universe at the 3:36 minute mark in the video)

    In The Beginning – 12 May 2015
    Excerpt: As I walked out of Steinhardt’s office for the last time, it occurred to me that our cosmos is once again a sphere. Our Earth has been demoted in recent centuries. It no longer enjoys its former status as the still centre of all that is. But it does sit in the middle of our observable cosmos, the sphere of light that we can detect with our telescopes. Gaze into this sphere’s reaches from any point on Earth’s surface, and you can see light coming toward you in layers, from stars and the planets that circle them, from the billions of galaxies beyond, and the final layer of light, the afterglow of the Big Bang.

    Here is a still shot of the image at the 3:36 minute mark of the preceding video

    Picture of Cosmic Microwave Background Radiation (CMBR)

    Here are a few supplemental notes as to the fine-tuning of the “flatness problem” and the “horizon problem”.

    The Cosmic Background Radiation
    Excerpt: These fluctuations are extremely small, representing deviations from the average of only about 1/100,000 of the average temperature of the observed background radiation. The highly isotropic nature of the cosmic background radiation indicates that the early stages of the Universe were almost completely uniform. This raises two problems for (a naturalistic understanding of) the big bang theory.
    First, when we look at the microwave background coming from widely separated parts of the sky it can be shown that these regions are too separated to have been able to communicate with each other even with signals traveling at light velocity. Thus, how did they know to have almost exactly the same temperature? This general problem is called the horizon problem.
    Second, the present Universe is homogenous and isotropic, but only on very large scales. For scales the size of superclusters and smaller the luminous matter in the universe is quite lumpy, as illustrated in the following figure. ,,, Thus, the discovery of small deviations from smoothness (anisotopies) in the cosmic microwave background is welcome, for it provides at least the possibility for the seeds around which structure formed in the later Universe. However, as we shall see, we are still far from a quantitative understanding of how this came to be.

    Did the Universe Hyperinflate? – Hugh Ross – April 2010
    Excerpt: Perfect geometric flatness is where the space-time surface of the universe exhibits zero curvature (see figure 3). Two meaningful measurements of the universe’s curvature parameter, ½k, exist. Analysis of the 5-year database from WMAP establishes that -0.0170 less than ½k less than 0.0068.4 Weak gravitational lensing of distant quasars by intervening galaxies places -0.031 less than ½k less than 0.009.5 Both measurements confirm the universe indeed manifests zero or very close to zero geometric curvature,,,

    Why astronomers say we live in a remarkably flat universe—and what that really means – January 2014
    Excerpt: the universe appears remarkably flat. It takes a lot of effort to find any curvature at all,
    per uncommondescent

    “The Universe today is actually very close to the most unlikely state of all, absolute flatness. And that means it must have been born in an even flatter state, as Dicke and Peebles, two of the Princeton astronomers involved in the discovery of the 3 K background radiation, pointed out in 1979. Finding the Universe in a state of even approximate flatness today is even less likely than finding a perfectly sharpened pencil balancing on its point for millions of years, for, as Dicke and Peebles pointed out, any deviation of the Universe from flatness in the Big Bang would have grown, and grown markedly, as the Universe expanded and aged. Like the pencil balanced on its point and given the tiniest nudges, the Universe soon shifts away from perfect flatness.”
    ~ John Gribbin, In Search of the Big Bang

  2. 2
    lifepsy says:

    It is presented as an unquestionable fact to the public that the universe is mostly comprised of a mysterious ether called “dark matter”, of which its existence cannot be experimentally tested or verified in any way. Its amazing that they get away with this sort of thing.

  3. 3
    anthropic says:

    If A, then B.

    B is not observed.

    Logic then dictates that we must rethink the existence of A.

    That includes intelligent technological aliens, the multiverse, dark energy, dark matter, and neo-Darwinian macroevolution.

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