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Alternatives to Einstein’s gravity face challenges from evidence

An animation of gravity at work. Albert Einstein described gravity as a curve in space that wraps around an objectâ such as a star or a planet. If another object is nearby, it is pulled into the curve.
Albert Einstein described gravity as a curve in space that wraps around an object such as a star or a planet. Another nearby object gets pulled into the curve/ NASA

From Katia Moskvitch at Quanta:

The neutron-star collision was just the beginning. New data in the months since that discovery have made life increasingly difficult for the proponents of many of the modified-gravity theories that remain. Astronomers have analyzed extreme astronomical systems that contain spinning neutron stars, or pulsars, to look for discrepancies between their motion and the predictions of general relativity — discrepancies that some theories of alternative gravity anticipate. These pulsar systems let astronomers probe gravity on a new scale and with new precision. And with each new observation, these alternative theories of gravity are having an increasingly hard time solving the problems they were invented for. Researchers “have to sweat some more trying to get new physics,” said Anne Archibald, an astrophysicist at the University of Amsterdam.

All attempts to directly detect dark matter and dark energy have failed, however. That fact “kind of leaves a bad taste in some people’s mouths, almost like the fictional planet Vulcan,” said Leo Stein, a theoretical physicist at the California Institute of Technology. “Maybe we’re going about it all wrong?” More.

But at least they recognize and admit it. There is no shame in being wrong. Admitting it puts us on the road to being right.


“The business of alternative gravity theories is a messy one,” Archibald said. Some would-be replacements for general relativity, like string theory and loop quantum gravity, don’t offer testable predictions. Others “make predictions that are spectacularly wrong, so the theorists have to devise some kind of a screening mechanism to hide the wrong prediction on scales we can actually test,” she said. More.


See also: Proposed dark matter solution: “Gravity is not a fundamental governance of our universe, but instead a reaction to the makeup of a given environment.” Dark matter could be the answer to a number of cosmology questions but it could also be the phlogiston or ether of today’s science – substances that were assumed to exist because their existence would solve a problem but th problem was not properly understood. When it was, no one needed those substances to exist. Time will tell, we hope.

Supernova analysis questions dark energy cosmic acceleration
Take back Nobel prizes for accelerating expansion of universe? Dark energy might be an illusion say some researchers. But we thought only a denialist was allowed to doubt the accelerating expansion of the universe. Rules change?


Post-modern physics: String theory gets over the need for evidence

Food for thought: http://www.cornell.edu/video/nima-arkani-hamed-spacetime-is-doomed mike1962
Bob O'H @3: The existence of spacetime? Um, buy a big clock? Did you know that nothing can move in spacetime by definition? Do you know why Karl Popper called spacetime "Einstein's block universe in which nothing happens?" Obviously not. You have not answered my question. What is spacetime made of? Or, as Kant would succinctly put it, if spacetime exists, where is it? FourFaces
Of related interest,
Confirming Einstein, scientists find 'spacetime foam' not slowing down photons from faraway gamma-ray burst (Update) - Mar 16, 2015 Excerpt: Albert Einstein formulated the general theory of relativity, one of the theory's basic assumptions: the idea that all light particles, or photons, propagate at exactly the same speed.,, The researchers analyzed data, obtained by NASA's Fermi Gamma-ray Space Telescope, of the arrival times of photons from a distant gamma-ray burst. The data showed that photons traveling for billions of years from the distant burst toward Earth all arrived within a fraction of a second of each other. This finding indicates that the photons all moved at the same speed, even though different photons had different energies. This is one of the best measurements ever of the independence of the speed of light from the energy of the light particles.,,, One of the attempts to reconcile the two theories (Quantum Mechanics and General Relativity) is the idea of "space-time foam." According to this concept, on a microscopic scale space is not continuous, and instead it has a foam-like structure. The size of these foam elements is so tiny that it is difficult to imagine and is at present impossible to measure directly. However light particles that are traveling within this foam will be affected by the foamy structure, and this will cause them to propagate at slightly different speeds depending on their energy. The fact that all the photons with different energies arrived with no time delay relative to each other indicates that such a foamy structure, if it exists at all, has a much smaller size than previously expected. "When we began our analysis, we didn't expect to obtain such a precise measurement," said Prof. Tsvi Piran, the Schwartzmann University Chair at the Hebrew University's Racah Institute of Physics and a leader of the research. "This new limit is at the level expected from quantum gravity theories. http://phys.org/news/2015-03-einstein-scientists-spacetime-foam.html NASA telescopes set limits on space-time quantum 'foam' - May, 28. 2015 Excerpt: At the smallest scales of distance and duration that we can measure, spacetime—that is, the three dimensions of space plus time—appears to be smooth and structureless. However, certain aspects of quantum mechanics, the highly successful theory scientists have developed to explain the physics of atoms and subatomic particles, predict that spacetime would not be smooth. Rather, it would have a foamy, jittery nature and would consist of many small, ever-changing, regions for which space and time are no longer definite, but fluctuate.,,, Chandra's X-ray detection of quasars at distances of billions of light-years rules out one model, according to which photons diffuse randomly through spacetime foam in a manner similar to light diffusing through fog. Detections of distant quasars at shorter, gamma-ray wavelengths with Fermi and even shorter wavelengths with VERITAS demonstrate that a second, so-called holographic model with less diffusion does not work. "We find that our data can rule out two different models for spacetime foam," said co-author Jack Ng of the University of North Carolina in Chapel Hill. "We can conclude that spacetime is less foamy that some (quantum) models predict." The X-ray and gamma-ray data show that spacetime is smooth down to distances 1,000 times smaller than the nucleus of a hydrogen atom. http://phys.org/news/2015-05-nasa-telescopes-limits-space-time-quantum.html Physical constant is constant even in strong gravitational fields – Sept. 19, 2014 Excerpt: An international team of physicists has shown that the mass ratio between protons and electrons is the same in weak and in very strong gravitational fields.,,, The idea that the laws of physics and its fundamental constants do not depend on local circumstances is called the equivalence principle. This principle is a cornerstone to Einstein's theory of general relativity.,,, The researchers compared the proton-electron mass ratio near the surface of a white dwarf star to the mass ratio in a laboratory on Earth. White dwarfs stars, which are in a late stage of their life cycle, have collapsed to less than 1% of their original size. The gravitational field at the surface of these stars is therefore much larger than that on earth, by a factor of 10,000. The physicists concluded that even these strong gravitational conditions, the proton-electron mass ratio is the same within a margin of 0.005%. In both cases, the proton mass is 1836.152672 times as big as the electron mass.,,, http://phys.org/news/2014-09-physical-constant-strong-gravitational-fields.html
There are two fairly profound problems with physicists hoping to find some type of variance in the universal constants of nature so as to confirm their exotic theories. Number 1, Atheistic Naturalism/Materialism itself has no clue why the universal constants should be constant in the first place. In fact, modern science was born out of the Christian presupposition that there should be unchanging universal laws governing the universe.
“Men became scientific because they expected Law in Nature, and they expected Law in Nature because they believed in a Legislator. In most modern scientists this belief has died: it will be interesting to see how long their confidence in uniformity survives it.” Lewis, C.S., Miracles: a preliminary study, Collins, London, p. 110, 1947. Stronger and More Comprehensive Tests Affirm the Universe’s Unchanging Physics - July 1, 2013 By Dr. Hugh Ross Excerpt: For thousands of years, the Bible has been on record stating that the physical laws governing the universe do not vary. For example, Jeremiah 33:25, God declares that he “established the fixed laws of heaven and earth” (NIV, 1984).,,, Laboratory measurements have established that variations any greater than four parts per hundred quadrillion (less than 4 x 10-17) per year cannot exist in the fine structure constant, which undergirds several of the physical laws.,,, ,,they confirmed with 99 percent certainty that possible variations in the fine structure must be less than two parts per 10 quadrillion per year over the past 10 billion years. This limit is about a thousand times more constraining than the one I described in More Than a Theory. http://www.reasons.org/articles/stronger-and-more-comprehensive-tests-affirm-the-universe%E2%80%99s-unchanging-physics
Moreover, most atheists do not seem to realize that if the universal constants were actually found to have even a small variance in them, as they presuppose, then this would destroy our ability to practice science rationally, for it would undermine our ability to mathematically model the universe in a reliable fashion. For example, if the speed of light constant, or if the invisible glue that holds nuclei together, varied, e=mc2 would be totally useless to us as a reliable description of reality:
Scientists Question Nature’s Fundamental Laws – Michael Schirber – 2006 Excerpt: “There is absolutely no reason these constants should be constant,” says astronomer Michael Murphy of the University of Cambridge. “These are famous numbers in physics, but we have no real reason for why they are what they are.”,,, The observed differences are small-roughly a few parts in a million-but the implications are huge (if they hold up): The laws of physics would have to be rewritten, not to mention we might need to make room for six more spatial dimensions than the three that we are used to.”,,, The speed of light, for instance, might be measured one day with a ruler and a clock. If the next day the same measurement gave a different answer, no one could tell if the speed of light changed, the ruler length changed, or the clock ticking changed. http://www.space.com/2613-scientists-question-nature-fundamental-laws.html
Of related note, although it would destroy our ability to do science if the universal constants were found to have some type of unpredictable variance, it is interesting to note that Darwinian evolution itself is not based on any known universal constant but is based on "unpredictable' randomness, and that is the primary reason it is, as Murray Eden pointed out, 'inadequate' as a scientific theory: Professor Murray Eden of MIT, in a paper entitled “Inadequacies of Neo-Darwinian Evolution as a Scientific Theory” stated that “the randomness postulate is highly implausible and that an adequate scientific theory of evolution must await the discovery and elucidation of new natural laws—physical, physico-chemical, and biological.”
“It is our contention that if ‘random’ is given a serious and crucial interpretation from a probabilistic point of view, the randomness postulate is highly implausible and that an adequate scientific theory of evolution must await the discovery and elucidation of new natural laws—physical, physico-chemical, and biological.” Murray Eden, “Inadequacies of Neo-Darwinian Evolution as a Scientific Theory,” Mathematical Challenges to the Neo-Darwinian Interpretation of Evolution, editors Paul S. Moorhead and Martin M. Kaplan, June 1967, p. 109. https://people.eecs.berkeley.edu/~christos/evol/compevol_files/Wistar-Eden-1.pdf
,,Moreover, presupposing that randomness and/or chaos can produce the unchanging universal constants of the universe, as the Atheistic Naturalists ultimately believes in his multiverse scenarios, is a direct contradiction that borders on sheer insanity. It is equivalent to someone believing down is up, and black is white. Whereas, on the other hand, Christian Theism predicts the constants of the universe to be unchanging. For instance Christianity predicts the universe to be "flat", whereas atheists have no clue why it is flat:
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 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 - 2000 How do we know the universe is flat? Discovering the topology of the universe June 7, 2017 by Fraser Cain Excerpt: With the most sensitive space-based telescopes they have available, astronomers are able to detect tiny variations in the temperature of this background radiation. And here's the part that blows my mind every time I think about it. These tiny temperature variations correspond to the largest scale structures of the observable universe. A region that was a fraction of a degree warmer become a vast galaxy cluster, hundreds of millions of light-years across. The cosmic microwave background radiation just gives and gives, and when it comes to figuring out the topology of the universe, it has the answer we need. If the universe was curved in any way, these temperature variations would appear distorted compared to the actual size that we see these structures today.,,, But they're not. To best of its ability, ESA's Planck space telescope, can't detect any distortion at all. The universe is flat.,,, Since the universe is flat now, it must have been flat in the past, when the universe was an incredibly dense singularity. And for it to maintain this level of flatness over 13.8 billion years of expansion, in kind of amazing. In fact, astronomers estimate that the universe must have been flat to 1 part within 1×10^57 parts. Which seems like an insane coincidence. https://phys.org/news/2017-06-universe-flat-topology.html Stephen Hawking Says Nothing Existed Before Big Bang; Christian Astrophysicist Hugh Ross Responds - By Michael Gryboski - Mar 5, 2018 Excerpt: Ross responded that while Hawking was correct that "time has a beginning," nevertheless "the beginning of time demands a Causal Agent capable of creating time independent of time. It is not enough to simply speculate that imaginary time also exists.",,, ,,,the (quantum fluctuation) model that Hawking is proposing for the origins of the Universe is problematic in light of modern astronomical observations.,,, "Recent observations showing that the images of distant quasars and blazars are not blurry, but rather are sharp, constrain the size of these quantum space-time fluctuations. The fluctuations are not large enough to escape the need for a Creator who creates space and time or for the universe to have a finite age." https://www.christianpost.com/news/stephen-hawking-nothing-existed-before-big-bang-christian-astrophysicist-hugh-ross-220309/
What is spacetime made of again? I’d like to see the physical evidence for its existence.
The existence of spacetime? Um, buy a big clock? :-) Bob O'H
Four faces,
The fact is that both Einsteinian and Newtonian gravity theories are falsified because they cannot explain the rotational velocity of galaxies without invoking some invisible or otherwise undetectable dark matter.
Isn’t it more accurate to say that they predict the existance of dark matter?
Einsteinian physics is just math and zero physics. It explains nothing.
Yet GPS systems are based on Einsteinian physics. Allan Keith
What is spacetime made of again? I'd like to see the physical evidence for its existence. Einsteinian physics is just math and zero physics. It explains nothing. In fact, it conjures up all sorts of pseudoscientific magic to explain why gravity appears to act instantaneously at a distance (as Newton correctly assumed) even though it is hypothesized to propagate at c. The fact is that both Einsteinian and Newtonian gravity theories are falsified because they cannot explain the rotational velocity of galaxies without invoking some invisible or otherwise undetectable dark matter. FourFaces

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