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Thread: A theory that challenges Newton’s and Einstein’s gravity and nixes dark matter...

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    Chris's Avatar Senior Member
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    A theory that challenges Newton’s and Einstein’s gravity and nixes dark matter...

    Einstein predicted that just as he had refined Newton's laws so too someday would someone refine his General Relativity.

    A theory that challenges Newton’s and Einstein’s gravity and nixes dark matter passed its first test

    ...Newton’s laws, for instance, are still what we use to do sophisticated things like figuring where to shoot a rocket so that we can land a probe on a comet. And Einstein’s laws are what we use every time we open the maps app on our phone, which helps us locate ourselves using GPS technology.

    These gravitational models, however, could not explain the movements of galaxies based on their estimated mass. In fact, we were off by such a large margin that physicists figured there must be more matter in the universe, which we can’t observe because it doesn’t interact with light. They dubbed it “dark matter,” and it is the chink in the Newton-Einstein gravity armor that Brouwer is exploiting.

    Brouwer hasn’t come up with a radical new theory from scratch. Instead, she is relying on work done by Erik Verlinde of the University of Amsterdam and building on that by Mordehai Milgrom of the Weizmann Institute of Science. Their theoretical work suggests that the force of gravity is stronger and dies off more slowly than outlined by Newton and Einstein.

    ...Science has a long history of moving through developments that challenge the status quo, albeit slowly. Only time will tell whether we remember Newton-Einstein or Verlinde-Brouwer.

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    Don (01-05-2017)

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    It would be cool if she is right. Its kind of weird to "adjust" why something doesn't work out by adding something that may not exist to account for it. I'm also glad that science is still science in the realm of astrophysics. Its never "settled."
    Many physicists are skeptical of her findings they may have fatal flaws that have not yet been caught.
    Skepticism is good.
    Last edited by Don; 01-05-2017 at 03:20 PM.


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    Chris (01-05-2017)

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    Emergent gravity may explain dark matter...

    New theory of gravity might explain dark matter
    November 8, 2016 - A new theory of gravity might explain the curious motions of stars in galaxies. Emergent gravity, as the new theory is called, predicts the exact same deviation of motions that is usually explained by invoking dark matter. Prof. Erik Verlinde, renowned expert in string theory at the University of Amsterdam and the Delta Institute for Theoretical Physics, published a new research paper today in which he expands his groundbreaking views on the nature of gravity.
    In 2010, Erik Verlinde surprised the world with a completely new theory of gravity. According to Verlinde, gravity is not a fundamental force of nature, but an emergent phenomenon. In the same way that temperature arises from the movement of microscopic particles, gravity emerges from the changes of fundamental bits of information, stored in the very structure of spacetime.

    Newton's law from information

    In his 2010 article (On the origin of gravity and the laws of Newton), Verlinde showed how Newton's famous second law, which describes how apples fall from trees and satellites stay in orbit, can be derived from these underlying microscopic building blocks. Extending his previous work and work done by others, Verlinde now shows how to understand the curious behaviour of stars in galaxies without adding the puzzling dark matter. The outer regions of galaxies, like our own Milky Way, rotate much faster around the centre than can be accounted for by the quantity of ordinary matter like stars, planets and interstellar gasses. Something else has to produce the required amount of gravitational force, so physicists proposed the existence of dark matter. Dark matter seems to dominate our universe, comprising more than 80 percent of all matter. Hitherto, the alleged dark matter particles have never been observed, despite many efforts to detect them.


    No need for dark matter

    According to Erik Verlinde, there is no need to add a mysterious dark matter particle to the theory. In a new paper, which appeared today on the ArXiv preprint server, Verlinde shows how his theory of gravity accurately predicts the velocities by which the stars rotate around the center of the Milky Way, as well as the motion of stars inside other galaxies. "We have evidence that this new view of gravity actually agrees with the observations, " says Verlinde. "At large scales, it seems, gravity just doesn't behave the way Einstein's theory predicts." At first glance, Verlinde's theory presents features similar to modified theories of gravity like MOND (modified Newtonian Dynamics, Mordehai Milgrom (1983)). However, where MOND tunes the theory to match the observations, Verlinde's theory starts from first principles. "A totally different starting point," according to Verlinde.

    Adapting the holographic principle

    One of the ingredients in Verlinde's theory is an adaptation of the holographic principle, introduced by his tutor Gerard 't Hooft (Nobel Prize 1999, Utrecht University) and Leonard Susskind (Stanford University). According to the holographic principle, all the information in the entire universe can be described on a giant imaginary sphere around it. Verlinde now shows that this idea is not quite correct—part of the information in our universe is contained in space itself. This extra information is required to describe that other dark component of the universe: Dark energy, which is believed to be responsible for the accelerated expansion of the universe. Investigating the effects of this additional information on ordinary matter, Verlinde comes to a stunning conclusion. Whereas ordinary gravity can be encoded using the information on the imaginary sphere around the universe, as he showed in his 2010 work, the result of the additional information in the bulk of space is a force that nicely matches that attributed to dark matter.

    On the brink of a scientific revolution

    Gravity is in dire need of new approaches like the one by Verlinde, since it doesn't combine well with quantum physics. Both theories, crown jewels of 20th century physics, cannot be true at the same time. The problems arise in extreme conditions: near black holes, or during the Big Bang. Verlinde says, "Many theoretical physicists like me are working on a revision of the theory, and some major advancements have been made. We might be standing on the brink of a new scientific revolution that will radically change our views on the very nature of space, time and gravity."

    https://phys.org/news/2016-11-theory...-dark.html#jCp
    See also:

    Emergent Gravity and the Dark Universe

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    donttread's Avatar Senior Member
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    Wasn't dark matter just created to make the math work even though we can't see it?

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    Quote Originally Posted by donttread View Post
    Wasn't dark matter just created to make the math work even though we can't see it?
    That is the way theoretical science works. It then needs to be teste.

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    Astronomers Confirm Key Einstein Theory...

    Einstein Was Right: Astronomers Confirm Key Theory
    July 26, 2018 — A consortium of astronomers said Thursday they had for the first time confirmed a prediction of Albert Einstein's theory of general relativity by observing the gravitational effects of a supermassive black hole on a star zipping by it.
    The German-born theoretical physicist had posited that large gravitational forces could stretch light, much like the compression and stretching of sound waves we perceive with the change of pitch of a passing train. Researchers from the GRAVITY consortium led by the Max Planck Institute for Extraterrestrial Physics realized that they had a "perfect laboratory" to test Einstein's theory with the Sagittarius A* black hole in the center of the Milky Way. Black holes are so dense that their gravitational pull can trap even light, and the supermassive Sagittarius A* has mass four million times that of our sun, making it the biggest in our galaxy.

    Astronomers followed the S2 star as it passed close to the black hole on May 19 at a speed in excess of 25 million kilometers (15.5 million miles) per hour. They then calculated its velocity and position using a number of instruments and compared it with predictions made by Einstein that the light would be stretched by the gravity in an effect called gravitational redshift. Newtonian physics doesn't allow for a redshift. "The results are perfectly in line with the theory of general relativity" and are "a major breakthrough towards better understanding the effects of intense gravitational fields," said the research team, whose findings are published in Friday's issue of Astronomy & Astrophysics.



    This artist's impression provided by the European Southern Observatory in July 2018 shows the path of the star S2 as it passes close to the supermassive black hole at the center of the Milky Way galaxy.

    This is the first time observers have been able to measure such an effect. The European Southern Observatory, whose Very Large Telescope in Chile was used to make the observations, had watched S2 pass by Sagittarius A* in 2016 but the instruments it was using then were not sensitive enough to detect the gravitational redshift. "More than 100 years after he published his paper setting out the equations of general relativity, Einstein has been proved right once more — in a much more extreme laboratory than he could have possibly imagined," said the ESO in a statement. Astronomers already use another effect predicted by Einstein's theory of general relativity — that a black hole can bend passing light. Called gravitational lensing, researchers have used it to peer behind black holes.



    Astronomers hope they can make practical use of the latest confirmation of Einstein's theory to track shifts in S2's trajectory due to gravity, which could yield information on mass distribution around the black hole. "I am always blown away by Einstein's predictions, by the power of his reasoning which yielded this theory and which has never been faulted," French astrophysicist Guy Perrin, a member of the GRAVITY consortium, told AFP. Partnering with the Max Planck Institute in the consortium were French research institute CNRS, the Paris Observatory and several French universities along with Portugal's CENTRA astrophysics center.


    https://www.voanews.com/a/einstein-w...y/4500809.html

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