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Is Dark Energy Just an Illusion? Neutron Star Collisions May Provide the Answer

Posted by Guy Pirro 03/19/2022 04:08PM

Is Dark Energy Just an Illusion? Neutron Star Collisions May Provide the Answer

Is dark energy just an illusion? The truth is that no one really knows -- More is unknown about dark energy than is known. Many researchers claim to “know” how much dark energy there is due to its apparent affect on the expansion of the Universe. But other than that, it is a complete mystery. If it exists at all, then roughly 68 percent of the Universe should be composed of this mysterious dark energy, with the equally mysterious dark matter making up about 27 percent. The rest -- everything on Earth, everything ever observed in the Universe with all of our instruments, all normal matter -- would add up to less than 5 percent of the Universe. The thing that is needed to decide between dark energy possibilities – be it a property of space, a new dynamic fluid, or a new theory of gravity -- is more and better data. Researchers at the Scuola Internazionale Superiore di Studi Avanzati (SISSA) in Trieste, Italy, have been working on this problem and now have the first simulation of neutron star mergers that reproduce a dark energy-like behavior on cosmological scales. So far, their findings that dark energy is just an illusion are consistent with data acquired by the LIGO and Virgo interferometers during recently captured binary neutron star collisions and may be further tested and supported by next-generation gravitational interferometers, such as the Einstein telescope in Europe and Cosmic Explorer in USA.


Comments:

  • eranbob [Robert Campbell]
  • 03/21/2022 07:07AM
It is quite likely that dark energy/dark matter does not exist. When large scale expansion observations are in such disagreement with theory, its pretty clear that the theories and governing equations are inadequate as the cosmological spatial scale. Newtonian mechanics and gravitation apply at low speeds and medium spatial scales, general relativity works on stellar spatial scales and near large (but not singular) gravitational fields and then another yet to be determined correction/theory applies at galactic and larger scales.

  • hlritter [Howard L Ritter]
  • 03/26/2022 12:10PM
Regardless of the explanation, I'm having trouble getting from neutron-star mergers to (the appearance of) an acceleration in the expansion of the universe. How do neutron-star mergers lead to "a dark energy-like behavior on cosmological scales"?
Howard:

That is a good question that the researchers do not appear to specifically address in their press release. So the simple answer to your question is I don’t know.
From what I can infer from their write-up, however, is that their approach to modified gravity that does not include dark energy (which they have just recently been able to model with a supercomputer) can be proven or disproven through subtle measurements in gravity waves. The best source of gravity waves today is neutron star mergers that can be detected by the LIGO and Virgo interferometers.

To me, that’s the connection between neutron star mergers, gravity, and their modified gravity approach. But that is only a guess on my part.

Hope this helps.

Guy Pirro

  • hlritter [Howard L Ritter]
  • 03/27/2022 02:58AM

@Princeton

Thanks, Guy. That actually is a complete answer to my question. You just made an important distinction – between merging neutron stars themselves producing the appearance of an accelerating expansion on the one hand, and on the other hand, merging neutron stars as the source of gravity waves that can help to test a model of non-Newtonian gravity that obviates the need for dark matter.