Far out cosmology: a new dark matter theory (Introduction)

by David Turell , Sunday, February 13, 2022, 19:57 (797 days ago) @ David Turell

Departure from current theory with new far distant spiral galaxy studies:

https://phys.org/news/2022-02-distant-galaxies-true-nature-dark.html

"At the center of spiral galaxies—those near to us but also those billions of light-years away—there is a vast spherical region made up of dark matter particles. This region has two defining characteristics: a density that is constant out to a certain radius that amazingly expands over time, while the density decreases. This suggests the existence of a direct interaction between the elementary particles that make up the dark matter halo and those that make up ordinary matter—protons, electrons, neutrons, and photons. We anticipate that this hypothesis is in direct conflict with the current prevailing theory used to describe the universe—known as Lambda-Cold Dark Matter—which posits that particles of cold dark matter are inert and do not interact with any other particle except gravitationally.

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"Dark matter makes up approximately 84% of the mass in the cosmos: "Its dominant presence throughout the galaxies arises from the fact that the stars and hydrogen gas are moving as if governed by an invisible element" explains Gauri Sharma. Up until now, attempts to study it have focused on galaxies near to our own: "In this study, however," she explains, "for the first time, we were seeking to observe and determine the distribution of the mass of spiral galaxies with the same morphology of those nearby, but much further away and therefore earlier by some seven billion years. The idea is essentially that these progenitors of spiral galaxies like our own could offer fundamental clues into the nature of the particle at the heart of the mystery of dark matter." Paolo Salucci adds that "by studying the movement of stars in approximately 300 distant galaxies, we discovered that these objects also had a halo of dark matter, and that, by starting out from the center of a galaxy, this halo effectively has a region in which its density is constant." This trait had already been observed in studies examining nearby galaxies, some of which were also the work of SISSA.

"The new research has revealed, however, that this central region had something that was wholly unexpected within the context of the so-called "standard model of cosmology." Sharma says that "as a result of the contrast between the properties of nearby and distant spiral galaxies—that is, between today's galaxies and their forebears from seven billion years earlier, we could see that not only is there an unexplained region with a constant density of dark matter, but also that its dimensions increase over time as if being subjected to a process of ongoing expansion and dilution." This evidence is very difficult to be explained if the dark matter particles did not interact, as posited in the Lambda-CDM model. "In the research we recently published," says Sharma, "we offer evidence of direct interaction between dark matter and ordinary matter, that over time slowly builds up a region of consistent density from the center of the galaxy outwards." But there's more.

"'Amazingly, the above region with constant density expands over time. It's a very slow process, but one that is inexorable" states Salucci. One possible explanation? "The simplest is that, in the beginning, when the galaxy was formed, the distribution of dark matter in the spherical halo was as predicted by the Lambda-CDM theory, with a density peak in the center. Later on, the galactic disc that characterizes spiral galaxies is formed, surrounded by a halo of extremely dense dark matter particles. As time passed, the effect of the interaction that we have posited meant that the particles were captured by the stars or expelled into the outer reaches of the galaxy." This process would create a spherical region of consistent density within the dark matter halo, with dimensions that increase proportionately over time and finally reach those of the galactic stellar disc, as described in the article in Astronomy and Astrophysics. "The results of the study pose important questions for alternative scenarios that describe dark matter particles (aside from Lambda-CDM), such as Warm Dark Matter, Self-Interacting Dark Matter and Ultra Light Dark Matter" says Sharma."

Comment: another step in trying to understand dark matter. The universe is vast, dangerous to life, yet because of the way it is built, we are here. dhw in the past has questioned why God made it that way. We are trying to find out. I don't know the answer, but currently simply assume that is what God needed to do. God must know what has to be done to achieve His purposes, but He doesn't tell us why, making it a challenge for us to discover, if we can. That is the difference between us. I accept God and His works as is/are and dhw tries to analyze everything about God using his (dhw's) human logic. The problem is God is not human and what He appears to have done may not make sense to us until we find the explanation. In the human body, so-called vestigial parts, like the appendix, are now shown to have very important roles. The lesson: don't judge God from our current ignorance. Can dhw learn? I would expect so.