Researchers from Prague published in the prestigious journal Physical Review Letters an alternative model for dark matter based on MOND that succeeds in predicting the existence of the cosmic background radiation. This is a significant achievement that the MOND model failed to explain, and for this it received the bulk of the criticism against it. the price? Two new fields in Teva. The authors of the article hope in the future to prove its existence with the help of the model's unique fingerprints on the gravitational waves.
The current theory of gravity, or by its familiar name general relativity, is immeasurably successful. It elegantly describes the dynamics between planets, stars, black holes and galaxies, the expansion of the universe and gravitational waves. Despite the successes, it is impossible to ignore a central "failure" that clouded its accuracy - if you take into account all the visible matter, the dark matter and the radiation in space, the universe is supposed to slow down its rate of expansion and shrink. Still, observations show that the universe is accelerating its expansion. These data yielded a new element to nature known as "dark energy" so that a general patronage would allow the universe to expand at an accelerated rate. Along with dark energy, several alternative explanations have been put forward that correct the theory of gravity at large distances. Such gravitational corrections are not new in the scientific literature and are mainly centered around the existence of dark matter, mainly because we know less about dark energy than dark matter.
Dark matter is physicists' favorite solution to gravitational anomalies in space. Along with the growing popularity, a small community has formed over the years that refuses to accept its existence. This community has engineered several competitors to dark matter, the most popular of which is MOND (Mond - Modified Newtonian Dynamics). The Mond theory was founded more than thirty years ago by an Israeli researcher named Mordechai Milgrom to explain the movement of the stars around the center of the galaxy. The supporters of the Mond model offer an alternative to the Newtonian gravitation theory at accelerations lower than one tenth of a billionth of a meter per second squared and manage to explain some important observations without assuming the existence of dark matter. Despite the successes, the model falls short in predicting the cosmic background radiation, an important observation that any theory of gravity must predict. Milgrom's idea did not ignite new predictions, but surprisingly, the Mond model is valid in almost every galaxy - old, young, small or large.
Why is dark matter more popular than Mund?
Dark matter is considered the preferred explanation because it is consistent with more observations from space. Besides the cosmic background radiation, dark matter is also able to explain the phenomenon of gravitational collapse. Mond's theory, on the other hand, is not able to describe any of the mentioned phenomena. In recent years, relativistic corrections were added to Mond that managed to explain the dimming phenomenon, but the cosmic radiation was left behind. "If the theory is not able to explain the cosmic background radiation, it is worthless," pointed out Constantinos Skordis, a researcher from the Czech Academy of Sciences in Prague.
In the October edition of the prestigious magazine PHYSICAL REVIEW LETTERS, Skordis and his colleagues Publish a model Inspired by Mond, who is able to explain the cosmic background radiation, the gravitational cooling and even the gravitational waves that have been discovered in recent years (a challenge that the original Mond model failed). The new model assumes the existence of two fields that fill the space that affect the existing gravitational field. One field is a scalar field, similar to the Higgs field, and the second field is a vector field, similar to the magnetic field that has a defined direction at every point in space. The researchers calibrated the new fields so that their effect on the early universe mimics dark matter. Thanks to the calibration, the researchers were able to reproduce the cosmic background radiation similar to that observed in space.
Skordis points out that his model is similar to all alternative models for gravity. In any such model, researchers are required to add fields to nature so that they can explain the observations. Skordis admits that unlike dark matter, which is based on a simple principle and symmetry laws, the upgraded Mund model does not rely on a fundamental principle, although the last word has not yet been said.
"This is a real breakthrough," noted cosmologist Stacey McGough from Ohio. "This is a significant achievement. The upgraded Mond model is able to explain the cosmic background radiation and the phenomenology of galaxies." He adds that "the new model is based on quite a few free parameters, so I still prefer the simple explanation of dark matter". McGough emphasizes that dark matter cannot explain all observations, for example the abundance of lithium or the conflicting results from the various experiments that measured the expansion rate of the universe. Will the model of Skordis and his colleagues be able to solve these questions? You still can't tell. Skordis intends to use his model in the future to test whether it predicts unique fingerprints in the gravitational waves.
And we remind the readers that despite the clear preference of astrophysicists, cosmologists and particle scientists, and despite the many efforts to locate it, dark matter has not yet been discovered. This does not mean that dark matter does not exist, but as the number of negative results increases, so does the difficulty of inventing a new method that has not been tried before.
More of the topic in Hayadan:
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It's the first time I've read the comment section on this site and I'm quite shocked by the arrogance of the readers here.
I am admittedly only a first year student in physics, but I can recommend you to read about the ether particle and understand that nothing is more understandable in the field of physics.
Shmulik Alon
You wrote "because of the equivalence principle it is not possible to know if the universe is contracting or expanding".
What principle of equivalence do you mean?
The universe has been contracting at an increasing rate for the past billion years.
The solution is under everyone's nose and for some reason they don't pay attention to it.
It is true that the galaxies are moving away at an increasing rate, because of the equivalence principle it is not possible to know whether the universe is contracting or expanding.
Accelerated expansion lacks any logic and forces one to believe in metaphysics (where logic ends and facts are stopped).
Proof of this can be found when looking at the supercluster Laniacea, all the galaxies in the supercluster move towards a common center of gravity, as you get closer to its center, the speed of the galaxy accelerates with the increase in the strength of the gravitational field (according to Newton's law of gravity).
There is no need for energy or dark mass if the universe is contracting and it is definitely contracting.
interesting
A breakthrough in the structure of the universe requires the acceptance of a new and surprising idea, which has never appeared in science.
To this day such an idea has not appeared, and the structure of the universe remains as it was perceived 100 years ago.
The attraction is still there, the combination of the letters HMR remains a meaningless word, and no one knows what is hidden behind the combination of the letters HMR. Nor does anyone know what the true orbit shape of the stars is, nor does anyone know how light passes through the space between the stars.
I suggest first of all to accept the amazing idea, that the infinite space is full of passive time, which is completely still and completely cold.
The passive time is a real time that exists in physical reality, and it is the medium through which the light waves pass.
Without passive time filling the infinite space, there is no possibility for sunlight to spread in the world.
The rest of the ideas appear in the article posted at the beginning of this thread.
Consider the imaginary possibility that the Doppler effect in light, on which we base the expansion of the universe, arises not from the expansion of the universe but from an energetic change of photons over time, so that as they move away from their point of origin they lose energy and so does wavelength, not speed.
Also try to imagine that in the big bang not all the energy created mass of detectable sizes. Today we are able to detect neutrinos because of their speed, but if there is material left in the explosion that spread without creating muons, because it is too tiny, the size of a neurino or smaller, we have no means to detect or measure them and they are able to be found everywhere, to a uniform extent in the universe.
And the most interesting. We are measuring the cosmic expansion of the ancient world. At a distance of 13 billion light years we measure the expansion after the big bang which is certainly the fastest. Each younger and closer light source moves away at the rate of expansion at that time. As we get closer to our time, the speed of expansion approaches zero and beyond this distance there is at least one galaxy approaching us.
Dark matter is galaxies and black holes that surround our universe at such distances that our current technology is unable to observe them. Thus their attraction causes the expansion of our universe
The universe started with two tiny explosions and in both of them all the matter was "dark" and all their movement vector was outwards, and as a result of this there was no "light" at all meaning all the radiation moved in the same direction as the "matter" outwards so the entire universe simply spread in darkness and absolute cold, The turning point happened at the meeting of the materials from the two compensating each other, in this collision the energy rays and waves began to take different directions and different colors. As it is said "and darkness over the abyss... and there was light"!
Thanks, corrected
Stacey McGough is a cosmologist, not a cosmologist
A suggestion for those who are undecided about the structure of the universe.
replace the pair of words dark matter with the pair of words passive time, prevent the use of the pair of words gravity,
And a wonderful new universe will be revealed to you, where the stars have eternal motion in a spatial screw orbit.
Any solution that does not contain dark matter has a problem with those galaxies that do rotate according to the equations of relativity.
aetzbar
You are boring.
Dark matter is nonsense, because matter is nonsense
The universe must be explained only with the help of continuous quantitative concepts, and there are only 5 such: length, area, volume, time and energy.
Matter does not appear here at all, because matter is a physical form, created by combining amounts of passive time and energy.
Passive time is a completely new physical concept, and it has a crucial role in the structure of the universe.
Passive time is absolute rest and absolute cold, and it fills the infinite space.
The stars move through him, and he does not hinder their movement.
Additional details in the attached article
http://img2.timg.co.il/forums/3/c8659042-cdd9-4060-b7fd-a3872d542a4b.pdf
"If you take into account all the visible matter, the dark matter and the radiation in space, the universe should slow down its rate of expansion and shrink" - slow down, right. shrink? Maybe sometime in the future (and probably not, because the overall mass is too small).