New Study Claims Dark Matter Doesn’t Exist

[SergUpstart 1]

The prevailing theory among scientists is that roughly three quarters of all the stuff in the universe is made up of “dark matter,” a mysterious substance that interacts with visible matter via gravity.

Despite its ubiquitousness, though, scientists have yet to find direct evidence of its existence.

According to a new study by an international team of scientists however, this search could be for nothing, NBC News reports. Instead, they argue that our limited scientific understanding of gravity may be unable to account for the strange gravitational behavior of galaxies. In other words, it’s not dark matter causing the behavior — we simply don’t fully understand the natural laws governing matter.

In their recent study, the team argues that an idea first established in the early 1980s called the modified Newtonian dynamics theory (MOND) could explain the existence of strange gravitational behavior of stars that scientists conventionally explained with dark matter.

In short, the theory replaces Newtonian dynamics and General Relativity as posited by Albert Einstein, and argues that the gravitational force of experienced by a star should be calculated in entirely different ways.

“What we’re really saying is that there is absolutely evidence for a discrepancy,” co-author Stacy McGaugh, head of the astronomy department at Case Western Reserve University in Cleveland, told NBC. “What you see is not what you get, if all you know about is Newton and Einstein.”

A number of theories have been put forward trying to explain what dark matter could be, from primordial black holes to weakly interacting massive particles known as WIMPS.

McGaugh argues that the MOND theory has been able to predict a number of astronomical observations since it was first brought up in the 80s.

“MOND is the only theory that has succeeded in this way,” McGaugh told  NBC. “It is the only theory that has routinely had all predictions come true.”

https://futurism.com/new-study-claims-dark-matter-doesnt-exist

[Curious layman 121]

15 minutes ago, SergUpstart said:

MOND is the only theory that has succeeded in this way,” McGaugh told  NBC. “It is the only theory that has routinely had all predictions come true"

Not all predictions.

https://en.m.wikipedia.org/wiki/Modified_Newtonian_dynamics#Outstanding_problems_for_MOND

Quote

The most serious problem facing Milgrom's law (MOND theory) is that it cannot completely eliminate the need for dark matter in all astrophysical systems: galaxy clusters show a residual mass discrepancy even when analysed using MOND.

 

[swansont 7441]

Indeed - from what I've read MOND works at certain scales but fails at others, depending on what analysis you do, like a blanket that can cover your feet or your head but not at the same time.

 

[SergUpstart 1]

26 minutes ago, Curious layman said:

The most serious problem facing Milgrom's law (MOND theory) is that it cannot completely eliminate the need for dark matter in all astrophysical systems: galaxy clusters show a residual mass discrepancy even when analysed using MOND.

The key word is completely. Dark matter in the form of brown dwarfs, asteroids, planets and interstellar gas certainly exists.

[swansont 7441]

14 minutes ago, SergUpstart said:

The key word is completely. Dark matter in the form of brown dwarfs, asteroids, planets and interstellar gas certainly exists.

That's not what is meant by dark matter, though.

[MigL 1475]

I had read about this a week or two ago in, of all places, Daily Mail, but could not find a link to the actual study, or their publication.

The report I read did not specify Milgrom's MOND, but simply MOND as in "modified' gravity.
The explanation was rather vague, and hand-wavy, but essentially uses the Machian idea of ALL other mass-energy in the universe affects local gravity at galactic scales.
If anyone has been able to find the actual study, and any publication of it, I would certainly appreciate a link.

PS
Found it buried in the NBC news link, buried in SergUpstart's link.

Testing the Strong Equivalence Principle: Detection of the External Field Effect in Rotationally Supported Galaxies - IOPscience

Edited January 13 by MigL

[Anthony Chan 0]

On 1/13/2021 at 3:42 PM, swansont said:

That's not what is meant by dark matter, though.

It is classed as baryonic dark matter as opposed to non baryonic. 

All the best. 

[swansont 7441]

35 minutes ago, Anthony Chan said:

It is classed as baryonic dark matter as opposed to non baryonic. 

All the best. 

Which has been shown to be insufficient to account for the effects observed; most baryonic matter is thought to be non-baryonic. Thus, if you use the generic term “dark matter” in this context, you must be referring to non-baryonic dark matter or all of it, not just the small fraction that’s baryonic

https://en.wikipedia.org/wiki/Baryonic_dark_matter

[Anthony Chan 0]

On 1/15/2021 at 12:51 PM, swansont said:

Which has been shown to be insufficient to account for the effects observed; most baryonic matter is thought to be non-baryonic. Thus, if you use the generic term “dark matter” in this context, you must be referring to non-baryonic dark matter or all of it, not just the small fraction that’s baryonic

https://en.wikipedia.org/wiki/Baryonic_dark_matter

Of course. My comment was in terms of brown dwarfs etc existing and being referred to as baryonic DM. I don't recall how tiny the percentage of total DM but it will certainly be there.

[beecee 526]

As already mentioned the relevant aspect with MOND, was that it doesn't explain all, and needs to be fudged differently depending on galactic type...or as someone put, like a blanket that cannot cover both your head and your tootsies at the same time.

The most convincing aspect of DM is still the Bullet cluster anomaly, I think, which to me anyway, is pretty strong.

https://www.nasa.gov/vision/universe/starsgalaxies/dark_matter_proven.html

[SergUpstart 1]

It seems that what the Voyagers found has a very direct relationship to the problem of dark matter

https://www.sciencealert.com/for-some-reason-the-density-of-space-is-higher-just-outside-the-solar-system

[swansont 7441]

31 minutes ago, SergUpstart said:

It seems that what the Voyagers found has a very direct relationship to the problem of dark matter

https://www.sciencealert.com/for-some-reason-the-density-of-space-is-higher-just-outside-the-solar-system

It’s not mentioned in the article. What is this “direct” relationship?

[MigL 1475]

The strong equivalence principle suggests gravity is geometric in nature, only the metric determines its effects, and does not have any extra external fields associated with it.
The strong equivalence principle can be tested by several methods.
Variations in the mass of fundamental particles, or the variation of G over the life of the universe, have determined that the upper range in the variation of G cannot be more than 10%.
It can also be tested by looking for extra forces, deviations from the forces predicted by GR, or the inverse square law.
This is, in effect, what this study has done.
It looked for the effects from the large scale gravitational field from an all-sky galaxy catalog, and concluded that there was statistically significant evidence of violation of the strong equivalence principle in weak gravitational fields in the vicinity of rotationally supported galaxies. They observed an external  field ( Machian ) effect of the MOND type, a theory of gravity inconsistent with tidal effects and the Lambda-CDM model.

Their paper

Testing the Strong Equivalence Principle: Detection of the External Field Effect in Rotationally Supported Galaxies - IOPscience

and a quote from the abstract

"The strong equivalence principle (SEP) distinguishes general relativity (GR) from other viable theories of gravity. The SEP demands that the internal dynamics of a self-gravitating system under freefall in an external gravitational field should not depend on the external field strength. We test the SEP by investigating the external field effect (EFE) in Milgromian dynamics (MOND), proposed as an alternative to dark matter in interpreting galactic kinematics. We report a detection of this EFE using galaxies from the Spitzer Photometry and Accurate Rotation Curves (SPARC) sample together with estimates of the large-scale external gravitational field from an all-sky galaxy catalog."

[SergUpstart 1]

18 hours ago, swansont said:

It’s not mentioned in the article. What is this “direct” relationship?

This follows from what is written in the article. The interstellar medium contains more interstellar gas and plasma (i.e., baryonic and lepton dark matter) than the interplanetary medium in the SS.

[swansont 7441]

2 hours ago, SergUpstart said:

This follows from what is written in the article. The interstellar medium contains more interstellar gas and plasma (i.e., baryonic and lepton dark matter) than the interplanetary medium in the SS.

And?

Since the article made no claim about dark matter, you need more than a hand-wave to say that it does.

Dark matter seems to outweigh visible matter roughly six to one

https://home.cern/science/physics/dark-matter

So unless the research the article refers to is claiming a 6x discrepancy in how much normal matter is out there (it isn’t), you aren’t getting rid of dark matter. The article points out two data sets just outside our solar system. Your claim, vague as it is, is a massive and unfounded over-extrapolation of the report.