Why "Dark matter" is still considered? [closed]

Question

Why the 'dark matter' is still the main research trend? It looks like a waste of time, money and resources.

https://www.youtube.com/watch?v=MvNCWMD6so4

Answer 1

I'm going to answer this question, not because I believe you want a thoughtful, coherent answer, but rather for others who may come across this question and look at the propaganda you've posted. I don't believe anything I can say will change your mind, but hopefully I can inform other, unsuspecting viewers

The Context

The video you've posted is from thunderbolts.info. This is a pseudo-scientific organization that widely promotes well-debunked and/or non-scientific concepts such as creationism or the ideas of the Electric Universe. This video specifically discusses the concept of Dark Matter and tries to make an argument that scientists have now finally disproven that dark matter exists. To back up this claim, they cite two news articles and have a voice over from an "astronomer" named Barry Setterfield. The disrepute of the video is pretty clear when, within the first minute, they state:

2016 may be remembered as the year that the hypothesis of Dark Matter was finally, officially falsified.

I certainly don't remember that occurring in 2016.

I'm going to next take a look at the two news articles this video is based one. They're both published on phys.org. One important point I want to mention here is that phys.org is not the author of these articles. This website is merely a physics-related news curator which accepts and culls news articles from a wide variety of sources. In both cases, these articles were submitted by the respective institutions or groups of people performing the research and so likely had a heavy slant to play up the importance or interpretation of their own work.

News Article 1

The first news article is titled Acceleration relation found among spiral and irregular galaxies challenges current understanding of dark matter. It is a report on a paper published by McGaugh et al. 2016 in the Physical Review Letters. The main author, Stacy McGaugh is a strong proponent of a hypothesis called MOND, which is a fairly weak, yet persistent contender for Dark Matter. It purports to explain the same things Dark Matter does, but without introducing new physics or mysterious, unexplained particles. It simply modifies the physics we already know.

The paper published by McGaugh details their measurement of the rotation curves of galaxies. Ironically, they find the exact same mass deficit one would be expected to find and would explain via Dark Matter. The focus of their paper however, is on a tight correlation between the expected centripetal acceleration due to baryonic matter and the observed centripetal acceleration. Note the important word here: correlation. All they've done is shown the two concepts are related via an empirical equation. They haven't disproved Dark Matter, they haven't even found evidence it doesn't exist, and they haven't found "new physics". Their paper, in my personal opinion, is weak at best. They make heavy-handed assumptions and don't often explain the details, relegated it to sentences like their assumptions "only affects details, not the basic result" (granted it is a letter, not a full blown paper).

Overall, I see nothing ground breaking or even important in this article or research paper and it seems clear to me that the phys.org article itself was likely written by Stacy McGaugh or one of the other paper authors.

News Article 2

The second article cited is titled Unexpected interaction between dark matter and ordinary matter in mini-spiral galaxies. The article itself is pretty devoid of anything substantial. I wasn't even sure what research the authors had performed and it was clear they simply wrote up this article to play up their own work.

After reading their paper, it seems their work is focused on studying dwarf, disk galaxies. They posit that baryonic matter plays a more important role in galaxy formation than others might have previously suspected but importantly, for this video, they appear to have no qualms with declaring Dark Matter as real. In fact they heavily use the concept of Dark Matter in their models and assumptions. What this video does is to cherry pick certain statements from this paper, misinterpret them, and claim stronger statements about Dark Matter that the original paper never stated. These claims are only backed up by explanations which simply restate the idea without actually providing a real explanation. This video citing this article seems like a clear cut case of the logical fallacy of Appealing to Authority.

Barry Setterfield

Let's discuss the main narrator of the video, Barry Setterfield. He is awarded the dubious title of "Astronomer" in the video (again an appeal to authority) and spends most of the video explaining the historical background and evidence for Dark Matter. I won't even get into the fact that he missed out on a lot of the history, choosing to jump right to Vera Rubin and completely missing Fritz Zwicky.

In any case, this narrator is a known young-Earth creationist. He has no scientific degrees (having only been through a couple of years of undergraduate work before dropping out). He has published papers describing how the speed of light is decaying over time which have not been well received. I should note that none of his published papers (as far as I can tell) are published in well-respected, peer-reviewed journals. Most are simply self-published, or else published in junk journals which have since gone under. His only claim to being an "astronomer" is that he helps run the christian backed, New Hope Observatory. I don't say any of this to cast aspersions, merely to provide context so that things aren't misinterpreted.

Throughout this video, he constantly makes unwarranted claims. For example, from the second news article he concludes that the authors indicated dark matter halos do not extend past the baryonic matter and thus

Dark Matter can only occur in those locations where ordinary matter can be found, not on its own or elsewhere.

From here he immediately jumps to the much stronger statement

This negates the whole idea of Dark Matter existing at all

So he misinterprets a paper's statement and moves on to make a much stronger claim. He attempts to back this up by making the studies he's talking about sound comprehensive. He specifically implies his above claims are validated by calling out the "2,696 data points" in the paper from the first news article. A large number of data points does not make someone correct and it doesn't bridge the gap between his citations and conclusions.

He finally concludes (with no real evidence) that Dark Matter cannot possibly exist based on his interpretation of only two very small studies. He then quickly casts aside MOND, the popular alternative to Dark Matter, in favor of an explanation from the Electric Universe "theory".

Electric Universe

As stated above, the concept of the Electric Universe is the idea that almost the entire universe is made of plasma and therefore almost all dynamics, including large-scale galaxy formation, are dominated by electric and magnetic forces. It is true to state that a large percentage of the baryonic matter in the universe is in a plasma form, but it is not correct to claim that implies electric forces should be the governing force when it comes to large-scale dynamics.

Setterfield calls out the idea that electric forces are $10^{39}$ times stronger than gravitational forces and so should completely overpower any gravitational affects. He is correct about the strength of the electric force compared to the gravitational force, but completely neglects the crucial fact that electric charges come in both positive and negative forms. As it turns out, almost all of the universe is electrically neutral on large scales and so these powerful electric forces are all cancelled out by the conflicting charges. Because of this, electric forces only play a significant role over something known as the Debye length, a well-known concept you'd learn in a first semester plasma physics course. The Debye length for every type of plasma is far, far short of being long enough to govern large-scale dynamics.

Setterfield ends the video by citing the work of Anthony Peratt who claims to have run simulations which showed that electric forces were capable of forming galaxies and even resulted naturally in the flat rotation curves that are currently explained by dark matter.

Anthony Peratt

One thing that strikes me as odd in this whole quest to demonize Dark Matter is that this video is quick to hold up "respected" scientists as proof that their research and ideas are valid, while work by many other respected scientists is invalid. This two-faced approach to scientific authority is just a bit too convenient.

In any case, Anthony Peratt is a "plasma cosmologist", i.e., a proponent of the electric universe theory. He published a collection of papers where he simulated two "clouds" of electrically charged plasma and showed that as they evolved, they appeared to form something that looked like a galaxy. There's numerous problems with this though.

1. His plasma clouds were not galactic in size and could not have produced real galaxies. He even admits he limited his initial plasma cloud size to

   The fraction of the length correspond[ing] to a local region that is capable of interacting with an adjacent local region in a neighboring filament.

   Anything larger wouldn't cut it in his simulations.

2. His results only "looked" like galaxies in that they had spirals and similar shapes. They did not really exhibit the complex nature of the large variety of real galaxies.
3. His spirals were a result of "winding" the matter as it spins. Scientists have long ago come upon the "winding problem" and know that arms in a spiral galaxy are not a result of winding matter but instead are density waves at the Lindblad resonances.

Overall, using this research as evidence of galaxies forming in an Electric Universe, devoid of Dark Matter, is hardly convincing and certainly not enough to overturn the century of work concerning Dark Matter by thousands of scientists across the world.

Dark Matter

The last point I want to make is about Dark Matter itself. Dark Matter is a hypothesis. Arguably, the first solid proposal for Dark Matter came from Fritz Zwicky in 1933. Zwicky found that the standard assumptions, physics, and observations did not all agree and that somewhere, something must be wrong. He chose to interpret that the problem lie in the amount of mass he was observing and that there was invisible mass he wasn't observing that was changing his results. Alternative theories such as MOND choose to claim the problem lies in our physics equations instead.

Nevertheless, Dark Matter has had fairly widespread support since it's inception and has been used to explain a variety of diverse problems over the years. It is used to explain the dynamics of galaxy clusters, the rotations of galaxies, observations in gravitational lensing, anisotropies in the CMB, and many more things. The ideas concerning Dark Matter have constantly been refined and improved. MACHOS have been all but thrown out; WIMPS are still a possible explanation; we believe Dark Matter must be "cold". This is how science works. A problem was found, a solution was posed, and over the years that solution has been reworked and molded to better explain observations. Importantly Dark Matter helps explain areas and concepts beyond its original invocation.

That's not to say the idea of Dark Matter isn't without its faults or criticisms. For example, such problems include

• the cuspy halo problem,
• the missing satellite problem,
• or the too-big-to-fail problem.

But, these problems aren't an invitation to throw out nearly 100 years worth of work in favor of a poorly supported and conceptually flawed "theory". Instead, they should be motivation to further refine our hypotheses and what we think we know about Dark Matter. There may come a day when something better than Dark Matter comes along, when another hypothesis is capable of explaining everything Dark Matter can and more. I will gladly drop Dark Matter on that day. But it is not this day.