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Dark matter exists: Observations disprove alternate explanations
Phys.org ^ | International School of Advanced Studies (SISSA)

Posted on 04/30/2019 8:34:49 PM PDT by ETL

Image result for Dark matter exists: Observations disprove alternate explanations
Acceleration as a function of radius in NGC 4455, one of the studied galaxies

As fascinating as it is mysterious, dark matter is one of the greatest enigmas of astrophysics and cosmology
It is thought to account for 90 percent of the matter in the universe, but its existence has been demonstrated only indirectly, and has recently been called into question

New research conducted by SISSA removes the recent doubts on the presence of dark matter within galaxies, disproving the empirical relations in support of alternative theories.

The study, published in the Astrophysical Journal, also offers new insights into understanding the nature of dark matter and its relationship with ordinary matter.

From the expansion of the universe to the movement of stars in the galaxies, there are many phenomena that cannot be explained by the presence of baryonic alone.

The generated by matter is insufficient to explain observable gravitational effects. This had led to the theory of the existence of undetectable dark matter, and the idea that galaxies are embedded in its spherical halo.

"Three years ago, a few colleagues at Case Western Reserve University strongly questioned our understanding of the universe and the in-depth work of many researchers, casting doubt on the existence of dark matter in the galaxies," explains Chiara Di Paolo, a doctoral student of astrophysics at SISSA.

"Analyzing the rotation curves of 153 galaxies, principally the 'classical' spiral kind, they obtained an empirical between total gravitational acceleration of the stars (observed) and the component which we would observe in the presence of only in the classical Newtonian theory.

This empirical relationship, which seemed valid in all the galaxies they analyzed and at any galactic radius, motivated the explanation of gravitational acceleration without necessarily calling into question dark matter, but involving, for example, theories of modified gravity such as modified Newtonian dynamics (MOND)."

Di Paolo and her collaborators wanted to verify this relationship, analyzing the rotation curves of galaxies other than the classical spiral kind—72 galaxies with low surface brightness (LSB) and 34 dwarf disc galaxies.

They produced more extended results, finding a relationship, which, besides total gravitational acceleration and its ordinary component, also involves the galactic radius and the morphology of the galaxies.

"We have studied the relationship between total acceleration and its ordinary component in 106 galaxies, obtaining different results from those that had been previously observed," explains Paolo Salucci, professor of astrophysics at SISSA and one of the research authors.

"This not only demonstrates the inexactness of the empirical relationship previously described but removes doubts on the existence of in the .

Furthermore, the new relationship found could provide crucial information on the understanding of the nature of this indefinite component."


TOPICS: Astronomy; Chit/Chat; Science
KEYWORDS: cosmology; darkenergy; darkforce; darkmatter; galaxies; missingmatter; speedofdark; stringtheory
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I find it confusing when they talk about the structure and dynamics of galaxies, given their enormous sizes, most of which are 10s or 100s of thousands of light years across, one light year being roughly 6 TRILLION miles. Since gravitational influences, like light, are thought to travel at the speed of light, how can these beasts even have a coherent structure, such as a neat spiral? Our own Milky Way spiral galaxy is roughly estimated at around 100,000 light years across.

Below is a link to an interesting related article on galaxy structure...

Why Aren’t Spiral Galaxies More Wound Up?
It’s rare to find a galaxy where the arms wrap around even a full 360 degrees. But after billions of years, why is that?

https://medium.com/starts-with-a-bang/ask-ethan-why-aren-t-spiral-galaxies-more-wound-up-7cd2e6731797

1 posted on 04/30/2019 8:34:49 PM PDT by ETL
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To: All
Related image
Messier 100
2 posted on 04/30/2019 8:36:05 PM PDT by ETL (REAL Russia collusion! Fake Dossier, Uranium-1 Deal, Missile Defense, Iran Deal, Nukes: Click ETL)
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Image result for spiral galaxy
3 posted on 04/30/2019 8:37:09 PM PDT by ETL (REAL Russia collusion! Fake Dossier, Uranium-1 Deal, Missile Defense, Iran Deal, Nukes: Click ETL)
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To: All
Image result for spiral galaxy
Spiral galaxy NGC 1232
4 posted on 04/30/2019 8:38:38 PM PDT by ETL (REAL Russia collusion! Fake Dossier, Uranium-1 Deal, Missile Defense, Iran Deal, Nukes: Click ETL)
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To: ETL

Amazing stuff! So amazing and complex that it is obvious an amazing, all-powerful God created this marvelous universe!


5 posted on 04/30/2019 8:39:15 PM PDT by LYDIAONTARIO
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To: ETL

They believe dark matter exists BUT they have no idea what it is.


6 posted on 04/30/2019 9:10:13 PM PDT by Williams (Stop Tolerating The Intolerant.)
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To: LYDIAONTARIO
Oh .. I get it now .. "dark matter" = what we used to call a "fudge factor".

I kinda like the old term because it makes me think of fudge. :)

7 posted on 04/30/2019 9:10:30 PM PDT by The Duke (President Trump = America's Last, Best Chance)
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To: ETL

Another picture:

https://www.cnn.com/videos/world/2019/04/30/space-black-hole-plasma-clouds-wobble-icrar-lon-orig.cnn

I thought nothing can escape from black holes, but this shows plasma spewing out.


8 posted on 04/30/2019 9:10:49 PM PDT by Innovative
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To: Innovative

Oops, by the time I posted the link they changed it. now it shows a hedgehog.

I did not confuse a black hole with a hedgehog.


9 posted on 04/30/2019 9:13:50 PM PDT by Innovative
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To: Innovative

Try this link:

https://www.cnn.com/2019/04/30/world/spinning-black-hole-jets-scn/index.html


10 posted on 04/30/2019 9:15:01 PM PDT by Innovative
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To: ETL

Thanks for posting.

Very interesting, but difficult to completely understand.


11 posted on 04/30/2019 9:23:14 PM PDT by zeestephen
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To: Innovative
This hedgehog? Dentinum repandum. An excellent edible..
12 posted on 04/30/2019 9:30:45 PM PDT by Fungi
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To: ETL

They’re trying to figure out the galaxy rotation curve problem.

The claim that this removes doubts about dark matter though is cultish in its ludicrousness.


13 posted on 04/30/2019 9:33:47 PM PDT by thoughtomator (The Clinton Coup attempt was a worse attack on the USA than was 9/11)
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To: Williams

> They believe dark matter exists BUT they have no idea what it is.

Dark matter is literally “presumed stuff where it would need to be to keep current theories intact”.

Used to be that the need to do something like this to keep the theory intact was considered enough to falsify the theory.

But if the theory is unfalsifiable by doctrine, you get nonsense like dark matter to make it work.


14 posted on 04/30/2019 9:36:05 PM PDT by thoughtomator (The Clinton Coup attempt was a worse attack on the USA than was 9/11)
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To: ETL
The research institute this work came from - International School for Advanced Studies (SISSA) - is in Trieste, Italy, which is about 75 miles east of Venice.

First time I have heard about it.

Logo

15 posted on 04/30/2019 9:37:51 PM PDT by zeestephen
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To: Innovative
Yeah, right. That’s what Richard Gere says.
16 posted on 04/30/2019 10:03:24 PM PDT by coaster123 (Men: Standard American handshake. Women: Curtsy.)
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To: LYDIAONTARIO

I know God exists or a Creator simply by seeing an attractive lady while grocery shopping. Duh!

I don’t need any fancy smancy advanced math for that one.

Sure, she just randomly evolved from nothing. Yah rrrriiiiggghhhttt. ;-)


17 posted on 04/30/2019 10:08:34 PM PDT by Sapwolf (Talkers are usually more articulate than doers, since talk is their specialty. -Sowell)
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To: ETL
Whenever confusion increases about such matters, I always come back to this

Everything makes sense.

18 posted on 04/30/2019 10:09:34 PM PDT by Sgt_Schultze (When your business model depends on slave labor, you're always going to need more slaves.)
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To: ETL

later


19 posted on 04/30/2019 10:30:23 PM PDT by imardmd1 (Fiat Lux)
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To: 6SJ7; AdmSmith; AFPhys; Arkinsaw; allmost; aristotleman; autumnraine; bajabaja; ...
Thanks ETL.

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20 posted on 04/30/2019 11:56:31 PM PDT by SunkenCiv (Imagine an imaginary menagerie manager imagining managing an imaginary menagerie.)
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