Why Dark Matter Probably Exists & It 'Looks' Like...

Talk to ME (ARVIN) on Patreon and More:

REFERENCES
VIDEOS:
PAPERS:

CHAPTERS
0:00 What you would see in the Sky if Dark Matter was visible
1:50 Where did the idea of Dark Matter come from?
4:32 Saily always stay online while traveling abroad
6:09 How do we know that Dark Matter existed seconds after the Big Bang?
8:00 How dark matter affected our current universe
9:38 How we know Dark Matter exists around galaxies: Gravitational Lensing
11:39 Why is MOND (Modified Newtonian Dynamics) not a good explanation?
12:45 Does JWST data disprove Dark Matter?
13:48 Why is Bullet Cluster the biggest evidence for Dark Matter?
16:38 Summarizing the evidence favoring Dark Matter's existence

SUMMARY
Most of the matter in the universe is completely invisible to us. It’s called dark matter because it does not absorb, reflect or emit any light. It makes up more than four times the amount of visible matter that we can detect. If we can’t see it, how do we know it’s there? Because of its effects on what we can be seen. Some argue that the James Webb Space Telescope (JWST) disproved the idea that dark matter exists. It didn't.

In the 1930s, Swiss astronomer Fritz Zwicky found that there simply wasn’t enough visible mass to account for the gravitation needed to keep the Coma cluster together. He proposed the existence of “missing” or “dark” matter, but he was dismissed. 40 years later, Vera Rubin found that the stars at the Andromeda galaxy’s edge were orbiting the central mass just as fast as stars closer to the center. This was impossible according to Newton's laws. This observation showed that there was more mass in galaxies than what we could actually see.

50 years later, today, we still don’t know what dark matter is, but we know it’s essential to the structure of the universe, and affected its evolution in the initial seconds after the big bang. We can see it by studying the tiny variations in temperature for the earliest detectable light of the universe – the Cosmic Microwave Background (CMB). These fluctuations represent tiny fluctuations in the density of matter. We can calculate what this pattern would have been without the presence of dark matter. But that’s not the pattern that we see. We see a pattern where the dark matter must be at least 4-5x ordinary matter.

As a result of the effects of dark matter, small clumps of ordinary matter were beginning to form prior to the CMB, creating regions of higher and lower density in the universe. Those early clumps acted as gravitational seeds that resulted in clusters and superclusters of galaxies. Without dark matter, ordinary matter may not have formed galaxies and clusters at all.

We also know that Dark Matter exists around individual galaxies because of gravitational lensing. This is where light from distant objects bends around massive clusters of matter due to their gravitational pull. When astronomers map these distortions, they find that the lensing effect cannot be accounted for by the visible matter within the galaxy. So most of the mass in galaxies based on their lensing effect is missing. It can then be deduced that a vast invisible dark matter halo must exist, which would account for the discrepancy that Vera Rubin found.

Some argue that MOND or Modified Newtonian Dynamics can account for the observations without the need for any Dark matter. It proposes that by manipulating Newton's equations, we can show that the gravitational force is weaker at the edges of galaxies. But there's not theoretical basis to make these changes other than to force fit the observational data. Also the recent JWST data does not rule out Dark matter, as some people have suggested. We should not jump to conclusions based on a few observations over a handful of years. Further research is needed to confirm the current findings. Our models may simply require some adjustments.
#darkmatter
One of the most compelling pieces of evidence for dark matter comes from the Bullet Cluster, which is the aftermath of a collision of two galaxy clusters. The gravitational lensing data shows that dark matter pulled ahead of the visible matter, which is exactly what we would expect if dark matter existed. because dark matter only interacts through gravity, It does otherwise interact with ordinary matter, so it passes right through it.

[matthewspartan]

Thanks! Here you go Arvin for your excellent work

[douglaswilkinson]

Most astrophysicists call dark matter an "observable effect for which a cause has not yet been discovered."

[russellamaru]

Thank you, Arvin Ash, for this incredibly clear, concise, and enlightening explanation of dark matter. You have clarified much of the controversy surrounding the existence of dark matter.

[captainzappbrannagan]

I love seeing the million subs! Congrats and all the best in the new year my friend :)
You should have a merch store!

[hankclay]

When you say "dark matter" must be the explanation, you are basically saying something is there causing these things. There has been no determination of what this unknown substance is, and still could be that we are missing something else that may be determined to be the cause.

[KingBritish]

Nice clear information as always from Arvin.

[michaelshafer]

Is dark matter DARK ? How many decades have we tried to identify what it is. Why is dark matter so unevenly distributed ? GR perfectly describes all movements in our solar system assuming there is no dark matter. Just a tiny amount would throw all of GR’s predictions for our solar system assuming

[brothermine]

It's worth discussing the attempts by MOND theorists to explain why MOND isn't falsified by the Bullet Cluster, and the attempts by Dark Matter theorists to explain why Dark Matter isn't falsified by the JWST observations of large early galaxies.

[nancyhope]

Explaining the bulletin cluster collision was brilliant.

[LendriMujina]

Though I'm a dark matter skeptic, the comment section here that seems downright _proud of their ignorance_ of what the theory _actually says, _ reducing it to fallacies and half-understood pop science, is making my head hurt with secondhand embarrassment. Some people just argue to hear themselves talk.

[billskelley]

New subscriber here. Nice videos, short, to the point, and informative. Thanks.

[edwardlewis]

1. How much dark matter is there in our Solar System?
2. Doesn't the Bullet Cluster observations suggest the presence of 2 black holes?

[bobdobs]

Dark matter has more to do with our ignorance, and limited data.we are more like fish thinking the universe is liquid.

[shethtejas]

So, dark matter matters ! Thanks Arvin for another fantastic vid.

[deathwarmedover]

A misunderstanding of gravity at low energy regimes will never be a thing to be found. Labelling it as an existent thing, subtracts from our understanding of its unknown origin. If you let the data speak, MOND jumps out and make a priori predictions with regard to JWST.

[Krispyru]

Why does dark matter have to be a particle at all? Why can’t it just be pockets in the space time fabric itself? Pockets that matter tends to clump into or fall into. We assume that matter is the only thing that bends space time but maybe space time is already bent.

[garyfilmer]

Thank you, Arvin, for this very interesting video. I am just remembering the work of those two great scientists, Fritz Zwicky and Vera Rubin. The discussions and theories about the nature of ‘Dark Matter’ remain fascinating, including from those who propose alternative ideas, including from those that say Dark Matter doesn’t exist! Retaining an open mind is always very important!

[EnginAtik]

How come we don’t observe any dark matter in the Solar system? If there was some dark matter component to ordinary objects, accelerating objects would weigh less since dark matter would not be bound to ordinary matter and lag behind. This would also mean that inertial mass and gravitational mass of the objects would be different. We don’t observe any such phenomena.

[alexalekos]

happy new year Arvin, thanks for this episode during our holidays

[christianhoffman]

00:38 They argue that because sensationalist media (I am making no distinction between what some call MSM and smaller online outlets because too many now seek out bias confirmation anyway) wrote it up like that. Of those who do not seek out bias confirmation there is a significant portion who simply think what trends tell them to think and the media that does not rely sensationalism often take advantage of this. News is no longer to inform. It is no longer seen as a vital function of a free society, a form of public service for which the publisher and those gathering the information are fairly compensated. No, it is seen as way to make a buck and in order to maximize profits you just tell your audience what they want to hear. Fox figured this out 30 years ago. If your audience is the sort who rejects science, because much of what is factual goes against their beliefs and makes them uncomfortable so they leap at the chance to hear about how "experts got it wrong", the sort of story we are talking about is perfect for them. That way the next time an expert tells them to stop smoking, beating their children or wear a mask they can then say to themselves "well you were wrong about dark matter" . They see "scientists" as a monolithic group with no distinction between studies so this sort of "thinking" works for them.