How Scientists Discovered Dark Matter

What kind of clues led to the discovery of Dark Matter and its place in the universe?

"NOVA Wonders: What's the Universe Made Of" premieres May 30, 2018 at 9/8c on PBS

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[cornholio]

"The gravitational spin of the massive black holes in the center of each galaxy is keeping the galaxies together! " Jay Mo

[Laynk]

Wait so what does this lady have to do with the discovery of dark matter? The video talks about Fritz Zwickys discovery and then just restates it all over again in excited tones once the woman is introduced. What did she do?

[adriang.cornejo]

Dear Sirs. As reference, the paper where is described a solution of the rotational velocities observed in spiral galaxies, without using dark matter (but adding the Coriolis force in the rotating system, from the General Theory of Relativity), is the following (from 2020):

[dko]

Cool video, but the music is too loud!

[raulgil]

The background music is very distracting!!! is it generated by the Dark Matter?

[redforest]

Weren't they able to figure out dark matter 'existed' through gravitational lensing during the collision of two galaxies? The lensing didn't stay with the visible matter but it stayed with another more massive source that wasn't visible--dark matter. (Correct me if I'm wrong, but that's how I understood it through some readings...I hardly know much about this field, it's just interesting)

[sweepsweep]

what if it isn't moving fast but appears to move fast?

[omnesadinfernum]

Now i understand why they say that most of the gravity in the universe has an unknown source. 🤔

[quantumofspace]

The expansion of the visible Universe was due to energy: 1) From the big bang  0, 2% of the total energy. 2) From the kinetic energy of rotation 4.7% of the total energy. 3) From the energy of the swirling quanta of the vacuum 92.7% of the total energy.

[JSchrumm]

Galaxies are a huge dynamo, I call bs on dark matter and yes on electromagnetism.

[michaelkahn]

Alternative Explanation of Dark Matter, Dark Energy, Gravity and Accelerated Expansion
- 4-D Hypershere model of Universe can easily explain Gravitation, Dark Matter, Dark Energy, Void, Accelerated Expansion and even the reason why the measurement values of Expansion Rate are around 70 km/sec-Mpc

Dark Matter, Dark Energy, Gravity, Void and Antigravity, ... all these are same phenomena. They just look different.
The problem of modern physics is they're trying to explain everything with particle physics and the physics is being cornered more and more to the dead end. To escape the dead end, they invent or design another imaginary particle in vain instead of trying to revise their way to approach to the problem.

I agree to the idea that the interaction between mass and space must be explained with quantum mechanics.
But that doesn't mean gravity is the QM phenomena.
That's because gravity is not a force.
Dark Matter, Dark Energy, Gravity, Antigravity, Void... all these are just joint effects of the expansion of the Universe and the curvature of spacetime.
Details are given below.

Einstein’s theory of General Relativity states that spacetime is curved by the presence of mass.
This curvature influences the motion other objects with mass and gives rise to gravitation.
Thus, gravity is a result of geometric features in spacetime.
However, we also observe gravitational effects – curvature of spacetime – in areas without any detectable mass.
This has given rise to the concept of dark matter, which is matter that does not interact in any detectable way with normal matter, except through gravity.
So, there is some large quantity of dark matter scattered throughout the universe, which curves spacetime and causes gravitational effects just like normal matter, but we cannot see or detect it with any known method.

An alternative theory to the identity of dark matter is proposed – it is not matter at all, but rather an intrinsic curvature of spacetime.
In other words, spacetime is not naturally flat. Even in the absence of matter, we observe some inherent curvature of spacetime.

So, the question is now – why is spacetime naturally curved? Why is it not flat in the absence of mass?
The universe is 4-dimensional, with 3 spatial dimensions and one dimension in time.
Rather than consider time as a linear dimension, we can consider it as a radial one.
Therefore, rather than describing the universe with a Cartesian coordinate system, we describe it with a 4-dimensional spherical coordinate system – 3 angular coordinates, φ1, φ2, φ3, and one radial coordinate in time, t.
We live on the 3-dimensional surface of a 4-dimensional bubble which is expanding radially in time.
Thus, the Big Bang represents t=0, the beginning of time.
The crucial point is that the expansion of the universe is not homogeneous in all directions.

The expansion rate at one point on the bubble’s surface may differ slightly from another point near it.
The universe is only roughly spherical in 4 dimensions, the same way that the Earth is only roughly spherical in 3 dimensions.
The same way we observe local mountains and valleys on the surface of Earth, we observe local “mountains” and “valleys” on the surface of the universe bubble.
The inhomogeneity of the expansion of the universe has given rise to natural curvature of spacetime. This natural curvature causes the phenomenon of “dark matter”. “Valleys” in spacetime pull matter in, similarly to the warping of spacetime of massive objects.
So “dark matter” is really “valleys” in spacetime that are expanding slower than the regions surrounding it.
These valleys tend to pull matter in and create planets, stars, and galaxies – regions of space with higher-than-average densities of mass.
Conversely, “mountains” in spacetime will repel matter away, an “anti-gravitational” effect, which gives rise to cosmic voids in space where we observe no matter.
Each point on the surface of the universe bubble traces out a time arrow in 4-dimensional space, perpendicular to the surface.
These time arrows are not parallel to each other since the universe is not flat.
This causes points to have nonzero relative velocity away from each other.
It is generally accepted that the universe is expanding faster than observable energy can explain, and this is expansion is believe to be still accelerating.
The “missing” energy required to explain these observations has given rise to the theory of dark energy.
The time dilation caused by non-parallel time arrows can be proposed as an explanation for dark energy.

Alternatively, dark energy is real energy coming from potential energy gradients caused by non-parallel time arrows.
As a sanity check, we can calculate the expansion rate of the universe based on the universe bubble model.
Since the radius of the universe bubble is expanding at the speed of light in the time direction, it increases at 1 light second per second.
Therefore, the “circumference” of the 3-dimensional surface increases by 2π light seconds per second, or about 1.88*10^6 km/s.
This expansion is distributed equally across the 3-dimensional surface, so the actual observed expansion rate is proportional to the distance from the observer.

At present, the age of the universe is estimated to be 13.8 billion years, so the radius of the universe bubble is 13.8 billion light years, or about 4233 megaparsecs (3.26 million light years to 1 Mpc).

Thus, we can calculate the expansion rate of the universe, per megaparsec from the observer, as:

Expansion rate =

The popularly accepted empirical expansion rate is 73.5 +/- 2.5 km/s/Mpc, so our calculated value is close.
There may be some additional source of expansion (or observed red shift) to make up for the discrepancy. For example, if two adjacent points have some gravitational gradient due to non-parallel time arrows, then light passing through these points will be red-shifted.

[Krish-jmve]

Maybe the host does not understand the word "Discovery".

[Gizemci]

dark matter is 4 element
earth water air fire

[denisflannery]

space is full of dark matter a vast ocean full of electric potential not as it is portrayed in this presentation :-)

[primemagi]

"As always man has great data. Thanks to engineers, material developers, chemists and endless other important people. Sadly they do not have the wisdom to understand & interpret the data of space & matter wisely. So like ignorant children make up fictional stories and present it as fact. I e. big bang, black hole, expansion, accelerated expansion, relativity, dark matter, on and on." Ferydon Shirazi.
This video illustrate it well. they do not know structure of matter, nature of gravity or their interaction. that include evolution of space bodies from comet, moons, planet star, or Galaxies. so they fictionalize. a visiting space man become a man with wings. a vertical take off jet become fire breathing dragon. MG1

[lassoatrain]

Thats not dark matter. Those are stretch marks left over from expansion. They wont go away.at least for a while . I have been wanting to tell you and i swear i was but i guess this is as good as time as any. We are going too have another universe. Its not all ny fault you know.