Best lecture on Dark Energy

Leonard Susskind astonishing lecture on Dark Energy

[leobulero]

please give date of lecture. very important!

[CarmeloValonerants]

Hey there Emergence...one thing that I would like to see on your channel would be a listing of your lecture sources and a possible date (year and month?) as sometimes, especially with my favorite lecturer Leonard Susskind I see some older lectures that I can't place...as I am huge fan and often try to find his latest stuff. When is this from? Thanks kindly and regardless keep posting these brilliant lectures and ideas....

[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.

[tokajileo]

background music completely unnecessary and annoying, shame on u for ruining this lecture

[mickeybrumfield]

It has been determined to be impossible to get too much Leonard Susskind.

[DeanTalboys]

If you base 99.999% of your assumptions on what you can see, don't be surprised if you are 99.998% wrong.

[rockfordlow]

Lecture does not need background valium music.

[Heaven]

Dark energy is actually Ether, not 7:33 the kind of Ether which Michelson and Morley postualted which is fixed ether, rather this ether is superfluid in nature and dark energy is the energy density of this cosmic superfluid ether, This is exactly what Nikola Tesla said .

[keppela]

Made the mistake of trying to watch this without a graduate degree in physics. My bad.

[fermin]

What form the gravitational wave?

We know what form sea waves, sound waves, but what about gravitational waves?

Are gravitational waves and electromagnetic waves produced by the same field?

[Googler]

13:03 Instead of submarine call it a pub crawl bus. The bus travels in antidesitter space between desitter pubs which are located in rural flat minkowski space fields. The pubs are all entangled by the legendary pub crawlers Juan and Leonard, leaving hefty unpaid tabs which cause the pubs to collapse into singularities.

[nicholassuntzeff]

In fact, George Lemaître used the cosmological constant in 1933 for his "primeval atom" theory which is the essence of the Big Bang theory. He interpreted the CC as vacuum energy and introduced a simple version of the equation of state we use today - p = -rho.

[TomHendricksMusea]

Dark Energy and Dark Matter May Be Anti Gravity.

This drawing makes a case for anti gravity, not gravity, as the force that comes from acceleration.

Einstein recognized that acceleration was equivalent to the force of gravity. He said that this was the happiest thought of his life.

Had he known that 95% of the universe was not matter but Dark Energy and Dark Matter, he would have recognized that acceleration was the equivalent to the force of ANTI GRAVITY.
He would have seen that it wasn't gravity from matter; but anti gravity from empty space that was the force.

The diagram shows how dark energy and dark matter from empty space push back more and more against matter as it accelerates.

Top, the globe has no acceleration.
Next picture, there is some acceleration and the arrows show resistance from empty space as the globe moves forward.
Finally as the globe approaches the speed of light, the resistance from empty space becomes massive and approaches infinite.
No matter can travel at the speed of light.

DARK ENERGY; Dark energy is energy that expands. In every part of the universe. It acts like anti gravity and is associated with the vacuum of space. My Suggestion is that this is a force of anti gravity expansion.

DARK MATTER ; Dark matter is labeled as a gravitational pull. Yet there are no baryons - no matter - that's been found to do the pulling. Many physicists are looking for the missing matter. My suggestion is the obvious - it's not there! The force is anti gravity that we know is there. That means dark energy and dark matter are the same thing. They are both antigravity.

Together dark energy and dark matter, or both together as anti gravity, represent 95% of the universe and they represent a single expansion force everywhere. Finally this may well be the same force that began with the Big Bang expansion,

Here is a diagram showing the make up of the universe.
95% anti gravity (dark energy + dark matter) and
5% hydrogen and helium gas, stars, neutrinos, and all other atoms combined.

ANTIGRAVITY 95% STARS, ETC. 5%

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***
Here's some support. There is a cosmological redshift that comes from the expansion of space itself. The galaxies are not moving, but the intervening space is stretching.

***
What is dark energy in simple terms?

Think of dark energy as the "evil counterpart" to gravity–an "anti-gravity" force providing a negative pressure that fills the universe and stretches the very fabric of spacetime. As it does so dark energy drives cosmic objects apart at an increasingly rapid rate rather than drawing them together as gravity does.Nov 24, 2022
What is dark energy? - Space.com

[KevinsDisobedience]

WAP does no real work explaining dark energy. The mechanism is still the constant coefficient of the vacuum. It merely says it must be this exact value otherwise we wouldn’t be here to observe it. I think Anthropic reasoning can do some work in explaining certain finely-tuned parameters, but the mistake is to think that tells us why it is what it is. There is still a constraint or mechanism for our lucky parameters, ie, still something to discover and understand.

[scottgreen]

Are you describing the reason for the universe being persistence of the past verses change of the future all balanced as now for now? No your answers is bigger but that’s what I see. No really, it would not surprise me if your answer of a fine tuning issue being a prime motivator to drive the universe, would lead to my answer. The universe is not done.

[jerry]

Not gravity, its mass. I'm sure. Remenber, mass is responsible for the curvature of space. Light is being pushed, not pulled. The interesting thing is, in either case, light continues its original path. Why? It's clear to me because of the fundamental law of physics that an object in motion stays in motion unless acted upon by a force, a principle articulated by Galileo. In other words, its undeflectable. Then, again, why?

[stonward]

Great physicists were almost all very young men - not bitter math experts like Suskind (or half a hundred other like him (no, no women)). Sorry, but it's the truth. Refute if ye can.

[RandomHandle]

What is with the awful background music?

[charlesbadrock]

Ultimate answers we need to know so the human race can take off the chains of Mythology of course with that could lead to the extinction of theism Cosmological area totally separate from Manmade Theological Mythologies the Intelligent Design Hypothesis for the cosmos is a possibility among a multitude of possibilities Random Natural Processes is another possibility pre existing universes multi universes infinite space so much we still don't know

[АлександрГодзиковский-ьр]

All this parameters and equations look like breathing of something ideal and super harmonic in its nature like as if "it" were alive. The process itself can't be chaotic in its nature since it's so fine tuned. There must be something in the field itself (property) giving this "inexplicity". It's created to observe, describe but not to explain in terms of "why".