Dark energy explained | Sean Carroll and Lex Fridman

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GUEST BIO:
Sean Carroll is a theoretical physicist, author, and host of Mindscape podcast.

PODCAST INFO:

SOCIAL:

[LexClips]

Guest bio: Sean Carroll is a theoretical physicist, author, and host of Mindscape podcast.

[MrDerushingo]

Great, now my brain hurts. Thank you physics!

[vanikaghajanyan]

2:28 On the “dark” invariance.
0.Comparing with Einstein's equations of 1915, we find a=-c^3/16πG. Strictly speaking, in order to determine the constant a, it was necessary to make a transition to the Poisson equation. Thus, a rigorous derivation of Einstein's equations can be given.
1.The transition to the non-relativistic limit allows us to determine a constant factor for the integral of the gravitational field according to: R(0)^0=(4πG/c^2)p; Δφ=-pc^3/4a=4πGр, where a=-c^3/16πG.
2.Therefore, the Poisson equation can be written as: ∆g(00)=8πGT(00)/c^4, where g(00) is the time component of the metric tensor (for a weakly curved metric the time component of the energy-momentum tensor: T(00)~=pc^2).
This equation is true only in the non-relativistic case, but it is applicable to the case of a homogeneous and isotropic Universe, when Einstein's equations have only solutions with a time-varying space-time metric. Then the energy density of the gravitational field: bye the way];
where the critical density value determining the nature of the model is: p=(3/8π)H^2/G. Hence it follows: g~πcH. And according to the strong equivalence principle: g=|a*|=πcH
[~r(pl)w(relic)^2].
3.However, а*=-2πcа/M (universe), what is
Expansion is a special kind of motion, and it seems that the Universe is a non-inertial frame of reference that performs variably accelerated motion along a phase trajectory, and thereby creates a phase space.
P.S.
0.From Kepler's third law follows: M/t=v^3/G, where M/t=I(G)=[gram•sec^-1] is the gravitational current. By the way, in SR: I(G)=inv; this follows from the Lorentz transformations: m=m(0)/√(1-v^2/c^2) and t=t(0)/√(1-v^2/c^2). Hence, obviously, we have I(G)=m/t=m(0)/t(0)=inv.
1.In the case of the Universe: (~ the "dark" const~inv).
That is: critical density value determining the nature of the model is: p=(3/8π)H^2/G. And
which is evidence of a phenomenon: spontaneous Lorentz transformations.
3.Thus;
Δφ(0)/Δφ=w(pl)^2/H^2~6, 4*10^121, where Δφ(0)=4πw(pl)^2; the “best” prediction.

[myaschaefer]

This something I've wanted to ask for a very long time. Everybody talks about dark energy pushing out. But what if it's actually opposite. where observable space, which isn't really a perfect vacuum, is simply being pulled from the outside by a more perfect vacuum? If the big bang took place in a perfect vacuum of limitless space, wouldn't that help resolve why the universe is homogenous in every direction? It might also help explain why objects further away are moving faster than objects closer to us? With the big suck, so to speak, pulling from the outside of the physical universe from every possible point. One more thing, make sure you give me credit if this is a break thru! Cheers! And thank you for reading.😆

[Jeff-ttwj]

I’ve been pretty agnostic my whole life. The older I get it just seems more and more plausible that there is some higher purpose or cause behind everything. The fact that any of it exists at all is just too insane and nonsensical for me to think otherwise.

[tonymarshharveytron]

Hello Lex and Sean,

Further to my earlier comment, in my hypothesis I explain a very simple experiment that anyone can do at home, that shows the presence of Dark Energy, which by default, also proves the existence of the Dark Matter I propose.

A very simple experiment to show a repulsive force is as follows. Take two pieces of A4 paper that are completely flat and not under any stress from bending. Cut a strip lengthways from the pair about 1 ¼ inches wide. Cut 3 or 4 smaller pieces from a similar strip to form squares, and place these between the two long strips at one end. Make a hole through the middle of the square of this top section, through which you can pass a suitable thin rod that allows the strips to swing freely. Make sure that the top pieces are pushed tight together, so that the strips hang freely down parallel to each other. Place these in a long glass vessel, such as a spaghetti jar, so that they are not influenced by air currents, cover if you think appropriate. You will notice that the gap between the two strips is slightly larger at the bottom than at the top.
If the spacer between the two strips is too small, the two strips will be pulled and pushed together.

This I believe shows that there does exist the negative force of repulsion acting in every direction due to the existence of proposed ‘ Dark Matter ‘ ‘ Harveytron ‘ cloud producing the ‘ Dark Energy ‘ repulsive force . I feel it also proves the existence of the two forces of gravity that I propose, where atomic matter containing the positively charged monopole ‘ Dannytron ‘ particles are attracted to each other if the distance between two atomic masses is too small.
From this simple, logical experiment that shows an action, and an explanation as to why the action is happening, it will be seen that it will be possible to collate all of the data, with regard to surface area of the paper strips, their weight and distance apart etc, and devise the mathematical equations to complement the observations.

Kind regards,

Tony Marsh.

[SteckdoseHz-htun]

Assuming that space-time is not uniform and only curves due to mass, but has its own structure, similar to the overtones or formats of a vibrating string, only three-dimensional. The idea here is to see a static system dynamically, to make it artificially more complex. So you could see the space-time of the universe as a function, or even make it audible :)

[cujimmy]

In a nutshell, we don't have a clue.

[pmc]

What if dark energy is simply quantum vacuum energy?

[shimtest]

unified theory keeps getting more ludicrous

[PeterRice-xhcj]

A billionth of a second is far too fast for us to experience, so it’s fair to say that in that short time interval we don’t have a sense of being. The problem is that the time frame we are aware of such as 1 second feeling like 1 second, is joined together by by extremely short time intervals where we don’t have a sense of being, so how do we have a sense o being at all. We also need to be focusing on a colour to have a sense of being even if we just picture something in our heads. If 100 years go by without us having any sense of being, to us it would seem like a blink of an eye, because we wouldn’t have any memory of not having a sense of being, such as an extremely short time interval.
If a group of people were individual zero dimensional points that mixed together to form one single zero dimensional point without any dimensions, every one would agree with what number they are looking at because every one would be one individual point. If zero dimensional points were not in any particular space or not separated by any space, they would be separated by time, each being zero dimensional universes. Our sense of being is zero dimensional, so does that mean we could be individual zero dimensional points. If we don’t have any sense of being such as in an extremely short time interval, we wouldn’t exist, not even being zero dimensional points.

[PeterRice-xhcj]

Imagine two colours that exist one side of the tennis net, and two colours that don’t exist the other side. Each colour could be part of two systems. Each colour could be its original self as a colour that exists or doesn’t exist, at the same time could also be a colour that originated from the other side of the net as a colour that did or didn’t exist that has already crossed the net to become a colour that does or doesn’t exist. So there are two colours that exist on one side of the net, and two colours that don’t exist on the other, all four existing simultaneously each being part of two systems. The empty spaces might think their the colours and think the colours are the empty spaces they are filling up. We are just observing one system.
When two colours switch spaces with each other, the way we can see the two colours as well as the spaces they fill up all move, is if the two colours move vertically across the net, and the two spaces they fill moving diagonally across the net. So a blue a red colour next to each other move across the net to the other side, and the two spaces they fill move diagonally across to meet up with the opposite colours. But shouldn’t we now be seeing two colours that don’t exist. If the colours and spaces they meet up with after they cross over the net change into each other (the empty space becoming the colour hence the colour becoming the empty space), could they avoid becoming two colours that don’t exist. In other words the side of the net for colours that don’t exist become the side for colours that do exist. Now if we look at the two colours from above the court with the top of our head pointing away from the net, we might see red on the left and blue on the right. Now if we look at the two colours from underneath the net with the top of our head pointing the same direction we see blue on the original left and red on the original right. Is this because we are now seeing the empty spaces as the colours. The empty space and colour we see are both part of two systems each originating from both sides of the net, as well as the two colours that don’t exist the other side of the net. The backbone of this system is you can’t have a colour filling a space up that is the same colour.
So if we look at the two colours from underneath the court with our head pointing away from the net, we see what would happen if they cross over the net and we were facing them from the side of the net they came from. Now by looking at the two colours before they cross over the net from underneath the court, could we be actually causing them to cross over the net to the other side. So when we look at the two colours from underneath the court, if that causes them to cross over the net to the other side, we are not actually looking from underneath the court, but looking at the other side of the court from above with our head pointing away from the net. Now if we look at the two colours from above on their original side, could the reason we can’t see the empty spaces be because we are looking at the two colours that don’t exist the other side of the net that are there right now. After all, the colours that don’t exist the other side of the court is a kind of future if the four colours that exist and don’t exist are all separated by time.

If you have say 10 different things you still have 10 of the same thing. The reason is because they are all in the same category of being a different thing. All numbers are just really a digit one a certain way up the number line. If we want a truly different thing we have to look at the gaps or boundaries in between numbers.

All logic is based on numbers, but could we create a new kind of logic based on gaps or boundaries in between numbers.

[MyChannel-vmdw]

Sean Carroll is a terrible science communicator. GET TO THE POINT.

[TodaySatan]

This guy sucks at explaining in Lehmans terms

[Billy-bcpk]

The biggest problem with a lot of how they approach this subject is silly, because instead of trying to discover dark energy based on how small it is, they should be trying to gauge how large it is. if it's rapidly expanding the universe, then perhaps it's not as small as people assume, but it's actually much larger and much faster. Macrocosmic steroscopy should be the way to go using large scale satellite mirrors, but thinking outside the box is verboten.

[JimmyHossa]

At no point would I hang out with Lex or his subscribers. This is the weakest group of nerds I’ve ever met.