Three BEWILDERING Cosmic Controversies | George Efstathiou [Ep. 436]

Modern cosmology is full of controversies, challenges, and unresolved tensions. This can, of course, be very frustrating. But it’s also extremely fun!

Especially if we approach these challenges with brilliant minds who aren’t afraid to tackle them head-on.

One such luminary is the renowned George Efstathiou. George is a British astrophysicist and Professor of Astrophysics at the University of Cambridge. He was the first Director of the Kavli Institute for Cosmology at the University of Cambridge from 2008 to 2016.

George joins me today for a cosmological episode in which we look at cosmic acceleration, Hubble tension, Sigma-8 tension, inflation theory, BICEP2, Planck collaboration, and more.

Tune in!

Key Takeaways:

00:00:00 Intro
00:04:18 Baseless claims in cosmology
00:13:47 Solving the Hubble tension
00:23:02 Axion-like early dark energy
00:27:54 Primordial magnetic fields
00:30:27 Solving the Sigma-8 tension
00:38:27 Inflation and the Multiverse
00:48:20 BICEP2
00:54:30 Existential question
00:56:32 Outro

Additional resources:

➡️ Learn more about George Efstathiou:

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[DrBrianKeating]

What’s the biggest mystery in the universe?

[advaitrahasya]

It's not about a mathematical model being "wrong".

It is about fixing the paradigm through which all the models are interpreted.

[nunomaroco]

Hi, just brilliant talk amazing don't need to be the most know scientist, many work in the shadows and they are equal great or even more, all the best.

[rajeevgangal]

New scientist is always the sensational one. Love George. Need someone like him to take on Erics of the world. Maybeba a friendly sparring session with profs Gupta, Penrose on cosmology. interested on his pragmatic take on Neil Turoks new model which seem data driven.

[isonlynameleft]

Thank you Brian for recognizing my brilliance in being one of the most intelligent audiences in the universe. The humbly accept 😌 🤣

[MatrixVectorPSI]

I was watching a presentation from Caltech. They said the universe is too complicated to explain with General Relativity and you can't actually do the math by hand. You have to do it on a supercomputer. And they have new models of the universe being rendered, eta 5 years. It takes into account permanent gravity wave transforms and its local effects versus that of the entire universe.

[rhbruning]

Spot on with the "alternative realities" you can't engage. It's kind to describe these different realities as different perceptions when they are really perpetuated and imposed.

[RWin-fpjn]

It is interesting to listen to George. As I am no expert of Lamba CDM, I got only parts of the discussion. But I do see genuine concerns about current models and genuine efforts to better understand the universe. What I can say, is that from a problem solving perspective, all discussed issues of Lambda -CDM cosmology have a single point of failure (SPOF). Meaning; once this SPOF is corrected, all issues would disappear; from the unconfirmed Dark Energy to troublesome Hubble tension to multiverse to mature early galaxies paradox, what have you.
This Single Point of Failure (SPOF) in this case is the human INTERPRETATION of observed redshift. There is sufficient supporting evidence that higher redshift is indeed related to further distance. The suggestion however that galactic redshift is in addition is related to higher speed via a doppler effect (however perfectly logic that sounds) is problematic, given recent observations. If not caused by a doppler effect (for which astronomers use the auxiliary fix of hypothetical emerging spacetime in between), then furthest galaxies are not to be associated with old age or high speeds relative to us. Just distance.
I would solve all. Doesn't mean there was no big bang. I bet there was. It just means that the redshift we see is not the result of expansion, even though the universe might yet be expanding. I actually think it is net-moving (contracting) towards the great attractor, that much seems defendable.
Ok, this begs the question; is there known physics that would link photon redshift to only distance? Well yes of course there is; Quantum Physics is full of it. At CERN they know that venturing the smallest distance possible requires extremely energetic particles as established distance is inverse related to established energy (dXdP>=h/2 is Heisenberg’s Law for that). But so would the reverse be true; to venture the furthest distances, photons with extremely low energy would be associated with furthest distance. So if our intra galactic fabric has properties of the QP world (spoiler alert; it HAS) then incoming low energy photons (thus more redshifted) would be photons associated with further distance. No extra galactic doppler effect needed. Eventually the furthest photon’s wavelength would stretch beyond the visible light, into the radio-wave frequency (think CMB). As for the importance of our intergalactic fabric; isn’t the angle of our solar systems relative to the galactic plane visible in the 360 polarization modes of the CMB. Why do we guess that is? I would go with the obvious solution solving all paradoxes. But then again, who am I…

[rockfordlow]

Hate to say this, loving these shows about our brief reality, but

[trucid]

He fails because he's unwilling to step out of the box. The alternate realities he mentioned with such disdain is exactly what we need to welcome.

[dosesandmimoses]

This was a great conversation .. thank you gentlemen

[shawns]

The fundamental phenomenon of dilation explains dark matter/galaxy rotation curves. Mass that is dilated is smeared through spacetime relative to an outside observer. It's the phenomenon behind the phrase "mass becomes infinite at the speed of light". A graph illustrates its squared nature, dilation increases at an exponential rate the closer you get to the speed of light. A time dilation graph illustrates the same phenomenon, it's not just time that gets dilated.
Dilation will occur wherever there is an astronomical quantity of mass because high mass means high momentum. This includes the centers of very high mass stars and the overwhelming majority of galaxy centers.
The mass at the center of our own galaxy is dilated. This means that there is no valid XYZ coordinate we can attribute to it, you can't point your finger at something that is smeared through spacetime. More precisely, everywhere you point is equally valid. In other words that mass is all around us.
Dilation does not occur in galaxies with low mass centers because they do not have enough mass to achieve relativistic velocities. It has been confirmed in 6 very low mass galaxies including NGC 1052-DF2 and DF4 to have no dark matter. In other words they have normal rotation rates. All binary stars have normal rotation rates for the same reason.

[will-mo]

concomitant ... concurrently ... present in understanding from multiple disciplines .. .fascinating

[alexsuited]

Hey I like the beagle, good dogs. Peace ✌️ 😎.

[ekkemoo]

Nice, engaging discussion, as I was there listening to it.

[readyfireaim]

Cosmological Information Dynamics:

a) Information-Based Cosmic Inflation:

Model cosmic inflation as an information expansion process:

dΦ/dt = HΦ + √(H/2π)ξ(t)

where H is the Hubble parameter and ξ(t) is a noise term representing quantum fluctuations.

This could provide new explanations for the observed homogeneity and flatness of the universe.

b) Dark Energy as Information Potential:

Propose a model of dark energy based on the information content of the vacuum:

ρ_Λ = (ℏc/16π²G) · ∫_0^k_P k³ tanh(ℏck/2k_BT_0) dk

where k_P is the Planck wavenumber and T_0 is a fundamental information temperature.

This could explain the observed acceleration of the universe's expansion.

[zdayz]

There was a new paper on time dilation in supernova. Sabina just did a quick summary of it... That would actually indicate that add a billion light years are redshift 1 that the universe is already moving away at the speed of light oh really one light month per month or rather three light months over 3 months... I thought the universe was only going the speed of light at like 5 billion light years...

[Thomas-gk]

21:00 - he is talking about a "cosmological conspiracy"? That´s funny, since the same term is used in quantum mechanics as a battleterm against superdeterministic approaches.

[stephenconliffe]

Undersranding Pri.mordial magnetiism...is a key imo...stay with it🤔...why .. magnetism is fundamental..first principle...then electricity...all of Creation is magneto electric?🙄cheers.

[alexsuited]

Primordial EMFS won't be there until they are excited. So in a void say the fields will be undetectable unless you figure in the whole of the system. But if introduced matter would entice the fields underlying and produce a new EMFSYSTEMS. Each galacty is a result of this occurring. The CMB may be a single event but if that's the case, then others would certainly have happened. Or the CMB is a collection of smaller events that effect each as a whole. Peace ✌️ 😎. Great video