Thomas Hertog on the Origin of Time | Closer To Truth Chats

Cosmologist and close collaborator of Stephen Hawking, Thomas Hertog discusses his new book, On the Origin of Time: Stephen Hawking's Final Theory, a look at the intellectual superstar’s final thoughts on the cosmos. Hertog offers a striking new vision of the universe’s birth that will profoundly transform the way we think about our place in the order of the cosmos and may ultimately prove to be Hawking’s greatest legacy.

Thomas Hertog is an internationally renowned cosmologist who was for many years a close collaborator of the late Stephen Hawking. He received his doctorate from the University of Cambridge and is currently professor of theoretical physics at the University of Leuven, where he studies the quantum nature of the big bang.

Closer To Truth, hosted by Robert Lawrence Kuhn and produced and directed by Peter Getzels, presents the world’s greatest thinkers exploring humanity’s deepest questions. Discover fundamental issues of existence. Engage new and diverse ways of thinking. Appreciate intense debates. Share your own opinions. Seek your own answers.

[andyc]

Back to watch this again 24 hours later. I think this no boundary theory has some serious insights to it. I feel this could be a genuine option, and I want to understand it more :)

[photonsonpixels]

Excellent discussion! Thank you so much.

[jamesnasmith]

Such a learning experience even for a bio-medical retiree. Thank you.

[rustyspottedcat]

Time -- emergent property --- of something timeless. (As it seems to be everything is emergent)

[tac]

Many of us instinctually sense the deception and the truth is like a face we know but a name we've forgotten.

[TerryBollinger]

28:10 TH "If you trace … the expansion of the universe … far enough back … the time dimension … evaporates and … turns into a spatial dimension. Why a space dimension? Because ... if you only have space dimensions you can close all dimensions like a sphere … a little bit like the South Pole of the earth."

Thomas, the missing piece in your excellent argument is thinking that _either_ space _or_ time is fundamental. The only state metric that stays invariant at cosmic scales is the product of space and time in units such as yr•ly. Only rest-mass-capable fermionic matter can "parse" such distance-squared metrics into what we think of as space and time. The result is a special relativity observer frame whose definitions of space and time can be extremely narrow in scope and scale, such as the xyzt frame of a ship traveling near lightspeed.

An all-encompassing time dimension was never a given — but then again, neither was space. The reason time _feels_ universal is that local xyzt instances create the stubbornly persistent dead-ends we label with terms such as causality, entropy, information, and history. These dead-ends then impact other local instances of xyzt. The result is a messy, piecemeal, always-ratcheting-forward entropic process that constantly creates information and thus the illusion of smooth, global time.

The local, emergent, condensed-matter-first nature of time _probably_ benefits your overall argument since it is, to say the least, a "no boundaries" definition of both space and time. The condensed matter connection also powerfully suggests a connection between timelessness and the similarly timeless — or, at least, oddly timed — momentum space interpretation.

How such a view of time and space works at the extremes of gravity — at event horizons — requires a more complete definition of what gravity _is._

Any deeper definition of gravity must break away cleanly from the silliness of the 1939 Fierz-Pauli graviton framework. Despite its popularity, that framework is nothing more than speculation about what a pseudo-gravity that resides _on_ spacetime might look like. Remove the artificial "flat space" constraint on such frameworks and real, geometric, Einstein gravity reemerges.

[marcusjackson]

Dr. Kuhn

I feel like you should have a conversation with Lex Friedman on the Lex Friedman Podcast. I've committed myself to bugging both of you on every platform i follow you two on, to connect and have a long-form conversation. You both occupy a similar content-space and interview many of the same people and I feel like a conversation between you two would be epic. Plan on seeing me in your comment section quite often going forward. Those of us who are fans of both you and Lex really want to see this happen.

[TerryBollinger]

17:45 TH "[When multiple habitable universes exist] the anthropic principle does not provide an answer [and] the theory becomes ambiguous..." This is a solid and mathematically persuasive argument against naïve anthropism. Nice.

[TerryBollinger]

1:00:09 TH _“… observation is … always done … at the quantum level … by one … photon or an interaction between fields. So we are not saying that human observations today fix the entire history of the universe.”_ More precisely, and as Feynman aptly noted in his Lectures about electron slit self-interference, the observation done by such a photon never rescales the wave function to a size any smaller than the momentum wavelength of the photon [1]. That’s no surprise since reducing the momentum wavelength of probe particles is as much a reason for building particle accelerators as reaching higher energies and temperatures.

What is perplexing is how little attention the critical role of dumb, simple linear momentum gets in most discussions of the nature of observation.

Outside of Feynman’s Lectures, statements like the above are surprisingly rare, with most discussions preferring to go in the opposite direction of making observation one of the most mystical processes in all of physics. Moreover, even in this quick mention, the focus is not clearly on the role of linear momentum since Thomas Hertog mentions _both_ photons and field interactions. Linear momentum wavelength is the deeper thread that connects both examples and, for that matter, any other experimentally meaningful example of rescaling a wave function.

(Notice that I intentionally avoid using the term “particle” since the history of experimental physics contains precisely zero examples in which the rescaling gives anything other than a smaller wave function within the finite, speed-of-light limited boundary of the earlier wave function. The _size_ of the wave function rescaling can be cosmic, e.g., an ancient photon wave function can rescale, with absorption, to the atomic scale on a detector in a telescope on earth and do so in an utterly timeless fashion. While such enormous timeless rescalings asymptotically give the impression of a “point-like” rescaling, it’s all a bit of a charade since it’s only the upper end of the wave function that can grow without limit, and even then, only at a considerable cost in terms of how much time, travel, and isolation it requires to create such vast photon wave function examples.)

One reason folks neglect the essential mathematical role of linear momentum in wave function rescaling is that a tiny amount of momentum energy goes an incredibly long way when rescaling wave functions. Classical physics trains us to believe that the proper way to isolate an experiment from an observer is to reduce the ratio of energy used to observe compared to the mass and energy of the experiment itself. Quantum mechanics, however, informs us that, at least in the case of linear momentum, this is a false limit. What counts is _not_ how small the energy is but how short the momentum _wavelength_ is, even if that wavelength is associated with almost no energy compared to the target.

Feynman uses an electron wave function as the target of his photon probes. That sounds like a small amount of mass, but compared to the modest photon wavelengths of his thought experiment, an electron is a stupendously large object to have its wave rescaled by the puny energy of the photon. Yet, as Feynman notes, this puny level of momentum energy becomes _the_ determining factor in whether the electron wave rescales to the point that it can no longer see both holes. Light intensity increases the odds of observing the electron but has no impact on the rescaling of the electrons observed.

What about a larger wave function target, however? What if the target is, say, 46 million times heavier than an electron, roughly the mass of a 2000-carbon-atom organic molecule? Surely more than the linear momentum of one puny photon is needed to rescale that wave function?

Nope. Successful quantum interference experiments with just such molecules [2] demonstrate the _same_ extreme rescaling sensitivity to single-photon impacts as electrons. Once again, only the momentum _wavelength_ counts for determining the rescaled size of the wave function, _not_ the ratio of probe energy to target mass and energy. Whether it’s an electron, a macromolecule, or — and please note this point carefully — an _entire universe, _ as Thomas Hertog somewhat indirectly proposes here, the rescaling power of that single photon remains invariant. Compared to that level of energy-vs-impact, any level of computational energy efficiency hypothesized in current quantum computing technologies pales.

There is another name for the forms of linear momentum whose rescaling power is unlimited but whose total energy is trivial compared to the target wave function. We call it information.

The connection between linear momentum and information is vital since overlooking it risks losing grasp of experimentally meaningful physics and drifting off into untestable mysticism. All quantum observation involves a transfer of linear momentum. It’s just that when classical systems exist at one or both ends of the transfers, the momentum transfer can be vanishingly small compared to one photon’s energy, and the transfer’s energy is far less than that. Unlike angular momentum, linear momentum is not measured in units of action and thus does not need to abide by the assumption that only _quantized_ units of energy give experimentally detectable outcomes. Furthermore, there’s no simple answer to how much rescale-capable momentum even one photon can generate, given the proper ratios of masses [3]. A single photon in a house of mirrors can do a _lot_ of observation, with every observation capable of rescaling an arbitrarily large mass’s wave function.

Another implication of information being the low-energy limit of linear momentum is that quantum experiments that _claim_ never to see anything happen in an always-empty branch of an experiment are not quite telling the truth. That’s because there should always be a tiny bit of momentum deposited in the supposedly empty branch, even as the primary energy of the photon lands on some other branch [4]. Careful examination of such experiments should verify this effect. One well-known, well-verified example of how linear momentum remains conserved even when added in vanishingly small quantities is the double momentum imparted by a photon reflected from a deep-space solar sail [5]. So little of the photon’s total energy is lost in these transfers that there is no easily perceptible change in its frequency. Nonetheless, the total momentum transfer of many photons is high enough to, in principle, accelerate such sails to near-light speed.

So, Thomas Hertog, what might this mean for your no-boundaries theory?

A subtle implication of mass-indifferent wave function rescaling — the ability of, e.g., the momentum in one photon to rescale and relocate the wave function of an object as small as an electron or, potentially, as large as the entire universe — is that this rescaling necessarily crosses the usual boundaries of space and time. The more profound suggestion is that our classically-biased thinking is upside down. Causality is _not_ the norm; the norm is a chaos of indefinitely low-energy, indefinitely-variable, boundary-free rescaling outside our local definitions of space and time. Our inertial-frame-based impositions of agreed-to xyzt scales — a marvelous little trick enabled by not-quite-xyzt half-spin — are the exception. A collection of almost continual rescalings via local momentum exchanges (who’d of thunk it: dumb little low-energy phonons as fundamental to spacetime emergence) allow atoms to agree on what is and is not a good size to be.

Recognizing that one photon can act as an observer is a more powerful tool for understanding many surprisingly deep problems in physics than one might expect. I strongly suspect these insights include how an otherwise scaleless and (in our perception) timeless universe can nonetheless wrap around itself to create “interesting” physics _without_ invoking arbitrary boundary conditions or infinitely distant and infinitely powerful observers. Nor is this some remote, unfathomable, untestable process since you are using small-scale examples of it at this very moment when single photons perceive and transform the vastly larger shapes of your eye corneas and lenses into directions for how to form an image on your retina. That small QED example of an integral-of-histories performance defies classical definitions of space and time as profoundly as the broader and deeper case of ≈10^81 xyz images (credit: R.L. Kuhn) of a _single_ universe-spanning electron pattern.


[1] R. Feynman, _Watching the Electrons [Feynman Lectures III Ch 1 Sec 6], _ The Feynman Lectures on Physics (1965).

[2] Y. Y. Fein, P. Geyer, P. Zwick, F. Kiałka, S. Pedalino, M. Mayor, S. Gerlich, and M. Arndt, _Quantum Superposition of Molecules Beyond 25 kDa, _ Nature Physics *15, * 1242 (2019).

[3] T. Bollinger, _How to Convert One Green Photon into Two Locomotives of Momentum, _ TAO Physics *2021, * 0930 (2021).

[4] T. Bollinger, _The Vacuum-Phonon (Sonon) Reinterpretation of QED, _ TAO Physics *2021, * 0926 (2021).

[5] A. Macchi and O. M. Maragò, _Light Pressure Across All Scales: Editorial, _ The European Physical Journal Plus (2021).

(a PDF copy of this 2023-04-21 comment is available at sarxiv dot org slash apa)

[rovosher]

What is the “action principle” that takes precedence in “quantum cosmology?” Does it emerge with time too? Does it evolve as other “laws” do?

[dongshengdi]

The multiverse problem.
By Paul Davies, a cosmologist not bound by any tradition.

"I usually say two cheers for the multiverse because there are good reasons of physics and cosmology for supposing that what we see may not be all you get. That there may be other regions of space and time that could be different. So it's not an unreasonable speculation. However, it falls far short of being a complete theory of existence, which is often presented as. That as if there's a multiverse, then we can forget about all the mysteries of the universe because it's all explained. Everything is out there somewhere. End of story.

Well, it's simply not true, because to get a multiverse, you need a universe-generating mechanism. Something has got to make all those big bangs go bang. So you're going to need some laws of physics to do that. And you can say, well, where do they all come from? So all you've done is shift the problem of existence up from the level of universe to the level of multiverse, but you haven't explained it.

I suppose, for me, the main problem is that what we're trying to do is explain why the universe is as it is by appealing to something outside of it. In this case an infinite number of universes outside of it. That, to me, is no better than traditional religion that appeals to an unseen unexplained God that is outside of the universe.

I'm prepared to accept that what we see isn't the totality, that there may be regions of space and time, other universes, if you like, that could be rather different from what we observe. But I certainly don't believe that all possible universes are out there, and that the explanation for the universe that we see is because everything imaginable exists, and that this particular one we see, just because it happens to be one that we live in. I think that falls far short of a proper explanation. Indeed, I think it's contradictory and absurd."
.
.
If all is random and our universe is the only universe, the chance existence of human awareness would seem incredible. Because the laws of physics would have to be so carefully calibrated to enable stars and planets to form and life to emerge, it would seem to require some kind of design. But there are other explanations.
.
Robert J. Spitzer, SJ, is a Jesuit priest, philosopher, physicist, educator, author, speaker, and retired President of Gonzaga University in Spokane, Washington

[jamesruscheinski]

time may disappear in vertical dimension for space expanding in horizontal dimension?

[jamesruscheinski]

at surface event horizon of black hole, space disappears and turns into energy? energy inside back hole disappears at planck time, where becomes time?

[ekekonoise]

Any books similar to hertog's origin of time?

[vanikaghajanyan]

1:10:25 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 (according to general estimates, this acceleration is: a=πcH*).
Real gravitational fields are variable in space and time, and, developing GR**, we can now talk about the fact that it is possible to generate a gravitational field in a non-inertial frame of reference (|a|=g).. That is, finally achieve global (instead of local in GR) compliance with the equivalence principle. Then the energy density of the relic radiation, that is, the evolving primary gravitational-inertial field (= space-time): J= quanta/cm^3, which is in order of magnitude consistent with the observational-measured data (about 500 quanta/cm^3).


By the way, it turns out that the universe is 1.6 trillion years old!


{The area of the "crystal sphere": S(universe)~n' λ(relic)^2~n'S(relic)}.
P.S.You can also use the Unruh formula, but with the addition of the coefficient q, which determines the number of phase transitions of the evolving system: q=√n', where n'=L/8πr(pl), L=c/H, the length of the phase trajectory. w(relic)=2√n'w(kepler), w(kepler)=√2πH.
Thus, T*(relic)=[q]ħa/2πkc(=0.4K), which is in order of magnitude consistent with the real: T(relic)/T*(relic)=2, 7/0, 4=6, 7.
{However, there is no need to have a factor of 1/2π in the Unruh formula in this case.}

*) - w(relic)^2=πw(pl)H,
|a|=r(pl)w(relic)^2 =g=πcH,
intra-metagalactic gravitational potential: |ф(0)|=c^2/2√8n'=πGmpl/λrelic,
m(pl)w(pl)=8πM(Universe)H;
{
w(relic)^2=πw(pl)H.

**) - See "GR was QG".

[jamesruscheinski]

what predictions can be made from time / energy uncertainty in quantum cosmology?

[jamesruscheinski]

testing quantum values in other cosmos would require finding energy of virtual particles at different planck times?

[georgeangles]

Time exists even if no one is around to keep it

[jamesruscheinski]

in this cosmos, energy of virtual particles and planck time might provide data for time / energy uncertainty in quantum cosmology?

[ReynaSingh]

The origin of time is a paradox. There can be no origin of time without already having time to begin with