Jan 282024
 

I first bought a hybrid (a Honda Civic) in 2004. I loved that car; it served us faithfully for 10 years. Our more recent Hondas were not hybrids, but the reasons were eminently practical: hybrids were in short supply, conventional gasoline cars were cheaper, and we use the car very little in any case, so…

Having said that, I certainly contemplated the idea of buying an all electric vehicle, but every time I think it through, I decide against it. Today, I saw a map that perfectly illustrates my lack of enthusiasm. Here it is:

This map shows the locations of supercharger stations where you’d have to stop for a 20-30 minute recharge, in order to complete a cross-country trip across the United States in a Tesla automobile.

In contrast, here’s a map of an actual trip I took in my Civic Hybrid back in 2005, along with the approximate locations where I stopped for gas (reconstructed from old receipts):

What can I say? I think EVs are great when you live in the suburbs and use your car for shopping and commuting to work. If I lived, say, in Kanata and commuted daily to work at, say, Place du Portage in Gatineau, purchasing an EV would make an awful lot of sense. But that’s not where we live or how we commute. We live on Ottawa Lowertown, which is to say almost downtown, we work at home, we use the car only occasionally, but as this example demonstrates, sometimes for lengthy road trips. EVs are not great for lengthy road trips. I am used to the idea of driving to Montreal Airport and back without worrying about stopping for gas. Or driving to Toronto non-stop.

And then, of course, there are the dreaded Canadian winters. It’s one thing to use waste heat from a gasoline engine to heat the interior of a car. It’s another thing to waste electric power stored in a battery for this, converting electricity inefficiently into heat, at the expense of range already reduced by the effect of cold weather on the batteries. And while heat pumps can help, there are no miracles when the outside air temperature is closer to -40 than -30 Centigrade, which is a not altogether uncommon occurrence (though it is certainly becoming less common) in these parts of Canada.

And then there’s the question of where the electric energy comes from. Renewables are okay, nuclear would be great. But too much of the electricity, even here in nuclear-rich Ontario, comes from natural gas fired plants. That’s not so great.

So for now, it’s either gasoline-powered or hybrid vehicles for us. EVs may be in our future, but I am not yet too keen on them, to be honest.

 Posted by at 3:05 pm
Jan 242024
 

Someone sent me a link to a YouTube podcast, a segment from an interview with a physicist.

I didn’t like the interview. It was about string theory. My dislike is best illustrated by a point that was made by the speaker. He matter-of-factly noted that, well, math is weird, the sum of \(1 + 2 + 3 + …,\) ad infinitum, is \(-\tfrac{1}{12}.\)

This flawlessly illustrates what bothers me both about the state of theoretical physics and about the way it is presented to general audiences.

No, the sum of all positive integers is not \(-\tfrac{1}{12}.\) Not by a longshot. It is divergent. If you insist, you might say that it is infinite. Certainly not a negative rational number.

But where does this nonsense come from?

Well, there’s the famous Riemann zeta-function. For values of \(s>1,\) it is indeed defined as

$$\zeta(s)=\sum_{n=1}^\infty \frac{1}{n^s}.\tag{1}$$

It is a very interesting function, at the heart of some unresolved problems in mathematics.

But the case of \(s=-1\) (which is when the right-hand side of the equation used to define \(\zeta(s)\) corresponds to the sum of all positive integers) is not an unresolved problem. As it is often presented, it is little more than a dirty trick befitting a cheap stage magician, not a scientist.

That is to say, the above definition of \(\zeta(s),\) as I said, is valid only for \(s>1.\) However, the zeta-function has what is called its analytic continuation, which makes it possible to extend the definition for other values of \(s,\) including \(s=-1.\) This can be accomplished utilizing Riemann’s functional equation, \(\zeta(s)=2^s\pi^{s-1}\sin(\tfrac{1}{2}\pi s)\Gamma(1-s)\zeta(1-s).\) But the right-hand side of (1) in this case does not apply! That sum is valid only when it is convergent, which is to say (again), \(s>1.\)

A view of the Riemann zeta-function, from Wikipedia.

So no, the fact that \(\zeta(-1)=-\tfrac{1}{12}\) does not mean that the sum of all integers is \(-\tfrac{1}{12}.\) To suggest otherwise only to dazzle the audience is — looking for a polite term here that nonetheless accurately expresses my disapproval — well, it’s dishonest.

And perhaps unintentionally, it also shows the gap between robust physics and the kind of mathematical games like string theory that pretend to be physics, even though much of it is about mathematical artifacts in 10 dimensions, with at best a very tenuous connection to observable reality.

 Posted by at 10:48 pm
Jan 192024
 

Japan’s SLIM (Smart Lander for Investigating Moon) made it to the lunar surface. Well… sort of. It accomplished its main goal of a targeted soft landing.

Unfortunately, its solar panels are non-operational. It’s unclear for now why (one speculation I read is that the lander may have tipped over after landing). Its batteries can power it only for a few hours. They’re hoping that perhaps later in the lunar day, or in a next lunar cycle, the lander will get sunlight from the right direction to be able to recharge its batteries after all.

Even so, Japan is now officially the fifth country to have landed a spacecraft on the Moon that remained (at least partially) operational on the lunar surface.

 Posted by at 2:01 pm
Jan 182024
 

I gave a brief invited talk today via Zoom, participating in a workshop on cosmological models, organized by Complutense University of Madrid, Spain.

The subject of my talk was John Moffat’s theory of gravitation, MOG/STVG, to which I made significant contributions myself over the past 18 years, in an on-going collaboration with John. Judging by the questions that followed my short presentation, I think it was reasonably well received.

The workshop was streamed live on YouTube, and the video is archived.

 

 Posted by at 9:25 pm
Dec 062023
 

A few days ago, I came across an article that described a remarkable paper, published in the USSR more than 50 years ago, with predictions on climate change.

Predictions that proved remarkably prescient.

I first read about Mikhail Budyko’s article in a recent review, published on EOS three years ago. What caught my attention, in particular, was Fig. 1 of that article, reproduced below, that shows just how spot on Budyko’s predictions happen to be.

Budyko’s 1972 predictions (solid gray lines) of a) surface temperature and b) changes in Arctic sea ice, compared to observational data from NASA Goddard and IPCC predictions.

Naturally, I wanted to see the original reference, which proved harder than I expected. While it was cited many times, the paper was almost impossible to find. Although I did locate it in an online Russian library, it was only an index entry, with the (unscanned) copy available only for reading in person.

But then… Fortunate favors the… foolish? Persistent? I stumbled upon a 2020 Russian-language publication containing full reprints of several papers by Mikhail Budyko, including the paper in question.

I took it upon myself then to translate the paper in its entirety, with help from one of our AI friends. (AI can do a remarkable job translating technically challenging content, much better than dedicated translation software, albeit some supervision is required.)

Yes, Budyko indeed accurately predicted human-induced climate change. His concerns about rapid changes, “tipping points” are also well-justified. Notably, his work was written before climate change became political football. It’s the work of an excellent climate scientist, not a political hack.

 Posted by at 11:57 pm
Dec 052023
 

Now that Roy Kerr’s paper on black holes and singularities is on arXiv, I am sure I’ll be asked about it again, just as I have been asked about it already on Quora.

Roy Kerr, of course, is one of the living legends of relativity theory. His axisymmetric solution, published in the year of my birth, was the first new solution in nearly half a century after Karl Schwarzschild published his famous solution for a spherically symmetric, static, vacuum spacetime. I hesitate to be critical of this manuscript since chances are that Kerr is right and I am wrong.

Kerr now argues that the singularity theorems are nonsense, and that his axisymmetric solution actually hides some nonsingular configuration of matter therein.

At a first glance, the paper seems well written and robust. Still… when I dug into it, there are a few things that caught my attention, and not in a right way. First, the paper takes argument with “singularity believers” using language that almost sounds like pseudoscience. Second, it has some weird factual errors. E.g., it asserts that black holes “as large as 100 billion solar masses have been observed by the James Webb Telescope” (not even close). Or, it describes the famous Oppenheimer-Snyder paper of 1939 as having “used linear, nineteenth century ideas on how matter behaves under extreme pressures” (actually, Oppenheimer and Snyder discuss the collapse of a “dust” solution with negligible pressure using the tools of general relativity with rigor). Kerr further criticizes the Oppenheimer-Snyder paper as attempting “to ‘prove’ that the ensuing metric is still singular”, even though that paper says nothing about the metric’s singularity, only that the collapsing star will eventually reach its “gravitational radius” (i.e., the Schwarzschild radius). Nonetheless, later Kerr doubles down by writing that “Oppenheimer and Snyder proved that the metric collapses to a point,” whereas the closest the actual Oppenheimer-Snyder paper comes to this is describing collapsing stars as stars “which cannot end in a stable stationary state”.

Never mind, let’s ignore these issues as they may not be relevant to Kerr’s argument after all. His main argument is basically that Penrose and Hawking deduced the necessary presence of singularities from the existence of light rays of finite affine length; i.e., light rays that, in some sense, terminate (presumably at the singularity). Kerr says that no, the ring singularity inside a Kerr black hole, for instance, may just be an idealized substitute for a rotating neutron star.

Now Kerr has an interesting point here. Take the Schwarzschild metric. It is a vacuum solution of general relativity, but it also accurately describes the gravitational field outside any static, spherically symmetric distribution of matter in the vacuum. So a Schwarzschild solution does not imply an event horizon or a singularity: they can be replaced by an extended, gravitating body that has no singularities whatsoever so long as the radius of the body is greater than the Schwarzschild radius associated with its mass. The gravitational field of the Earth is also well described by Schwarzschild outside the Earth. So in my reading, the crucial question Kerr raises is this: Is it possible that once we introduce matter inside the event horizon of a Kerr black hole, perhaps that can eliminate the interior Cauchy horizon or, at the very least, the ring singularity that it hides?

I don’t think that is the case, and here is why. Between the two horizons of a Kerr black hole, the “radial” coordinate is now the timelike coordinate, with the future pointing “inward”, i.e., towards the Cauchy horizon. That means that particles of matter do not have trajectories that would allow them to avoid the Cauchy horizon; no matter what path they follow, they will reach that horizon in finite proper time.

Inside the Cauchy horizon, anything goes, since closed timelike curves exist. So presumably, it might even be possible for particles of matter to travel back and forth between the past and the future, never hitting the ring singularity. But that’s not what Kerr is suggesting in his paper; he’s not talking about acausal worldlines inside the Cauchy horizon, but some “nonsingular interior star”. I don’t see how to make sense of that suggestion, because I don’t see how a stationary configuration of matter could exist inside the inner horizon. Wobbling back-and-forth between yesterday and tomorrow in a closed timelike loop is not a stationary configuration!

For these reasons, even as I am painfully aware that I am arguing with a Roy Kerr so there’s a darn good chance that he’s right and I’m spouting nonsense, I must say that I remain unconvinced by his paper. The language he uses (e.g., describing the business of singularities as “dogma”) is not helping either. Also, his description of the interior of the rotating black hole sounds a bit off; to use his own words, “nineteenth century” reasoning, much more so than the Oppenheimer-Snyder paper that he criticizes.

 Posted by at 7:31 pm
Dec 022023
 

I just came across a quote attributed to Einstein: “If I had foreseen Hiroshima and Nagasaki, I would have torn up my formula in 1905.

The problem with this quote is that it is utter nonsense, and not something Einstein likely would have said, ever.

An image of Einstein that is just as real as some of the quotes attributed to him. Courtesy of Midjourney.

The “formula” of mass-energy equivalence simply states that an object’s resistance to motion (its inertia) is proportional to its energy-content. That is all. Yes, I know that in the popular imagination, \(E=mc^2\) is frequently associated with the nuclear age. But that’s nonsense. \(E=mc^2\) is not about “converting” anything into anything. Mass-energy is mass-energy, and it is conserved. Whether it is in the form of the nuclear binding energy of a uranium atom (or for that matter, the chemical binding energy of carbon atoms in a fireplace log) or in the form of the kinetic energy of photons released by a nuclear or chemical reaction has absolutely nothing to do with \(E=mc^2\): the formula does not explain nuclear fission any more than it explains the chemical reactions that govern the burning of wood.

But then, what about this quote, which appears in a number of reliable places, including Wikiquotes?

It is attributed to a book published by a William Hermanns, who supposedly interviewed Einstein on a number of occasions between the late 1920s and Einstein’s death in 1955.

The person appears real. I found, in Google’s archive, the May 2, 1955 issue of Life, which includes a personal recollection of one of Life’s own editors, William Miller, of his very last visit to Einstein, when he actually met William Hermanns.

Hermanns’s book, Einstein and the Poet: In Search of the Cosmic Man, is also real: In fact, it even has a Kindle edition.

But… how much of it is true?

Considering that Hermanns has an exceptional biography (which one can read on a Web site dedicated to his life) it is more than a bit odd that the only references to his name in Wikipedia are Einstein-related. Yet his name does not appear in notable Einstein biographies, including Abraham Pais’s definitive scientific biography, or Walter Isaacson’s exceptionally good Einstein bio.

When I read the few pages of Hermanns’s book that are available as a Kindle preview, I grow even more suspicious. For instance, according to Hermanns, already in 1927 Einstein was “marked by Nazis as ‘Enemy number One of the Nation,’ and the object of at least seven plots to take his life.” News to me.

But then, Hermanns goes on to quote Einstein who supposedly said, “When I was about five, my father gave me a compass as a toy. I wanted to find out why the needle never deviated […] When I asked my uncle, an engineer, he immediately proceeded to teach me some fundamentals of algebra, with this advice: ‘What you don’t know, call x, then hunt til you find what it is.’ From that time on, I have called everything I didn’t know x, especially magnetism.

As I asked ChatGPT just moments ago, can you imagine Einstein saying these words, in 1927, to a stranger who just visited him?

Long story short, I don’t know what to think. Based on what I have read, I do not believe Hermanns’s accounts of his conversations with Einstein are credible. At the very least, they must be severely distorted versions of Einstein’s words, probably deeply colored, warped by Hermanns’s imagination. For what it’s worth, ChatGPT concurs: “The lack of independent verification and recognition in authoritative sources casts doubt on the accuracy and credibility of his accounts. Your reservations about accepting Hermanns’ narratives as factual are well-founded.”

 Posted by at 11:32 pm
Nov 302023
 

I made some mistakes in the past. I never made a half-a-billion dollar mistake.

Neither did Chris Lewicki, but he came awfully close.

I just read this delightful account of how Lewicki almost fried the innards of the Spirit rover, destined for Mars, during an engineering test that took place just weeks before the rover was launched.

I can only imagine the sinking feeling in his stomach he must have felt when he thought that the rover was ruined. My mistakes never came close in value, but the sensation is uncomfortably familiar.

Fortunately, in his case, the disaster never actually materialized. In simple terms, yes, he plugged a cord into the wrong outlet, but fortunately, the other end of the cord was not plugged in.

To this day, Lewicki must feel like one of the luckiest persons on the planet.

The illustration is from his blog post, but its appearance suggests that it might have been produced by DALL-E. Or maybe Midjourney or Stable Diffusion? The style looks very reminiscent of AI-produced cartoon images.

 Posted by at 6:17 pm
Nov 302023
 

So the other day, as I was doing a Google Search (can’t exactly remember what it was that I was searching for but it was machine learning related), up pops this invitation to participate in a challenge.

Turned out to be the Google Foobar challenge, Google’s secret recruiting tool. (Its existence is not really a secret, so I am not really revealing any great secrets here.)

Though I have no plans to become a Google employee (and I doubt they’re interested in me on account of my age anyway) I decided to go through the challenge because, well, it’s hard to say no to a challenge, and it was an opportunity to practice my Python skills (which need a lot of practice, because I have not yet used Python that much.)

Well, I did it. It was fun.

More importantly, I enjoyed it just as much as I enjoyed similar challenges as a math geek in my early teens. And if that’s not a gift from life, I don’t know what it is.

And yes, I am now much better at Python than I was just a few days ago. I certainly appreciate why the language has become popular, though I can also see its non-trivial pitfalls.

 Posted by at 6:03 pm
Nov 302023
 

This morning, like pretty much every morning, there was an invitation in my inbox to submit a paper to a journal that I never heard of previously.

Though the unsolicited e-mail by itself is often an indication that the journal is bogus, predatory, I try to be fair and give them the benefit of the doubt, especially if the invitation is from a journal that is actually related to my fields of study. (All too often, it is not; I’ve received plenty of invitations from “journals” in the medical, social, biological, etc., sciences, subjects on which I have no professional expertise.)

So what are the signs that I am looking for? Well, I check what they published recently. That’s usually a good indication of what to expect from a journal. So when I read a title that says, say, “Using black holes as rechargeable batteries and nuclear reactors,” I kind of know what to expect.

Oh wait. That particular paper appears to have been accepted for publication by Physical Review D.

Seriously, what is the world of physics coming to? What is the world of scientific publishing, by and large, coming to? Am I being unfair? Just to be sure, I fed the full text of the paper on black hole batteries to GPT-4 Turbo and asked the AI to assess it as a reviewer:

 Posted by at 11:06 am
Nov 082023
 

Sometimes it feels… so pretentious.

Here I am, saying all sorts of clever things in my blog. I once declared blogs to be write-only media, my way of shouting at the world without the world saying anything in return, but that kind of ceased being true when I decided, eons ago, to share my blog posts on social media, where a few friends at least reacted occasionally.

So who do I think I am, proclaiming my wisdom to the world, really?

For instance, a few days ago I thought I’d blog about the first precision clock arriving in America centuries ago, and promptly failing, leading to a better understanding of how the gravitational acceleration on the surface of the Earth may change with geographic location. But is there anything I can add to the subject other than what’s in the article I am citing?

Or take this report from earlier today, about Singapore’s Prime Minister expressing very much the same concerns that I have about the world experiencing a moment of danger not unlike the moments before the Great War. OK, so I blog about it. Is there anything I can add other than, hey, look, I am ever so clever, even Singapore’s PM shares my views!?

I suppose I feel most comfortable blogging about my actual research or my work. These are subjects that I can address with some competence.

Or maybe just blog about cats. They know how to be wise and silent, after all.

Meanwhile, in the world of humans…

F-15s strike weapons facility in Syria

By Lauren C. Williams and Jennifer Hlad

ABOARD A MILITARY PLANE—Two U.S. F-15 fighter jets attacked a weapons storage facility in eastern Syria on Wednesday, in what Defense Secretary Lloyd Austin called a “precision self-defense strike” in response “to a series of attacks against U.S. personnel in Iraq and Syria by the [Iranian Islamic Revolutionary Guard Corps]-Quds Force” and related groups.

So I must now follow my cats’ example and resist the urge to blog about how the US and Iran might already be at war…

 Posted by at 9:51 pm
Nov 012023
 

A few minutes ago, I checked Google News on my phone and lo and behold, there was a link to Universe Today, a new article discussing my latest manuscript on multiple gravitational lenses.

I knew that this was in the works, as the author approached me with some questions earlier in the day, but I didn’t expect it to appear this quickly, and, well, seeing it on my phone like this was a nice surprise.

Had the author asked, I’d have happily granted permission to use one of my generated images or animations involving multiple lenses.

Meanwhile, my paper on a four-satellite configuration used to detect deviations from Newtonian gravity was published by Astrophysics and Space Science, one of the Nature journals. I am officially permitted (in fact, encouraged) by Springer to share the link to an online read-only version of the published paper.

 Posted by at 1:25 am
Oct 122023
 

I’m doing more work on gravitational lensing. In particular, the little ray tracing model that I developed can now use actual astronomical images as sources. Here’s a projection of a nice spiral galaxy as it would be seen through a pair of non-coplanar, imperfectly lined up lenses:

Somehow, I suspect, no astronomer would recognize (at least not without a spectral analysis) that these are four images of the same rather nice-looking galaxy, NGC-4414:

These lensing examples also demonstrate how difficult it is to reconstruct either the original view, or the mass distribution of the lens itself, when all we see is something like the first image above.

 Posted by at 9:35 pm
Oct 082023
 

I am simulating gravitational lenses, ray tracing the diffracted light.

With multiple lenses, the results can be absolutely fascinating. Here’s a case of four lenses, three static, a fourth lens transiting in front of the other three, with the light source a fuzzy sphere in the background.

I can’t stop looking at this animation. It almost feels… organic. Yet the math behind it is just high school math, a bit of geometry and trigonometry, nothing more.

NB: This post has been edited with an updated, physically more accurate animation.

 Posted by at 5:35 pm
Oct 052023
 

I don’t know much about attosecond light pulses but my wife and I did note that one of the recipients of this year’s physics prize was a physicist who studied just a year ahead of Ildiko at ELTE (Eötvös University). She doesn’t recall if she ever bumped into Ferenc Krausz, though.

And of course one of the recipients of the Nobel prize in physiology or medicine was Katalin Kariko, for her groundbreaking work in mRNA vaccines. Well-deserved indeed! I actually know (a little bit) more about mRNA vaccines than about attosecond physics, which might seem odd, considering that physics is my home turf, and organic chemistry is like an alien landscape. But the generation of ultrashort photon pulses is a very specialized field of study, to which I never paid much attention.

Anyhow, Kariko and Krausz are now added to that long list of scientists who were born, and studied in, Hungary, but who eventually ended up abroad, where they did the bulk of the work that earned them this recognition.

 Posted by at 7:03 pm
Oct 032023
 

Here’s my phone screen as of a few minutes ago:

That’s in Centigrade of course.

What can I say? OK, our balcony thermometer only shows 28.3 C. Even so… not exactly typical early October weather for Ottawa.

 Posted by at 5:08 pm
Sep 292023
 

I’ve been meaning to mention this: A few days ago, the sample capsule of the OSIRIS-REx mission returned safely to the Earth, carrying inside a sample taken from the asteroid Bennu.

This is a remarkable achievement, the first* successful sample return of its type. I wonder what we will learn from the material that was obtained, but I’m sure it will reveal some intriguing secrets, especially about the history and formation of the solar system.

Love the way the capsule was sitting on the ground, upright, not even tilted. Could it be more picture perfect than this?

I am also mildly (but pleasantly) surprised that I have not heard any panicmongering about a capsule bringing back extraterrestrial microbes or whatever. OK, I wasn’t specifically looking but still. It’s a relief.


* I don’t know what possessed me when I wrote “first”; granted, OSIRIS-REx brought back a lot more material, supposedly, but the first successful such missions were the two Hayabusa missions of the Japanese Space Agency.

 Posted by at 6:09 pm
Sep 292023
 

OK, not exactly a surprising result but still, a fantastic experimental achievement: Yes, Virginia, antimatter falls downward.

Why is this important? Well, we kind of knew that it was inevitable. I mean, if antimatter were to fall upward, it’d have meant that our entire understanding of gravitation is wrong. That even our understanding of special relativity is probably wrong.

So it was a rather safe bet that antimatter follows the same geodesics as normal matter and falls downward.

But physics, lest we forget it, is ultimately not about erudite speculation. It is about experiment and observation.

And this amazing experiment achieved the almost impossible: it observed antihydrogen atoms in a vertical vacuum chamber at cryogenic temperatures and, as expected, most of those hydrogen atoms ended up at the bottom.

 Posted by at 12:33 am
Sep 162023
 

My friend John Moffat has a finite quantum field theory that, I think, deserves more attention than it gets.

The theory is nonlocal (then again, so is quantum physics to begin with). However, it does not violate causality. So its nonlocality is a mathematical curiosity, not a physical impossibility.

The essence of the theory is present in the form of its “nonlocal field operator”. Given, e.g., a scalar field in the form \(\phi(x),\) the field is transformed as

$$\tilde\phi(x)=\int d^4x’f(x-x’)\phi(x’).$$

Now if we just used the Dirac delta-function \(f(x-x’)=\delta^4(x-x’),\) we’d get back \(\phi(x).\) But what if we use some other function, the only restriction being that \(f(x)\) must be an entire function, which is to say, unambiguously defined without poles or singularities over the entire complex plane?

Well, then, assuming again that \(f(x)\) is an entire function, we can integrate iteratively in parts, until we arrive at an expression in the form,

$$\tilde\phi(x)={\cal F}(\partial_x)\phi(x),$$

where \({\cal F}(\partial_x)\) is a derivative operator, typically some power series in the form \(\lambda_i\partial_x^i\), acting on \(\phi(x).\)

Why is this good for us? Because this field redefinition can suppress high-energy divergences in the theory, essentially doing away with the need for renormalization, which, of course, is a Big Claim indeed but I think John’s theory works.

John’s first substantive papers on this topic were titled Finite quantum field theory based on superspin fields (J. W. Moffat, Phys. Rev. D 39, 12 (1989)) and Finite nonlocal gauge field theory (J. W. Moffat, Phys. Rev. D 41, 4 (1990)). Unfortunately these papers predate arxiv.org so only the paywalled versions are available. They are beautiful papers that deserve more recognition. More recently, John wrote another paper on the subject, collaborating with a student. One of these days, I’m hoping to spend some time myself working a bit on John’s theory because I believe it has merit: The theory appears to remain causal despite the nonlocal operator, and by doing away with the need for renormalization, it makes canonical quantization almost trivially possible. I keep wondering if there is, perhaps, a catch after all, but if that’s the case, I have yet to find it.

 Posted by at 1:37 pm
Sep 122023
 

I gave a talk on the Solar Gravitational Lens in Montreal back in July, using the above title.

Video of the talk is now available online, courtesy of the Interstellar Research Group.

I just listened to it myself and I didn’t cringe too much hearing my own voice or watching myself, which is probably a good sign?

 Posted by at 12:31 am