David Quintero

TIL: there's a whale "speaking" in the 52 hertz frequency, where no other whale speaks or can hear. It has been called the "world's loneliest whale". It's argued that it can be a malformed animal or a hybrid, but it has been recorded since the late 1980s and it has been detected along many different places of the Pacific ocean, a sign of a healthy specimen.

In 2010 another simultaneous recording of the 52 hertz song was detected elsewhere, suggesting that even the loneliest whale of the world could have a potential soulmate.

52-hertz whale - Wikipedia
https://en.wikipedia.org/wiki/52-hertz_whale

TIL: the number of atoms outside galaxies is roughly the same of atoms inside galaxies. This is because of the long filaments or tendrils that emanate from galaxies and connect with another galaxies.

These filaments are supposed to be like the tracers of dark matter, where the gas (normal atoms) coalesce.

(From Daniel and Kelly's Extraordinary Universe podcast, episode: "Do we live in a super bubble?")

The Austromarxism was a current of democratic socialism from the 1920s and the beginning of the 1930s.

In 1919 the Socialdemocrat Party (SDAP) won the elections in Vienna, beginning the period of the "Red Vienna". Vienna was a Land, with great autonomy. It approved the 8 working hours, subsidies to unemployment, public housing (64 000 !), rent controls, public health care and education, new libraries and parks, more taxes to the rich (including a tax for having servants), etc.

Although not everything was wonderful in the "Red Vienna". After WWI, the unemployment skyrocketed and there was hyperinflation. Even with the strong public housing politics, many people still lived in hostels, there were shortages of many products, including electricity, that stopped at 20:00. In addition of this, the Red Vienna was a red island in the middle of a very conservative Austria.

I learnt of this in the Spanish translation of Edmonds' The Murder of Professor Schlick: The Rise and Fall of the Vienna Circle.

Austromarxism - Wikipedia
https://en.wikipedia.org/wiki/Austromarxism

Something I learnt recently in the online course on quantum foundations I'm following is that, in the double slit experiment, you can put in one slit a vertical polarizer, in the other an horizontal. You'll get two bands, as expected, since you're measuring.

But you can introduce, after the two slits with polarizers, diagonal polarizers, and you'll get the interference pattern! With the diagonal polarizers you don't know where the photons come from, you lose information, you have "undone" your measurement, so to say.

Curiously, you can explain everything with classical physics: a vertical and horizontal rays of light can't interfere, so two bands on the screen. And the diagonal polarizer allows interference again.

Interesting bit in Sean Carroll's last AMA episode. The Dirac equation is *not* a replacement of the Schrödinger equation, something many times implied or explicitly alluded.

The Dirac equation is a classical equation for particles of spin 1/2 with electric charge, like the Klein-Gordon equation is a classical equation for scalars. The Dirac equation is more like Maxwell's equations with spin 1/2. When quantized, the Dirac equation gives you quantum field theory, and that's what it's done nowadays.

Indeed, Schrödinger tried an explicitly relativistic invariant equation and arrived to Klein-Gordon, but it didn't fit the experimental data for an electron in the atom. BTW, the Schrödinger equation with a relativistic hamiltonian is perfectly compatible with special relativity.

(These are good news for MWI fans like Carroll himself, since they need an universally valid Schrödinger equation).

Beginning the third and last season of Dark. The series certainly maintains the high level.

Sean Carroll says in his last AMA that he has applied probably more than 50 times to different positions, and what he has received has been mostly rejections.

In a society that only tells stories of successes, it's refreshing to hear from relevant figures (in this case in physics) about failure, a very natural state of we humans.

I'm going to move tomorrow to a new flat, after 15 years. Same city, but still... this puts me into a(n) (even more) philosophical mood.

I'm slightly worried by the process. I don't have much: one table and one chair and the typical stuff for living (dishes, clothes, clutery, cleaning items...). What I have most are books, nearly 200. But even with that, I expect my moving to be easy for the company, compared with many others.

TIL: "vendeko" is a still not accepted prefix meaning 10^{-33}, near the Planck scale if we talk about meters. There are others, like vendeka for a positive exponent. And there're also xenno and xenna, 10^{-30} and 10^{30}. Also not accepted. I learnt this in Greg Egan's "Schild's Ladder".

A quote by Douglas Hofstadter, from one his columns in Scientific American (On Number Numbness):

"[...]If [the] numbers [have] millions or billions of digits, the numerals themselves (the colossal strings of digits) would cease to be visualizable, and your perceptual reality would be forced to take another leap upward in abstraction — to the number that counts the digits in the number that counts the digits in the number that counts the objects concerned.[...]"

(From: https://www.mrob.com/pub/math/largenum.html)

In his last AMA, Sean Carroll is asked if, as David Deutsch has claimed, the many worlds interpretation of QM is as sure as Darwinian evolution. Carroll says that no, that although his credence on the MWI is 90 - 95 %, his credence on evolution is much higher.

He mentions two (for him) slightly weak points. On the one side, the problem of probability. I think he perhaps means how to derive the Born rule. He says he considers this solved but he's not 100% sure. And on the other side, the question of why if MWI is right then the world looks so classical. I didn't know this last point was a problem...

David Wallace is the half physicist, half philosopher that wrote that book about the many worlds interpretation of QM that had parts that were over me.

Now he has a "new" title on the philosophy of physics that basically deals with: "the nature of space and time; the origin of irreversibility and probability in the physics of large systems; how we can make sense of quantum mechanics."

Philosophy of Physics: A Very Short Introduction | Oxford Academic
https://academic.oup.com/book/32801?login=false

More interesting parts from Carroll's last AMA: the famous "it from bit" by John Wheeler is not that information is behind nature as a more fundamental layer of reality, as many who probably haven't read the original paper by Wheeler have said.

Wheeler meant that the "it" came from collapses of wave functions (those were the bits). I guess this would eventually lead him to his participatory universe interpretation of quantum mechanics.

I think it was Penrose who suggested a version of quantum mechanics that was non linear due to the interaction with the gravitational field. But let's be honest, a fundamental theory worth its salt should be linear.

I've watched "The Watchers", by Ishana Night Shyamalan, the daughter of M., who is one of the producers of the film.

It's an horror movie, with some resemblance to The Village. It contains lots of frights and shocks that make your heart skip a beat, so don't watch it if this is uncomfortable for you.

As with many of these kind of films, a considerable suspension of disbelief is demanded from the viewer. But it's a good movie, I think, and in the line of Shyamalan father, it ends well.

I think I've read so many sketches of proofs of Gödel's theorem that somehow they should amount to the full rigorous proof.

My final grades after my third year learning German are 7.7/10. Certainly not bad, but they have been in descent during the course.

I recognise that I don't study too much, but not due to laziness, but because I'm into many stuff. I like reading, learning more things about Physics (following a course on the Foundations of QM right now), there's work, socialising, dancing, exercise...

I want to continue learning German, but I should probably think about it a bit more.

Vacuum cleaners: automatic like a Roomba or manual:

So the question is, after finishing "Ring", continue with the Xeelee saga with Destiny's Children or jump to another Baxter's saga like "Manifold" (Time, Space and Origin).