Let’s Discuss the Lorentz Transforms – Part the Last: The Real Derivation, or The Nail in the Casket

In this post there are a lot of references to the previous one – it is essential that you read it before getting down to this.

In my previous posts (see the list below below) I tried to express my doubts whether there is a real physical substrate to the Lorentz transforms. The assumptions about the constancy of the speed of light, the homogeneity of space-time, and the principle of relativity do not and cannot lead to the deduction of the Lorentz transforms – Einstein himself, for one, gets quite different transforms, and from those he goes over directly to the Lorentz transforms obviously missing a logical link (see Einstein p. 7, and also Part 1 of this discussion). As for the light-like interval being equal to zero, we saw that it can be attached to such assumptions only in error and cannot in itself be a foundation of a theory. I have to conclude that all that fine, intricately latticed construction of scientifictitious, physics-like arguments with the air of being profound is nothing but a smokescreen creating the appearance of a physical foundation while there is none.

What is then the real foundation of the Lorentz transforms? Let’s start from the rear end, the Minkowski mathematics. Historically, this appeared later than special relativity as a non-contradictory model of the Lorentz mathematical world; previously mentioned Varićak was among those who took part in its creation. Notwithstanding its coming later in history, it can be used as the starting point for derivation of the Lorentz transforms.

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Let’s Discuss the Lorentz Transforms – Part the Last: The Real Derivation, or The Nail in the Casket
Source: geektimes

Let’s Discuss the Lorentz Transforms – Intermission: Rapidity, and What it Means

I thought my previous post rather funny, and was surprised seeing it initially receive so few views. I thought the entertainment flopped, but fortunately I was wrong. I therefore feel it my duty before my readers to address the subject of the Landau & Lifschitz proof of the invariance of the interval.

You can find the summary of it in Wikipedia. Making their starting point the light-like interval always being equal to zero, Landau & Lifschitz seem to make a great fuss about it. The Wikipedia article even says: ‘This is the immediate mathematical consequence of the invariance of the speed of light.’ No, it is not.

I beg everyone’s pardon, but the light-like interval always being equal to zero is nothing else but the following statement: ‘The length of a ray of light will always be equal to the length of this ray of light’. Sounds like a cool story, bros and sis, but I cannot see what further inferences can be drawn from it. The ‘proof’ of this truism cannot fail under any circumstances whatever – whether you keep the speed of light invariant, or keep or change the metric of space or time or both – or make both metric and speed of light change – the light-like interval will remain equal to zero. I am okay with anyone wanting to prove it if they feel like it, but you cannot make it an ‘immediate mathematical consequence of the invariance of the speed of light’. Neither is it possible to make the constancy of the speed of light a consequence of the invariance of the light-like interval for the reason already mentioned: this is a truism. It does not prove anything, nor can it be a consequence of anything. When Landau & Lifschitz insist that this is a consequence of the constancy of the speed of light, that is either an error or a downright subterfuge, a means employed to create a spectre of logical connection between two unconnected notions, and charge this ghostly connection with pretended significance. And, since the following proof of invariance of an arbitrary interval hangs on the invariance of the light-like interval, we can altogether dismiss it: the necessity of introduction of such a measure as interval cannot be derived from the statement that a length of something will be equal to itself in whatever frame of reference it is measured.

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Let’s Discuss the Lorentz Transforms – Intermission: Rapidity, and What it Means
Source: geektimes

Let’s Discuss the Lorentz Transforms – Part 2: The Equation of the Sphere, or Is It?

The previous discussion done, we have surmounted the difficult waters and are now sailing into something much more pleasure-like and hopefully even entertaining.

As I promised, we will be discussing the invariance of the interval, that is to say, the following relation:

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Let’s Discuss the Lorentz Transforms – Part 2: The Equation of the Sphere, or Is It?
Source: geektimes

Let’s Discuss Relativity of Simultaneity

There is one only too obvious problem with relativity of simultaneity in the way it is normally introduced, and I have never found an answer to it – what’s more, I never read or heard anyone formulate it. I will be grateful for an enlightening discussion.

The framework of the thought experiment introducing relativity of simultaneity is this. Two rays of light travel in opposite directions and reach their destination simultaneously in one frame of reference and at different moments in the other.

For example, in the Wikipedia article on the subject you can read:

‘A flash of light is given off at the center of the traincar just as the two observers pass each other. For the observer on board the train, the front and back of the traincar are at fixed distances from the light source and as such, according to this observer, the light will reach the front and back of the traincar at the same time.

‘For the observer standing on the platform, on the other hand, the rear of the traincar is moving (catching up) toward the point at which the flash was given off, and the front of the traincar is moving away from it. As the speed of light is finite and the same in all directions for all observers, the light headed for the back of the train will have less distance to cover than the light headed for the front. Thus, the flashes of light will strike the ends of the traincar at different times’.

I am always not a little surprised at the modesty displayed by the authors of such illustrations. If we grant the statement ‘the light headed for the back of the train will have less distance to cover than the light headed for the front’ to be true – how then do we evaluate the magnitude of the effect? Or, in other words, how much longer is one distance in comparison to the other?

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Let’s Discuss Relativity of Simultaneity
Source: geektimes

How in-app chats help e-learning platforms to be more interactive?

e-Learning is an extension of/ alternative to a traditional classroom setup. e-learning, commonly known as ‘online learning’ or ‘virtual learning’ is ideally a one-way or two-way digital communication established on a device with video and voice call integration using internet access. The last two years made us realize how technology can facilitate and improve communication. Digital technology had its impact in almost every industry including the sensitive education sector.

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How in-app chats help e-learning platforms to be more interactive?
Source: geektimes

It's alive

I wonder why IT developer interviews are so strange most of the time. It feels as if the people are looking for computer science teachers, not engineers. All those theoretical questions that have no relation to the working reality. It is strange to be looking for eloquent teachers, who can perfectly explain any term or pattern, and then ask them to do the actual work. Maybe it is the imprint from the years spent in university when the teachers looked like all-knowing gods and seemed to solve any issue in your life. May be, may not. Anyway, these teachers stay in unis and don’t do the work.

You know, what would be my universal answer to all interview questions? “I have no idea how and why it works, but I can use it, and I can use it for good”. This is the reality. Actually, no one knows exactly these hows and whys. What is a computer? What is electricity? What is an electron? No one knows for sure. But it works and we use it.

Imagine a famous author, like Stephen King, asked a question about the difference between deus ex machina and Mary Sue. Would his answer change the quality of his books? He may or he may not know all those scientific literature terms, but he can use the language and use it for good.

Every time I turn on my computer it is a wonder. I have no idea what is going on, but it awakes, it becomes alive, and I can communicate with it in its own sublime and subtle language.

Have you ever realised that all these electronic devices are monsters, Frankenstein’s monsters? Some pieces of dead matter were put together, and then, with some electricity involved, it suddenly awoke. “It’s alive!”. Had Frankenstein any idea why it turned alive? Of course not, or why he was so surprised? Every developer experiences this feeling almost every day. “It’s working!”

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It's alive
Source: geektimes

[Translation] Conceptogram as a method to create more effective technical documentation

Konstantin Kotelnik, an analyst at Innotech, ponders over making technical documentation easier to understand for developers and helping the clip-thought generation work effectively with large quantities of data. Read the article to find out about the potential emergence of a graphical IT-Esperanto and the standardisation of technical language.

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[Translation] Conceptogram as a method to create more effective technical documentation
Source: geektimes

How I gave my old laptop second life

17-19 min read

Hi y’all, my name is Labertte and I use Arch btw.
Probably like every other Linux user, I’d like to buy a ThinkPad, put some lightweight distribution like Arch or Gentoo on it, and then go to Starbucks, get a soy latte and tell everyone that I use «linux». But I decided to go a little different route and give a chance to my old laptop that I was using about five or seven years ago.

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How I gave my old laptop second life
Source: geektimes

FL_PyTorch is publicly available on GitHub

FL_PyTorch: Optimization Research Simulator for Federated Learning is publicly available on GitHub.

FL_PyTorch is a suite of open-source software written in python that builds on top of one of the most popular research Deep Learning (DL) frameworks PyTorch. We built FL_PyTorch as a research simulator for FL to enable fast development, prototyping, and experimenting with new and existing FL optimization algorithms. Our system supports abstractions that provide researchers with sufficient flexibility to experiment with existing and novel approaches to advance the state-of-the-art. The work is in proceedings of the 2nd International Workshop on Distributed Machine Learning DistributedML 2021. The paper, presentation, and appendix are available in DistributedML’21 Proceedings (https://dl.acm.org/doi/abs/10.1145/3488659.3493775).

The project is distributed in open source form under Apache License Version 2.0. Code Repository: https://github.com/burlachenkok/flpytorch.

To become familiar with that tool, I recommend the following sequence of steps:

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FL_PyTorch is publicly available on GitHub
Source: geektimes

How abortion in the age of surveillance capitalism turns Internet into a dystopia

The reversal of Roe v. Wade, which launched a furious debate about abortion rights, has a side — and a very itchy side. In June 2022, the Supreme Court struck down federal protections for abortion rights in the United States, turning the decision on the legality of abortion over to the state level, many of whom had long been waiting for it: they had «trigger» laws banning abortion, and state prosecutors were preparing to prosecute for violating or trying to circumvent them.

Not even a week later, news emerged that the blow to women’s rights might come from an unexpected (for naive Americans who are not familiar with the «Yarovaya Package» and other niceties of Russian legislation) side, when the willingness to «leak» personal data even without a decision was confirmed by the developers of major applications for women. Thus, suddenly, own gadgets and all the IT infrastructure that surrounds the modern man for his convenience, suddenly showed its downside: the possibility of total control over human life and actions.

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How abortion in the age of surveillance capitalism turns Internet into a dystopia
Source: geektimes