Time dilation Updated 2025-07-16
One of the best ways to think about it is the transversal time dilation thought experiment.
Twin paradox Updated 2025-07-16
The key question is: why is this not symmetrical?
One answer is: because one of the twin accelerates, and therefore changes inertial frames.
But the better answer is: understand what happens when the stationary twin sends light signals at constant time intervals to each other. When does the travelling twin receives them?
By doing that, we see that "all the extra aging happens immediately when the twin turns around":
  • on the out trip, both twins receive signals at constant intervals
  • when the moving twin turns around and starts to accelerate through different inertial frames, shit happens:
    • the moving twin suddenly notices that the rate of signals from the stationary twin increased. They are getting older faster than us!
    • the stationary twin suddenly notices that the rate of signals from the moving twin decreased. They are getting older slower than us!
  • then when the moving twin reaches the return velocity, both see constant signal rates once again
Figure 1.
Twin paradox illustration with twins sending light signals at regular intervals
. Source.
Another way of understanding it is: you have to make all calculations on a single inertial frame for the entire trip.
Supposing the sibling quickly accelerates out (or magically starts moving at constant speed), travels at constant speed, and quickly accelerates back, and travels at constant speed setup, there are three frames that seem reasonable:
  • the frame of the non-accelerating sibling
  • the outgoing trip of the accelerating sibling
  • the return trip of the accelerating sibling
If you do that, all three calculations give the exact same result, which is reassuring.
Another way to understand it is to do explicit integrations of the acceleration: physics.stackexchange.com/questions/242043/what-is-the-proper-way-to-explain-the-twin-paradox/242044#242044 This is the least insightful however :-)
Bibliography:
Physics from Symmetry by Jakob Schwichtenberg (2015) page 66 shows one in terms of 4x4 complex matrices.
More importantly though, are the representations of the Lie algebra of the Lorentz group, which are generally also just also called "Representation of the Lorentz group" since you can reach the representation from the algebra via the exponential map.
Lorentz boost Updated 2025-07-16
Two observers travel at fixed speed relative to each other. They synchronize origins at x=0 and t=0, and their spacial axes are perfectly aligned. This is a subset of the Lorentz group. TODO confirm it does not form a subgroup however.
Indefinite orthogonal group Updated 2025-07-16
Generalization of orthogonal group to preserve different bilinear forms. Important because the Lorentz group is .
Truth table Updated 2025-07-16
Concurrent Versions System Updated 2025-07-16
It is said, that once upon a time, programmers used CSV and collaborated on SourceForge, and that everyone was happy.
These days, are however, long gone in the mists of time as of 2020, and beyond Ciro Santilli's programming birth.
Except for hardware developers of course. The are still happily using Perforce and Tcl, and shall never lose their innocence. Blessed be their souls. Amen.
Git Updated 2025-07-16
Perforce Updated 2025-07-16
Siemens Updated 2025-07-16
SubRip Updated 2025-07-16
Gordon Linoff Updated 2025-07-16
Infinitely many SQL answers.
As mentioned at Ciro Santilli's Stack Overflow contributions, he just answers every semi-duplicate immediatly as it is asked, and is therefore able to overcome the Stack Overflow maximum 200 daily reputation limit by far. E.g. in 2018, Gordon reached 135k (archive), thus almost double the 73k yearly limit due to the 200 daily limit, all of that with accepts.
This is in contrast to Ciro Santilli's contribution style which is to only answer questions as he needs the subject, or generally important questions that aroused his interest.
2014 Blog post describing his activity: blog.data-miners.com/2014/08/an-achievement-on-stack-overflow.html, key quote:
For a few months, I sporadically answered questions. Then, in the first week of May, my Mom's younger brother passed away. That meant lots of time hanging around family, planning the funeral, and the like. Answering questions on Stack Overflow turned out to be a good way to get away from things. So, I became more intent.
so that suggests his contributions also take a meditative value.
www.data-miners.com/linoff.htm mentions he's an SQL consultant that consulted for several big companies.
LinkedIn profile: www.linkedin.com/in/gordonlinoff/ says he now works at the New York Times.
2021 Reddit thread about him: www.reddit.com/r/programming/comments/puok1h/a_single_person_answered_76k_questions_about_sql/ mentions that by then he had:
answered 76k questions about SQL on StackOverflow. Averaging 22.8 answers per day, every day, for the past 8.6 years.
Ron Maimon Updated 2025-07-26
Ron is mostly known for simultaneously:
Ron seems to share a few philosophies which Ciro greatly agrees with as part of Cirism, which together with his knowledge of physics, make Ciro greatly respect Ron. Such philosophies include:
However he also subscribes to some theories which Ciro Santilli considers conspiracy theories, e.g. his ideas about the Boston Marathon bombing that got him banned from Quora (a ban which Ciro strongly opposes due to freedom of speech concerns!), but the physics might be sound, Ciro Santilli does not know enough physics to judge, but it often feels that what he says makes sense.
chat.stackexchange.com/transcript/message/7104585#7104585 mentions that he was at Cornell University and did all but dissertation, but he mentions that he was still self-taught:
Eugene Seidel: On your personal info page you write that you are not a physics Ph.D. but does that mean you were a physics undergrad in college then went to grad school and finished ABD... or are you entirely self taught?
Ron Maimon: ABD. I am self- taught though, I only went to school for accreditation. I had a thesis worth of work at the time I left grad-school,
Eugene Seidel: ok thanks
Ron Maimon: I was just kind of sickened by academic stuff that was going on--- large extra dimensions were popular then.
Eric Walker: Anyway, thanks Ron -- I'll get back to you with more questions soon, I'm sure.
Ron Maimon: Also I was at Cornell, my advisor left for Cincinnatti, and I was not in very good standing there (I was kind of a jerk, as I still am). Some friends wanted to start a biotech company called "Gene Network Sciences", and I joined them.
This is corroborated e.g. at: web.archive.org/web/20201226171231/http://pages.physics.cornell.edu/~gtoombes/Student_Index.html (original pages.physics.cornell.edu/~gtoombes/Student_Index.html down as of 2023).
Bibliography:
Backlinks:
Video 1.
Ron Maimon interview with Jeff Meverson (2014)
Source.
Ripped from Jeff's "Quoracast": player.fm/series/quoracast-podcast/ron-maimon-truther Ron mentions he was an early-Usenet user. Key points:
Aminoacyl tRNA synthetase Updated 2025-07-16
Binds an amino acid to the correct corresponding tRNA sequence. Wikipedia mentions that humans have 20 of them, one for each proteinogenic amino acid.
Lysozyme Updated 2025-07-16
Breaks up peptidoglycan present in the bacterial cell wall, which is thicker in Gram-positive bacteria, which is what this enzyme seems to target.
Part of the inate immune system.
It is present on basically everything that mammals and birds excrete, and it kills bacteria, both of which are reasons why it was discovered relatively early on.
Adobe Flash Updated 2025-07-16
Bash (Unix shell) Updated 2025-07-16
The more heavily a project relies on it, the more you start to regret it.
C (programming language) Updated 2025-07-16
It gets the job done, but cannot make a large codebase DRY without insanity.
As of 2020, C is like Latin, and we are in the Middle Ages, where it has become a lingua franca.
It is interesting to note how late C appeared: 1972, compared e.g. to Fortran which is from 1957. This is basically because C was a "systems programming language", i.e. with focus on pointer manipulation, and because early computers were so weak, there was no operating system or many software layers in the early days. Fortran however was a numerical language, and it ran directly on bare metal, an application that existed before systems programming.
Examples under c.
C++ Updated 2025-07-16
C plus plus is what you get when you want to have all of:
  • ability to write DRY code, which is e.g. impossible in the C
  • low level control, notably not having garbage collection, as possible in the C
  • somewhat backwards compatibility with C

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