You think time ages you. Everyone does. But Einstein proved something that changes everything: time is not fixed. The faster you move through space, the slower you move through time. At the speed of light, time doesn't slow down. It stops.

In this video, inspired by Richard Feynman's legendary approach to special relativity, we break down exactly why light never ages, what spacetime actually is, and why every second of your life you are already moving through the universe at the speed of light.

This is not science fiction. This is physics. And it will change how you see time forever. //

“you are always moving at the speed of light through spacetime.”

That motion is divided between space and time. If you are sitting completely still in spacetime then you are spending the maximum amount of time.

The faster you move through space, the slower you move through time.

Yet these promises of a self-running state are illusory, because AI is never truly autonomous. Systems have to be built and maintained by a cadre of engineers and data scientists whose expertise political leaders cannot evaluate. The ruler who turns to AI to reduce a dependence on unreliable humans may end up relying, more blindly than before, on the few AI specialists who keep the system running. And this new digital Praetorian Guard may have the same weaknesses as the old, which makes it a threat to the ruler. //

Roman emperors typically had tens of thousands of people serving in the Praetorian Guard; modern autocrats rely on standing armies. But with AI, autocrats will need only a small clique of engineers to build and maintain large-scale AI systems. This might benefit rulers since they will have fewer people to watch, yet it also concentrates points of failure, since a devastating disruption requires only a handful of engineers and makes it easier for members to scheme against the leader. The new guard’s members may also be indispensable. A dictator can replace generals without destroying the army. But running complex machine-learning systems requires such a specialized set of skills that engineers can be difficult to replace without disruptions, giving these actors great leverage. //

AI will not let autocrats dismiss all their enforcers. Someone still has to make arrests and run the prisons, and autocrats can buy loyalty by offering supporters state jobs. But it will let authoritarians downsize, and the number of officials ultimately matters less than how the ruler oversees them. Keeping track of scheming or incompetent subordinates has always been the autocrat’s chief burden. AI could lighten it, letting rulers watch their officials more closely without paying as much active attention.

In the near term, then, AI may greatly benefit autocracies. Despite the many obstacles to deployment, the technology is already bringing autocratic regimes the upsides of cheaper surveillance, smarter censorship, and fewer human subordinates to fear and distrust. But for autocratic rulers, the temptations of artificial intelligence may re-create the same trap they are seeking to escape. The more a regime depends on AI, the more it depends on the people who keep AI running. And those people, like every other praetorian class in history, will quickly discover what their indispensability is worth.

Recently, I read an article about device fingerprinting, which argues that we’re in the post-tracking-cookie era. They’re no longer needed, because every browser can be fingerprinted with 100% accuracy.

https://royfish.dev/fingerprints-are-the-new-cookies

There’s an EFF page which allows you to test your device fingerprinting. https://coveryourtracks.eff.org/

The information theory idea is that while there are millions of people who have the same time zone, time zone offset, fonts, etc., it’s the combination of all these things that makes it possible to identify.

The EFF has a page on this, which explains. After establishing that 33 bits of entropy is needed for identification:

So for instance, if we know someone’s birthday, and we know their ZIP code is 40203, we have 8.51 + 23.81 = 32.32 bits; that’s almost, but perhaps not quite, enough to know who they are: there might be a couple of people who share those characteristics. Add in their gender, that’s 33.32 bits, and we can probably say exactly who the person is.

The Liberty Bell, with its famous crack, hasn’t been rung in 180 years, but that hasn’t stopped scientists from pondering what the bell might have sounded like when tolling. In honor of the nation’s 250th anniversary, researchers at Penn State University have modeled its acoustic properties, drawing on data collected from one of the bell’s replicas. The work was first presented at a meeting of the Acoustical Society of America in Philadelphia earlier this year, followed by an article in Physics Today.

Historians aren’t sure exactly when the Liberty Bell acquired its distinctive crack, just that it occurred sometime between 1817 and 1846. An 1846 account in the Public Ledger described the ringing of the bell on February 23 that year and mentioned that the bell had developed a crack, which someone had attempted to fix by filing the sides down. But it didn’t work: The February 23 ringing extended the crack even more, so much so that “the old Independence Bell … now hangs in the great steeple irreparably cracked and forever dumb.” Nobody has heard it ring since.

This wasn’t the first time the bell had cracked; the rim cracked shortly after it arrived in Philadelphia in 1752, the first time the clapper struck while testing the sound. It was recast by two local foundry workers, John Pass and John Stow, not once but twice, because the first recast produced a sound that one bystander likened to coal scuttles banging together.

The second recast’s sound was deemed acceptable, and the bell was typically used to summon the Assembly, among other purposes, until it fell into disuse after the American Revolutionary War. As for why the bell was so prone to cracking, a 1975 study of the bell’s chemical composition revealed that the metals used formed “an extremely brittle alloy” that also made it easier for souvenir collectors to chip off pieces from the rim. //

Autapomorphy Ars Praetorian
8y
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Subscriptor
Since it's hard to imagine frequencies based on a number, I calculated the following based on equal temperament tuning using a standard concert pitch where A4 is 440 Hz.

174 Hz = -16.06 semitones. That's 6 cents flat relative to F2
323 Hz = -5.35 semitones. That's 35 cents flat relative to E3
381 Hz = -2.49 semitones. That's 49 cents flat relative to G3
510 Hz = +2.56 semitones. That's 44 cents flat relative to C4
623 Hz = + 6.02 semitones. That's 2 cents sharp relative to D4#