[BigParm]

It’s an interesting property of the universe that there’s no way to measure time directly. It clearly exists, yet all you can measure is change of things besides time.

Time lock puzzles take variable time depending on hardware. You can’t really set an accurate specific release time.

Any change in the universe that a computer can detect is just another spoofable input.

Blockchain tries to solve essentially the same problem but the best it can reliably do is establish a chronology. That’s not a specific time. And it has fundamental vulnerabilities, however unlikely you think they are to be exploited in established systems.

Intel is building proof of elapsed time into their chips but that’s not trustless.

Timelock puzzles and blockchain are imo hacky solutions to one of the most important outstanding problems in cryptography: securely and trustlessly agreeing on elapsed time.

[bsdetector]

> there’s no way to measure time directly. It clearly exists, yet all you can measure is change of things besides time.

If it can't be measured then it can't be said to clearly exist.

Imagine a cellular automata where particles have lots of "slots" that could be used for moving or interacting. As the particle speeds up and more slots are used for moving, there are fewer slots for the kind of interaction change that we use to measure time. At the highest speed, with all possible slots used for motion, the particle would experience no change, which is indistinguishable from no time passing.

Does that sound familiar to anything? It's certainly possible that light being a speed limit, time dilation, relativity, and so on are in some way actually describing change rather than time.

[throwaway69123]

What about time crystals? https://en.wikipedia.org/wiki/Time_crystal

[idiotsecant]

Time crystals aren't the only thing that has properties that change in an orderly, predictable fashion. Plain old uranium has the same property. The answer to both is the same - put them on a very fast rocket and do a lap around the galaxy and see how well they agree with you on how much time has elapsed.

[illiac786]

Is it not rather that time does not elapse everywhere at he same speed, simply put?

Based on this, of course, measuring it becomes difficult.

It's akin to measuring gravity. You can — for a specific point in space and time. (Time is even worse, since it is specific to a given _trajectory_ in space)

But I have no idea what Im talking about.

[ben_w]

It's identical to measuring gravity. In relativity, acceleration and gravity are indistinguishable, and it's acceleration which breaks the paradoxical symmetry that gives the name to the twins paradox.

[crotchfire]

What about time cubes? https://en.wikipedia.org/wiki/Time_Cube

[vmfunction]

>Timelock puzzles and blockchain are imo hacky solutions to one of the most important outstanding problems in cryptography: securely and trustlessly agreeing on elapsed time.

Digital cryptography will always being a cat and mouse. DES, RSA, Elliptic curve... With intro of quantum computing, it will just fasten up the pace. Some government has start experimenting with quantum entanglement (https://apnews.com/article/china-google-justice-department-6...)

It is all about your threat model. Even that I'm sure someday some smart guy will also figure out how to figure out how to beat that.

[koliber]

On human scale, is this a real problem? Consensus gives us the ability to measure elapsed time with a high probability. It seems kind of analogous how fundamental particles are probability fields. That means that in theory a baseball could teleport. But because a baseball is big spontaneous teleportation is not a real concern for anyone.