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Cosmologically Unique IDs

237 points by jfantl

by lisper

4 subcomments

This analysis is not quite fair. It takes into account locality (i.e. the speed of light) when designing UUID schemes but not when computing the odds of a collision. Collisions only matter if the colliding UUIDs actually come into causal contact with each other after being generated. So just as you have to take locality into account when designing UUID trees, you also have to take it into account when computing the odds of an actual local collision. So a naive application of the birthday paradox is not applicable because that ignores locality. So an actual fair calculation of the required size of a random UUID is going to be a lot smaller than the ~800 bits the article comes up with. I haven't done the math, but I'd be surprised if the actual answer is more than 256 bits.
(Gotta say here that I love HN. It's one of the very few places where a comment that geeky and pedantic can nonetheless be on point. :-)

by m4nu3l

0 subcomment

A more realistic estimate of the total number of addressable things should take into account that for anything to be addressable, its address should be stored somewhere at least once.
If it takes at least Npb particles to store one bit of information, then the number of addressable things would decrease with the number of bits of the address.
So let's call Nthg the number of addressable things, and assume the average number of bits per address grows with Nb = f(Ntng).
Then the maximum number of addressable things is the number that satisfies Nthg = Np/(Npb*f(Ntng)), where Np is the total number of particles.

by j-pb

1 subcomments

Great insights and visualisations!
I build a whole database around the idea of using the smallest plausible random identifiers, because that seems to be the only "golden disk" we have for universal communication, except for maybe some convergence property of latent spaces with large enough embodied foundation models.
It's weird that they are really under appreciated in the scientific data management and library science community, and many issues that require large organisations at the moment could just have been better identifiers.
To me the ship of Theseus question is about extrinsic (random / named) identifiers vs. intrinsic (hash / embedding) identifiers.
https://triblespace.github.io/triblespace-rs/deep-dive/ident...
https://triblespace.github.io/triblespace-rs/deep-dive/tribl...

by adityaathalye

2 subcomments

Just past page 281 of Becky Chambers's delightful "the galaxy, and the ground within".
```
  Received Message
  Encryption: 0
  From: GC Transit Authority --- Gora System (path: 487-45411-479-4)
  To: Ooli Oht Ouloo (path: 5787-598-66)
  Subject: URGENT UPDATE
```
Man I love the series.
Looks like this multispecies universe has centrally-agreed-upon path addressing system.

by ekipan

3 subcomments

I forget the context but the other day I also learned about Snowflake IDs [1] that are apparently used by Twitter, Discord, Instagram, and Mastodon.
Timestamp + random seems like it could be a good tradeoff to reduce the ID sizes and still get reasonable characteristics, I'm surprised the article didn't explore there (but then again "timestamps" are a lot more nebulous at universal scale I suppose). Just spitballing here but I wonder if it would be worthwhile to reclaim ten bits of the Snowflake timestamp and use the low 32 bits for a random number. Four billion IDs for each second.
There's a Tom Scott video [2] that describes Youtube video IDs as 11-digit base-64 random numbers, but I don't see any official documentation about that. At the end he says how many IDs are available but I don't think he considers collisions via the birthday paradox.
[1]: https://en.wikipedia.org/wiki/Snowflake_ID
[2]: https://youtu.be/gocwRvLhDf8

by rini17

1 subcomments

From real life we know that people prefer to have multiple anonymous IDs, or self-selected handles, either makes fully deterministic generation schemes moot.
Also, network routing requires objects that have multiple addresses.
Physics side of whole thing is funny too, afaik quantum particles require fungibility, i.e. by doxxing atoms you unavoidably change the behavior of the system.

by bluecoconut

2 subcomments

Fun read.
One upside of the deterministic schemes is they include provenance/lineage. Can literally "trace up" the path the history back to the original ID giver.
Kinda has me curious about how much information is required to represent any arbitrary provenance tree/graph on a network of N-nodes/objects (entirely via the self-described ID)?
(thinking in the comment: I guess if worst case linear chain, and you assume that the information of the full provenance should be accessible by the id, that scales as O(N x id_size), so its quite bad. But, assuming "best case" (that any node is expected to be log(N) steps from root, depth of log(N)) feels like global_id_size = log(N) x local_id_size is roughly the optimal limit? so effectively the size of the global_id grows as log(N)^2? Would that mean: from the 399 bit number, with lineage, would be a lower limit for a global_id_size be like (400 bit)^2 ~= 20 kB (because of carrying the ordered-local-id provenance information, and not relative to local shared knowledge)

by QuiCasseRien

0 subcomment

I really love everything related to Cosmology but I always struggle with two contrary concepts that lead to paradox (for me) :
- Infinity : from school, we learn our universe is infinite.
- We often do calculation with upper limit like this one : 10^240. This is a big number butttttt it's not infinite you know. 10^240+1, 10^240+2...
So :
1. if it's infinite, why doing upper limit calculation ?
2. if it's limited, what is there outside that limit ?
Extremly paradoxal

by ktpsns

1 subcomments

Quite offtopic, but: I found UUIDs being overused in many cases. People then abused them to store data, making them effectively "speaking IDs" or "multi column indices".

by manofmanysmiles

1 subcomments

I'd propose using our current view of physical reality to own a subset of the UIID + version field if new physics is discovered.
10-20 bits: version/epoch
10-20 bits: cosmic region
40 bits: galaxy ID
40 bits: stellar/planetary address
64 bits: local timestamp
This avoids the potentially pathological long chain of provenance, and also encodes coordinates into it.
Every billion years or so it probably makes sense to re-partion.

by small_model

0 subcomment

We will probably end up with something like each planet has its own local addressing, and the big router in the sky does NAT, each solar system has a router and so on.

by alex_tech92

0 subcomment

It is interesting how much of our infrastructure relies on the assumption that 'close enough' is actually 'good enough' for uniqueness. When we move from UUIDs to things like ULIDs or Snowflake IDs, we are really just trading off coordination cost for a slightly higher collision risk that we will likely never hit in several lifetimes. Thinking about it on a 'cosmological' scale makes you realize how much of a luxury local generation is without needing a central authority. It is that tiny bit of entropy that keeps the whole distributed system from grinding to a halt.

by factotvm

1 subcomments

> In order to fix this, we might start sending out satellites in every direction
Minor correction: Satellites don't go in every direction; they orbit. Probes or spaceships are more appropriate terms.

by philipwhiuk

0 subcomment

Note that they almost immediately contract from 'the universe' to 'the visible universe', which isn't the same thing at all.

0 subcomment

by dvh

0 subcomment

Another blow to the "all electrons are the same electron" theory. Why have only 1 electron with so many possible ids /s

by frikit

1 subcomments

The best way to solve this is not to, and just giving up on the idea of identification.
If you have an infinite multiverse of infinite universes, and perhaps layers on that, with different physics, etc., you can’t have identity outside of all existence.
In Judaism, one/the name of God is translated as “I am”. I believe this is because God’s existence is all, transcending whatever concepts you have of existence or of IDs. That ID is the only ID.
So, the cosmic solution to IDs is the name of God.