Comment by buzzerbetrayed
6 days ago
Getting the entire universe to agree on a single clock for creating timestamps sounds absurdly difficult. Probably impossible?
6 days ago
Getting the entire universe to agree on a single clock for creating timestamps sounds absurdly difficult. Probably impossible?
"Agreement" of time is probably nonsense, yeah. I realized after posting so I edited in the parenthetical, but as [3] notes, locality probably makes this less of a real issue.
Apparently with the birthday paradox 32 bit random IDs only allow some tens of thousands per second before collision chance passes 50%. Maybe that's acceptable?
[3]: https://news.ycombinator.com/item?id=47065241
You don't need the universe to agree. You need your ID system to agree within a reasonable margin of error.
The temperature of the cosmic microwave background can be used as a universal clock.
So can neutron star spin rates
Neutron star spins collectively can be used as a pretty accurate clock.
How? You are here on earth, looking at a neutron star. It pulses about N times a minute. I am 5ly away, looking at the same neutron star. Yes, i see the pulses happening at about N times per second, but the pulse delay you see at time T(a) is not the same pulse delay i see at time T(a), it would be another 5 years before i see the same pulse you saw.