If protons decay. There isn't really any reason to believe they're not stable.
replyAnd recent DESI data suggests that dark energy is not constant and the universe will experience a big crunch in a little more than double its current age, for a total lifespan of 33 billion years, no need to get wild with the orders of magnitude on years into the future. The infinite expansion to heat death over 10^100 years is looking less likely, 10^11 years should be plenty.
replyhttps://www.sciencedaily.com/releases/2026/02/260215225537.h...
Protons can decay because the distinction between matter and energy isn't permanent.
replyTwo quarks inside the proton interact via a massive messenger particle. This exchange flips their identity, turning the proton into a positron and a neutral pion. The pion then immediately converts into gamma rays.
Proton decayed!
That's such an odd way to use units. Why would you do 10^56 * 10^-9 seconds?
replyThis was my thought. Nanoseconds are an eternity. You want to be using Planck units for your worst-case analysis.
replyIf you go far beyond nanoseconds, energy becomes a limiting factor. You can only achieve ultra-fast processing if you dedicate vast amounts of matter to heat dissipation and energy generation. Think on a galactic scale: you cannot have even have molecular reaction speeds occurring at femtosecond or attosecond speeds constantly and everywhere without overheating everything.
replyMaybe. It's not clear whether these are fundamental limits or merely technological ones. Reversible (i.e. infinitely efficient) computing is theoretically possible.
replyIf you have a black hole as an infinite heat sink this helps a great deal.
replyNanoseconds is a natural unit for processors operating around a GHz, as it's roughly the time of a clock cycle.
replyIf a CPU takes 4 cycles to generate a UUID and the CPU runs at 4 GHz it churns out one every nanosecond.
If we think of the many worlds interpretation, how many universes will we be making every time we assign a CCUID to something?
reply> many worlds interpretation
replyThese are only namespaces. Many worlds can have all the same (many) random numbers and they will never conflict with each other!
In that interpretation the total number of worlds does not change.
replyWe don't "make" universes in the MWI. The universal wavefunction evolves to include all reachable quantum states. It's deterministic, because it encompasses all allowed possibilities.
replyHumpf…
replyYou just had to collapse my wave function here…
Protons (and mass and energy) could also potentially be created. If this happens, the heat death could be avoided.
replyConservation of mass and energy is an empirical observation, there is no theoretical basis for it. We just don't know any process we can implement that violates it, but that doesn't mean it doesn't exist.
Conservation laws result from continuous symmetries in the laws of physics, as proven by Noether's theorem.
replyTime translation symmetry implies energy conservation, but time translation symmetry is only an empirical observation on a local scale and has not been shown to be true on a global universe scale.
replyProton decay is hypothetical.
replySo is the need for cosmologically unique IDs. We're having fun.
replyI got a big laugh at the “only” part of that. I do have a sincere question about that number though, isn’t time relative? How would we know that number to be true or consistent? My incredibly naive assumption would be that with less matter time moves faster sort of accelerating; so, as matter “evaporates” the process accelerates and converges on that number (or close it)?
replyTimes for things like "age of the universe" are usually given as "cosmic time" for this reason. If it's about a specific object (e.g. "how long until a day on Earth lasts 25 hours") it's usually given in "proper time" for that object. Other observers/reference frames may perceive time differently, but in the normal relativistic sense rather than a "it all needs to wind itself back up to be equal in the end" sense.
replyThe local reference frame (which is what matters for proton decay) doesn't see an outside world moving slower or faster depending on how much mass is around it to any significant degree until you start adding a lot of mass very close around.
reply