Drew mentions this and points out that it’s a new OS design and will therefore take a long time. He argues that an OS based on the linux design would be much easier.

Charge conservation would unambiguously be violated, which is why this decay is not expected. The half-life you quote is an experimental lower-bound.

Charge conservation would indeed be violated, which is why this decay is not expected. Dave is mistaken: the half-life they’re referring to is an experimental lower-bound, not a actual expected value.

They are not expected to decay. The half-life they’re thinking of is a lower-bound based on current measurements, not an actual expected half-life.

Not all radio noise is from the CMB. There’s also thermal noise, though this would be minimized too if our hypothetical radio at the end of time is near absolute zero.

One clarification: electric charge, angular momentum, and color charge are conserved quantities, not symmetries. Time is a continuous symmetry though, and its associated conserved quantity is energy.

Similarly, information isn’t a symmetry, but it is a conserved quantity. So I assume you’re asking if there’s an associated symmetry for it from Noether’s theorem. This is an interesting question: while Noether’s theorem ensures that any continuous symmetry will have a corresponding conserved quantity, the reverse isn’t necessarily true as far as I know. In the case of information conservation, this normally follows naturally from the fact that the laws of physics are deterministic and reversible (Newton’s laws or the Schrodinger equation).

If you insist on trying to find such a symmetry, then you can do so by equating conservation of information with the conservation of probability current in quantum mechanics. This then becomes a math problem: is there a transformation of the quantum mechanical wavefunction (psi) that leaves its action invariant? It turns there is: the transformation psi -> exp(i*theta)*psi. So it seems the symmetry of the wavefunction with respect to complex phase necessitates the conservation of probability current (i.e. information).

Edit: Looking into it a bit more, Noether’s theorem does work both ways. Also, the Wikipedia page outlines this invariance of the wavefunction with complex phase. In that article, they use it to show conservation of electric current density by multiplying the wavefunction by the particle’s charge, but it seems to me the first thing it shows is conservation of probability current density. If you’re interested in other conserved quantities and their associated symmetries, there’s a nice table on Wikipedia that summarizes them.

I suspect you may be misunderstanding time dilation. From the perspective of a particle, time always passes by at 1 second per second. If you yourself were to travel at relativistic speeds (relative to, say, Earth) your perspective of time wouldn’t change at all. However, observers on Earth would see your “clock” to tick slower. That is, anything you do would progress more slowly from their perspective. In the very early Universe, a given particle would see most other particles moving at relativistic speeds, and so would see their “clocks” tick slower. These sorts of relativistic effects would influence interactions between particles during collisions, decay rates, etc, but are all things we know how to take into account in our models of the early Universe.

The required temperature depends on the mass of the particles you’re considering. You could say photons are always relativistic, so even the photon gas that is the cosmic microwave background is relativistic at 2.7 K. But you’re presumably more interested in massive particles.

If you apply the kinetic theory of gases to hydrogen, you’ll find that the average kinetic energy will reach relativistic levels (taken to be when it becomes comparable to the rest mass energy) around 10¹² K. For the free electrons (since we’ll be dealing with plasmas at any sort of relativistic temperatures), this temperature is around 10⁹ K due to the smaller mass of the electron. These temperatures are reached at the cores of newly-formed neutron stars (~10¹² K) [1] and the accretion disks of stellar-mass black holes (~10⁹ K) [2], but not at the cores of typical stars. Regarding time dilation, an individual particle’s clock would tick slower from the perspective of an observer in the center-of-mass frame of the relativistic gas, but I don’t think this would have any noticeable effect on any of the bulk properties of the gas (except for the decay of any unstable particles). Length contraction would probably affect collision cross-sections, though I haven’t done any calculations for this to say anything specific. One important effect would be the fact that the distribution of speeds would follow a Maxwell–Jüttner distribution instead of a Maxwell-Boltzmann distribution, and that collisions between particles could be energetic enough to create particle-antiparticle pairs. This would affect things like the number of particles in the gas, the relationship between temperature and pressure, the specific heat of the gas, etc.

You mention the early history of the Universe in your other comment. You can look through this table on Wikipedia to see the temperature range during each of the epochs of the early Universe, as well as a description of what happened. The temperatures become non-relativistic for electrons at some point during the photon epoch.

[1] https://doi.org/10.1063%2F1.4909560

[2] https://doi.org/10.1016%2Fj.isci.2021.103544