With enough mirrors and light bouncing around the size of the universe itself can be a "storage media" of the past with different photons all around carrying "how this location looked X years ago". "All" you have to do to know what happened is find the right photon to see whatever it is you want to see.
https://github.com/yarrick/pingfs
"pingfs is a filesystem where the data is stored only in the Internet itself, as ICMP Echo packets (pings) travelling from you to remote servers and back again."
Also https://en.wikipedia.org/wiki/Delay-line_memory
Storing data as acoustic waves gave a higher capacity in practice, as propagation is slower thus fitting a larger number of symbol per time unit.
I understand that we'd have to account for the movement of objects, of course, but with computers, seems like a small hurdle...
By Greg Egan, so highly recommended.
It's a beautiful nightmare, isn't it?
> whether two spatially separated events occur at the same time – is not absolute, but depends on the observer's reference frame.
But What I don’t understand about this is why is “time” framed as observer based? In my mind, the events do happen at the same time and just are unable to be observed as such. I feel like time is a figment of our imagination, it’s just a measurement. In my pea brain time makes sense more as a constant and the other things are something else that impacts the latency of observance
Yes, it is. It is 420 million years in the past in our frame of reference. The link you posted is about how frames of reference of other observers might differ from ours. However, doesn't make the notion "420 million years in the past [in our frame of reference]" any less well-defined.
Not so, I would say.
Space and time are inherently linked under special (and General) relativity. For two observers who have relative motion between them, the space (distance between two 'events') and time (between the said events) are both different.
When some poem or a song talks about the universe being frozen at a given instant of time, that can be only in a given reference frame. There's no absolute time for the universe.
Its a logical consequence of the speed of light being constant in all inertial reference frames, regardless of the velocity.
This is an axiom of special relativity, but it has also been verified at (admittedly low) relative velocities.
That in itself is somewhat absurd, but it leads to further absurdities when you do the math. In order for the speed of light to remain invariant, you can no longer speak of an absolute (preferred) frame of reference.
You can of course, privilege certain reference frames e.g. Earth, but its rather arbitrary.
Ed: I've slipped into the fallacy a bit. Reference frames don't have locations, so they can't be "nearby". Just pretend I said "reference frame of a nearby object".
- I leave Earth and travel 1ly at speed c
- I arrive one year later
- An Earth telescope will see the destination as it was when I left
- It will take another year to see me arrive
So in a way that's already happening because I'm traveling quite quickly - twice as fast as it seems from Earth's perspective - and I arrive in what appears from Earth to be the past.