Tag Archives: space-time

April Fools’ Day Model of Space-Change

It is 1 April. This is NOT a joke but it may not be real. It’s a science thought experiment.

There’s a tiny bit of physics in my distant past but I am not a real physicist. In the last few years I’ve noticed the models of information I’m investigating resemble the ‘multi-worlds interpretation’ of quantum mechanics, which I have only heard about via radio, TV and Wikipedia. Quantum Mechanics is always rubbing up against Relativity, another idea about which I have a frustratingly inadequate understanding. I decided to investigate these worlds of weirdness but I find my brain getting horribly scrambled when I try to visualise space-time. I can’t and I don’t think anyone can. Our visual system has evolved for seeing a 3D world and that world changes. Humanity had lived, before the early 20th Century in a non-relativistic world. Those who do ‘get modern physics’ seem to rely on a mathematical understanding of the concepts.

In my models of information, I’d been thinking about the lack of a time-dimension in most computation. We usually model change in the world as a series of states, where data about a new state replaces the previous states. This starts to cause difficulties when computers have parallel paths of computation, as current multi-core processing chips do. Software has begun to address the problems with ‘immutability’. In simple terms, instead of replacing a value, a new value is added to the end of  a sequence, so historic values are retained. We have gone back before the memory-constrained computer age to learn from the Victorian hand-written ledger.

I became aware of research work at Cambridge University to reconcile ‘QM and R’ which also modelled time as state-change but I’ve found it very difficult to think about ‘the state change dimension of space’ as a sequence of events without falling back on ideas of time, speed and rate of change. The ‘idea of time’ which may be a cultural concept is deeply woven into our current paradigm.

In trying to free my mind of time, I’ve been hanging out in ‘the difficult time questions’ corner of Quora. Someone gave me a breakthrough by describing a simple clock:
Imagine going into deep space where gravity and friction to movement can be assumed to be zero. Throw an object. The distance it has travelled is a clock.

An April Fool thought experiment of time:
Make the object a spacecraft containing a holographic camera. Time passed can now be measured as a distance. Let us assume we prepared by asking someone to invent a unit of distance and mark it repeatedly on a very long tape, alongside the path of our space-craft. We don’t know the size of that unit. Now retrieve the holographic camera and put the recording medium in a holographic projector and project it onto a screen.
Think of the ‘slide-show’ as you being equivalent to you travelling along a sequence of equally spaced ‘holographic plates’. Consider changing the distance between plates in some regions of the recording (analogous to compressing time) or having instantaneously (enough) reversed the spacecraft during recording. Evidence of events would be passed in the opposite order but time would still be one way. Time could appear to be reversed if the projector was modified to play the recording in reverse order but that’s model hacking not reality.

Stage 2 – imagine this model as a streamed live-view of the universe, with the universe interfering with distances, as Relativity tells us it does, and has been observed. The problem is that a lot of the science assumes time is constant and that’s difficult to disprove from inside the space-time paradigm. We can only observe a space/state-change view and we may have invented time. Have fun with it.

Change Time

After some time trying to think about almost nothing, the last 24 hours have been an alarm call. As others come out of hibernation too, they post interesting stuff and Radio 4 provoked me with a discussion on facts and truth. Now Marc Cooper is at it, with difficult  links about computation and I’m all on Edge https://www.edge.org/response-detail/26733
Before I read about “discrete tensor networks”, I need to write down my own ideas about time, so I will know in the future what I thought, before my mind was changed.

I am ill-equipped for this task, having only 1 term of university maths to my name so I intend to talk in vague, abstract terms that are hard to argue with.

Much of physics is very dependent on Time, like almost all of computer science and business management theory. You can’t have change without time, it seems. Einstein talked about space-time, mostly in the language of mathematics. I can just about order a beer in math(s) but I can’t hold a whole conversation. I know what the first 3 dimensions are: left-right, up-down and back-forward. My personal model of the 4th dimension is that same space in continuous state-change through time. There are a few things I’m not happy about:

  • There is no evidence that time is either continuous or constant.
  • We only have evidence of time being a one-way dimension.
  • What the heck does ‘continous state-change’ mean? Is state a particle or a wave? Make your mind up, physics!
  • There’s that troubling many-worlds interpretation of the universal ‘WAVE’function (which I don’t understand either) which says that everything that might have happened did, in other universes. I don’t like this. Yes, that’s my entire justification – I don’t like the conclusion of a thought process I don’t even understand. It doesn’t feel right.

I’ve been learning about the functional programming language Clojure which does not ‘mutate (change) state’. It doesn’t have ‘variables’ like the more common imperative languages such as FORTRAN, BASIC, C, Java or Python. In Clojure, data flows through functions and is transformed from one form to another on the way. It is basically magic. In a pure functional program, no state is changed. State-change is called a “side-effect”. Sadly, side-effects are required to make a program do anything useful in the real world. Arguably, the purest magic is encapsulated in the world of mathematics and the physical world is a messy place that breaks things.

Clojure models time. It does not model the real world by replacing the current value in a variable and throwing the old value away but by chaining a new value onto the end of a list of all previous values.

Now let us extend this idea ‘slightly’ in a small thought-experiment, to a 3-D network of every particle state in the universe.

Space-time now has 2 regions:

  1. The past – all historic states of those particles as a theoretical chain of events
  2. The future – all possible future states of the universe; effectively an infinity of all possible future universes that could exist, starting from now.

Which brings us to what I mean by ‘now’ – a moving wave at the interface between the past and the future, annihilating possible future universes. Time becomes a consequence of the computation of the next set of states and the reason for it being a one-way street becomes obvious: the universe burned its bridges. Unless the universe kept a list, or we do, the past has gone. Time doesn’t need to be constant in different parts of the universe, unless the universe state ticks are synchronous but it seems likely to be resistant to discontinuities in the moving surface. I imagine a fishing net, pulled by current events.

It’s just an idea. Maybe you can’t have Time without change.

[ Please tell me if this isn’t an original idea, as I’m not very well read.
I made it up myself but I’m probably not the first. ]