What does it mean to move through time?

atyy

For simplicity, just think of moving through time exactly the same way as in Newtonian physics. For example, if you throw a ball straight up, its vertical displacement as a function of time is y=ut-gt²/2. You can invert this to get t as a function of y, which you can plot on a graph with t on the vertical axis and y on the horizontal axis. That's a Newtonian "spacetime" diagram.

harrylin

Yes, "time" depends on movements: from the start, the concept of time has been based on natural clocks such as the solar day. If everything is frozen then all clocks are frozen as well.

yoron

It's a very nice question Bob, and one that have me question both 'distances', as well as 'time'. Defined from my view, which then will be a idea of 'locality' the local 'time/clock' always will be an invariant, a 'constant' coupled to 'c'. But if I then look at some other frame of reference like something moving relative me they will seem out of 'sync' with my definition of my clocks durations. And as the Lorenz contraction must be a 'symmetry' in my book, to make sense of what 'A' sees, relative what I see, then the question to me becomes one of what a 'distance' really is, as well as that time dilation.

If I define it from locality then what you see will be your reality, as what I see will be mine. The reason we find them different is conceptual, meaning that to do this we have to compare our frames of reference relative each other. What that states to me is that you at no 'time' or 'place' ever will find a contradiction, other than conceptually, when comparing.

But it doesn't answer the question of why it can happen, it just give me a reason, which then, to me, must be 'c'.

If distances and time is 'plastic' relative motion, mass (& energy, whatever that is), then SpaceTime is plastic. And the 'plasticity' is defined locally. But we also have this 'radiation propagating' (and gravity). Radiation is what you observe, all measurements are done through, and in, it. Radiation is the constant 'c' joining my definition of a 'distance' and a 'time' to yours through Lorentz transformations.

Gravity is something else, it's coupled to mass and to me representing a 'constant inertia' relative accelerated (uniform, but to me as I define it as inertia, all) motion. We define it in 'displacements' relative some positional 'point' (inside times arrow 'locally' defined). To see what I'm aiming on here we need to consider the equivalence principle, making all 'mass' constantly uniformly accelerating..

In fact, looking at this way there is no motion without a 'inertia' involved, at some stage, even though 'uniformly moving' at some later stage. That we can't define where that uniform motion came from doesn't state that there wasn't a 'inertia/acceleration/gravity' involved at a initial SpaceTime point. Although the idea of a 'inflation' makes it somewhat tricky.

And then we have mass.
And 'energy' as some weird idea of a 'ground state', as I see it.

But compare that to indeterminacy.