[throwawaytemp27]

That makes no sense to me. One particle goes in one direction at a particular velocity and another particle goes in another direction at another velocity. They diverge over time. When you travel through time, which particle’s path do you follow through space?

I often think along the gp’s lines and would love an explanation of why it’s wrong?

[Beldin]

It all depends on your point of view (literally, frame of reference). The Earth can be considered:

- stationery (geocentric observer)

- orbiting the Sun (heliocentric observer)

- spiraling about the Sun (galaxy-centric observer)

All of these are simultaneously correct and bonkers in conjunction. Hence, you need a frame of reference if you're specifying movement.