JesseM
Science Advisor
- 8,519
- 17
SR, and the time dilation equation, do not say anything about "the speed of time", that's your misconception right there. The time dilation equation is about the rate of a clock as perceived in a frame where it's moving at speed v; nothing more. If you take two events on a clock's worldline and Δt is the time between them as measured by the clock, then naturally Δt is also the time between those events in the frame where the clock is at rest, where Δx for that pair of events is 0. If you plug Δx=0 into the Lorentz transformation equation Δt' = γ(Δt - vΔx/c2), you get the equation Δt' = γΔt, which is the time dilation equation (here Δt is the time between two events on a clock's worldline as measured by the clock itself, and Δt' is the dilated time between those same two events in an inertial frame where the clock is moving at speed v. So, in this frame the clock takes a time of Δt' to tick forward by a time increment Δt, and this is the only case that the time dilation equation was ever intended to cover).John Huang said:My point is a logical issue.
In above example, two systems have constant relative velocity so that the speed of time in the moving system t' and the speed of time in the stationary system t