I've just started learning about special relativity. Apart from realising that everything I thought I knew about reality was a lie, I'm trying to wrap my head around a few concepts relating to the fundamentals of spacetime.
My current understanding:
The units of spacetime are absolute and are called spacetime intervals, which can be spacelike/timelike
- Space and time can be considered components of spacetime - therefore we can think of time as a 'temporal distance'
Everything is travelling through spacetime at a constant speed: the speed of light
- Spatial and temporal speed can be considered components of spacetime speed
- I've found the concept of distributing this constant spacetime speed to spatial and temporal speed helpful, e.g. increasing your spatial speed will decrease your temporal speed
However, I'm still having trouble with a few issues.
- How exactly do we measure temporal speed?
I often see the language used of 'your clock ticks slower' in relation to time dilation, but I don't understand exactly what this actually means. For instance, when we say that you move through space slower, it is referring to the fact that less spatial distance in e.g. m is covered per unit time. Similarly, what units are being discussed in phrases like 'A's clock ticks once every two seconds'? Does it mean that one unit of proper time passes every two seconds of coordinate time or vice versa? What exactly are the units of temporal speed and how do clocks represent this?
- How can time dilation be related to length contraction?
When considering time dilation, I've thought of it as decreasing temporal speed in order to increase spatial speed. But when applying the reverse to space, it seems to me that increasing spatial speed should result in some sort of length dilation and not contraction. How can I understand this concept using the approach of distributing speed to time and space respectively?
Geniuses of the internet, please enlighten me.