length and time are discrete (granular)?

I think space and time [which is one and the same thing because you can convert one to another by just going fast! and light speed connnects the length and time - in fact that's how unit of length is defined nowadays] ultimately has to be discrete.

Think about this:
How do we measure time?
By some periodic process like sunrise or motion of pendulam or nowadays oscillations of quartz crystals etc.
Notice that we are gradually improving the smallest unit ["quantum"] of time we can measure.

In fact time is nowadays defined as:

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.

So currently it is smallest unit of time we can measure roughly 10^-10 of a second.
Breathtaking by human standards but think about it:
it is only mere 10 positions after decimal point. To goto continous time we need millions and millons of digits!

But any physical periodic process will have an ultimate period. Pick the smallest of such a process. That has to be the smallest unit of time with any meaning. what does it mean to say 1/2 of that time? 1/10 of it? how do you measure, "feel" it? what about √2 part of it?
To me period of that process is the ultimate quantum of time.

In fact in my view, real numbers themselves are huge mathematical abstraction living in plato's world. It is no better [in fact worse] than complex numbers!

Now since time is discrete, space has to be too.