It makes sense that the equations do not contain a time variable within the context of loop quantum gravity as Prof. Rovelli explains it. The granualarization of spacetime seems to negate the need for a time variable at the planck unit scale.

To replicate GR or even SR, it should be possible to derive from the equations that time is also quantised at the same level, thus although it is the area of foam cell boundaries that takes discrete values, those should be seen as equally products of Planck lengths or with Planck times. In GR there is no preferred frame so we cannot say whether any area boundary is spatial or temporal, they are not inherently distinct.

I think that time is not fundamental …. at least not a dimension equivalent to the 3 dimensions of space… it is relative to some cycle… either in Caesium or in the solar system… what is the definition of a second.. the time taken for some specified transitions in caesium… THOSE TRANSITIONS DEFINE A SECOND, THEY ARE NOT CAUSED WITHIN A SECOND…

SORRY😅😅😅STILL AN UNDERGRADUATE…

Yes, I think that the time is a label that describes a cronological order of events, but this order is not fundamental. In the probabilistic view (second law of th.) the entropy grows as the time goes on, but this assertion is statistical only. In a fundamental way, we can not build a clock to stablish a temporal order in the cosmos. But this label is usueful when we split the behavior of systems in order to describe them. The dynamical systems are good examples of these.

It makes sense to me because for example, when we calculate distance using speed and time, we didn’t actually use a distance variable. There may also be other ways that we could calculate distance using distance variable.

I guess time is emergent, just like space, and both of them are probably just a way of describing the relationship between some “fundamental nodes” of reality. It could be that fundamentally the quantum fields (or whatever their ontology is) are “what’s real” and then if you describe their relationship (for example as a measure of entanglement) then you end up with what we classically call space and time.

Yes. I believe that ‘time’ is a local property (of the quanta) because when LQG quanta interact there is a before-interaction-after. This means that there is a causal relationship (in the interaction). To be shown is how ‘time’ as we know it emerges from local time.

I am not sure that time as it is popularly understood is very relevant.
I get into a car at at home and wake up somewhere else – just two events that relate as a sequence – however the driver of the car experiences many more sequential events over the same journey. Time would be perceived very differently from each of these perspectives… But causality would still be maintained.

Stated before, time is emergent, not fundamental. It is not in gravitational equations.

So the semantic of the word spacetime becomes only space.

This does seem a divorce.

Time is not required for what the math is describing so no not necessary.

In the context of Loop Quantum Gravity (LQG), it does indeed make sense that the equations describing the structure of spacetime do not include a separate time variable in the same way that classical physics or general relativity do. This feature is a fundamental aspect of LQG and is known as the “problem of time.”
In LQG, spacetime is discretized into discrete units, and the theory describes the quantum properties of these discrete structures. Unlike classical physics or general relativity, where time is treated as an independent and continuous parameter, LQG treats time differently. Time, in LQG, is typically treated as an emergent concept rather than a fundamental one.
One of the key insights of LQG is that the equations of the theory are formulated in terms of certain operators that act on quantum states, such as the Hamiltonian constraint operator. These operators encode the dynamics of the theory and govern how the quantum states of the discrete spacetime evolve. However, these operators do not have an explicit time variable in the same way that classical Hamiltonians do in classical mechanics.
Instead, LQG incorporates the concept of “evolving relational observables.” These observables represent the relative relationships between different parts of the quantum spacetime. They describe how one part of the quantum geometry is related to another part and how these relationships change over “time.” In this sense, time is defined through the relationships between these observables, and it emerges from the dynamics of quantum geometry.
This approach to time in LQG is quite different from the classical notion of time as an absolute and independent parameter. It reflects the fact that in a quantum theory of gravity, the structure of spacetime itself is expected to undergo quantum fluctuations and changes at the smallest scales, which challenges the traditional notion of time as an external and unchanging background.
So, in summary, it makes sense in the context of Loop Quantum Gravity that the equations describing the structure of spacetime do not include a separate time variable, as time is treated as an emergent concept arising from the relationships between quantum observables rather than a fundamental and independent parameter.