From what I understand (armchair physicist here, having read Greene’s books and whatever I can find on the net) String Theory describes the fundamental particles and forces of nature in terms of the different modes of vibration of “strings” - Planck-scale extended objects. There’s also something about these strings being attached (sometimes?) to n-dimensional “branes”.
From what I can see, String Theory deals with what happens to the strings as they move through time, but contents itself with time being the mysterious background ticking of a cosmic clock. I know that time is neither a particle or a force – at least, I think I know that but no one seems quite sure of the exact nature of time – but if String Theory is truly a TOE, shouldn’t time emerge as one of its “results”, in the same way that particles and forces do? Is it the case that time is just accepted as an “axiom” in String Theory?
I’m a bit confused. Both in 10-dimensional string theory and 11-dimensional M-theory, time is one of the dimensions, with the rest being dimensions of space. They are both theories of “spacetime”, just as relativity theory is. (They must be, since relativity theory falls out of string theory as a special case.)
I think it’s true that string theory doesn’t explain, existentially, what time is, but it’s not true that it doesn’t include it.
Time is just an “idea” as it were. It does not exist as an entity. Time does not make a clock run. It runs as a result of it being mechanically driven. When a clock runs faster or slower it is not due to “time” magically having an effect on it.
Gravitational fields, wormholes et al do not have an effect on time, for it does not exist. They may however have effects on instruments which measure “time”, but that is not the same as effecting “time” itself.
Time is just our way of mapping the passage of events using a solid gauge.