What was existing 13.9 billion years ago?
WfJc: assuming that there are inviolate universal laws, like the infamous " perfect human life to be sacrificed" applying in all domains, , ( tongue firmly in cheek here) , then
some natural laws reach back in time beyond the BB. ( Penrose, Krauss) example:
Energy is indestructible and can not be created. therefore:
minus 13.9 bys,and counting backward? it was energytime, eternal energy existing in timespace,
now we have "coffeetime, teatime" , Einstein's spacetime.
The Big Bang happened only at a single point in time, but time as a dimension stretches indefinitely in all directions, always has, always will.