As ShreevatsaR says, the question is meaningless in the context of physics. So here are other examples with until where the time boundary can be interpreted:
To my ear, I was at the office until 5 PM includes the boundary -- it implies I was at the office at 5 PM. I won't see you until I get home, on the other hand, seems to me to allow situations in which I'll see you as I get home, thus excluding the boundary. Reasonable people may disagree.
Depending on the context, until now can include or exclude now:
Expanding the company will change what until now has been a friendly culture.
Until now, scientists didn't know why gravity matters.
Until today and until tomorrow both change their situation at some point during the boundary condition/day.
Summary: until has no specific effect on the boundary. The boundary determination, in the rare cases where it has a meaning, is a semantic and contextual issue of the sentence, rather than of until.