There is only one reality and that is what exists above and beyond the dividing timeline--Heaven, God's eternal light. And each year when we celebrate the Birth of Christ, leading to the Passion and Resurrection, we acknowledge His timelessness
Time is subjective.
No physics, relativity, quantum mechanics, or string theory will be found here because, honestly, they aren't part of this vernacular.
All the chalkboards of the world filled with equations characterizing energy and mass reflect society's penchant for defining and classifying what it sees and experiences to fit its limited perspective. That's right, humanity limits the universe even while trying to imagine a bigger box that scientists believe they are "thinking outside." No matter how you look at it, it's still a box. A box that contains light and time. Except God, who created light and time, can't be contained.