system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If the Big Bang theory is correct, how could nothing exist before the universe existed? What existed before the universe existed?

I know it would be hard to explain to a 5 year old. Just want a better understanding.

EDIT: question is somewhat unclear. How can nothing exist? What does it mean for nothing to exist?
gpt
1. The big bang only addresses the very early universe, and not the origin of the universe.

2. Since time is a dimension of the universe, the phrase "before the universe existed" makes about as much sense as "north of the north pole".