What Does Hawking Mean by Negative Energy at the Big Bang?

[Physics Slayer]

I was reading "Brief answers to big questions" By Hawking, the above pic is from a page of the book, it says that at the time of the big bang there was an equal amount of positive and negative energy, and that the negative energy never went anywhere, the space-time itself is a store of negative energy! I don't really understand what he means by this. In all fairness he does go on to admit that without mathematics this idea is hard to grasp.
can someone try to explain the above in the best way they can (with or without math) or lead me to resources to further dwell into.

Thanks

 

[jbriggs444]

Hawking did here the best that he could to express without mathematics something that cannot be properly expressed without mathematics. What you are looking at, even though it was written by a respected scientist is a popularization. It is an attempt to give you a taste. Popularizations, generally, are not usable as a basis upon which to reason one's way to a proper understanding of the subject matter. Better to work from a textbook.

The idea of energy conservation that is being relied upon here is on shaky ground to begin with.

https://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html