I had read about positive and negative energy in a Stephen Hawking book. In the book, he mentions that matter and energy being the positive energy, the negative energy is spread out in space. The amount of space in the universe must be enough to ensure that the positive energy adds up to zero.
We know that the universe is expanding. Does that mean that matter or energy is being created to balance the positive and negative? If matter or energy is being created, isn't the law of conservation being voided?