the other partial theories depend on quantum mechanics in an essential way. A necessary first step, therefore, is to combine general relativity with the uncertainty principle. As we have seen, this can produce some remarkable consequences, such as black holes not being black, and the universe not having any singularities but being completely self-contained and without a boundary. The trouble is, as explained in Chapter 7, the uncertainty principle means that even ΓÇ£emptyΓÇ¥ space is filled with pairs of virtual particles and antiparticles. These pairs would have an infinite amount of energy and, therefore, by Einstein's famous equation E=mc2, they would have an infinite amount of mass. Their gravitational attraction would thus curve up the universe to infinitely small size.
