My physics friend suggested that "the answer to why matter exists in the universe" is because all massive particles are just the fabric of space excited into little packets. To illustrate, imagine a blanket on the ground. Then, pinch a small bit of the blanket and twist it. This is a particle that has mass.
It was intriguing to hear this (he's only studied up through Freshman year of college physics), but there are clear flaws (i.e. angular momentum of a "particle" tied to a "blanket"??).
Regardless, it made me wonder about vacuums. Is there any theory that suggests that a vacuum actually has energy in some form or another?
Best Answer
Particles are not regarded as bits of curved spacetime, but rather as excitations of quantum fields.
It has been suggested that spacetime curvature can cause structures that behave a bit like objects (though not fundamental particles) and these objects are called geons. However it remains unclear whether these would be stable. It also isn't known what impact quantum gravity effects would have on the formation and stability of geons.
The vacuum has a precise definition in quantum field theory and it has a mean energy of zero by definition. However we can have gravitatinal waves propagating where no matter is present, and there is an energy associated with these gravitational waves. You could regard this as a vacuum having energy, though normally we wouldn't call it a vacuum if gravitational waves are present. This energy is in effect the energy of the spacetime curvature, though this turns out to be a rather elusive quantity.