Does empty space have energy?

Question

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?

Answer 1

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.

Answer 2

Does empty space have energy? Yes. See Vacuum Energy, and Dark Energy, which is driving the expansion of our universe.

Answer 3

Yes empty space does have energy.When you apply quantum mechanics and special relativity, empty space inevitably has energy. The problem is, way too much energy. It has 120 orders of magnitude more energy than is contained in everything we see!

Answer 4

After looking at the other answers and comments, I understand the question little bit better now. So, will take a shot at it.

The question is about own energy of vacuum/space, not about the energy spread in space from big bang etc. There is a difference between the two.

Just like many other questions, this also needs looking at gravity.

Gravity is curving of space in presence of mass/energy. Right?

If space curves in presence of mass, then mass and space must be interacting in some way. Without interaction, the curving would not be possible.

If space is capable of interacting with mass/energy, it has to have its own properties. Can something have properties without having any energy?

I would think empty space has its own energy. Otherwise gravity won't be there.