Tau.Neutrino said:
I have a question about expansion.
All these virtual particles, they pop into and out of
existence all over the universe,
That’s a lot of space time activity,
All across the universe, all the time, on an on going basis.
Are so many particles appearing and disappearng having
an effect on the expansion of the universe?
They pop into and out of existence in very square meter
of the entire universe.
The universe must feel that,?
In a sense it’s the other way around.
As the universe expands, there is more space for these virtual particles to pop into and out of (for appropriate definitions of space). When the universe was very young, such as during the inflation era, it was too small for any virtual particles to exist (for appropriate definitions of small).
As for virtual particle self interactions and the effect that they have on space. The predominant interaction is creation and annihilation. That has a neutral effect on space. The second most important effect is attraction, when a particle pair is created, they electrostatically attract one another (more than they electrostatically repel) and gravitationally attract one another. This is why in early cosmologies it was believed that the expansion of space was slowing down. The uncertainty was by how much.
Until hard data came in and it was found that the expansion of space was speeding up. Extra energy was coming from somewhere. Latent energy like the latent energy of phase transitions condensation and freezing.