[vlovich123]

Stupid question I’m sure, but do our estimates for the total amount of matter in the universe account for this effect? Could this effect end up being the source of dark matter? Or is too infrequent to generate enough matter to explain the discrepancy?

[whatshisface]

If by "this effect" you mean particles fluctuating so that every field has at least some role to play in every interaction, it also applies to empty space, which has a nonzero energy density due to its own fluctuations. In fact, empty space has an enormous energy density due to this stuff. It is so enormous that it's implausible, and that's considered to be one of the major unsolved problems in physics.

If by "this effect" you mean radiation occasionally interacting to produce particles, that actually doesn't change the amount of gravity in the universe when it happens, because energy is what gravitates and it's conserved in particle interactions.

https://en.wikipedia.org/wiki/Cosmological_constant_problem

[jdbburg]

Not a stupid question. However, I think that this process (whether it is included in calculations or not) shouldn't contribute to the dark matter issue. Electrons and positrons are "normal" matter and if they are anywhere near e.g. a star, they will contribute to the plasma around the star and therefore be visible. Also, even if it were not visible, my intuition is that the process is too rare to produce enough mass to account for the dark matter

[simonh]

Best estimates are that photons only make up about 0.005% of the energy density of the universe. There's just not enough of them.