Question

Can virtual particles of the vacuum form most of the needed dark matter?

Answer 1

We can ponder the virual particles (also known as vacuum fluctuations) as ponderous, despite of the fact that they exist only virtually, resembling an energetic noise.  

As such they vanish almost immediately after arising, so they do not touch the energy conservation low. Or rather they do not touch its average level in universe.  

However, this average of as low density as it seems may form a gigantic input to the portion of lacking dark matter in the universe.