Have we actually proved scientifically there's a force or physical matter acting on something and it's not just being obscured from our vantage point?
-- In the case of dark matter, the answer is yes. Dark matter has been indirectly observed from the gravitational lensing of the dark matter shrouds surrounding galaxies - notably in situations where the shrouds of two colliding galaxies separate from the galaxies themselves. It's a "picture" as exact as many things astronomers have observed.