Does dark matter in the universe acts as a pulling force or a pushing force?

Scientists have claimed that in this world there are two kinds of forces which help in keeping everything in its place called dark matter and dark energy. But are these two forces act as a pulling force which pulls the universe or pushing force which pushes the universe.Also lights bend when it passes through these forces so is pushing this light beam away or pulling this light beam near itself.

Which scientists have called dark matter and dark energy forces? Dark matter is a form of matter that doesn't feel any force other than gravity (so far as we have observed). It's true that dark matter bends light because it has mass and it makes up about $5/6$ of all the mass in the universe. The gravity from this mass is what bends light through gravitational lensing (like a magnifying glass made of gravity and without a focal point). So in a way, this gravity from dark matter acts as a pulling force; dark matter itself though is not a force.

That said, nothing is keeping everything in its place; things are constantly moving around and (usually) flying away from everything else. Dark energy is also not a force, it is an unattributed type of energy that happens to have a negative pressure and so it drives accelerated expansion of the universe. But it is not a pushing force and in a flat universe, it does not bend light.

• What kind of acceleration is it and is there any mathematical model for it – sayan chattopadhyay Nov 12 '14 at 16:10
• @sayanchattopadhyay there are many complex models for it and it is asymptotically exponential acceleration – Jim Nov 12 '14 at 16:15