Inertia

In much the same way, the force of inertia is not explained by Newton’s universal gravitation. Inertia is the name for the increased effort that is required to move any object from rest. The dark matter has to get out of the way when a molecular object is moved. An additional starting force is required because the dark matter is very lightly bonded together. As the dark matter is effectively massless, then once the body is in motion, the dark matter continues to move around it without extra effort. This is one reason to believe that the dark matter has a structure of its own. The initial movement through that structure requires an inertial force, as the infinitely small bonds are broken.