The Dobler Effect

We know that the universe is expanding, but what is causing this? Just as blowing a balloon up requires air, so does our universe have a force pushing it outward? Physicists thus call this force in empty space dark energy. But they still can't explain where this propelling force comes from or even what it really is. In addition to this mysterious energy, scientists have also discovered that most of the universe is invisible. So how did we discover these strange pieces of the universe? Calculations to determine the rotation rate of our universe show that there must be more mass than we can see. The observable univer just isn't heavy enough to cause the speed at which we are rotating.