Why is the universe full of spinning objects? Almost all celestial objects are rotating in some way about their axes. Why is this and should we expect the rotation to slow as the universe ages?
The MinutePhysics channel on YouTube made a wonderful short animation that answers your very question. It explains how a cloud of gas and dust with zero net angular momentum collapses down to form a flat spinning object such as a galaxy or our Solar System.

The answer involves a few things:


The universe conserves angular momentum in every interaction between
physical objects.
Mathematics says a big cloud of gas and dust must have exactly one plane in which the overall angular momentum is zero.
When particles of gas and dust collide, any angular momentum they have outside that plane is cancelled, so over millions of years and (countless numbers of collisions) the cloud ends up flattening.
But as they collide, their angular momenta within that one plane are
conserved, so the flattened system ends up spinning.