In other words, we can't be very certain about our position and at the same time about our velocity. That's what the uncertainty principle tells us. And this has to do with the duality nature of subatomic particles, electrons and protons, as well as a duality of light. In other words, when you go from a large ball from this ball to a subatomic particle, our particle loses its solid sphere like properties. It stops acting like a solid sphere and starts acting more like a wave. And therefore, we can no longer pinpoint exactly where our object is and at the same time, what its velocity is, what its momentum.