One of my favorite YouTube series, Minute Physics, just released a fascinating video on the size of the universe. It boils down to this: we can observe a certain amount of the universe from Earth. When we observe stuff that's really far away, the light takes so long to travel to our eyes that by the time we see it, it's already moved far, far away. Earth within this huge observable universe (95 billion light years) is about the same scale as a teeny tiny virus is within our solar system. We are a TINY part of the universe.