Isn't it facinating how humans are always amazed by tall skyscrapers, big machines, giant ships etc? It seems, our perception of size of every object is a function of awareness of our own dimensions. When we say, "Wow! Look at the size of this Elephant is?" we really meant how big is it compared to us. If we had to choose between a wrestler and a marathon runner to lift a huge log, we would bet on the wrestler without hesitation. Why? Because, in the physical world size does matter.
But, come to think of it, the word "big" is an ambiguity. Size is always relative. Size, like beauty, is in the eyes of the beholder. A person standing in a open field able to see the horizon is all directions will perceive our planet as a huge, never ending landscape of incomprehensible prortions. But, take the same man to the moon, and his perception of our planet will be very different. A blue planet with finite dimensions. View the same Earth from a distant star, it will be no more than a spec in the distance. That being the case, any object on this planet is not really big in the true scale of things.
The same holds true at the other end of the size spectrum as well. Imagine your self sitting on an electron revolving around the neucleus of an atom. This atom os one among many making up a molecule. There are millions of such molecule that make up the tip of a needle. For you, this subatomic world is your universe, a universe in another universe!
Dimensions of any physical object are relative in this existance. Only "thought" escapes this relativity. Perhaps this ability to think is what makes our existance "big" in the true sence of the word.