The universe is mostly vacuum. In the remote regions between galaxies, you would be lucky to find a single atom in a space the size of the Louisiana Superdome. The atoms are packed more densely in our own world of solids and liquids and gases, but even here it is not as crowded as you might think. A close-up of an atom would reveal that the nucleus, which carries 99.9 percent of the weight, hovers in the center of the atom like a BB suspended in the Superdome; except for a few electrons that waft about the stadium like ghostly gnats, the rest is empty space.
So since we and our world are made of such insubstantial stuff, it is surprising how much thought and energy (not to mention money) scientists spend trying to unravel the riddle of matter. Shouldn’t they be worrying instead about the nature of the vacuum, ...
