Almost all of the ordinary matter (99.9999999% of it) is empty space. If you took out all of the space in our atoms, the entire human race (all 7.7 billion of us) would fit into the volume of a sugar cube.
Some days, you might feel like a pretty substantial person. Maybe you have a lot of friends, or an important job, or a really big car.
But it might humble you to know that all of those things – your friends, your office, your really big car, you yourself, and even everything in this incredible, vast Universe – are almost entirely, 99.9999999 percent empty space.
If the nucleus were the size of a peanut, the atom would be about the size of a baseball stadium. If we lost all the dead space inside our atoms, we would each be able to fit into a particle of dust, and the entire human species would fit into the volume of a sugar cube.