Almost every substance we know originated in stars

The early universe was largely made up of hydrogen and helium which combined to create stars. When stars reach a certain size, nuclear fusion forces atoms together to create heavier elements such as carbon and oxygen. Almost all the other chemical elements were forged inside stellar interiors, supernova explosions, the cores of massive stars, or stars merging. 

Atoms are primarily made of empty space

An atom is composed of an electron, or electrons orbiting a nucleus of protons and neutrons. It is held together by the electrostatic force. Most of an atom is empty space. If an atom were about as big as a baseball stadium, the nucleus would be the size of a pea in the very center and the electrons would be somewhere on the outside edge.

The properties of all substances are defined by the atomic structures they build

Every substance we know is made up of atoms arranging themselves and bonding together in different ways. Solid things are structured in a tight, neat, order. Gasses in loose, less structured ways.

The universe is primarily empty space too.

Actual physical matter only makes up 5% of the known universe and that is primarily made of empty space. The other 95% of the universe is made up of unknown and unmeasurable substances called dark matter and dark energy. 

I’ll add more facts that amaze me here as I find them. Add your own in the comments!