Two theories about the origins of atoms prevail. In the Big Bang theory, much nucleosynthesis took place moments after an enormous explosion. In the universe, atoms are synthesized in stars (from other atoms). Atoms are made from radioactive change processes. On earth, most of what you see is what you get. There are some radioactive atoms that decay. some atoms escape earth's gravity, or are shot away in space ships. Hundreds of pounds of atoms arrive from the sun, and meteorites and other objects fall to earth. Nevertheless, pretty much what we have is what we have. The alternative explanation is called creation theory .

Whichever explanation one accepts, there is little controversy about earth's collection of atoms. It took humankind up until about 200 years ago to accept the notion of atoms, and the ideas about atomic structure are just 100 years old. The ideas of nuclear structure are less than 100 years old, and contemporary scientists struggle to develop a synthesis of all known data into a single, satisfactory nuclear model.