One of the constant things that one encounters in the world of science is idealization.

A theory of everything has been the Holy Grail of some of the greatest physicists of the last century, from Albert Einstein to Stephen Hawking. A theory of everything, a single, all-encompassing theoretical framework which would be able to explain, coherently explain and link together all the physical aspects of the universe, from the atomic scale to galaxies, from the choppiness of the quantum world to the smoothness of relativity.

According to NASA