Physics plays on different *length scales*, from millions of kilometers (stars and galaxies) down to the scale of single atoms (tens of nanometers). Depending on the length scale, different physical theories play a role. While gravity is essential for galaxies down to humans, it is much less relevant on the scale of single [[Atom|atoms]] or molecules. [[Quantum Mechanics|Quantum mechanics]] starts to play a role on the nanometer scale all the way down to femtometers and below. ![[length_scales.excalidraw.light.svg]] >[!read]- Further Reading >- [[Quantum Mechanics]] >- [[Time Scales]] >[!ref]- References