Classical physics In contrast to classical physics, "modern physics" is a slightly looser term which may refer to just quantum physics or to 20th and 21st century physics in general. Modern physics includes quantum theory and relativity, when applicable. A physical system can be described by classical physics when it satisfies conditions such that the laws of classical physics are approximately valid. In practice, physical objects ranging from those larger than atoms and molecules, to objects in the macroscopic and astronomical realm, can be well-described (understood) with classical mechanics. Beginning at the atomic level and lower, the laws of classical physics break
Voyage to the Bottom of the Sea radiation belts had only recently been discovered, and much of what the film says about them is made up for the film. Discoveries since then clearly invalidate what the film says: the Van Allen belts (actually somewhat more radiation-dense portions of the magnetosphere) are made up of sub-atomic particles trapped by the Earth's magnetic field in the vacuum of space and cannot catch fire, as fire requires oxygen, fuel and an ignition source, all of which are insufficient in the Van Allen Belts. Unburned hydrocarbon emissions have never reached concentrations that could support a "skyfire." The film's submarine design is