Physics
Physics is the search for the simplest rules that explain how the universe behaves — how things move, how energy flows, and what space and time actually are. It spans scales from subatomic particles to the cosmos itself. Fathom starts with one deep thread through cosmology, and grows outward from there.
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Cosmology
The physics of the universe as a whole: its origin, expansion, contents, and fate.
Radiation
Energy on the move — as electromagnetic waves or fast particles — including the emissions from unstable atomic nuclei.
Relativity
Einstein's two theories of space, time, and gravity — special relativity for uniform motion, general relativity for gravity as curved spacetime.
The Two-Body Problem
Two masses bound by gravity trace predictable ellipses around their shared centre of mass — the one gravitational problem we can solve exactly, and the home of the Lagrange points.
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