The Permissible Universe
A map of everything that can exist
An interactive mass-radius diagram showing ~200 cosmic objects from quarks to supermassive black holes, positioned according to fundamental physical limits. Click any object or boundary line to learn more.
This visualiser maps 200+ cosmic objects and is best experienced on a larger screen.
The Four Limits
The universe permits only certain combinations of mass and size. These four boundaries carve out the "permissible" zone where matter, energy, and structure can exist.
Where They Meet
The Schwarzschild and Compton lines intersect at a single point: the Planck mass (~22 micrograms). This is the only mass where an object could be simultaneously a black hole and a quantum particle. It marks the boundary where general relativity and quantum mechanics must somehow merge - the domain of quantum gravity, still not fully understood.
The Big Questions
The Permissible Universe isn't just a map - it's a window into the deepest mysteries of physics.