FORBIDDEN NUMBER
18 / 21
The Anti-De Sitter Radius (Negative Cosmological Constant)
A negative number that our universe does not permit
WHY IT IS FORBIDDEN
Our universe has a positive cosmological constant (Λ > 0). A negative Λ would yield a collapsing anti-de Sitter spacetime — a geometry that is physically forbidden in our cosmos.
Anti-de Sitter space is central to theoretical physics (AdS/CFT correspondence) despite being physically unrealized in our universe.
Some numbers cannot be spoken · rotates daily