Spherically symmetric
Spherically symmetric spacetimes are a class of spacetime with a group of isometry parametrized by $\textrm{SO}(3)$, with orbits $S^2$.
1. History
2. Topology
3. Metrics and coordinates
The most general metric form for spherically symmetric spacetime is given by
$$ds^2 = -e^{2\nu(r,t)} dt^2 + e^{2\lambda(r,t)} dr^2 + Y^2(r,t) \left[ d\theta^2 + \sin^2 \theta d\varphi^2 \right]$$4. Tensor quantities
5. Symmetries
By definition, spherically symmetric spacetimes admit at least the symmetry group $\operatorname{SO}(n)$