the CMB power spectrum tells us

Cosmic inflation

Cosmic inflation explains the universe's uniform temperature

Friedmann equations

Friedmann equations govern cosmic expansion in homogeneous and isotropic models

Symmetry (physics)

Symmetry leads to energy conservation

Time dilation

Clocks run slower in stronger gravitational fields

Renormalization group

Renormalization group (RG) explains physics changes with observation scale

Riemannian geometry

Riemannian geometry is essential for understanding curved spacetime