  We compute the CMB angular power spectrum in the presence of a radiation-like
solid - elastic matter with the same pressure to energy density ratio as
radiation but with nonzero shear modulus. For the values of shear modulus that
are close enough to zero, so that the effect of the solid on large-scale
anisotropies remains within cosmic variance, we find that there is an
observable effect of the solid on small-scale anisotropies.

General Relativity and Quantum Cosmology