Even if our basic theory is that economy is elastic in response to nominal stress and plastic in response to real stress, a sudden change in rigidity combined with a large nominal shock could cause a very large plastic deformation in the economy.

FORBES: NGDP in the Long Run and Economic Plasticity

Unlike large glass mirrors which are subject to the vagaries of humidity, thermal dynamics and constant deformation from gravity itself, liquid mercury which remains molten at room temperature can reflect as much as 75 percent of incoming starlight with little of the fuss associated with large conventional mirrors.

FORBES: Liquid Mirror Telescope Technology Finally Going Mainstream