  Cosmological shock waves are induced during hierarchical formation of
large-scale structure in the universe. Like most astrophysical shocks, they are
collisionless, since they form in the tenuous intergalactic medium through
electromagnetic viscosities. The gravitational energy released during structure
formation is transferred by these shocks to the intergalactic gas as heat,
cosmic-rays, turbulence, and magnetic fields. Here we briefly describe the
properties and consequences of the shock waves in the context of the
large-scale structure of the universe.
