Heliospheric shocks are being studied by in situ measurements while all shocks outside of the solar system are detected only due to the electromagnetic radiation produced by heated or accelerated charged particles. Heliospheric shocks have Mach numbers M ≲ 10 while astrophysical shocks may achieve M ~103. The incident plasma velocity in the heliosphere vu/c ~10-3, while supernova remnant shocks may have vu/c ~10-3 and gamma-ray bursts shocks are highly relativistic. Despite substantial differences in the key shock parameters, the basic common feature is the large scale electric field which develops within the shock. It is this electric field which decelerates ions and energizes electrons.