  We estimate the stochastic gravitational-wave background arising from all
stellar core-collapse events in the universe based on the gravitational-wave
signal predictions of recent numerical simulations. We focus on waveforms from
slowly or non-rotating stars and include rapidly rotating, highly massive
progenitors as extreme case limits. Our most realistic estimates are more than
one hundred times below the sensitivity of third-generation terrestrial
gravitational-wave detectors and likely weaker than cosmological contributions
to the stochastic gravitational-wave background.
