This image from an online Italian newspaper shows photographs of one of the most powerful phenomena in the cosmos.
Nothing, not even at the speed of light $c$, can escape a black hole one it has been caught. So how is it possible mathematically that a black hole, which "swallows" the stars and gas approaching its powerful accretion disk, can then eject some of the gas into two thin jets of plasma at speeds $V_{pl}$ close to the speed of light?
The black hole is defined by its event horizon. This is the point at which the escape velocity reaches $c$. But the accretion disc forms outside the event horizon, so stuff can still escape from it. It is this outer stuff that finds its way into the jets, super-accelerated beyond escape velocity by magnetic fields being dragged round the hole.
If the escape velocity at the point of acceleration outside the black hole is $V_s$ then $c > V_{pl} > V_s$.
