Black hole jets reach far beyond galaxies' visible edges, potentially deciding their fate

Galaxies are enormous and hold hundreds of billions of stars. These stars form from cold, dense gas. Every large galaxy, including the Milky Way, is wrapped in a huge envelope of gas called the circumgalactic medium, or CGM. This reservoir of raw material stretches 10–20 times the size of the visible portion of the galaxy.

Source: Phys.org