What are radio galaxies? | Space

A radio galaxy is a galaxy that dominates the sky over Earth in radiowaves. These bright radio wave emissions come from billowing lobes of gas that extend far beyond the visible structure of the galaxy, often for millions of light-years.

These radio lobes usually occur in pairs and are created when the heart of a galaxy is home to a so-called active galactic nucleus (AGN), an extremely bright region dominated by a supermassive black hole superheating and feeding on the surrounding material, causing it to glow.