Microquasar artwork. A microquasar is a small black hole orbiting a larger star. The black hole sends out fast jets of plasma (one seen, blue, lower centre to top right) from its poles. Its immense gravitational pull sucks matter from its companion star (blue), forming an orbiting accretion disc (white, lower centre) around the hole. This emits X-rays as it rotates faster and gets hotter as it nears the hole. The jets emit radio waves, and are similar to those seen emitted from quasars. A quasar is a supermassive black hole found at the centre of some active galaxies which makes the galaxy's nucleus extremely bright.