Final answer:
The end of the quasar stage in a galaxy is not simply due to a black hole consuming all surrounding matter. Instead, the decline in quasar activity is related to the balance of matter accretion and the energy effects on the host galaxy. As matter becomes less available and the black hole's impact disperses feeding material, the quasar dims.
Step-by-step explanation:
The statement that quasar activity ends because the central black hole swallows up all the matter around it is false. Quasars, which are active galactic nuclei, are incredibly luminous objects powered by supermassive black holes at the centers of galaxies. The life cycle of a quasar is influenced by the balance between the black hole accreting matter and the impact of the energy emitted by the quasar on the surrounding galactic material.
A supermassive black hole gathers material from its host galaxy, forming an accretion disk. This process emits tremendous amounts of energy and can affect the gas and dust within the galaxy. Over time, as the available matter is consumed or dispersed, the quasar's luminosity diminishes, but not solely due to the black hole consuming all the surrounding matter.
There are several reasons for a decline in quasar activity. For one, the rate at which material falls into the black hole can decrease as the surrounding matter is exhausted or as stellar winds and outflows from the black hole disperse the feeding material. Furthermore, the ratio of the black hole’s mass to the mass of the surrounding galactic bulge suggests a mechanism that limits the black hole's growth, keeping the mass of the black hole at about 1/200 of the mass of the galactic bulge. Eventually, the black hole enters a quiescent state, where occasional disruptions, like a passing star, can cause temporary flare-ups in quasar activity but do not sustain it indefinitely.