We can say it — but only partially, and with some important nuance.
✦ The Short Answer:
Supermassive black holes influence, but do not fully determine, the formation and evolution of galaxies.
Their role is powerful, but it is not the only driver. Galaxy evolution is a dance of gravity, dark matter, gas, star formation, mergers, and feedback — and the black hole is a key (but not sole) partner.
✦ The Long Answer: What the Black Hole Does
1.
Co-evolution
: The galaxy and its black hole grow together
- The mass of the central black hole is strongly correlated with the mass of the galaxy’s bulge (the M–sigma relation).
- This suggests a coevolutionary process: as the galaxy grows, so does its central black hole — and vice versa.
2.
Feedback mechanisms
: The black hole regulates star formation
When the black hole actively accretes matter, it becomes a quasar or active galactic nucleus (AGN). In this state:
- It emits enormous energy — radiation, particles, and jets.
- This energy can heat or expel surrounding gas, preventing it from cooling and forming stars.
- This process is called AGN feedback, and it may:
- suppress star formation (“quench” the galaxy),
- or trigger it, by compressing gas in certain regions.
3.
Influence on galaxy structure
- The black hole may shape the inner structure of the galaxy (e.g., nuclear bulges, or even bars).
- But its influence does not extend to the outer regions of the galaxy (e.g., spiral arms), where dark matter dominates the dynamics.
✦ What the Black Hole Does
Not
Do
- It does not initiate galaxy formation in most models.
- It does not govern the full galactic rotation — its gravitational domain is limited to the central few light-years.
- It does not shape the halo or spiral arms directly.
✦ Summary Table
|
Role of Black Hole |
Effect on Galaxy |
|
Co-evolution |
Correlated growth with bulge |
|
AGN Feedback |
Regulates star formation |
|
Gravitational Influence |
Dominant only in central region |
|
Structural Role |
May affect inner morphology |
|
Rotation & Outer Dynamics |
Not controlled by black hole |
✦ Philosophical Resonance
The black hole is not the tyrant, but the dark heartbeat.
It breathes energy into the galactic core, but does not dictate every motion.
The galaxy is not a satellite of the black hole — it is a companion, born in the same cosmic storm.
✦ So can we say…?
Yes, you might say:
“The dynamics of the galaxy’s evolution respond to the black hole within it — but are not determined by it. The black hole is not the origin of everything, but it is the interior abyss that shapes the destiny of light.”
If you’d like, I can help you compose a short piece titled:
「星系之心：黑洞如何呼吸出宇宙的演化」
or
“Abyss and Spiral: On the Quiet Power of Black Holes in Galaxy Formation”
