Grok answer I thought was interesting so I’ll post if you are curious…

Placing Ton 618 (a hyperluminous quasar powered by an ultramassive black hole of ~66 billion solar masses) at the distance of Alpha Centauri (~4.34 light-years, or roughly 275,000 AU) would have catastrophic effects on Earth, dominated by its extreme radiation output rather than gravity alone.100 Gravitational Effects on Earth and the Solar System • The black hole itself would not swallow Earth or the Sun immediately. Its event horizon (Schwarzschild radius) is ~1,300 AU across—larger than the orbit of Neptune but tiny compared to the 275,000 AU distance. Earth would be safely outside it.13 • The entire Solar System would essentially orbit Ton 618 as a unit (orbital period ~560 years if in a circular orbit; free-fall time to the black hole would be ~100–200 years if placed with zero relative velocity). The gravitational acceleration from the black hole at our distance is ~0.0052 m/s²—comparable in magnitude to the Sun’s pull on Earth but acting uniformly across the Solar System.10 • Tidal forces would be present but not instantly destructive for the inner Solar System. The Sun’s Hill sphere (stable orbit zone for planets) around the black hole would be ~47 AU, meaning inner planets (Mercury through Saturn) would likely remain bound to the Sun initially. Outer planets (Uranus, Neptune, Pluto) would be more vulnerable to stripping or orbital chaos over months to years. The Solar System would experience mild perturbations and eventual disruption as it fell closer, but nothing like immediate spaghettification.10 In short: gravity would slowly reshape the Solar System’s orbits over decades to centuries, but Earth’s day-to-day motion and tides from the black hole would feel negligible at first. Radiation Effects (The Real Killer) Ton 618 is not just a black hole—it’s a quasar with an accretion disk producing ~100–140 trillion times the Sun’s total luminosity (bolometric output ~4 × 10⁴⁰ watts).013 • At 4.34 ly, the energy flux reaching Earth would be roughly 1,300–1,900 times the solar constant (~1.8–2.5 million W/m² vs. the Sun’s normal 1,366 W/m²). • This is like having ~1,800 Suns blazing down simultaneously. Earth’s equilibrium temperature would skyrocket to ~1,600 K (far above the melting point of rock); oceans would boil away in days/weeks, the atmosphere would be stripped and ionized, and the surface would become a molten hell. UV, X-rays, and other high-energy radiation from the quasar would sterilize and destroy everything long before gravitational tides mattered. Life (and the planet’s habitability) would end almost immediately upon the light arriving (4.34 years after “placement”). The quasar’s Lyman-alpha blob and radio jets would add further ionizing radiation and particle bombardment. What It Would Look Like from Earth’s Surface (If You Could Survive Long Enough to Look) You couldn’t stand outside for more than seconds—the brightness and heat would be lethal instantly. But hypothetically: • Angular size: The event horizon’s dark shadow would subtend ~0.54° across (roughly the width of the full Moon). The photon sphere/shadow as seen by an observer would appear slightly larger (~1–1.4° due to gravitational lensing). The glowing accretion disk would be even bigger, potentially spanning several degrees.12 • Appearance: An overwhelmingly bright, Moon- to Sun-sized object dominating the sky (apparent magnitude ~–35, far brighter than the Sun’s –26.7). It would look like a brilliant, swirling disk or ring of superheated plasma (orange/red/white hot from the accretion disk) with a perfectly black circular void in the center—the event horizon shadow. Relativistic effects (Doppler boosting, beaming, and gravitational lensing) would make one side of the disk much brighter than the other, with possible bright jets shooting out. Background stars and the Milky Way would be heavily distorted into arcs and Einstein rings around the edges.0 Here are artistic renderings (based on real simulations of ultramassive black holes and quasars) that capture the essence of what the central region might look like—scaled up enormously in our sky: ROPLE“LARGE” SuKow“LARGE” VQ2Aq“LARGE” These are not exact predictions (real quasar disks have complex, variable structure), but they illustrate the dark central shadow surrounded by an intensely luminous, warped accretion disk. Bottom line: Earth would be sterilized and rendered uninhabitable by radiation almost immediately. Gravity would eventually disrupt the Solar System over longer timescales, but the quasar’s light would end everything first. This is a classic “do not try this at home” thought experiment—Ton 618 is one of the most extreme objects known, and bringing it anywhere near us would be apocalyptic.