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LordRobin------RM t1_j27885y wrote

Reply to comment by s1ngular1ty2 in Black hole question by Impossible_Pop620

I thought it was tidal forces, not the simple strength of the gravitational field, that destroyed objects as they passed the event horizon. I’ve read several times that you could fall into the event horizon of, say, a supermassive black hole and not feel a thing. The event horizon for a black hole of that size is so far away from the singularity that tidal forces are almost non-existent.

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PhobosDown t1_j27b0xy wrote

Exactly right - the more massive the black hole the gentler the tidal forces at the event horizon.

For example, stars can be torn apart by a million solar mass black hole, creating tidal disruption events that have been observed in synoptic surveys. At a billion solar masses though, the black hole swallows stars whole because the tidal forces aren’t strong enough to disrupt the star before it enters the event horizon.

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LordRobin------RM t1_j27s8do wrote

Wow, has this been observed?

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PhobosDown t1_j29t44q wrote

Tidal disruptions have been, yes. They are also simulated in supercomputers and they were predicted decades before they were observed!

The direct “swallowing” of a star by a billion solar mass black hole has not been observed. One way to think about it is this event would just involve the center of the galaxy decreasing in brightness by 1 star’s worth, whereas a tidal disruption event is like fireworks - a lot of energy gets released and if we happen to have a telescope checking on that galaxy at least every few weeks, we’ll see it.

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LordRobin------RM t1_j2c1e4h wrote

Right, now that I take the time to think about it, a “swallowing” wouldn’t look exciting at all, even observed from within the galaxy. The doomed star’s light would just red-shift as it approached until the wavelength was unobservable.

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s1ngular1ty2 t1_j27alyq wrote

His entire premise is laughable at best so I'm not going to waste more time explaining why your misconception is also wrong.

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