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I know there are stars much larger than the sun and that we've discovered "small" black holes, so, let's say that the Pistol Star, which is at least 80x the mass of the sun, and the smallest known black hole, XTE J1650-500, around 4x the mass of the sun, collide. Would the pistol star "eat" the black hole, or is there some property that a black hole has that is immune to the star's power?

I would think that the star would turn the black hole inside out, and like explode or something, but there's also the possibility that once a black hole rips space time the way it does maybe that can't be easily undone. I'm assuming the matter within the black hole isn't going to magically pop back into existence either as it's been broken down into it's most basic parts.

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    $\begingroup$ The black hole would win. Black holes always win when they come into contact. $\endgroup$
    – userLTK
    Mar 26, 2018 at 13:58
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    $\begingroup$ @userLTK that's not strictly true for the smallest ones -- they just disappear ("evaporate") on their own. slim - please propose a mechanism by which any blob of "normal mass" , at any temperature, could affect a black hole. $\endgroup$ Mar 26, 2018 at 14:46
  • $\begingroup$ @CarlWitthoft Are you saying the black hole could evaporate without additional matter to consume? That would be a different situation from what I'm describing right? $\endgroup$
    – slim
    Mar 26, 2018 at 14:53
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    $\begingroup$ My impression is that these theoretical tiny black holes might evaporate even if there's matter nearby, but I'm far from educated on that topic. $\endgroup$ Mar 26, 2018 at 15:02
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    $\begingroup$ You cannot destroy a stellar-mass or bigger black hole. You can only merge it or feed it to become more massive. Only the tiniest (speculative, I.e. unobserved) holes can evaporate within astronomic time scales. $\endgroup$
    – Walter
    Mar 27, 2018 at 7:06

1 Answer 1

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You ask if

there some property that a black hole has that is immune to the star's power?

The short answer is "yes" -- the property of being a black hole. Assuming the collision is at a reasonably low relative velocity, the black hole would consume most of the mass of the star, so that eventually you would be left with a much bigger black hole and a certain amount of matter and radiation heading away from the site where the collision took place. The details of how long this would take, how much matter and energy would escape and so on will vary depending on the exact structure of the star and the details of the collision.

Essentially you can't disrupt a black hole much by throwing matter into it (if the matter you throw in is VERY dense, like another black hole or a neutron star there will be some temporary disturbance to the event horizon, but it will settle down in a fraction of a second), all it does is absorb the matter and get bigger. Even if the matter is super-hot dense fusing plasma from the centre of giant star. In the course of falling in, the matter gets distorted and heated (much hotter than the interior of even a large star) and sometimes whirled around the black hole, and this can appear as a huge explosion, but in the middle of it, the black hole is sitting there absorbing matter, largely unperturbed.

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  • $\begingroup$ So, a star couldn't attract a smaller black hole within it? They would never collide at high speed, so the black hole would basically strip off the bark of the star until it disappeared? $\endgroup$
    – slim
    Mar 26, 2018 at 21:51
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    $\begingroup$ A small black hole (probably smaller than the 4 solar mass one you mention) could fall into a star and stay there for a while. It would orbit within it, being slowed down by the momentum of the matter it absorbed until it came near to rest near the centre of the star, which it would continue to absorb. The "it" which would disappear is the star, not the hole. $\endgroup$ Mar 27, 2018 at 6:30
  • $\begingroup$ I thought pronouns referred the last subject usage, not the original subject of the sentence, but that's for another stack exchange! lol $\endgroup$
    – slim
    Mar 27, 2018 at 14:47

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