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One of today's lucky ten thousand. Most galaxies have a black hole at the center that mass at least a hundred thousand times more than our sun: https://en.wikip

One of today's lucky ten thousand. Most galaxies have a black hole at the center that mass at least a hundred thousand times more than our sun: https://en.wikipedia.org/wiki/Supermassive_black_hole https://en.wikipedia.org/wiki/Supermassive_black_hole

gunian 2y ago
does that mean all galaxies will eventually be consumed by the black holes at their center?
- NKosmatos 2y ago
  That’s one of the theories, called Big Crunch: https://en.wikipedia.org/wiki/Big_Crunch https://en.wikipedia.org/wiki/Big_Crunch There are other (more probable) theories about the end of the universe, and if you’re up to it you can read more here: https://en.wikipedia.org/wiki/Ultimate_fate_of_the_universe https://en.wikipedia.org/wiki/Ultimate_fate_of_the_universe I’m in favor of the Big Chill, since I like the concept of entropy as introduced by the second law of thermodynamics: https://en.wikipedia.org/wiki/Heat_death_of_the_universe https://en.wikipedia.org/wiki/Heat_death_of_the_universe
  - gunian 2y ago
    sometimes it feels weird reading anything non fiction because we know so little about reality
  - thrance 2y ago
    The Big Crunch has nothing to do with Sagittarius A*, the black hole at the center of our galaxy. No theories actually predict that it will consume all stars in our galaxy.
- SideburnsOfDoom 2y ago
  No. Does this mean that solar systems will eventually be consumed by the stars at their centre, planets falling out of their orbits due to gravity? It does not. Gravity doesn't work like that. The planets may be consumed, when the star runs out of fuel and swells a lot, and such is the Earth's fate. But that scenario is not one that happens to black holes.
SideburnsOfDoom 2y ago
> mass at least a hundred thousand times more than our sun The sun is 99.86% of the mass of solar system. So if you orbit the centre of mass of the solar system, you orbit the sun, more or less. Give or take a small correction for Jupiter. But ... there are a lot more than a hundred thousand stars in the milky way. So if I guess right, the ratio of central mass vs the rest would be very different for the Milky way? It's more of a blob. Even at "The current best estimate of its mass is 4.2 million solar masses" it does not dominate? https://en.wikipedia.org/wiki/Sagittarius_A https://en.wikipedia.org/wiki/Sagittarius_A*
- Cthulhu_ 2y ago
  It's not a singular source of gravity at the center though, it's the collection of all mass in the galaxy interacting with each other as well. Like a daisy chain of gravity, which explains why it looks like a spiral instead of an evenly distributed circle. (I think anyway, I just made it up, I'm not learned in this area, just a HN shitposter)
  - SideburnsOfDoom 2y ago
    Right, not a point source and not exactly a blob either; more like swirls. I'm not learned in this area either.

gunian 2y ago

does that mean all galaxies will eventually be consumed by the black holes at their center?

NKosmatos 2y ago
That’s one of the theories, called Big Crunch: https://en.wikipedia.org/wiki/Big_Crunch https://en.wikipedia.org/wiki/Big_Crunch There are other (more probable) theories about the end of the universe, and if you’re up to it you can read more here: https://en.wikipedia.org/wiki/Ultimate_fate_of_the_universe https://en.wikipedia.org/wiki/Ultimate_fate_of_the_universe I’m in favor of the Big Chill, since I like the concept of entropy as introduced by the second law of thermodynamics: https://en.wikipedia.org/wiki/Heat_death_of_the_universe https://en.wikipedia.org/wiki/Heat_death_of_the_universe
- gunian 2y ago
  sometimes it feels weird reading anything non fiction because we know so little about reality
- thrance 2y ago
  The Big Crunch has nothing to do with Sagittarius A*, the black hole at the center of our galaxy. No theories actually predict that it will consume all stars in our galaxy.
SideburnsOfDoom 2y ago
No. Does this mean that solar systems will eventually be consumed by the stars at their centre, planets falling out of their orbits due to gravity? It does not. Gravity doesn't work like that. The planets may be consumed, when the star runs out of fuel and swells a lot, and such is the Earth's fate. But that scenario is not one that happens to black holes.

SideburnsOfDoom 2y ago

> mass at least a hundred thousand times more than our sun The sun is 99.86% of the mass of solar system. So if you orbit the centre of mass of the solar system, you orbit the sun, more or less. Give or take a small correction for Jupiter. But ... there are a lot more than a hundred thousand stars in the milky way. So if I guess right, the ratio of central mass vs the rest would be very different for the Milky way? It's more of a blob. Even at "The current best estimate of its mass is 4.2 million solar masses" it does not dominate? https://en.wikipedia.org/wiki/Sagittarius_A https://en.wikipedia.org/wiki/Sagittarius_A*

Cthulhu_ 2y ago
It's not a singular source of gravity at the center though, it's the collection of all mass in the galaxy interacting with each other as well. Like a daisy chain of gravity, which explains why it looks like a spiral instead of an evenly distributed circle. (I think anyway, I just made it up, I'm not learned in this area, just a HN shitposter)
- SideburnsOfDoom 2y ago
  Right, not a point source and not exactly a blob either; more like swirls. I'm not learned in this area either.