Is the Milky Way galactic blackhole slowly sucking us in?

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    Blackhole Milky way
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Discussion Overview

The discussion revolves around the nature of black holes, particularly in the context of their gravitational effects on galaxies and nearby objects. Participants explore the concept of black holes as potential "draining holes" of galaxies and clarify misconceptions about their behavior and gravitational influence.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant suggests that black holes might act like "draining holes" in galaxies, comparing their structure to a whirlpool.
  • Another participant counters this idea, explaining that black holes do not behave like literal holes that consume everything nearby, emphasizing that their gravitational effects are similar to those of normal stars at a distance.
  • A different participant reinforces this point by stating that if a black hole of solar mass replaced the Sun, the orbit of the Earth would remain unchanged, as long as the distance is maintained.
  • One participant elaborates on the gravitational effects of black holes, using an analogy involving the compression of Earth to illustrate that gravitational pull only increases when approaching the black hole closely.

Areas of Agreement / Disagreement

Participants generally disagree on the initial characterization of black holes as "draining holes." While some clarify the nature of black holes and their gravitational effects, there is no consensus on the metaphorical interpretation of their role in galaxies.

Contextual Notes

Some claims rely on specific assumptions about distance and mass, and there are unresolved nuances regarding the behavior of black holes in different contexts.

arabianights
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with the newest discovery of biggest black holes in the universe, i suddenly had this weird thought: what if they're a draining hole of the galaxy, the spiraled arms and the shape, all looks awfully similar to a whirlpool, with black holes at the center of nearly all galaxies
 
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Don't be afraid, this is NOT how black holes work. They are not literal "holes" in space that devour everything nearby. A black hole of 2 times the mass of the sun behaves EXACTLY like a normal star of that mass as long as objects stay outside a distance equal to the radius of the normal star.

For example, if the radius of the star was 1 million km, then as long as you stayed at a distance of at least 1 million km from an equal mass black hole, the gravitational pull is exactly the same. It is only once you get closer to the black hole that the gravity increases, since it is compacted into a much smaller volume of space.

If you compressed the Earth to 1/2 it's size, it would have no impact on how the Moon orbited, but the surface gravity would be somewhere on the order of 4 times as much as it is now. Make sense?
 
Black holes aren't cosmic vacuums. If a black hole the mass of the Sun (which wouldn't normally occur in nature, but can in principal) were to replace the Sun, we would continue to orbit around it at the same rate. This back hole is really heavy, but REALLY far away.

Don't lose sleep over it.
 
Drakkith said:
... if the radius of the star was 1 million km, then as long as you stayed at a distance of at least 1 million km from an equal mass black hole, the gravitational pull is exactly the same. It is only once you get closer to the black hole that the gravity increases, since it is compacted into a much smaller volume of space.

If you compressed the Earth to 1/2 it's size, it would have no impact on how the Moon orbited, but the surface gravity would be somewhere on the order of 4 times as much as it is now. Make sense?

Awesome example of gravity. Imo as easy to absorb as the "rubber sheet" analogy, but much much more descriptive of the physics.
 

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