Zero gravity in spiral galaxy center?

In summary, the center of a spiral galaxy can have a low pressure void, but this does not apply to pressure in galaxies. An object at the center would experience zero net gravity due to being equally acted upon by surrounding mass, but this is where the similarities to vortices and hurricanes end. The fluid model does not apply to stars in galaxies, and dark matter is also not a fluid. In order to fall into a supermassive black hole, an object must first get rid of angular momentum through mass segregation or three body interactions. The increased spin of the black hole is a result of this process. Most black holes have an accretion disk of matter, causing them to eventually fall into
  • #1
protonic_mass
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In many vortex's, the center has low pressure, from the center of a stirring cup of tea to the centere of a hurricane or storm system. I'm trying to crudely model how this might apply to the center of a spiral galaxy. If the behavior is similar, and the center has a low pressure void, wouldn't an object in the middle experience zero net gravity as it would be equally acted upon by the surrounding mass?

That being the case, how could the model fit in a black hole which is super massive?
 
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  • #2
Vortices and hurricanes are both phenomena arising from fluid mechanics They have nothing in common with galaxies.

protonic_mass said:
...the center has a low pressure void, ...
Pressure does not apply to galaxies.
protonic_mass said:
...wouldn't an object in the middle experience zero net gravity as it would be equally acted upon by the surrounding mass?

You are correct inasmuch as a body at the centre of the galaxy would not be pulled in any direction, whereas a body on the edge of the galaxy would be pulled toward the centre, but that's about where the similarities end.
 
  • #3
Only the gas in a galaxy can be reasonably treated as a fluid. The stars are essentially collisionless, so the fluid model doesn't apply. In most models, dark matter is also a collisionless particle, so it isn't a fluid either.

protonic_mass said:
That being the case, how could the model fit in a black hole which is super massive?

Mass segregation and multi-body interactions can drive more massive objects towards the center.

http://en.wikipedia.org/wiki/Mass_segregation

For something to fall into the SMBH, it needs to first get rid of angular momentum. Three body interactions can accomplish this. Or, an accretion disk can form around the SMBH, and other processes can transfer the angular momentum outwards.
 
  • #4
Calion said:
For something to fall into the SMBH, it needs to first get rid of angular momentum. Three body interactions can accomplish this. Or, an accretion disk can form around the SMBH, and other processes can transfer the angular momentum outwards.

I thought that whatever angular momentum gets eaten by the BH, is converted into an increased spin of the BH itself.
 
  • #5
ellipsis said:
I thought that whatever angular momentum gets eaten by the BH, is converted into an increased spin of the BH itself.

That's true if the stuff makes it into the black hole. I was referring to stuff outside of the black hole. Since the stuff (gas, stars, etc) probably isn't falling straight towards the black hole, it will have some angular momentum and go into orbit around the black hole, rather than falling in. However, three body interactions (say, the SMBH, and two stars) can transfer angular momentum, leading to one object falling in.
 
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  • #6
Calion said:
it will have some angular momentum and go into orbit around the black hole, rather than falling in.
It forms an accretion disk, yes, but it is not stable. The gas and dust will compact and collide, giving off huge amounts radiation, and causing the material to eventually fall into the SMBH.

It is generally believed that most BHs are not naked. Most have an accretion disk of matter:
dnews-files-2013-04-black-hole-dance-of-doom-jpg.jpg
 

1. What is zero gravity in the spiral galaxy center?

Zero gravity in the spiral galaxy center refers to the state in which there is no net force acting on an object due to the gravitational pull of the surrounding matter. This occurs at the exact center of a spiral galaxy where the gravitational forces of the stars, gas, and dust are balanced, resulting in a weightless environment.

2. How is zero gravity in the spiral galaxy center different from outer space?

While both the spiral galaxy center and outer space are considered to have zero gravity, they differ in their origin. The zero gravity in the spiral galaxy center is a result of the balance of gravitational forces from surrounding matter, while the zero gravity in outer space is due to the absence of significant gravitational forces from celestial bodies.

3. Can humans survive in zero gravity in the spiral galaxy center?

Yes, humans can technically survive in zero gravity in the spiral galaxy center, as long as they have the necessary life support systems and protection from the extreme conditions of the center, such as intense radiation and extreme temperatures. However, it is currently impossible for humans to reach the center of a spiral galaxy.

4. What are the potential effects of zero gravity in the spiral galaxy center on living organisms?

The effects of zero gravity on living organisms in the spiral galaxy center would be similar to those experienced in outer space. These effects include bone and muscle loss, changes in blood circulation, and vision problems. However, the extreme conditions in the center of a spiral galaxy may also pose additional risks, such as exposure to high levels of radiation.

5. How does zero gravity in the spiral galaxy center affect the formation and behavior of stars and planets?

The zero gravity in the spiral galaxy center plays a crucial role in the formation and behavior of stars and planets. The balanced gravitational forces allow for the formation of dense star clusters, while the lack of strong gravitational pull allows for the expansion and evolution of gas and dust clouds, leading to the formation of new stars and planets.

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