Can a black hole self-destruct?

In summary, the conversation discussed the possibility of matter being converted into energy in a black hole and its effect on gravitational pull, the role of rotation in countering gravitational attraction, and the relationship between angular momentum and force inside the photon sphere of a black hole. It also touched on the question of why the nucleus of an atom is not like a mini-black hole.
  • #1
rcgldr
Homework Helper
8,855
632
Curious about this. One possiblity is that matter in the black hole would be converted into energy, which might reduce the gravitational pull. Would it be possible that "dark matter' is created with anti-gravitational effects? Or maybe if enough mass is accumulated, combined with a high rate of spin, that the outer matter would pull the black hole appart?

Another issue I don't understand is that I've read that gravity in a black hole is stronger than the strong force. I had the impression that the closer the objects, the more dominate the strong force would be.

Last question, why isn't the nucleus of an atom like a mini-black hole? How closely packed are these?
 
Last edited:
Astronomy news on Phys.org
  • #2
Jeff Reid said:
Curious about this. One possiblity is that matter in the black hole would be converted into energy, which might reduce the gravitational pull.

The gravitational pull is related to the total energy, which includes matter. Converting matter into energy or vice versa would NOT change the gravitational pull in any way.

Jeff Reid said:
....Or maybe if enough mass is accumulated, combined with a high rate of spin, that the outer matter would pull the black hole appart?......

You're thinking that the inertial force associated with rotation would counter the gravitational attaction. However, inside the Schwarzschild radius this force is directed inwardly, not outwardly.

:biggrin:
 
  • #3
mijoon said:
The gravitational pull is related to the total energy, which includes matter. Converting matter into energy or vice versa would NOT change the gravitational pull in any way.
You're thinking that the inertial force associated with rotation would counter the gravitational attaction. However, inside the Schwarzschild radius this force is directed inwardly, not outwardly.

:biggrin:

Yep - actually the break-point is at r=3M, which is the photon sphere.

If you take the effective potiential
http://www.fourmilab.ch/gravitation/orbits/

[tex]
V=\sqrt{(1-\frac{2M}{r})(1+L^2/r^2)
[/tex]

and take the "force" as the rate of change of the effective potential with radius, i.e. F=dV/dr, you find that the force is equal to

[tex]
\frac{M + (3M-r)\frac{L^2}{r^2}} {\sqrt{r(r-2M)(r^2+L^2)}}
[/tex]

Here M is the mass of the black hole (in geometric units), r is your schwarzschild radial coordinate, and L is your angular momentum.

Focusing on the numerator and Ingoring the denominator, you can thus see that the "sign" of the contribution of angular momentum, L, to the total force changes character at r=3M. Outside the photon sphere, having L>0 reduces the force. Inside the sphere, having L>0 actually _increases_ the force!This is actually consrervative - at the photon sphere itself, there is no change in force due to L in the numerator, but it's clear that increase L always increases the denominator, thus even at the photon sphere (r=3M), increasing L decreases the force.
 
Last edited:

1. Can a black hole self-destruct due to its own gravity?

Yes, it is theoretically possible for a black hole to self-destruct due to its own gravity. This is known as Hawking radiation, where the black hole's intense gravity causes virtual particles to be created and then annihilated, with one particle being pulled into the black hole while the other escapes. Over time, this process can cause the black hole to lose mass and eventually evaporate.

2. How long would it take for a black hole to self-destruct?

The time it takes for a black hole to self-destruct due to Hawking radiation is dependent on its mass. Smaller black holes will evaporate faster than larger ones. For a black hole with the mass of the Sun, it would take approximately 10^67 years to completely evaporate.

3. Can a black hole self-destruct without any external factors?

Yes, a black hole can self-destruct without any external factors. This is because Hawking radiation is a natural process that occurs within the black hole itself, causing it to lose mass over time. However, external factors such as colliding with another black hole can also contribute to a black hole's destruction.

4. What would happen to objects near a black hole if it self-destructed?

If a black hole were to self-destruct, it would release a large amount of energy in the form of radiation. This radiation could potentially harm or destroy any objects nearby, depending on their distance from the black hole and the strength of the radiation released.

5. Is there any evidence of black holes self-destructing in the universe?

As of now, there is no direct evidence of black holes self-destructing in the universe. However, scientists have observed the effects of Hawking radiation on smaller black holes, which supports the theory of black hole self-destruction. Further research and observations are needed to confirm this phenomenon in larger black holes.

Similar threads

  • Astronomy and Astrophysics
Replies
1
Views
1K
  • Astronomy and Astrophysics
Replies
14
Views
2K
  • Astronomy and Astrophysics
Replies
12
Views
1K
  • Astronomy and Astrophysics
Replies
8
Views
1K
  • Astronomy and Astrophysics
Replies
5
Views
1K
  • Astronomy and Astrophysics
Replies
6
Views
2K
  • Astronomy and Astrophysics
Replies
12
Views
1K
Replies
1
Views
1K
  • Astronomy and Astrophysics
Replies
2
Views
1K
  • Astronomy and Astrophysics
Replies
11
Views
2K
Back
Top