Blackhole decay and gravitational wave

  • Thread starter nabodit
  • Start date
16
0
hi
i have few unclear things but i'm not sure if this is the correct thread.
1.can anyone explain me how does a black hole deacy. please include no mathematics and only logic.
2.is gravity wave something like electromagnetic wave transmitted by gravitons instead of a photon?but i heard; by some one not related to science; that it{wave of gravitons} comes in existance if only it is in motion relative to something. now doesnt that mean that it can come in existance and fade to black simultaneously[as something can be in motion or rest according to different observers at the same time].
im not sure if it exists only in motion or at all times.
 

EnumaElish

Science Advisor
Homework Helper
2,285
123
Yahoo search on " "black hole decay" " yields (inter alia):

Link # One
see esp. ---> Link # Two
Link # Three
Link # Four
Link # Five (Look toward the end to see:
This image is a simulation of the production and decay of a black hole in a proposed linear collider detector. The black hole quickly evaporates into every type of matter particle. The "democratic" selection of decay products is a distinct signature of black hole decay.
etc.)
 
Last edited:
16
0
the 3rd link u precribed says that only negative energy or particle or energy enters the blackhole but not positive thus making it decay. is this true than black hole fed on other particle increases instead of decaying!
 

EnumaElish

Science Advisor
Homework Helper
2,285
123
AFAIK, antimatter particles would annihilate (cancel out) matter particles inside the BH, thus reducing the size of the BH. But I'm not a physicist so you shouldn't interpret this information as the "last word on BH decay." It's anything but.

{P.S. There are messages posted on this or similar issues under threads in Quantum Physics, see e.g. Hawking's preprint: Information loss in Black holes.}
 
Last edited:

pervect

Staff Emeritus
Science Advisor
Insights Author
9,554
828
Anti-matter particles would make a black hole grow - they have positive energies.
 

EnumaElish

Science Advisor
Homework Helper
2,285
123
I hear you pervect. Unless they have negative energy as this link suggests:
According to quantum theory, the vacuum of space isn't empty but seethes with pairs of elementary particles winking in and out of existence. One partner in each pair has negative energy, which keeps that particle gravitationally bound to the black hole, while the other has positive energy, which gives it enough oomph to escape from a black hole. [...] Now, consider the negative-energy particles that the black hole has absorbed. According to general relativity theory, mass and energy are equivalent. Therefore, a black hole that absorbs a negative-energy particle loses mass. If there are no nearby planets or other detritus to nourish it, a black hole absorbing negative-energy particles will eventually vanish.
Or, more likely, I misnamed a "neg. energy" particle as "antimatter." Which would explain why I never thought myself fit for a physics degree -- or vice versa, whichever was first. :smile:

{P.S. Oh, BTW, vice versa means the other way around, too, in Latin. Ahem.}
 
Last edited:
196
0
Particles with negative energy and antimatter are different things. Both matter and antimatter can have positive and negative energy, so when matter and antimatter come into contact, although the particles are destroyed, their energy is still conserved, just released in the form of radiation. However, when negative energy and positive energy come into contact, they cancel each other out, and don't have to emit radiation in order to conserve energy (since one unit of energy plus negative one unit of energy is zero units of energy, so energy is still conserved without radiation being released). Hawking states that the reason the particles from the vacuum fluctuations always have negative energy is because the strong gravitational field gives them negative potential energy as they cross the event horizon:
... a real particle close to a massive body has less energy than if it were far away, because it would take energy to lift it far away against the gravitational attraction of the body. Normally, the energy of the particle is still positive, but the gravitational field inside a black hole is so strong that even a real particle can have negative energy there. It is therefore possible, if a black hole is present, for the virtual particle with negative energy to fall into the black hole and become a real particle or antiparticle. Its forsaken partner may fall into the black hole as well. Or, having positive energy, it might also escape from the vicinity of the black hole.
- Hawking, A Brief History of Time

However, in Hawking's latest article (http://arxiv.org/abs/hep-th/0507171), it almost sounds like he's saying quantum tunnelling is the reason for black hole decay, which is atleast a different picture from the idea of negative energy particles falling in, although I don't know enough about it to know if it gives different predictions:
My work with Hartle showed the radiation could be thought of as tunnelling out from inside the black hole.
 

pervect

Staff Emeritus
Science Advisor
Insights Author
9,554
828
EnumaElish said:
I hear you pervect. Unless they have negative energy as this link suggests:Or, more likely, I misnamed a "neg. energy" particle as "antimatter." }
As you guessed, (hypothetical) matter with a negative energy density is not called anti-matter. Sometimes it's called exotic matter.

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

Related Threads for: Blackhole decay and gravitational wave

  • Posted
Replies
3
Views
3K
Replies
8
Views
3K
  • Posted
Replies
1
Views
1K
  • Posted
Replies
3
Views
2K
Replies
3
Views
985
  • Posted
Replies
12
Views
2K
Replies
2
Views
453
  • Posted
Replies
4
Views
575

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top