SR forbides BHs and GR demands them

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In summary, the statement on the other message board about SR forbidding Black Holes should be taken with caution as it may not accurately reflect the current understanding of gravitation in the context of special and general relativity. It is important to keep in mind that gravitation is not treated by special relativity, which is only concerned with the kinematics of observers in different states of motion. For reliable information, it is recommended to consult reputable sources such as a public library.
  • #1
Johnny R
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I read a statement on another message board the SR forbides BHs and GR demands them.

Does SR forbide Black Holes, if so, why?
 
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Beware of boards!

Hi, Johnny R,

Johnny R said:
I read a statement on another message board the SR forbides BHs and GR demands them.

Does SR forbide Black Holes, if so, why?

Did you ask for clarification from the poster, call him P, in this "other board"?

The first guess which occurred to me was that P meant that a Lorentzian spacetime conformal to Minkowski spacetime won't admit event horizons. That probably won't make sense :uhh: but never mind, because I think the more important point is this:

P's remark should be tempered by observing that gravitation is not treated by str, which arises as the relativistic theory of kinematics, i.e. relations between time and distance measurements for observers in different states of motion ("kineo" is a Greek root suggesting "motion"). Early attempts to model the gravitational interaction using various types of force law or classical relativistic fields in Minkowski spacetime failed; this was part of the motivation for Einstein's exploration down the path which eventually led to gtr. It's also important to be aware that str is the foundation for gtr in a precise sense: gtr models spacetime as a Lorentzian manifold, subject to conditions encapsulated in the Einstein field equation (EFE), and the tangent spaces of a Lorentzian manifold have the same geometry/trigonometry used in str, which basically means that kinematics is infinitesimally equivalent in gtr and str, and also that Minkowksi spacetime can be viewed as just a particular vacuum solution of the EFE. Unfortunately, it takes a fair amount of background in physics/math to understand what I just said!

If you're worried that you might be obtaining contradictory information in different "boards" or from different posters in said "boards", you might see my remarks near the top of http://math.ucr.edu/home/baez/RelWWW/HTML/more.html [Broken]
See also the cautionary remarks by myself, Moonbear, ZapperZ, and some others in the PF thread at https://www.physicsforums.com/showthread.php?t=168397&highlight=Google+Wikipedia?
The discussion there focuses on Wikipedia, but all of these posters seem to agree that the local public library is still your best bet for obtaining reliable information.
 
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Special Relativity (SR) is a fundamental theory in physics that describes the relationship between space and time. It is a crucial part of our understanding of the universe and has been tested and confirmed through numerous experiments.

Now, as for the statement that SR forbides Black Holes (BHs), it is not entirely accurate. SR itself does not forbid BHs, but rather, it is General Relativity (GR) that predicts their existence.

GR is a more advanced theory that builds upon SR and describes the effects of gravity on the structure of space and time. It predicts that massive objects, such as stars, can collapse under their own gravity and form BHs.

So, while SR does not explicitly forbid BHs, it does not fully account for the extreme conditions that lead to their formation. On the other hand, GR, with its more comprehensive understanding of gravity, predicts and demands the existence of BHs.

In summary, SR does not forbid BHs, but it is GR that provides the necessary framework to understand and predict their existence. Both theories are essential in our understanding of the universe, and it would be incorrect to say that one forbids something that the other demands.
 

1. What does "SR forbides BHs and GR demands them" mean?

This statement refers to the conflict between the theories of Special Relativity (SR) and General Relativity (GR) when it comes to the existence of black holes (BH). SR suggests that BHs cannot exist, while GR predicts their existence.

2. Why does SR forbid the existence of BHs?

In SR, the speed of light is considered to be the fastest possible speed in the universe. This means that nothing, including light, can escape from a BH's gravitational pull, making it impossible for an observer to see the BH. Therefore, SR suggests that BHs cannot exist because they cannot be observed.

3. How does GR reconcile the existence of BHs?

In GR, spacetime is described as a fabric that can be curved by the presence of massive objects. When a massive object, such as a star, collapses under its own gravity, it creates a curvature in spacetime that is strong enough to trap even light, resulting in a BH. GR explains that BHs exist due to the extreme curvature of spacetime caused by the collapse of massive objects.

4. Are there any observations or evidence of BHs?

Yes, there is strong evidence for the existence of BHs based on observations of their effects on nearby matter. For example, the motion of stars and gas near the center of our galaxy suggests the presence of a supermassive BH. In addition, gravitational waves, which were predicted by GR, have been detected from the merging of two BHs.

5. Can both SR and GR be correct about BHs?

Currently, there is no known way to reconcile the conflict between SR and GR when it comes to BHs. However, both theories have been extensively tested and proven to be accurate in their respective domains. It is possible that a new theory that combines elements of both SR and GR may be able to explain the existence of BHs in the future.

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