Falling into a black hole

In summary, falling into a black hole is a complex and intriguing topic that continues to fascinate scientists and challenge our understanding of the universe.
  • #1
pervect
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I've been reviewing what I could find about the current knowledge of what it would be like to fall into a black hole, and I think I'm beginning to get a
picture. Some of the URL's I've visited are

http://math.ucr.edu/home/baez/PUB/generichole [Broken]
http://lanl.arxiv.org/abs/gr-qc/9902008
http://casa.colorado.edu/~ajsh/schwp.html
http://www.gothosenterprises.com/black_holes/inside_black_holes.html
http://nrumiano.free.fr/Estars/int_bh.html

Plus my textbooks, Wald, "General Relativity" pg 156

Here's what I'm getting - corrections would be welcome

The static Schwarzschild solution has two separate flat space-time regions, joined by a non-traversible wormhole.

If the singularity was caused by an actual collapsing shell of matter, but the idealization that the collapse is spherically symmetrical is made, the situation will be different. The collapsing matter surface itself will block any access to the alternate flat space-time regions (Wald). I believe that this implies that the matter surface will also block access to the singularity (?). In other words, the way I'm reading this, because of the infinite time dilation near the center of a black hole, a sufficiently determined observer who accelerates hard enough actually can "catch up" to the infalling matter surface! (??) (Or is that better read as - must catch up to the matter surface (?)).

Life apparently gets even more interesting when the collapse is not spherically symmetrical, for instance if there is angular momentum or charge present. Here, exactly what happens is apparently still a matter of some debate. But the latest work, the second of my link collection, suggests the it appears to be generally similar to the Schwarzschild case, except for the existence of a "weak" null singularity whose physical interpretation is not fully understood at this point.
 
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  • #2



Hello there,

Thank you for sharing your research and thoughts on falling into a black hole. It is a fascinating and complex topic that has been studied by many scientists over the years.

From what you have gathered, it seems like you have a good understanding of the current knowledge on the subject. However, I would like to offer some corrections and clarifications.

Firstly, the idea of a wormhole connecting the two flat space-time regions in the Schwarzschild solution is a theoretical concept that has not been proven or observed. It is a mathematical solution that arises from the equations of general relativity, but its physical existence is still a matter of debate.

Secondly, in the case of a collapsing matter shell, the singularity is not blocked by the matter surface. The singularity is a point of infinite density and curvature, and it is not affected by the presence of matter. In fact, the singularity is often described as the "center" of the black hole, and it is where the laws of physics break down.

As for the possibility of an observer catching up to the matter surface, it is important to note that the infinite time dilation near the singularity is a theoretical concept and not something that can be physically observed. In reality, an observer falling into a black hole would experience extreme gravitational forces and would not be able to survive.

Lastly, you are correct in saying that the behavior of black holes with angular momentum or charge is still a matter of debate. These characteristics can greatly affect the structure of the black hole and the behavior of matter falling into it. More research is needed in this area to fully understand the complexities of these types of black holes.

Overall, you have a good grasp on the current knowledge of falling into a black hole, but it is important to remember that much of it is still theoretical and not fully understood. I encourage you to continue exploring this topic and staying updated on the latest research in this field.
 
  • #3



Your understanding of the current knowledge of falling into a black hole seems to be quite accurate. The links you have provided are reputable sources and cover the various aspects of black hole physics. The Schwarzschild solution does indeed have two separate flat space-time regions, and the singularity is only accessible from the inside of the black hole. This means that the collapsing matter surface will block any access to the singularity from the outside.

As you mentioned, the situation becomes more complex when the collapse is not spherically symmetrical. In this case, the presence of angular momentum or charge can affect the structure of the black hole and the behavior of matter falling into it. The existence of a "weak" null singularity is still not fully understood and is an area of ongoing research.

One correction I would make is regarding your statement about an observer being able to "catch up" to the infalling matter surface. This is not possible due to the infinite time dilation near the center of a black hole. The observer would actually experience a never-ending journey towards the event horizon, never reaching the matter surface or the singularity.

Overall, your understanding of falling into a black hole is well-informed and you have provided good sources for further exploration. Black holes are still a fascinating and mysterious area of study in physics, and there is still much to learn and understand about them.
 

1. What happens when you fall into a black hole?

When an object falls into a black hole, it is pulled towards the singularity at the center of the black hole. At the same time, the immense gravity of the black hole causes the object to be stretched and compressed, a process known as spaghettification. Eventually, the object reaches the singularity and is crushed into an infinitely small point.

2. Can you survive falling into a black hole?

No, it is not possible for a human or any known object to survive falling into a black hole. The intense gravitational forces and spaghettification would be lethal. Additionally, the extreme time dilation near the event horizon would cause time to slow down, making it impossible to escape.

3. What is the event horizon of a black hole?

The event horizon is the point of no return for an object falling into a black hole. It is the boundary where the escape velocity exceeds the speed of light, meaning that even light cannot escape from within this boundary. Once an object crosses the event horizon, it is impossible for it to escape the black hole's gravitational pull.

4. Do black holes have an end point?

Yes, black holes have a theoretical end point known as the "evaporation" stage. As black holes emit Hawking radiation, they lose mass and eventually become smaller and smaller until they completely evaporate. This process is extremely slow and only occurs for very small black holes.

5. Can black holes be used for time travel?

No, black holes do not allow for time travel. While they do cause time dilation near the event horizon, it is not possible for an object to travel back in time by entering a black hole. Additionally, the extreme gravitational forces would make it impossible for an object to survive the journey into a black hole.

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