Topology and the swartzschild solution - where is the mass?

In summary, the conversation discusses the emergence of the Schwarzschild and Kerr solutions from topological considerations, as well as the role of mass and charge in these solutions. The professor points out that mass does not play a role in the classification of black holes, and the conversation touches on the interpretation of the parameter M as the total mass of the spacetime. The conversation also mentions the absence of a singularity in the Schwarzschild solution and the isotropic nature of the space in the Kerr solution.
  • #1
YangMills
14
0
My professor and I were discussing the emergence of the Swartzschild solution from topological considerations, corresponding to the manipulations of a point singularity. He pointed out to me that mass nowhere enters into the considerations, and so classifying black holes according to mass is fallacious. I am not entirely sure how he arrived at this point, however, and have forgotten the general process. Could someone please explain this to me, and/or provide me with some other references?

Also, I recall reading somewhere that the Kerr solution emerges from considerations of a circle in a plane, using topology (as with the Swartzschild and points). Supposedly the killing field emerging from the isotropic nature of the space generates angular momentum. How would a charge arise if we were considering the Kerr-Neumman solution?

Thank you in advance
 
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  • #2
First, it's Schwarzschild, writing names correctly is (at least for me) a sign of respect to those great persons.
Second, there is no singularity. The Schwarzschild solution isn't defined on all of [tex]\mathbb{R}^4[/tex], but on [tex]\mathbb{R}^4 - {0}[/tex], which is topologically different, but I assume that's what you meant. Just to be mathematically sound.
Then on this space you just consider the most general static and asymptotically flat vacuum solution, which happens to be spherically symmetric and characterized by a parameter [tex]M[/tex], which up to now is completely arbitrary, can even be negative. (Israel theorem) In the case of [tex]M=0[/tex], you can actually continue the solution onto all of [tex]\mathbb{R}^4[/tex], but if [tex]M\neq 0[/tex], this isn't possible. Now asymptotical flatness allows you to give (at spatial infinity, by comparison with the Newtonian case) an interpretation of this parameter [tex]M[/tex], namely that of the total mass of the spacetime. And then you say: physical objects must have positive mass.
Not sure if that is what you meant, if not, just ask more.
 

Related to Topology and the swartzschild solution - where is the mass?

1. What is topology?

Topology is a branch of mathematics that deals with the properties of a space that are preserved under continuous deformations, such as stretching and bending, but not tearing or gluing. It helps us understand the structure and connectivity of objects in a space.

2. How does topology relate to the Schwarzschild solution?

The Schwarzschild solution is a mathematical solution to Einstein's field equations in general relativity, which describes the curvature of space-time around a non-rotating, spherically symmetric mass. The topology of space-time in the Schwarzschild solution is crucial in understanding the behavior of light and matter near massive objects such as black holes.

3. What is the significance of the mass in the Schwarzschild solution?

The mass in the Schwarzschild solution represents the amount of matter present in the object that is causing the curvature of space-time. It is a fundamental parameter that determines the strength of the gravitational field and the behavior of objects in its vicinity.

4. Where is the mass located in the Schwarzschild solution?

The mass in the Schwarzschild solution is located at the center of the spherical space-time, which is known as the singularity. However, this singularity is not a physical point, but rather a mathematical concept that represents the point at which the gravitational field becomes infinitely strong.

5. Can the mass in the Schwarzschild solution be measured?

No, the mass in the Schwarzschild solution cannot be directly measured as it is a mathematical parameter used to describe the curvature of space-time. However, it can be indirectly inferred by observing the effects of the gravitational field on the motion of objects around the massive object, such as the orbit of planets around a star or the motion of stars in a galaxy.

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