Is the Schwarzschild metric dimensionless?

In summary, the question is whether the expression on the right hand side of the given formula is dimensionless. The solution is that it is indeed dimensionless and this is necessary for the formula to be valid.
  • #1
help1please
167
0

Homework Statement



The problem is I am wanting to know if the expression on the right hand side is dimensionless.

Homework Equations



[tex]ds^2 = (1 - \frac{2GM}{c^2 r})c^2 dt^2[/tex]

The Attempt at a Solution



Since the Schwarzschild radius is [tex]r = \frac{2GM}{c^2}[/tex] would I be right in saying that

[tex]\frac{2GM}{c^2 r}[/tex]

is dimensionless?
 
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  • #2
help1please said:

The Attempt at a Solution



Since the Schwarzschild radius is [tex]r = \frac{2GM}{c^2}[/tex] would I be right in saying that

[tex]\frac{2GM}{c^2 r}[/tex]

is dimensionless?

Yes, it is.
 
  • #3
Note that it would have to be if the formula is valid since you're subtracting that quantity from 1, which is dimensionless.
 
  • #4
Of course it is. Note that sometime we write metric in this form:[tex]1-\frac{2GM}{r}[/tex]
just a matter of unit conventions.
 
  • #5
thanks every1
 

Related to Is the Schwarzschild metric dimensionless?

1. What is the Schwarzschild metric?

The Schwarzschild metric is a mathematical formula that describes the curvature of spacetime around a non-rotating, spherically symmetric mass. It was first derived by Karl Schwarzschild in 1916 as a solution to Einstein's field equations in general relativity.

2. How is the Schwarzschild metric used in physics?

The Schwarzschild metric is used to describe the gravitational field around a massive object, such as a star or black hole. It plays a crucial role in understanding the behavior of objects in this strong gravitational field, and has been confirmed by numerous astronomical observations.

3. What are the key features of the Schwarzschild metric?

The Schwarzschild metric has several key features, including a singularity at the center of the massive object, a critical radius known as the event horizon, and time dilation effects near the event horizon. It also predicts the phenomenon of gravitational lensing, where light from distant objects is bent by the massive object's gravitational field.

4. What does the Schwarzschild metric tell us about black holes?

The Schwarzschild metric is the first mathematical model that accurately describes the properties of a black hole, including the event horizon and the singularity at its center. It also tells us that the size of the event horizon is directly proportional to the mass of the black hole, meaning that the larger the mass, the larger the event horizon.

5. Are there any limitations to the Schwarzschild metric?

While the Schwarzschild metric is a very accurate model for describing the behavior of a non-rotating, spherically symmetric mass, it does have limitations. For example, it does not take into account the effects of rotation or the presence of other masses. In these cases, more complex metrics, such as the Kerr or Reissner-Nordström metrics, must be used.

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