# Understanding Standing Waves & How They Fit in Black Holes

• ColdFusion85
In summary, the article explains that waves inside a black hole are limited to standing waves due to the event horizon, which is fixed at zero for all time. The reason for this is that information and waves cannot escape from a black hole. The geometry of a black hole, including its singularity, can still be subject to the laws of physics.
ColdFusion85
I am reading an article on black holes and they state, "Now what kinds of waves are possible inside a black hole? The answer is standing waves, waves that "fit" inside the black hole with a node at the event horizon."

Can anyone explain to me why they know the answer is standing waves, and what do they mean when they say they "fit" inside the black hole??

Hummm I think they mean electromagnetic waves particles such as photons are not able to leave the black hole since even at the speed of light it cannot escape the tremendous gravity. For the fitting, I have at the moment no idea.

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Any specific solution to a DE (in this case the wave equation) depends on the boundary conditions.

Since information cannot escape from a black hole, waves themselves may not escape from a black hole. The event horizon (i.e. the boundary of the black hole) must therefore be fixed at zero for all time.

The solution to such problems is a standing wave, as any 'non' standing wave violates this boundary condition.

Claude.

That makes things much clearer. Thanks Calude Bile.

But surely the geometry inside a black hole is so messed up we can't even think about standing waves within them? The geometry of a singular point with infinite density. Hmmm, nice.

The Black Hole is not just a singularity, it is has a finite volume that is the region of space where light cannot escape from its embrace. I see no reason why laws of physics cannot be applied to this space.

The singularity itself is a different matter.

Claude.

## 1. What are standing waves?

Standing waves are a type of wave phenomenon that occurs when two waves with the same frequency and amplitude travel in opposite directions and interfere with each other. This results in a pattern of nodes and antinodes, where the amplitude of the wave remains constant at certain points and cancels out at others.

## 2. How do standing waves fit into black holes?

Standing waves play a crucial role in understanding the behavior of black holes. In the theory of general relativity, black holes are described as having an event horizon, which is the point of no return for anything that enters the black hole. Standing waves can form on the event horizon, and these waves can carry information about the properties of the black hole, such as its mass and angular momentum.

## 3. Can standing waves be observed in real life?

Yes, standing waves have been observed in various physical systems, such as musical instruments, water waves, and electromagnetic waves. In the case of black holes, standing waves are not directly observable, but their effects can be detected by studying the gravitational waves emitted by black hole mergers.

## 4. How do standing waves help us understand black holes better?

By studying the standing waves on the event horizon of a black hole, scientists can gain insight into the properties and behavior of these enigmatic objects. For example, the frequency and amplitude of the standing waves can reveal information about the size and spin of the black hole, which can help us refine our understanding of its structure and formation.

## 5. Are there any unanswered questions about standing waves and black holes?

While standing waves have provided valuable insights into the nature of black holes, there are still many unanswered questions. For instance, the exact mechanisms that produce standing waves on the event horizon are still not fully understood. Additionally, there is ongoing research into the relationship between standing waves and other phenomena associated with black holes, such as Hawking radiation and the information paradox.

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