Gravitational Radiation

In summary, gravitational radiation occurs when a mass is accelerated, similar to how electromagnetic waves are produced when a charge is accelerated. This causes a loss of energy for the object, resulting in a decrease in its orbital speed. In the case of pulsar pairs, the close proximity and fast orbital speed cause a significant loss of energy through gravitational radiation, making it visible to us. There is no known simple relationship between gravitational and Hawking radiation, even for Kerr black holes.
  • #1
deliveryman
Could someone please explain Gravitational Radiation in Laymen terms, and how it causes a decrease in orbital speed like in pulsars.
 
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  • #2
An analogy is what happens if you accelerate a charge. Take a charge, like and electron and accelerate it back and forth. shake or vibrate it.) Doing so will produce electromagnetic waves, which will carry energy away from the charge. (but as long as you keep shaking it, you are putting energy back in.) The faster you shake it, the higher the frequency of the waves. (and the more energetic.)

The same thing happens if you accelerate a mass; It will produce gravity waves.

Take a mass and vibrate it, and it will generate gravitational radiation. The larger the mass,the more radiation, and the faster you vibrate, the higher the frequency.

A body in orbit is constantly accelerating, thus it must constantly emit gravity waves. But unlike the example when you were shaking the charge, there is nothing to put back the energy carried away. As a result, the object loses orbital energy and must fall into a lower orbit to compensate. (Note, as the object falls into a lower orbit its orbital velocity increases, but its gravitational potential decreases faster, so it loses total energy. As it orbits faster, its accleration increases, the frequency of the gravity waves increase and it loses energy faster.

Now gravity waves are very, very weak, so they carry energy away slowly in most cases.

Some pulsar pairs orbit so closely to each other that they are losing energy as gravitational radiatiation fast enough for us to see it.
 
  • #3
Janus,

Is there any instance (e. g., for a Kerr black hole) where a simple relationship between gravitational and Hawking radiation holds?
 

1. What is gravitational radiation?

Gravitational radiation, also known as gravitational waves, is a form of energy that is transmitted through space-time in the form of waves. It is caused by the acceleration of massive objects, such as the collision of two black holes, and is predicted by Einstein's theory of general relativity.

2. How is gravitational radiation different from electromagnetic radiation?

Gravitational radiation is different from electromagnetic radiation in several ways. Firstly, it is much weaker than electromagnetic radiation, making it difficult to detect. Secondly, it interacts very weakly with matter, allowing it to pass through objects without being affected. Lastly, it travels at the speed of light and does not require a medium to propagate, unlike electromagnetic radiation.

3. How is gravitational radiation detected?

Gravitational radiation is detected using specialized instruments called interferometers. These instruments measure very small changes in the distance between two points caused by the passing of gravitational waves. The most sensitive interferometer, the Laser Interferometer Gravitational-Wave Observatory (LIGO), was able to detect gravitational waves for the first time in 2015.

4. What are the potential applications of gravitational radiation?

Gravitational radiation has many potential applications in different fields of science. For example, it can provide information about the formation of the universe, the behavior of black holes, and the structure of space-time. It can also be used to test the predictions of Einstein's theory of general relativity and to further our understanding of gravity.

5. Can gravitational radiation be harmful to humans?

No, gravitational radiation is not harmful to humans. Due to its weak interaction with matter, it does not pose any health risks. In fact, the amount of gravitational radiation that reaches Earth is so small that it has no noticeable effect on our daily lives. However, the study of gravitational radiation and its potential applications can greatly benefit humanity in the long run.

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