Exploring the Magnetic Field Generated by a Spinning Mass

In summary, There is a manifestation of gravitational interaction called "gravitomagnetism" which follows from a first order approximation of Einstein's equation and is sometimes referred to as PN1 or the Maxwell approximation. However, it is not exactly like the magnetic field, even in analogy, and this similarity only holds in PN1. Higher approximations do not maintain this analogy.
  • #1
kurious
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I read somewhere that a spinning mass with no charge creates a mass version of a magnetic field.Is this true?
 
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  • #2
kurious said:
I read somewhere that a spinning mass with no charge creates a mass version of a magnetic field.Is this true?
It depends on how rigorous you want to be. Firstly, I suggest posting this to the Relativity forum, where you have a better chance of attracting people who know the answer and are interested enough to answer. I will tell you what I have read/heard.

There is a manifestation/form of gravitational interaction called "gravitomagnetism." I have seen no reason to doubt its existence. It follows naturally from a first order approximation of Einstein's equation. That is, the zeroth order approximation gives you Poisson's equation for Newtonian gravity (basically the F ~ r-2 law), and the first order approximation is one order more accurate (so it includes more detail, like getting the kinetic energy from expanding the relativistic energy term of a particle). This first order approximation is also sometimes called the PN1 (Post Newtonian to first order) or the Maxwell approximation (I think).

Strictly speaking, this is not exactly like the magnetic field, even in analogy. In fact, it is only like this in PN1. Any higher (PN2, PN3, etc.) and you lose the analogy, so I've heard/read.
 
  • #3


Yes, it is true that a spinning mass with no charge can create a magnetic field. This phenomenon is known as the mass version of a magnetic field, or the gravitational equivalent of a magnetic field. It is a consequence of Einstein's theory of general relativity, which explains the relationship between gravity and the curvature of spacetime.

When a mass spins, it creates a distortion in the surrounding spacetime, known as a gravitational field. This field can then interact with other masses, causing them to experience a force, just like how a magnetic field interacts with charged particles. However, unlike a magnetic field, which is created by moving charges, the mass version of a magnetic field is created by the curvature of spacetime caused by a spinning mass.

This concept has been confirmed by various experiments, including the Gravity Probe B mission, which measured the frame-dragging effect caused by Earth's rotation. It is also a crucial factor in the behavior of objects in the vicinity of rotating black holes.

In summary, while a spinning mass with no charge does not create a traditional magnetic field as we know it, it does create a mass version of a magnetic field through the curvature of spacetime.
 

1. What is a spinning mass and how does it generate a magnetic field?

A spinning mass is an object that is rotating on its axis. This rotation causes the charged particles within the mass to also rotate, creating a magnetic field. This phenomenon is known as the "magnetic dipole moment". The strength of the magnetic field is determined by the speed and direction of the rotation.

2. What are the practical applications of exploring the magnetic field generated by a spinning mass?

Understanding the magnetic field generated by a spinning mass can have various practical applications. It can help in designing efficient motors and generators, as well as in studying the Earth's magnetic field and its impact on our daily lives. Additionally, this knowledge can also be used in space exploration and navigation.

3. How can we measure the magnetic field generated by a spinning mass?

The magnetic field generated by a spinning mass can be measured using a magnetometer, which is a device that detects the strength and direction of a magnetic field. The data collected by the magnetometer can then be analyzed to understand the characteristics of the magnetic field.

4. Can the magnetic field generated by a spinning mass be manipulated?

Yes, the magnetic field generated by a spinning mass can be manipulated by changing the speed or direction of the rotation. This can be achieved by altering the parameters of the spinning mass, such as its size, shape, and composition. Additionally, external magnetic fields can also be used to influence the magnetic field of the spinning mass.

5. How does the magnetic field generated by a spinning mass differ from a stationary magnetic field?

The main difference between a magnetic field generated by a spinning mass and a stationary magnetic field is the source of the field. A stationary magnetic field is produced by a permanent magnet or an electric current, while a spinning mass creates a magnetic field due to its rotation. Additionally, the strength and direction of the two types of magnetic fields may also differ depending on the source and surrounding environment.

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