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Yes, black holes can precess. In binary consisting of two black holes, both spins and the orbital angular momentum will precess about the total angular momentum. In April, LIGO and Virgo announced the first detection of a binary black hole merger where the black hole spins were precessing: GW190412

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They do, for a short time. However, a spin which is precessing has higher magnetic potential energy than a spin which is completely aligned with the field, so the precessing state is unstable. The mechanism by which spins "decay" from a precessing state to a state in which they are aligned with the external field is provided by the spin-phonon ...

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In a classical experiment Rasetti proved that $\mathbf{B}$ was the effective field within a magnetized matter. Here is the abstract: The deflection of mesons in a magnetized ferromagnetic medium was investigated. A beam of mesons was made to pass through 9 cm of iron, and the resulting distribution of the beam was observed. Two arrangements were employed. ...

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The reason is that $\vec{B}$ is the fundamental field. Traditionally (and in Maxwell’s traditional notaion), this was not really appreciated, and was $\vec{H}$ treated as if it were the fundamental one; however, this was incorrect. The reason for the mistake was that $\vec{H}$ was easier to measure, as its sources was the free (i.e., experimenter-controlled)...

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Torque, angular velocity and angular momentum are not inherently vectorial quantities. One way to demonstrate that is to consider motion in some space with more spatial dimensions than our familian three spatial dimensions. In a space with 4 spatial dimensions the following applies: to specify orientation of a state of rotation you need to specify the plane ...

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The vectors describing rotation are chosen along the axis of rotation because that is the only fixed direction in a rotating system. Given that choice, they do a good job of representing the magnitude and direction of rotational quantities, and as long as the axle remains fixed, they relate to each other and the various linear quantities in a ...

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If the object precesses or not, or does something inbetween, namely nutate, depends on the ratio of Larmor frequency to the rotation frequency of the object. If you start from a situation where the magnet is tilted with respect to the field and then you let go, you obtain perfect precession only, if the rotation frequency is infinite. One may think of ...

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The magnetization in a bar magnet is due to the alignment of the spin magnetic moments of the electrons, not to currents. The precession would depend on the cross product $\mu\times{\bf B}$. Since $\mu$ is aligned along $\bf B$, there is no torque and no precession.

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