Suppose that a large piece (e.g., 5 M_ε) of purple, magnetized iron is rotating 5 times per day. If this object were able to collapse gravitationally to form a black hole, which one of the following properties could an outside observer measure for the matter inside the black hole?

Question

Quizplus · Accepted Answer

An outside observer can measure the rotation of a black hole through its effect on nearby matter or radiation. However, they cannot measure the magnetic field, color, or composition of the matter inside the black hole as these properties are completely trapped inside the event horizon and cannot be observed from outside.

Suppose That a Large Piece (E