Changing The Reference Frame
Every isolated unstable black hole decays rapidly to a stable black hole; and (modulo quantum fluctuations) stable black holes can be completely described (in a Cartesian coordinate system) at any moment in time by these eleven numbers:
- mass-energy M,
- linear momentum P (three components),
- angular momentum J (three components),
- position X (three components),
- electric charge Q.
These numbers represent the conserved attributes of an object which can be determined from a distance by examining its gravitational and electromagnetic fields. All other variations in the black hole will either escape to infinity or be swallowed up by the black hole.
By changing the reference frame one can set the linear momentum and position to zero and orient the spin angular momentum along the positive z axis. This eliminates eight of the eleven numbers, leaving three which are independent of the reference frame. Thus any black hole which has been isolated for a significant period of time can be described by the Kerr–Newman metric in an appropriately chosen reference frame.
Read more about this topic: No-hair Theorem
Famous quotes containing the words changing the, changing, reference and/or frame:
“A love affair should always be a honeymoon. And the only way to make sure of that is to keep changing the man; for the same man can never keep it up.”
—George Bernard Shaw (1856–1950)
“Why do otherwise sane, competent, strong men, men who can wrestle bears or raid corporations, shrink away in horror at the thought of washing a dish or changing a diaper?”
—Frank Pittman (20th century)
“If we define a sign as an exact reference, it must include symbol because a symbol is an exact reference too. The difference seems to be that a sign is an exact reference to something definite and a symbol an exact reference to something indefinite.”
—William York Tindall (1903–1981)
“I can imagine no more comfortable frame of mind for the conduct of life than a humorous resignation.”
—W. Somerset Maugham (1874–1966)