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, reference and/or frame:
“Is there anything
To be serious about beyond this otherness
That gets included in the most ordinary
Forms of daily activity, changing everything
Slightly and profoundly....”
—John Ashbery (b. 1927)
“These roses under my window make no reference to former roses or to better ones; they are for what they are; they exist with God to-day. There is no time to them. There is simply the rose; it is perfect in every moment of its existence.”
—Ralph Waldo Emerson (1803–1882)
“Painting seems to be to the eye what dancing is to the limbs. When that has educated the frame to self-possession, to nimbleness, to grace, the steps of the dancing-master are better forgotten; so painting teaches me the splendor of color and the expression of form, and as I see many pictures and higher genius in the art, I see the boundless opulence of the pencil, the indifferency in which the artist stands free to choose out of the possible forms.”
—Ralph Waldo Emerson (1803–1882)