Figure 1 - uploaded by Yvo Petkov

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# Computer plot of the cross-section of an extreme black hole showing the static limit and horizon using the Kerr bookkeeper (Boyer-Lindquist) coordinate r (not R). From inside the horizon no object can escape, even one traveling at the speed of light. Between the horizon and the static limit lies the ergosphere, shaded in the figure. Within this ergosphere everything—even light—is swept along by the rotation of the black hole. Inside the ergosphere, too, a stone can have a negative total energy (Section 10).

Source publication

## Contexts in source publication

**Context 1**

... Kerr metric for three space dimensions-not discussed in this book- reveals that the horizon has a constant r-value in all directions (is a sphere) while the static limit has cusps at the poles. Figure 1 shows this result. This figure is drawn using the Kerr bookkeeper (Boyer-Lindquist) r-coordinate, which shows only one possible way to view these structures. ...

**Context 2**

... figure is drawn using the Kerr bookkeeper (Boyer-Lindquist) r-coordinate, which shows only one possible way to view these structures. When Figure 1 is plotted in terms of the reduced circumference R/M instead of r/M, then the radius of the horizon is greater in the equatorial plane than along the axis of rotation, giving the horizon the approximate shape of a hamburger bun. ...

**Context 3**

... a cross-section of the extreme black hole in the equatorial plane. That is, display the static limit and horizon in bookkeeper coordinates on a plane cut through the horizontal axis of Figure 1, as if viewing that figure downward along the vertical axis from above. Label the static limit, horizon, and ergosphere and put in expressions for their radii. ...