A A= 2.164/

"ring around the sky"

(No possible shell observer)

Figure 15 Schematic drawing: View of black hole and stars seen by radial plunger and shell observer The right column gives pie-chart views of the black hole from shells through which the traveler plunges. (See Figure 10 and equation [31].) Black sectors represent the angle spanned by the black hole as it is viewed at various distances from the hole. These radial distances are given in the center column. The left column gives the corresponding pie<hart view for the radially inward-plunging traveler (Apply equation [40] to the critical angles for the shell viewer given in equation [31].) Letters A through F represent directions of stars evenly spaced around the sky for a viewer remote from the black hole. At r= 100 M, only a small section of the sky is dark, and only the stars whose directions lie nearest to that of the black hole show disturbed positions. At a stationary position just outside the horizon, the shell viewer sees most of the sky black. The star images are squeezed around behind him because of the bending of light around the black hole In contrast, the plunging viewer passes through this shell at almost the speed of light. To her, only a 90-degree segment in front of her is dark and the stars are sweeping around in the sky toward the hole. Even inside the horizon, atr-M, the black hole fills less than half the sky for the plunging viewer Notice that star positions are in general displaced forward more for the moving viewer than for the stationary spectator, showing that the changes in apparent star positions arise mainly from the aberration effect, due to the speed of the observer (equation [40]) In the final seconds of her journey the sky behind the plunging traveler is black, nearly empty of stars, and the sky ahead is black because of the black hole. Cleaving the forward half of the firmament from the backward half is a bright ring around the sky This figure does not show secondary and higher-order star images from light that wraps once or many times around the black hole. (This figure is based on the work of M. Sikora, courtesy of M. Abramowicz.)

Was this article helpful?

0 0
Telescopes Mastery

Telescopes Mastery

Through this ebook, you are going to learn what you will need to know all about the telescopes that can provide a fun and rewarding hobby for you and your family!

Get My Free Ebook

Post a comment